The Degradation of Human Hair Studied by FT-Raman Spectroscopy

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Analysis of the Rock Accretions in the Lower Pecos Region of Southwest Texas

Calcium oxalate (whewellite) was found to be the primary component of crusts on limestone in the dry rock shelters throughout the Lower Pecos region of Texas. This material forms a translucent patina that covers the pictographs in this area. Evidence from analyses using SEM/EDS, FTIR, XRD, Raman spectroscopy, and AMS is presented that suggests the oxalate-rich crusts were produced by metabolic activity of lichen or fungi on or near the surface of the limestone substrate. The paucity of hyphae and microbes in samples studied using SEM may indicate that the organisms responsible for the production of the oxalate are no longer present on the shelter walls. Radiocarbon ages of three oxalate samples range from 2100 to 5570 years B. P., indicating that the crust may be used for obtaining chronological information on the rock art

Towards an Understanding of the Interaction of Hair with the Depositional Environment

NoThere is developing interest in the analytical use of human hair from archaeological contexts in key research areas such as DNA, trace elemental and isotopic analyses. Other human tissues, especially bone, that have been used for trace element, isotopic and DNA analyses have had extensive study concerning their diagenesis, but this has not been done for hair. Consideration must be given to the complex interaction of hair with its buried environment, thereby laying a firm basis for the use of hair in future research. Since human hair is known to survive under a diverse range of environmental conditions, a pilot study has investigated the basic processes of hair degradation, using samples from different climatic zones and burial types. Variation in the degree of preservation of archaeological hair was characterized by light microscopy, electron microscopy, and FT-Raman spectroscopy, relating morphological change of the surface and internal structure of hair to its biochemical integrity. The results demonstrate a breakdown of cortical cell boundaries and disruption of the cuticular layering, coupled with infiltration of material from the burial matrix that suggests a progressive loss of cohesion that is in part due to microbiological activity. Medullated hair is shown to be more susceptible to physical breakdown by providing two routes for microbial and environmental attack. At the molecular level the proteinaceous component undergoes alteration, and the S-S cystine linkages, responsible for the strength and resilience of hair in living individuals, are lost

Low risk of seizure recurrence after early withdrawal of antiepileptic treatment in the neonatal period.

The risk of seizure recurrence within the first year of life was evaluated in infants with neonatal seizures diagnosed with a combination of clinical signs, amplitude-integrated electroencephalogram (EEG) monitoring, and standard EEG. Fifty eight of 283 (4.5%) neonates in tertiary level neonatal intensive care had seizures. The mortality in the infants with neonatal seizures was 36.2%. In 31 surviving infants antiepileptic treatment was discontinued after one to 65 days (median 4.5 days). Three infants received no antiepileptic treatment, two continued with prophylactic antiepileptic treatment. Seizure recurrence was present in only three cases (8.3%)--one infant receiving prophylaxis, one treated for 65 days, and in one infant treated for six days. Owing to the small number of infants with seizure recurrence, no clinical features could be specifically related to an increased risk of subsequent seizures. When administering antiepileptic treatment, one aim was to abolish both clinical and electrographical seizures. Another goal was to minimise the duration of treatment and to keep the treatment as short as possible. It is suggested that treating neonatal seizures in this way may not only reduce the risk of subsequent seizure recurrence, but may also minimise unnecessary non-specific prophylactic treatment for epilepsy