The Use of Mass Spectrometry to Differentiate Blue Dyes From Indigo and Woad

Indigo has a long and prestigious history, from the ancient past to our blue jeans today. Indigotin is a dark blue colorant molecule that is produced from many plants, including indigo (Indigofera), woad (Isatis), and knotweed (Polygonum) when the leaves are crushed, fermented, and then reacted with oxygen. All of the indigo-producing plants undergo the same chemistry, so they are difficult to differentiate from each other in archaeological textiles. There are many analytical approaches to the characterization of blue dyes in conservation science, though few are able to reliably distinguish between blues obtained from the various plant sources. Archaeologists and conservators are interested in sourcing the colors that ancient people used, as this provides insight into their selection of materials and the chemical technology necessary to produce dyes. We present here the initial stages of work to use direct analysis in real time (DART) mass spectrometry (as well as other ionization methods) to differentiate blue dyes made from indigo, woad, and knotweed on a variety of fiber substrates. Based on the results for the lab-prepared materials, we will apply the best method to archaeological fibers previously shown to contain indigotin

Neo-Hookean fiber composites undergoing finite out-of-plane shear deformations

The response of a neo-Hookean fiber composite undergoing finite out-of-plane shear deformation is examined. To this end an explicit close form solution for the out-of-plane shear response of a cylindrical composite element is introduced. We find that the overall response of the cylindrical composite element can be characterized by a fictitious homogeneous neo-Hookean material. Accordingly, this macroscopic response is identical to the response of a composite cylinder assemblage. The expression for the effective shear modulus of the composite cylinder assemblage is identical to the corresponding expression in the limit of small deformation elasticity, and hence also to the expression for the Hashin-Shtrikman bounds on the out-of-plane shear modulus

Electron Kinetics in a Positive Column of AC Discharges in a Dynamic Regime

We have performed hybrid kinetic-fluid simulations of a positive column in AC Argon discharges over a range of driving frequencies f and gas pressure p for the conditions when the spatial nonlocality of the Electron Energy Distribution Function (EEDF) is substantial. Our simulations confirmed that the most efficient conditions of plasma maintenance are observed in the dynamic regime when time modulations of mean electron energy (temperature) are substantial. The minimal values of the root mean square (rms) electric field and the electron temperature have been observed at f/p values of about 3 kHz/Torr in a tube of radius R = 1 cm. The ionization rate and plasma density reached maximal values under these conditions. The numerical solution of a kinetic equation allowed accounting for the kinetic effects associated with spatial and temporal nonlocality of the EEDF. Using the kinetic energy of electrons as an independent variable, we solved an anisotropic tensor diffusion equation in phase space. We clarified the role of different flux components during electron diffusion in phase space over surfaces of constant total energy. We have shown that the kinetic theory uncovers a more exciting and rich physics than the classical ambipolar diffusion (Schottky) model. Non-monotonic radial distributions of excitation rates, metastable densities, and plasma density have been observed in our simulations at pR > 6 Torr cm. The predicted off-axis plasma density peak in the dynamic regime has never been observed in experiments so far. We hope our results stimulate further experimental studies of the AC positive column. The kinetic analysis could help uncover new physics even for such a well-known plasma object as a positive column in noble gases

Characterizing Evulsion in the Later Stone Age Maghreb: age, sex and effects on mastication

This paper assesses the earliest evidence for widespread dental modification in Northwest Africa. The intentional modification of teeth has implications for an individual’s appearance, sense of identity and perceived status. The range of modifications reported varies from alterations of shape or color to the complete removal of healthy teeth (evulsion or ablation). The availability of well-dated collections reveals that Northwest Africa was the first region where the custom of tooth evulsion was widely practiced. Analysis of Iberomaurusian (Late Stone Age, n=77) and Capsian dental material (n=12) shows that evulsion was present in most male and female individuals (>94%). The most common Iberomaurusian practice involved removal of both upper central incisors (around 65%) although removal of fewer, none and more teeth was also recorded. Observations of the extent of alveolar remodeling of different sockets revealed that teeth were frequently removed at different ages, suggesting that the cultural significance was age transgressive and may have related to an event that individuals experienced more than once. During the Capsian period the prevalence of evulsion was lower in males than in females, but when present more teeth were removed with evulsion frequently involving both mandible and maxilla. Tooth wear analysis shows that evulsion affected not only the appearance of the individual but also the functioning of the masticatory complex

Provision of Reference Services and Use of Information Resources by Undergraduate Students in University Libraries in Bayelsa State

This study investigated the provision of reference services and use of library information resources by undergraduates in universities in Bayelsa state, Nigeria. The study used a correlational survey research methodology, and the instrument for gathering data was a questionnaire. 17451 undergraduate students from the four universities in Bayelsa State made up the study\u27s population, with a sample size of 349 representing 20% of the total population. 349 copies of the questionnaire were distributed and 346 were retrieved and found usable. Data were analyzed with frequency count, simple percentages, mean, and standard deviation while Pearson\u27s product moment correlation coefficient was used to test the hypotheses at 0.05 significant level. The study\u27s findings showed a strong positive link between responding to reference requests and undergraduate students\u27 use of library information resources at universities in Bayelsa State (r =.598; p 0.05). The usage of library information resources by students is significantly positively correlated with the referral service (r =.168; p 0.05), user education (r =.482; p 0.05), and current awareness services (r =.236; p 0.05). Undergraduate students\u27 use of library information resources at universities in Bayelsa State is significantly positively correlated with selective information distribution (r =.127; p 0.05). According to the study\u27s findings, reference services provided by librarians are still essential for university libraries to achieve their primary goals. The study concluded that librarians and libraries urgently need to prioritize offering reference services to undergraduates in light of their favorable impact on library use

Oral health in Late Pleistocene and Holocene North West Africa

Archaeological sites in North West Africa have yielded a rich record of human occupation, including well dated human burials from the Late Pleistocene Iberomaurusian and early Holocene Capsian periods. The transition broadly coincides with climatic amelioration at the end of the Holocene enabling expansion into slighter dryer inland areas. Here we investigate possible changes in oral health and subsistence behaviours during the transition between the Iberomaurusian (n = 109 individuals) and the Capsian (n = 19 individuals), based on the study of dental remains. Frequencies in oral pathologies (caries, abscesses, periodontal disease and antemortem tooth loss) were studied to assess possible differences between the late Pleistocene and early Holocene. The Late Pleistocene Iberomaurusians were characterised by high caries frequencies (60% of observed teeth). The Capsians displayed very similar patterns in oral pathologies but a slightly lower percentage of carious teeth (49%). The similarity in oral health in Iberomaurusian and Capsian populations is consistent with similarities in diet and oral hygiene. The implication of cultural and biological continuity between the Iberomaurusian and Capsian periods is supported by indicators, such as exploitation of wild plants and snails, tooth evulsion and craniofacial and dental morphology. © 201

Degradation of polystyrene by tropical bacterial and fungal isolates

Plastic waste is one of the major contributing factors to the growth of municipal solid wastes globally. It is a threat to public health and negatively impact the aquatic and terrestrial animals due to its persistence in the environment. Bacterial and fungal isolates were tested for their ability to degrade polystyrene. The cultures were grown on mineral salts medium supplemented with polystyrene as the sole carbon source in 250 mL conical flasks. The polystyrene reduced from 1 g (week 0) to 0.7g (week 7). Statistical analysis of variance (one-way ANOVA) shows a significant difference between the reduction in weight of polystyrene in the experimental flask compared to the control (P<0.05). Gas chromatography mass spectrometry analysis of biodegradation products shows that some toxic polystyrene constituents such as O-xylene, cis-9-hexadecenal and 3-phenol pentadecyl were removed