SN/T 5275-2019Technical specification for identification of ivory and its products (English PDF)

3.1 Ivory

The specialized upper incisors of the Mammal Proboscis.

3.2 Living ivory elephant tusk

Ivory derived from Asian elephants (Elephas maximus) and African elephants (Loxodonta africana and Loxodonta cyclotis), also Called elephant tusks.

3.3 Mammoth tusk

From the extinct elephant family Mammoth (Mammuthus primigenius) ivory.

3.4 Raw ivory

Any shape of ivory that has not been polished or engraved, including whole ivory and any form of ivory and ivory slices.

3.5 Worked ivory

Ivory that has been fully or partially processed (engraved, polished, shaped, etc.), including the entire ivory whose entire surface has been polished or engraved.

Among them, the ivory products made of living ivory are living ivory products, and those made of mammoth ivory are mammoth ivory products.

3.6 Ivory cavity

The cavity at the root of the ivory gradually becomes smaller along the extension direction of the ivory.

3.7 Schreger structure

The three-dimensional structure that exists in the dentin of ivory. In the cross section of ivory, it can be seen that radiating from the center to the outer edge, regularly arranged, and clockwise Net-like or sharp-angled texture formed by arcs or near-oblique lines extending in a counterclockwise direction; more regular arrangement and broken lines can be seen on the longitudinal section of ivory Continuing nearly linear texture, or undulating ripples, mountain-like texture.

3.8 Schreger lines

The ivory cross section constitutes the arc-shaped lines of the Shi's structure.

3.9 Schreger angles

The angle formed by the intersection of the Shi's lines extending outward in different directions. Among them, the opening facing the cementum layer is the convex Shi's angle, and the opening facing the angle to the pulp cavity is the concave Shih's angle, and the one near the cementum layer is the Shih's angle on the outer edge.

8.1 Morphological identification method

8.1.1 Visual observation

8.1.1.1 Observe items such as color and shape.

8.1.1.2 Observe the cross section, longitudinal section and some texture features (Shishi structure).

8.1.2 Microscopic observation

8.1.2.1 Clean the cross-section of the sample and place it under a magnifying glass or stereo microscope.

8.1.2.2 Observe the structural characteristics of the cross-section and longitudinal section of the sample with reflected light.

8.1.3 Baking and hot needle test

8.1.3.1 Take the sample to be inspected, roast it on the flame of an alcohol lamp, and smell its smell.

8.1.3.2 Take the steel needle and burn it on the flame of an alcohol lamp. After the needle tip is red, quickly pierce the sample to be tested, and then take it out while it is hot and observe Change the contact point of the hot needle on the sample and smell it.

8.1.4 Fluorescence inspection

8.1.4.1 Remove foreign objects attached to the sample that may affect the inspection result.

8.1.4.2 Under darkroom conditions, place the sample under UV light with a wavelength of 365 nm, and observe the fluorescence reaction of the sample.

8.1.5 Measurement of the outer edge of the Shi's angle

8.1.5.1 Smooth the sample manually or mechanically so that the Shi's structure of the cross-section is fully revealed.

8.1.5.2 Use imaging equipment to record the cross-sectional image of the sample.

8.1.5.3 Set the ring-shaped area (width approximately 1/10 of its radius) at the outermost edge of the sample cross-section as the identification area. All in this area any Shishi angle is regarded as the outer Shishi angle.

8.1.5.4 Use the drawing software to divide the cross-sectional image into 20 equal parts, and mark the intersection of the Shih line that coincides with the equal line in the identification area.

8.1.5.5 Randomly select 2 points on each bisecting line to determine the convex and concave Shih angles to ensure that the selection is different the type Shi's angles are evenly distributed in the identification area. If the bisecting line does not coincide with any intersection, select the 2 closest to the bisecting line Mark the intersection. The Shih angle determined by the marked intersections of each sample is the Shih angle of the outer edge of the identification object.

8.1.5.6 The ray is drawn inward or outward along the extension direction of the two Shi-shi lines through the marked point (the ray should be as far as possible from the arc.

Lines coincide), which form the two sides of the Shi's angle at the outer edge to be measured, using Image J software (http.//rsb.info.nih.gov/ij/download.html) or the angle measurement function of other software with the same function can measure the measurement value of each outer edge of the Shi's angle.

8.1.6 Judgment Index

8.1.6.1 Shape

The whole ivory is crescent-shaped or sickle-shaped, with thick one end (commonly known as root) and thinner end (commonly known as tooth tip). Mammoth ivory the curvature is large, mostly distorted. Due to the long buried underground, the surface or all of it is fossilized, and the color changes and mineral deposits appear on the surface.

Even the formation of irregular spots.

8.1.6.2 Color

Generally, the natural color of tooth white (white, milky white, porcelain white, light rose white), due to environmental influences, may be light yellow, ginger yellow, Dark yellow, light brown, dark brown, etc. The surface of some ivory has a grease luster or waxy luster.

8.1.6.3 Odor

Ivory and its products generally produce a burnt smell after baking.

8.1.6.4 Hot needle test

Ivory and its products cannot be penetrated by the hot needle, leaving only the needle tip marks, without sunken needle holes, no white smoke and strong odor.

8.1.6.5 Fluorescence

Under ultraviolet light with a wavelength of 365 nm, ivory and its products show blue-white or blue-violet fluorescence, and mammoth ivory sometimes has purple spots.

8.1.6.6 Cross section

The unique Shi's structure can be seen on the cross section of ivory and its products, and the center of the cross section (sometimes to one side) can be seen.

The cross section may have a ring-like structure similar to tree rings; compared to existing ivory, mammoth teeth generally have thicker skin (cementum Layer), refer to Appendix A.1.

8.1.6.7 Longitudinal section

The longitudinal section of ivory and its products can be seen relatively regularly arranged, intermittent, nearly linear texture, or undulating ripples and mountain-like textures.

8.1.6.8 Outer edge Shi's angle

The Shi's angle on the outer edge of live ivory is generally obtuse (average greater than 115°), and the Shi's angle on the outer edge of mammoth ivory is generally an acute angle (average).

Less than 90°), the outer edge of the Shi's angle has species identification significance, but in the interval of 90°~115°, the outer edge of the ivory and mammoth ivory exists.

In the overlap zone. Refer to Appendix A.2 for the Shi's angle on the outer edge of living ivory and mammoth ivory.

8.2 Molecular biology detection methods

8.2.1 Sample processing and DNA extraction

8.2.1.1 Sample preparation

Use 10% sodium hypochlorite or deionized water to scrub the surface of the sample, rinse with absolute ethanol and dry at room temperature, and finally irradiate the sample with a UV lamp Surface for 30 minutes.

8.2.1.2 Sample preparation

Use mechanical equipment (electric drill or electric saw) or manual method to apply to the outermost cementum part of the ivory root (the end of the ivory connected to the skull) Obtain sample fragments about.200 mg to 500 mg. If this part does not exist or cannot be determined, it is necessary to take samples from multiple points at the bottom of the sample. quality Smaller samples can be sampled according to actual conditions.

8.2.1.3 Decalcification of samples

Take about.200 mg of sample debris in a centrifuge tube. Take 2 tubes for the same sample. Add 1 mL of 0.5 mol/L EDTA solution (pH 8.0) to each tube.

Incubate overnight at 37°C (48 hours at room temperature can also be incubated, and samples with severe calcification can be extended to 72 hours), centrifuge at 12,000 g for 2 minutes, and retain 1/4 to 1/3 the decalcification solution and the precipitation are used for DNA extraction.

8.2.1.4 DNA extraction

CTAB method (refer to Appendix B for reagent configuration) extract sample DNA and set extraction control. Add 1 mL to the sample after decalcification in 8.2.1.3 CTAB extraction buffer, 20 µL proteinase K and 10 µL RNase A, lysed in a warm bath at 65°C for 2h~3h (if the sample is difficult to lyse, it can be suitable when prolonging the lysis time or even overnight), during the warm bath lysis, the sample can be taken out and shaken to accelerate the lysis. Centrifuge at 12 000 g for 15 min, supernatant Transfer to a new centrifuge tube. Add an equal volume of chloroform, mix well, centrifuge at 12,000 g for 15 minutes, and transfer the supernatant to a new centrifuge tube.

Add 0.6 volume of isopropanol and 0.1 volume of potassium acetate solution, mix gently by inverting, and place at room temperature for 20 minutes. Centrifuge at 12 000 g for 15 min, Discard the supernatant, add 500 µL of 70% ethanol solution, and mix by inversion several times. Centrifuge at 12 000 g for 10 min, discard the supernatant, and add 50-100 µL Dissolve DNA in TE buffer. The extracted DNA can be directly used for PCR amplification or stored at -20°C for later use, and it needs to be stored at -70°C for a long time.

An equivalent DNA extraction kit can also be used to extract the sample DNA and operate according to the kit instructions.

8.2.2 Nest's PCR detection method

8.2.2.1 Nested PCR amplification primers