The effect of light exposure on the degradation of latent fingerprints on brass surfaces: the use of silver electroless deposition as a visualization technique.

We have studied the degradation of sebaceous fingerprints on brass surfaces using silver electroless deposition (SED) as a visualization technique. We have stored fingerprints on brass squares either (i) in a locked dark cupboard or (ii) in glass-filtered natural daylight for periods of 3 h, 24 h, 1 week, 3 weeks, and 6 weeks. We find that fingerprints on brass surfaces degrade much more rapidly when kept in the light than they do under dark conditions with a much higher proportion of high-quality prints found after 3 or 6 weeks of aging when stored in the dark. This process is more marked than for similar fingerprints on black PVC surfaces. Identifiable prints can be achieved on brass surfaces using both SED and cyanoacrylate fuming (CFM). SED is quick and straightforward to perform. CFM is more time-consuming but is versatile and can be applied to a wider range of metal surfaces than SED, for example brass surfaces which have been coated by a lacquer.

Identification of forged Bank of England £20 banknotes using IR spectroscopy.

Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm(-1)), ν(C-H) (ca. 2900 cm(-1)) and ν(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.

Enhancement of aged and denatured fingerprints using the cyanoacrylate fuming technique following dusting with amino acid-containing powders.

We have carried out experiments to investigate the aging of latent fingerprints deposited on black PVC over a period of 4-15 weeks. A thumbprint was used in each case and before deposition of the print the donor rubbed their thumb around their nose to add sebaceous deposits. We have studied the effect of heat, light, and moisture and we find that moisture is the most significant factor in the degradation of the latent print. We have attempted to enhance these latent prints by dusting with valine powder or powders composed of valine mixed with gold or red fluorescent commercial fingerprint powders. To make a direct comparison between "treated" and "untreated" prints, the prints were cut in half with one-half being "treated" and one-half not. Our studies show the best results being obtained when powders of valine and red fluorescent powders are applied prior to cyanoacrylate fuming.

Performance evaluation and labeling comprehension of a new blood glucose monitoring system with integrated information management.

BACKGROUND: This study evaluated performance and product labeling of CONTOUR® USB, a new blood glucose monitoring system (BGMS) with integrated diabetes management software and a universal serial bus (USB) port, in the hands of untrained lay users and health care professionals (HCPs). METHOD: Subjects and HCPs tested subject's finger stick capillary blood in parallel using CONTOUR USB meters; deep finger stick blood was tested on a Yellow Springs Instruments (YSI) glucose analyzer for reference. Duplicate results by both subjects and HCPs were obtained to assess system precision. System accuracy was assessed according to International Organization for Standardization (ISO) 15197:2003 guidelines [within ±15 mg/dl of mean YSI results (samples <75 mg/dl) and ±20% (samples ≥75 mg/dl)]. Clinical accuracy was determined by Parkes error grid analysis. Subject labeling comprehension was assessed by HCP ratings of subject proficiency. Key system features and ease-of-use were evaluated by subject questionnaires. RESULTS: All subjects who completed the study (N = 74) successfully performed blood glucose measurements, connected the meter to a laptop computer, and used key features of the system. The system was accurate; 98.6% (146/148) of subject results and 96.6% (143/148) of HCP results exceeded ISO 15197:2003 criteria. All subject and HCP results were clinically accurate (97.3%; zone A) or associated with benign errors (2.7%; zone B). The majority of subjects rated features of the BGMS as "very good" or "excellent." CONCLUSIONS: CONTOUR USB exceeded ISO 15197:2003 system performance criteria in the hands of untrained lay users. Subjects understood the product labeling, found the system easy to use, and successfully performed blood glucose testing.

Improving the quality of self-monitoring blood glucose measurement: a study in reducing calibration errors.

BACKGROUND: Two independent studies reported that 16% of people who self-monitor blood glucose used incorrectly coded meters. The degree of analytical error, however, was not characterized. Our study objectives were to demonstrate that miscoding can cause analytical errors and to characterize the potential amount of bias that can occur. The impact of calibration error with three selfblood glucose monitoring systems (BGMSs), one of which has an autocoding feature, is reported. METHODS: Fresh capillary fingerstick blood from 50 subjects, 18 men and 32 women ranging in age from 23 to 82 years, was used to measure glucose with three BGMSs. Two BGMSs required manual coding and were purposely miscoded using numbers different from the one recommended for the reagent lot used. Two properly coded meters of each BGMS were included to assess within-system variability. Different reagent lots were used to challenge a third system that had autocoding capability and could not be miscoded. RESULTS: Some within-system comparisons showed deviations of greater than +/-30% when results obtained with miscoded meters were compared with data obtained with ones programmed using the correct code number. Similar erroneous results were found when the miscoded meter results were compared with those obtained with a glucose analyzer. For some miscoded meter and test strip combinations, error grid analysis showed that 90% of results fell into zones indicating altered clinical action. Such inaccuracies were not found with the BGMS having the autocoding feature. CONCLUSIONS: When certain meter code number settings of two BGMSs were used in conjunction with test strips having code numbers that did not match, statistically and clinically inaccurate results were obtained. Coding errors resulted in analytical errors of greater than +/-30% (-31.6 to +60.9%). These results confirm the value of a BGMS with an automatic coding feature.

Evaluation of a new blood glucose monitoring system with auto-calibration for home and hospital bedside use.

A new self-calibrating blood glucose monitoring system (BGMS) was evaluated in a series of clinical studies with both ambulatory subjects and with hospitalized patients. The new BGMS requires a 0.6microL sample volume, provides results in 15s, and uses a glucose dehydrogenase chemistry that is oxygen independent. In the first study, Ascensia Contour meters calibrated to whole blood were tested by health care professionals (HCP) and lay users at two clinical sites. Both HCPs and lay users obtained results that fulfilled the ISO 15197:2003 criteria that 95% of self-monitoring blood glucose (SMBG) measurements should fall within +/-20% (for blood glucose (BG) concentrations> or =4.2mmol/L or +/-0.83mmol/L for BG concentrations<4.2mmol/L) of the laboratory value. Lay users and HCPs obtained 97.2 and 96.7% of glucose results within ISO criteria, respectively. In a second study, HCPs assayed blood samples from patients at the hospital bedside using meters calibrated to give whole blood glucose and meters calibrated to give plasma glucose results. Overall, 94.7% of the measurements met the ISO 15197:2003 criteria. Most lay subjects rated the BGMS as either excellent or very good in a questionnaire, and were able to use it properly without training. These findings indicate that this new BGMS is a convenient and accurate instrument system suitable for both hospital bedside use by HCPs and for SMBG by people who routinely monitor their blood glucose.

Evaluation of a new blood glucose monitoring system with auto-calibration.

BACKGROUND: The Ascensia CONTOUR System (Bayer HealthCare LLC, Elkhart, IN) is a new blood glucose (BG) monitoring system (BGMS) that uses glucose dehydrogenase chemistry and that combines low sample volume, fast response time, an auto-control marking feature, and an auto-calibration function in a small package. METHODS: The system was evaluated at four diabetes clinics with ambulatory subjects who had diabetes. The BGMS was tested by both health care professionals (HCPs) and lay users. It was also evaluated at high altitude (10,200 feet) and, in conjunction with the Ascensia MICROLET VACULANCE (Bayer), for use with samples obtained from four alternative anatomical sites. RESULTS: When the system was used with blood from fingersticks, both lay users and HCPs obtained results that fulfilled the International Organization for Standardization (ISO) 15197:2003 accuracy criteria, which advocate that 95% of BG measurements should fall within +/-15 mg/dL (for BG concentrations <75 mg/dL) or +/-20% (for BG concentrations > or = 75 mg/dL) of the laboratory value. Lay users obtained 96.9% of glucose results, and HCPs obtained 96.4% of glucose results, within ISO accuracy criteria. People with diabetes who had no prior experience using the system also obtained acceptable results (97.0%), as did the HCP using fingerstick samples from subjects in the high altitude study (97.0%). Among the alternative anatomical sites tested, only the results from the palm met the ISO criteria (97.5%), although the results from all four sites (palm, thigh, abdomen, and forearm) were clinically acceptable when assessed using error grid analysis. Most subjects rated the BGMS as either excellent or very good in a questionnaire, and were able to use it properly without training. CONCLUSIONS: These findings indicate that the Ascensia CONTOUR System, which does not require calibration by the user, is a convenient and accurate instrument with useful features for people who routinely monitor BG.