## 3 Results  
Thin sections of the sculpture's wood were analyzed with a Leitz Laborlux Pol 12 petrographic microscope (Figure 2), and images were acquired using a Leica MD170 HD camera and Leica Application Suite v4.3 software polarizing filters (used in parallel mode). Specifically, vessels were gathered in radial chains, often placed side by side, with decreasing dimensions according to the growth period of the tree. The perforation plates showed a simple organization. Multi-seriate rays, composed of fewer than 10 uniform cells with different heights, were observed. These characteristics, in agreement with [PERSON]'s suggestion, allowed us to consider _Ceiba_ sp. as the original plant, _Angiosperm_ (hardwood). On the artwork's surface was a clearly distinguishable whitish biological patina (Figure 3). Microscopy observations, in vitro cultures, and molecular investigations allowed us to identify the bacterial (_Bacillus_ sp., _Streptococcus_ sp.) and fungal (_Penicillium_ sp., _Aspergillus_ sp.) colonies. In our previous studies, the _Thymus vulgaris_ EO was successful when applied as an antimicrobial agent to control microbial colonization, acting on bacterial and fungal colonies, as well as on complex biofilm [40; 41; 42; 43]. Several studies showed that compounds of natural origin, such as plant extracts, display antimicrobial and antioxidant activity that differ in relation to several factors: organic/inorganic artefacts; indoor/outdoor environments; bacterial or fungal colonizer; biological activity of the EO and HA solutions and mechanisms of action [51]. The antimicrobial actions of essential oil and hydro-alcoholic solutions have been preliminarily evaluated in vitro, using ADD and WPD methods, against both bacterial- and fungal-isolated colonies. Shown in Figure 4 is the antimicrobial activity of the 12.5% _T. vulgaris_ EO (Figure 4a), the control solution 3% \(v/v\) benzalkonium chloride (Figure 4b), and the 70% \(v/v\) Et-OH (Figure 4c) assayed vs. _Streptomyces_ sp. colonies with the ADD method. Different inhibition halo (i.h.) diameters were distinguishable: (**a**) i.h. \(>\) 9 mm; (**b**) i.h. \(>\) 6 mm; (**c**) i.h. = almost not observable. For the _T. vulgaris_ hydro-alcoholic solution, the antimicrobial activity was evaluated by the WPD method: the 100% HA solution produced an i.h. \(>\) 9 mm (Figure 4d); i.h. \(<\) 4 mm was obtained with the 70% Et-OH solution (Figure 4e). In the ADD and WPD assays, 3% \(v/v\) benzalkonium chloride and 70% \(v/v\) Et-OH solutions represent control solutions; the benzalkonium chloride (phase) solution was diluted in water to achieved a final concentration equal to 3% (vol/vol). Assays were performed in duplicate. Results of the ADD and WPD assays performed in this study, as shown vs. the Streptomyces. colonies in Figure 4, are summarized in Table 1. Although the EO showed increased antimicrobial activity, the HA solution was able to produce inhibition halos ofat least 9 mm. A reduced diameter is shown for the benzalkonium-Cl and Et-OH control solutions, producing halos less than 6 mm in diameter. The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) were assessed with the microdilution method, performed in a 96-well microtiter. The minimum inhibitory concentration (MIC) corresponds to the lowest concentration of the sample at which the tested microorganisms did not demonstrate any visible growth. The minimum bactericidal/fungicidal (MBC/MFC) concentrations were determined as the lowest concentration of the antimicrobial able to kill the 99.5% of the original inoculum in the sub-culture (antimicrobial-free media) [39]. In 96-well microtiters, 30 microliter aliquots of 12.5%, 25%, 50%, and 100% EO solutions were mixed with an equal volume of a microbial culture and a liquid nutritive medium, measuring the absorbance at 500-600 nm, after 18-36 h of incubation at 30 + 1 \({}^{\circ}\)C. As the control, the commercial biocide benzalkonium chloride (3%, \(v/v\)) was utilized. The _T.