Validation of a field‐ready handheld meter for plasma β‐hydroxybutyrate analysis

Plasma metabolite analysis is frequently used to assess the energetic state and energy intake of birds. Plasma β‐hydroxybutyrate (BUTY) is a common metabolite used in these studies, and is correlated with fasting and mass loss. BUTY is typically quantified in laboratory assays that are costly, time‐consuming, and prone to human error. We tested the accuracy and precision of a field‐ready handheld BUTY meter. We compared BUTY concentration values obtained in the laboratory and with the handheld meter in plasma samples from 19 Grasshopper Sparrows (Ammodramus savannarum), and assessed precision with repeat analysis of a single sample. The handheld meter reported BUTY concentrations in < 2 min, was highly precise, and as accurate as the laboratory assay method—all ideal for field conditions. Collecting blood samples for laboratory analysis, particularly from remote field sites, involves a series of risks and challenges for permitting or the logistics of storage and shipping, as well as the associated costs. Analyzing samples on site, whether with the unit we tested or other similar handheld meters, makes plasma metabolite analysis practical and possible in field conditions and for taxa where this technique has been underused due to permitting, transport, or other logistical constraints of laboratory analysis methods. The cost of analysis is similar on a per sample basis, but, without the need to store and transport samples, using handheld meters in the field may be cheaper.     

Small integrating meter for assessing long-term exposure to magnetic fields.

A small, lightweight meter has been developed for magnetic-field measurements, particularly those needed for exposure-assessment purposes. This meter, known as the AMEX-3D, continuously measures all three axes of magnetic-flux density and electronically combines the data into a single estimate of cumulative exposure to the root-mean-square (rms) resultant flux density. The AMEX-3D weighs about 120 g, measures 2.7 cm x 5.1 cm x 10.2 cm, and is battery powered. Two panel-mounted jacks are provided for measuring battery voltage and for reading cumulative exposure data from the unit. The instrument has, within 3 dB, a flat response to magnetic flux densities at all frequencies in its 30-1,000 Hz bandwidth. A detailed analysis of error sources in the AMEX-3D leads to an estimate of +/- 20% as the accuracy of the instrument over its dynamic range, which extends from 0.02 to 15 microT. The AMEX-3D was tested in the field by asking electric-utility distribution linemen to wear AMEX-3D and EMDEX meters simultaneously while working. Agreement between the two measures of exposure was excellent.     

Microbial Carbonate Precipitation as a Soil Improvement Technique

In order to evaluate MCP as a soil strengthening process, a five meter sand column was treated with bacteria and reagents under conditions that were realistic for field applications. The injection and reaction parameters were monitored during the process and both bacteria and process reagents could be injected over the full column length at low pressures (hydraulic gradient < 1; a flow rate of approximately 7 m/day) without resulting in clogging of the material. After treatment, the column was subjected to mechanical testing, which indicated a significant improvement of strength and stiffness over several meters. Calcium carbonate was precipitated over the entire five meter treatment length. Improvement of the load bearing capacity of the soil without making the soil impermeable to fluids was shown with microbial carbonate precipitation, and this is a unique property compared to alternative soil treatment methods that are currently available for use in the subsurface.     

Precision and costs of techniques for self-monitoring of serum glucose levels.

The poor correlation between serum and urine glucose measurements has led to the development of new techniques for monitoring the blood glucose level in diabetic patients. Either a nurse or the patient can perform these tests, which involve spreading a single drop of blood onto a reagent strip. A colour change that is proportional to the serum glucose level can be read visually or with a reflectance meter. Evaluated against simultaneous serum glucose levels determined by the hospital biochemistry laboratory, those of the new techniques employing reflectance meters all showed excellent correlation (r2 = 0.85 to 0.96). Reagent strips used without meters showed poorer correlation (r2 = 0.69 to 0.90). The instruction given to the patients and one nurse enabled them to obtain more accurate results with one of the meters than nurses not specially trained (r2 = 0.94 and 0.92 v. 0.85 respectively). The mean cost per glucose determination with the new techniques was 75, compared with +1.45 for the laboratory determinations done with automated equipment. It was concluded that the new techniques compared well with the reference method, particularly when reflectance meters were used, and that they were easily applied by the patient, as well as the medical staff, at a reasonable cost.     

Simplified methods for monitoring petroleum‐contaminated ground water and soil vapor

Portable meters and simplified gas Chromatographic (GC) techniques were investigated for monitoring volatile hydrocarbon (HC), CO₂, and O₂, concentrations in groundwater, exhaust gases, and soil vapor during in situ remediation using soil vapor extraction (SVE) and air sparging (AS). Results of groundwater samples analyzed in‐house using a headspace technique compared well to split samples analyzed by a certified analytical laboratory (r² = 0.94). SVE exhaust gas HC and CO₂ concentrations measured using a GT201 portable HC/O₂ meter and a RA‐411A meter (GasTech), respectively, were highly correlated with in‐house laboratory GC analyses (r² = 0.91). O₂ concentrations fell in a small range and meter analyses were not well correlated with laboratory analyses. Results of soil gas monitoring were not as well correlated as those for exhaust gases for HC, CO₂, or O₂, perhaps due to environmental conditions such as changes in relative humidity or the wider range of soil gas values. Overall, the meters were good indicators of vapor contamination, they greatly simplified estimates of total HC mass removal, and they allowed estimates of the biological contribution to contaminant removal during the remediation process.     

Evaluation of the quality of bedside monitoring of the blood glucose level in a teaching hospital.

We evaluated the precision and accuracy of monitoring of the blood glucose level in the laboratory and at the bedside with one of four glucose meters by an experienced operator and by 39 nurses in a teaching hospital. For precision studies aqueous quality control materials were used. A total of 85 blood samples were tested. The precision of the glucose meters (expressed as the coefficient of variation [CV]) in the hands of the experienced operator ranged from 6.7% to 11.1%. The correlation between the values obtained by the experienced operator and the reference values obtained in the laboratory was high (0.95 to 0.98). The precision of the values obtained by the nurses using the meters ranged from 13.7% on medical wards to 45.7% in the intensive care unit (ICU). The correlation between these values and those obtained in the central laboratory ranged from 0.72 to 0.82. Twenty-four percent of the glucose values determined on medical wards and 62% of those determined in the ICU deviated from the reference value by at least 20%. Of the 85 patients 12 (14%) would have received different insulin dosages had the reference value been available at the same time as the glucose meter reading: in 3 of the patients the discrepancy was 6 units of insulin or greater. Continuous quality control of bedside monitoring of the blood glucose level is needed. In addition, personnel who use glucose meters should receive adequate training.     

A high accuracy linear rate meter.

By implementing analog computer techniques using digital circuits, an instantaneous rate meter was built with approximately 100 times the accuracy of commercially available rate meters. The circuit is accurate to within +/- 0.2 events/min over a range of rates of 0.2-900 epm. Modifications can be made to provide a digital display of rate. The circuit design techniques used in developing the rate meter may be used to generate a wide variety of functions of time with very high accuracy.     

Accuracy of mini peak flow meters in indicating changes in lung function in children with asthma.

OBJECTIVE--To assess whether mini flow meters used to measure peak expiratory flow can track changes in lung function and indicate clinically important changes. DESIGN--Comparison of measurements with a spirometer and different brands of mini flow meter; the meters were allocated to subjects haphazardly. SUBJECTS--12 boys with asthma aged 11 to 17 attending boarding school. MAIN OUTCOME MEASURES--Peak expiratory flow measured twice daily for three months with a spirometer and at least one of four brands of mini flow meter. RESULTS--The relation between changes in lung function measured with the spirometer and those measured with the mini flow meters was generally poor. In all, 26 episodes (range 1-3 in an individual child) of clinically important deterioration in lung function were detected from the records obtained with the spirometer. One mini flow meter detected six of 19 episodes, one detected six of 15, one detected six of 18, and one detected three of 21. CONCLUSIONS--Not only are the absolute values of peak expiratory flow obtained with mini flow meters inaccurate but the clinical message may also be incorrect. These findings do not imply that home monitoring of peak expiratory flow has no place in the management of childhood asthma but that the values obtained should be interpreted cautiously.     

Evaluating the Accuracy of Modern Glucose Meters

Background: Self-mmonitoring of blood glucose (SSMBG) is important for all patients with diabetes, as it provides valuable feedback on the effects of diet, exercise, and medications. To maximize the potential benefits of SMBG, clinicians must have confidence in the accuracy of their patients' glucose meters.Objective: The aim of this article is to review several issues related to glucose meter accuracy and ways that accuracy can be enhanced.Methods: A MeDLINE search of English-language articles using the terms SMBG, glucose meter,and accuracy as an initial screen was performed. After articles describing the use of outdated technologies or vague methodologies were excluded, appropriate articles that analyzed various aspects regarding meter accuracy were selected.Results: Glucose meter accuracy studies are complicated by issues related to the reference method, the sample being assayed, nd he ay n which accuracy s reported. error rid analysis ives linicians a means to valuate the clinical importance of meter error. Modern glucose meters have many technological improvements and enhanced clinical accuracy; however, the accuracy of readings depends not only on the instrument but also on patient technique and other aspects of the overall testing process.Conclusions: SMBG has proven to be a valuable tool for the management of diabetes whether it is used to guide insulin dosing, provide feedback on the effect of meals, or detect hypoglycemia. Accuracy of SMBG can be optimized by patient education and continued improvements in meter technology.     

Development of a method for reliable power input measurements in conventional and single‐use stirred bioreactors at laboratory scale

Power input is an important engineering and scale‐up/down criterion in stirred bioreactors. However, reliably measuring power input in laboratory‐scale systems is still challenging. Even though torque measurements have proven to be suitable in pilot scale systems, sensor accuracy, resolution, and errors from relatively high levels of friction inside bearings can become limiting factors at smaller scales. An experimental setup for power input measurements was developed in this study by focusing on stainless steel and single‐use bioreactors in the single‐digit volume range. The friction losses inside the air bearings were effectively reduced to less than 0.5% of the measurement range of the torque meter. A comparison of dimensionless power numbers determined for a reference Rushton turbine stirrer (N_P = 4.17 ± 0.14 for fully turbulent conditions) revealed good agreement with literature data. Hence, the power numbers of several reusable and single‐use bioreactors could be determined over a wide range of Reynolds numbers between 100 and >10⁴. Power numbers of between 0.3 and 4.5 (for Re = 10⁴) were determined for the different systems. The rigid plastic vessels showed similar power characteristics to their reusable counterparts. Thus, it was demonstrated that the torque‐based technique can be used to reliably measure power input in stirred reusable and single‐use bioreactors at the laboratory scale.     

西藏壳斗科的地理分布

在野外考察、分类清理和修订的基础上讨论了西藏壳斗科的地理分布。自然分布的西藏壳斗科植物,共３属３３种,集中分布于藏东南的河谷地带和喜马拉雅山脉的聂拉木县,印度栲、刺栲、喜马拉雅石栎和西藏石栎是这些地区海拔２００米以下群落建群种;通麦栎、俅江栎和薄片青冈是西藏海拔１８００－２５００米地段森林植物被的建群种;硬叶高山栎类则是海拔２５００米以上硬叶常绿阔叶林及高山灌丛植被的建群种。种的区系成分分析表明：     

Action of a 50 Hz magnetic field on proliferation of cells in culture

Proliferation of SV40-3T3 mouse fibroblasts and human HL-60 promyelocytes was studied after treatment with a sinusoidal 2 mT_rms 50 Hz magnetic field. A single exposure of 60 minutes caused quasicyclic changes in the cell number of SV40-3T3 cultures as function of time after treatment, which was interpreted to be due to the induction of chronobiological mechanisms by the field. Moreover, small variations in cell cycle distribution were measured during postexposure incubation for both cell lines. To discriminate between the effect of the magnetic vector and the induced electric field, HL-60 cell exposure was also performed on organ culture dishes. These dishes consist of two coaxially centered, isolated compartments in which different electric field levels are induced in the medium during treatment. Cell growth was affected in the outer compartment only where the induced electric field ranged from 8 to 12 mV_peak/meter at 2 mT, but it was not affected in the inner compartment (field range 0–4 mV_peak/meter). This suggests that the effects on cell growth are due to the induced electric field and are expressed only above a threshold of between 4 and 8 mV_peak/meter. Bioelectromagnetics 18:177–183, 1997. © 1997 Wiley-Liss, Inc.     

Validation of a glucose meter at an intensive care unit

IntroductionHyperglycemic patients admitted to Intensive care units (ICUs) have higher morbidity and mortality than normoglycemic patients. Blood glucose levels of ICU patients are usually measured with a glucose meter. The aim of this study was to evaluate a glucose meter (StatStrip, Nova Biomedical) to assess its agreement with the standard laboratory method for testing glucose.Material and methodsEighty-nine different samples were collected from patients (76.4% men and 23.6% women) admitted to an ICU from September to December 2010. Each blood sample was collected into two tubes, a lithium heparin tube and an EDTA tube. The total blood aliquot was used to measure glycemia using the glucose meter. The lithium heparin tube was processed at the same time for measuring plasma glucose (Cobas 6000 Analyzer, Roche Diagnostics, SA). Agreement between the two methods was assessed according to the EP-9-A2 Clinical Laboratory Standards Institute guideline.ResultsMean whole blood glucose level measured by the glucose meter was 126.53 + 49.28 mg/dL (range, 33.5-431 mg/dL), while mean plasma glucose value measured by the laboratory reference method was 138.13 + 78.6 mg/dL (range, 43-451 mg/dL). Correlation coefficient was 0.99, with a 95% confidence interval of 0.98 to 0.99. Coefficient of determination (R2) was 0.97, and intraclass correlation coefficient was 0.99 with a 95% CI of 0.98 to 0.99.ConclusionsThe tested glucose meter (StatStrip) shows a good linear association, precision, and accuracy when compared to the laboratory reference method. This device is adequate for glucose monitoring.     

Mate location and recognition in Glenea cantor (Fabr.) (Coleoptera: Cerambycidae: Lamiinae): roles of host plant health, female sex pheromone, and vision

Glenea cantor (Fabricius) is an important pest of kapok trees [Bombax ceiba L.=Gossampinus malabaricus (DC.) Merr.] in southern China and Vietnam, and its adults are diurnally active. We carried out both field and laboratory experiments to examine the mechanisms that brought G. cantor sexes together from a long distance and facilitated mate location and recognition in a close range. Long-range sex pheromones are not involved in mate location. Mutual attraction of sexes to weakened kapok trees where adult feeding, mating, and oviposition occur plays the key role in mate location from a long distance. In a close range, vision and a female sex pheromone that operates over a short distance (3-3.5 cm) and/or by contact are major cues males use for mate location and recognition. Males seem to use combined chemical and visual cues to achieve mating. Male antennae, particularly the terminal five segments, are critical for males to detect and recognize females. Removal of male palpi has no significant effect on mate location and recognition by males.     

Differences in functional organization of the visual center in frogs and cats

Functional characteristics of responses of tectal neurons in the frog and the primary visual cortex of the cat obtained under indentical experimental conditions during changes in the brightness and duration of flashes within the range of 6 log units were compared. In frogs most units have short summation times and relatively lower thresholds; the response latency is 5–7 times longer than in cats. The overwhelming majority of tectal units can respond only to a narrow range of photic energy that differs for different cells. Most cells in cats respond to changes in brightness of between 4 and 5 log units; they have long summation times, short latent periods, and relatively higher thresholds. The differences found on comparison of the various functional characteristics of the cells in the visual center show that frogs have fixed mechanisms of temporal and spatial interaction responsibile for detection of stimulus brightness. In cats this interaction between individual cell populations and this mutual inhibition between adjacent cells are not prominent. The increased complexity and overlapping of interneuronal connections leads to convergence of day and twilight vision stimuli on the same neuron and to the ability of single units to respond to the whole "working" range of light brightness for the cat visual system.     

Calibration of the Minolta SPAD-502 leaf chlorophyll meter

Use of leaf meters to provide an instantaneous assessment of leaf chlorophyll has become common, but calibration of meter output into direct units of leaf chlorophyll concentration has been difficult and an understanding of the relationship between these two parameters has remained elusive. We examined the correlation of soybean (Glycine max) and maize (Zea mays L.) leaf chlorophyll concentration, as measured by organic extraction and spectrophotometric analysis, with output (M) of the Minolta SPAD-502 leaf chlorophyll meter. The relationship is non-linear and can be described by the equation chlorophyll (mol m^–2)=10(^M0.265), r ²=0.94. Use of such an exponential equation is theoretically justified and forces a more appropriate fit to a limited data set than polynomial equations. The exact relationship will vary from meter to meter, but will be similar and can be readily determined by empirical methods. The ability to rapidly determine leaf chlorophyll concentrations by use of the calibration method reported herein should be useful in studies on photosynthesis and crop physiology.Abbreviations Chl- chlorophyll - M- SPAD-502 meter value     

Summary of measured radiofrequency electric and magnetic fields (10 kHz to 30 GHz) in the general and work environment

We have plotted data from a number of studies on the range of radiofrequency (RF) field levels associated with a variety of environmental and occupational sources. Field intensity is shown in units of volts/meter (V/m) for electric field strength and amps/meter (A/m) for magnetic field strength. Duty factors, modulation frequencies, and modulation indices are also reported for some sources. This paper is organized into seven sections, each cataloging sources into appropriate RF frequency bands from very-low frequency (VLF) to super-high frequency (SHF), and covers frequencies from 10 kHz to 30 GHz. Sources included in this summary are the following: Coast Guard navigational transmitters, a Navy VLF transmitter, computer visual display terminals (VDTs), induction stoves or range tops, industrial induction and dielectric heaters, radio and television broadcast transmitters, amateur and citizens band (CB) transmitters, medical diathermy and electrosurgical units, mobile and handheld transmitters, cordless and cellular telephones, microwave ovens, microwave terrestrial relay and satellite uplinks, and police, air traffic, and aircraft onboard radars. For the sources included in this summary, the strongest fields are found near industrial induction and dielectric heaters, and close to the radiating elements or transmitter leads of high power antenna systems. Handheld transmitters can produce near fields of about 500 V/m at the antenna. Fields in the general urban environment are principally associated with radio and TV broadcast services and measure about 0.1 V/m root-mean-square (rms). Peak fields from air traffic radars sampled in one urban environment were about 10 V/m, 300 times greater than the rms value of 0.03 V/m when the duty factor associated with antenna rotation and pulsing are factored in. Bioelectromagnetics 18: 563–577, 1997. Published 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Megaichnus igen. nov.: Giant Paleoburrows Attributed to Extinct Cenozoic Mammals from South America

In the last ten years, more than 1,500 large burrows have been discovered in southern and southeastern Brazil, dug in rocks that include weathered granitic and basaltic rocks, sandstones, and other consolidated sediments. Their presence in geological units of Plio-Pleistocene age suggests that large extinct mammals produced these structures. The internal walls exhibit scratches and grooves left by the animals that inhabited these structures. The burrows are straight or slightly sinuous tunnels that measure up to tens of meters in length. One smaller type measures up to 1.5 meter in diameter, and the larger type can reach 2 meters in height and 4 meters in width, suggesting that such structures have been produced by at least two kinds of organisms. This contribution proposes a classification for these ichnofossils under the generic designation Megaichnus igen. nov., consisting of two ichnospecies identified so far: M. major and M. minor ispp. nov. Although the exact identity of the producers of the burrows is yet unknown, the dimensions and morphology point to ground sloths and giant armadillos.     

Electric-field exposure of persons using video display units

Electric fields produced by a selection of video display units have been measured over a frequency range from DC to 1 MHz. The magnitude and the time variation of the electric fields were both recorded by means of a single broadband capacitive sensor located on the surface of a simple simulation of the human body. The electric field at a given location was found to be the sum of three discrete components, each having a different spatial and time variation. These components are produced by, respectively, the charged CRT screen, the flyback transformer, and the low-voltage circuitry. For the units tested, operator exposures are substantially below the limits of existing workplace guidelines.     

Aerosol dissemination of veterinary pathogenic and human opportunistic thermophilic and thermotolerant fungi from thermal effluents of nuclear production reactors

The extent to which veterinary pathogenic and human opportunistic species of thermophilic and thermotolerant fungi disseminate in aerosols from heated effluents of nuclear production reactors of the Savannah River Plant (SRP), South Carolina, has been measured. Aerosol samples were taken at 140 sites, from directly over thermal effluents to more than 100 kilometers from the SRP boundary. Sampling methods included settle plates (134 sites, 1, 103 plates for a total of 2, 805 hrs.), liquid impingement (78 sites, 1 cubic meter each), filtration (79 sites, 1 cubic meter each), and a particle sizing cascade impactor (Andersen Sampler) (17 sites, 1 cubic meter each). Soils, foams, and microbial mats from thermal effluents (a total of 191 samples), and vegetation (560 samples) were sampled to study distribution of particular species. Sampling was done under a variety of conditions: hot weather and cold, wet and dry, day and night, windy and calm, reactor(s) operating and not, disturbed vegetation and undisturbed. At 102 of the aerosol sampling sites, sophisticated meterological analyses were used to allow sampling of air in the plume which originated from thermal effluents. Soil, foam, microbial mat, vegetation, and aerosol samples were quantitatively plated for detection of viable units; filters were halved and then both plated and observed microscopically.Significant dissemination of thermophilic and thermotolerant fungi from thermal effluents was not detected. Thermophilic and thermotolerant fungi were widely distributed in soil, air, and on vegetation. Dactylaria gallopava, the indicator species and dominant fungus in microbial mats lining SRP thermal effluents and the cause of epidemic fatal phaeohyphomycosis in flocks of turkeys and chickens in South Carolina, Georgia, and elsewhere, was isolated from air at a maximum of 50 meters from effluents (8 viable units per cubic meter of air in the plume of an effluent during a strong wind).By acceptance of this paper, the publisher and/or recipient acknowledges that the U.S. Government's right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper, along with the right to reproduce and to authorize others to reproduce all or part of the copyrighted paper.