Migration of latent fingermarks on non-porous surfaces:observation technique and nanoscale variations

Latent fingermark morphology was examined over a period of approximately two months. Variation in topography was observed with atomic force microscopy and the expansion of the fingermark occurred in the form of the development of an intermediate area surrounding the main fingermark ridge. On an example area of a fingermark on silicon, the intermediate region exists as a uniform 4nm thick deposit; on day 1 after deposition this region extends approximately 2µm from the edge of the main ridge deposit and expands to a maximum of ~ 4µm by day 23. Simultaneously the region breaks up, the integrity is compromised by day 16, and by day 61 the area resembles a series of interconnected islands, with coverage of approximately 60%. Observation of a similar immediate area and growth with time on surfaces such as Formica was possible by monitoring the mechanical characteristics of the fingermark and surfaces though phase contrast in tapping mode AFM. The presence of this area may affect fingermark development, for example affecting the gold distribution in vacuum metal deposition. Further study of time dependence and variation with donor may enable assessment of this area to be used to evaluate the age of fingermarks

Thiophene Derivative Monomers Co-electropolymerized on Microelectrodes within Arrays for Tailored Surface Chemistry and Electrochemical Properties

Potentiodynamic co-electropolymerization of two thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl)methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), in aqueous solutions (0.02 M total monomer, 0.05 M sodium dodecyl sulfate (SDS) and 0.1 M LiClO4) on gold microband electrodes in an array was investigated. A modified Steglich esterification reaction between monomer 1 and succinic anhydride produced monomer 2 at 93.6% yield. Seven deposition solutions of the two monomers, defined by mol% of monomer 2 (0, 25, 34, 50, 66, 75, 100) generated seven sets of polymer films by cyclic voltammetry in a specially designed cell to conserve monomer. The onset potential for monomer oxidation and total monomer deposited (m) were calculated from the deposition voltammograms. Decreasing monomer deposited (m) from 0 to 100 mol% 2 is attributed to a decreasing pH that inhibits electropolymerization. Cyclic voltammetry (CV) of the resulting films in aqueous buffer yielded capacitances that decrease similarly to the decrease in m for solutions from 0 to 75 mol% 2. Thus, the electrochemical behavior of the polymer film itself, which depends on the ability of ions to transport through the film, is unaffected by the comonomer composition. However, for films from solutions in which only monomer 2 is present (100 mol% 2), the capacitance is the same as the bare gold. These films have a minimal background current and further modified by a chemical reporter would make a suitable sensor platform. The facility of electron transfer at films by ferrocyanide, measured by the potential difference in CV between faradaic current peaks, was not significantly affected by the mol% 2, either, except for the 100 mol% 2 case. The ratio of monomers 2 and 1 in the films, determined by micro-attenuated total reflectance Fourier transform infrared spectroscopy and supported by X-ray photoelectron spectroscopy, linearly tracks the ratio in the deposition solutions. It is proposed that this deposition behavior, which differs from prior reports of other thiophene mixtures, is enabled through SDS solubilization. These studies demonstrate electrochemical capacitance of the films is unimpeded by the polymer composition and yet can be formed with predictable numbers of carboxylic acid and hydroxyl functional groups for further modification

Environmental effects on magnetic fluorescent powder development of fingermarks on bird of prey feathers

A comparison study of the effects of environmental conditions on the development of latent fingermarks on raptor feathers using green magnetic fluorescent powder was undertaken using both sebaceous loaded and natural fingermark deposits. Sparrowhawk feathers were stored in indoor conditions for 60 days (Study 1), and buzzard feathers were left exposed to two different environmental conditions (hidden and visible) for 21 days (Study 2), with developments made at regular ageing periods. In Study 1, latent fingermarks were successfully developed (Grade 1–4) on the indoor feathers up to 60 days after deposition – 98.6% of the loaded deposits and 85.3% for natural deposits. Under outdoor conditions in Study 2, both loaded and natural deposits were affected by environmental exposure. Latent fingermarks were successfully developed up to 14 days after deposition on the outdoor feathers, with some occasional recovery after 21 days. The visible feathers recorded 34.7% (loaded) and 16.4% (natural) successful developments (Grade 1–4), whereas the hidden feathers recorded 46.7% (loaded) and 22.2% (natural) successful developments, suggesting that protection from the environment helps to preserve latent fingermarks on the surface of a feather. Environmental exposure accelerated the deterioration of ridge detail and the number of successful developments

Seagrass science is growing: a report on the 12th International Seagrass Biology Workshop

This conference report describes the programme of the 12th International Seagrass Biology Workshop, its highlights, areas of growth for the workshop, and potential future directions for the workshop series. The report is written with an eye toward where it fits within the field of seagrass research

The influence of alcohol content variation in UK packaged beers on the uncertainty of calculations using the Widmark equation

It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v – 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12 months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations

Micro-Relief Surface Depression Storage: Changes During Rainfall Events And Their Application To Rainfall-Runoff Models

Micro-relief surface depression storage is one of the dynamic components of the rainfall-runoff process. The quantification of the effect of rainfall intensity and duration on the micro-relief was the subject of this study. Micro-relief measurements were made on 88 soil bin samples before and after the application of simulated rainfall events. The surface depression changes are described with empirical equations, using basic rainfall, surface hydrology, and soil parameters and their cross products as independent variables. A rainfall-runoff model demonstrates the value of a dynamic description of the surface depression storage function

Effects of Colony Creation Method and Beekeeper Education on Honeybee (Apis mellifera) Mortality

The two-part study reported here analyzed the effects of beekeeper education and colony creation methods on colony mortality. The first study examined the difference in hive mortality between hives managed by beekeepers who had received formal training in beekeeping with beekeepers who had not. The second study examined the effect on hive mortality between hives that were initiated as nucleus or package colonies. Colonies created from package bees were more likely to survive for 1 year than nucleus colonies. Colonies managed by beekeepers who had received formal education also exhibited better survival rates than those managed by non-educated beekeepers

Micro-Relief Surface Depression Storage: Changes During Rainfall Events And Their Application To Rainfall-Runoff Models

Micro-relief surface depression storage is one of the dynamic components of the rainfall-runoff process. The quantification of the effect of rainfall intensity and duration on the micro-relief was the subject of this study. Micro-relief measurements were made on 88 soil bin samples before and after the application of simulated rainfall events. The surface depression changes are described with empirical equations, using basic rainfall, surface hydrology, and soil parameters and their cross products as independent variables. A rainfall-runoff model demonstrates the value of a dynamic description of the surface depression storage function