2.1.1 Histological analysisnext section
A bone sample was analysed according to the protocol outlined by Maat et al. (2000); the intestine samples, liver and kidney, were typed according to their shape and internal position in the mummy’s bundle of viscera (Van der Sanden 1996, 116). Small tissue biopsies (0.5 cm x 0.5 cm) that were macroscopically identified as liver and kidney tissues were analysed according to the methods described in Mekota & Vermehren (2005).
After rehydration in Solution III for 48 hours, samples were fixed for 24 hours in 4% formaldehyde, dehydrated and finally embedded in paraffin blocks. The embedded samples were cut into 3µm-thick sections using a microtome (Leica, RM2245). The paraffin sections were histochemically counterstained with either haematoxylin and eosin stain (H&E) or Gram stain (Mulisch & Welsch 2010, 214; 243-244).
2.1.2 Atomic force microscopy
Atomic force microscope (AFM) imaging, a well-established technique for obtaining information on the surface properties of a sample, was used to determine the collagen preservation in histological skin samples of the mummy.
2-4-µm-thick transverse sections of Zweeloo Woman’s skin were processed as described in section 2.2.1, applied to glass slides, dewaxed and rehydrated in a descending alcohol series. The samples were then analysed using an atomic force microscope (NanoWizard®II, JPK Instruments, Berlin, Germany) operating in intermittent contact mode. Measurements were performed in ambient conditions. Silicon cantilever (BS Tap 300, Budget Sensors, Redding, USA) with typical spring constants of 40 N/m and nominal resonance frequencies of 300 kHz were used. The tip radius was smaller than 10 nm. Image analysis was carried out using SPIP (SPIP 22.214.171.124, Image Metrology, Denmark).
2.1.3 CT scanning
A single radiographic evaluation of the entire skeleton was performed in 16 layers using a CT scanner (CT Gemini TF, Philips, NL). The scanning parameters were: 120 KV; 98 mAs; slice thicknesses 0.8 and 1 mm; reconstruction interval 0.75 mm, rotation time 0.5 sec; filter D, image matrix 512x512. The total number of axial slices was 1378. Post-processing, including axial scans evaluation and multiplanar reconstructions, was performed using a Workstation EBW Brilliance (Philips, NL).