Touch needles

Probe-nadel, /. touch needle, -nabme, /. sampling sample, -nebmen, n. sampling, -nebmer, m. sampler. 

Georgius Agricola used the touchstone and touch needles for examining bullion, coins, and jewelry, but did not test with acid the... 

The Probierbuchlein contains elaborate directions for making sets of standard touch needles for comparison with alloys to be tested by their streak on the touchstone. These sets are composed of alloys of silver and gold, silver and copper, gold and copper, and gold, silver and copper. Each set numbers, usually, from twenty to thirty needles. Agricola s De Re Metallica incorporates these in his more systematic account. 

Touch needles and touchstones, from Lazarus Ercker, Beschreibung... 

Touch needle A small bar of gold, either pure, or alloyed with silver in a known proportion, for trying the fineness of a gold or sliver article by comparing the streaks made by the article and the bar on a touchstone. Touch paper 2059 Paper impregnated with potassium nitrate. It bums steadily without flame and is used for Igrrltlng fireworks. Saltpeter paper. Touchstone 3190 A stone or piece of black pottery used for assaying. 

Quickly transfer the slide (without removing the coverslip) into a rack and submerge it in Wash buffer 1 (2 X SSC and 0.05% SDS). Similarly, transfer each of the other slides into the soaked rack. Use needle to gently assist with the falling of the coverslips from the hybridization areas of the slides. Be careful not to touch any of the printed area. Shake the slides for 5 min at room temperature. 

Bring the syringe to the level of the injection port, straight on. No angles. Then let the needle touch the septum at the center. 

It is interesting to watch the crystallization of a drop of a slightly supersaturated, warm soln. of potassium nitrate on a glass slip under the microscope. Crystallization starts at the edges. Here, rhombohedral crystalline 17 plates (left, Fig. 78) are first formed with axial ratios a i c=O5910 1 0 7011 these are quickly followed by needle-like rhombic crystals. As a matter of fact, both forms of crystals appear in the photograph (left, Fig. 78). Immediately the rhombohedral crystals touch the rhombic crystals, the former lose their sharp outlines, and needle-like rhombic crystals sprout forth on all sides. Hence, as M. L. Frankenheim 18 showed in 1837, potassium nitrate is dimorphous. The rhombic crystals are unstable above, and stable below, 129° and, conversely, the rhombohedral crystals are stable above, and unstable below, 129°. Hence, 129° is a transition temp. ... 

The second type of sample is composed of single crystals [19]. The crystals are plate-like (flakes) and have sub-millimeter size. They were glued by silver epoxy to the sample holder by one of their side faces. The opposite face of the flakes was used as a needle to gently touch the noble metal counter electrode in liquid helium. In this way we tried to make, preferentially, a contact along the ab plane. On average in... 

The versatility of immunophenotypic analysis has enhanced its usefulness. Immunophenotyping can be performed on a variety of specimens including cryop-reserved tissue sections, routinely preserved tissue sections, cells in suspension, tissue-touch preparations ( touch preps ), fine-needle aspiration smears, cytology thin preps and smears, as well as bone marrow aspirate smears. With the evolution of medical science and technical ability the number and types of antigens that can be detected in each type of preparation have greatly increased. Furthermore, as an additional result of these technical and scientific advances, immunophenotyping, particularly of routinely fixed tissue sections, can be performed reliably in many laboratories. 

Transfer the peptide solution with GELoader Tips (Eppendorf AG, Hamburg, Germany) into the nanospray needle and centrifuge it down to the tip of the needle. Be careful not to touch the metal coating and the tip (see Note 3). 

The surface of the nanospray capillary tips is coated with a thin metal film to apply the voltage. Do not scratch this coating or touch it, as this may reduce the spray performance. Be careful not to break the thin tip of the needle when mounting it in the tip holder. 

When acupuncture needles are inserted into the skin, the patient feels a slight sensation of touch, but no pain (if there is pain, the needle is likely in the wrong place). Once inserted, the acupuncturist can manipulate the needles by rotating or vibrating them to achieve the desired effect, or may simply leave the needles in the skin for a set period of time. Most often, when acupuncture is used for the relief of pain, small wires are connected to the needles to deliver small electrical impulses (usually only a few microamps and at a frequency of 5-2000 Hertz (impulses per second). Higher frequencies are used for major surgical procedures, whereas lower frequencies are used for general pain relief. 

Put a steel needle which just touches the Hg drop. 

We will discuss the operating principle of atomic force microscopy (AFM) and other scanning force microscopies in more detail in Chapter 7. At this point, simply think of this technique as analogous to an antiquated record player, in which the needle gently touches the surface of the record to produce music. Similarly, the AFM tip either gently taps, or hovers immediately above, the surface of a planar substrate. 

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