Micro pipette

The ratio (p/G) has the units of time and is known as the elastic time constant, te, of the material. Little information exists in the published literature on the rheomechanical parameters, p, and G for biomaterials. An exception is red blood cells for which the shear modulus of elasticity and viscosity have been measured by using micro-pipette techniques 166,68,70,72]. The shear modulus of elasticity data is usually given in units of N m and is sometimes compared with the interfacial tension of liquids. However, these properties are not the same. Interfacial tension originates from an imbalance of surface forces whereas the shear modulus of elasticity is an interaction force closely related to the slope of the force-distance plot (Fig. 3). Typical reported values of the shear modulus of elasticity and viscosity of red blood cells are 6 x 10 N m and 10 Pa s respectively 1701. Red blood cells typically have a mean length scale of the order of 7 pm, thus G is of the order of 10 N m and the elastic time constant (p/G) is of the order of 10 s. 

In summary, as far as measuring the initial specimen, it is recommended that the ordinary micro pipettes be aspirated by automatic means. It is also recommended that where large numbers of tests are to be performed on a single sample that... 

Materials required Sample solution in methanol, distilled water, 20% Na2C03, Folin-Ciocalteu s phenol reagent, water bath, graduated tube, cuvette, micro pipette (0.1 ml), pipette of 1,2 and 10 ml, test tubes of 20 ml, pure ferulic acid (Serva, Germany), Shimadzu UV 160 spectrophotometer. 

The whole atomizer may be water cooled to improve precision and increase the speed of analysis. The tube is positioned in place of the burner in an atomic absorption spectrometer, so that the light passes through it. Liquid samples (5-100 mm ) are placed in the furnace, via the injection hole in the centre, often using an autosampler but occasionally using a micro-pipette with a disposable, dart-like tip. Solid samples may also be introduced in some designs, this may be achieved using special graphite boats. The sample introduction step is usually the main source of imprecision and may also be a source of contamination. The precision is improved if an autosampler is used. These samplers have been of two types automatic injectors and a type in which the sample was nebulized into the furnace prior to atomization. This latter type was far less common. 

D 0.1 mL with the 100-lambda glass micro-pipette designated TC... 

A variable was considered as having an effect when the difference in recoveries between high and low conditions was greater than two times their standard deviation. The higher than 100 percent recovery average obtained for most elements (Tables XII and XIII) was attributed to a micro-pipette with wrong calibration. However, no attempt was made to verify this assumption because it did not affect the conclusions drawn from the data, which were the following ... 

The solvent should be put into the tank about an hour before the thin layer sheet is introduced. The plates are then run either for a fixed time (when the final position of the solvent front must be marked), or up to a fixed distance (12-35 cm), pre-marked with a pencil. The sample (2-5 pi) is taken with a micro syringe (e.g. Hamilton type) or micro pipette (Shandon) and dropped to a point on the lower end of the thin layer. The position of the point must be chosen in such a way that it will not be covered by the liquid solvent when the thin layer plate is placed in it. The location of the starting point should be clearly indicated by a pencil mark. If a wider thin layer plate is used, more chromatograms can be run simultaneously. In this case the individual samples should be placed at least 1 5 cm apart along the starting line. 

Pipetman Ultra Micro Pipette (French manufactured)... 

Elkay "Socorex" Micro Pipette (Swiss manufactured) Elkay Products, Inc. 95 Grand Street Worcester. MA 01610 15 H... 

Pipetman Ultra Micro Pipette (French manufactured) Analtech, Inc. 75 Blue Hen Drive Newark, DE 19711 12 1... 

Q=k/t+Q where is a constant. Generally, an empirical calibration curve is used. A tall jacketed cylinder with two fine marks, a micro-pipette delivering drops of-uniform size, and a stop-watch, are required. 

A variant is the micro-pipette method, which is also similar to the maximum bubble pressure technique. A drop of the liquid to be studied is drawn by suction into the tip of a micropipette. The inner diameter of the pipette must be smaller than the radius of the drop the minimum suction pressure needed to force the droplet into the capillary can be related to the surface tension of the liquid, using the Young-Laplace equation [1.1.212). This technique can also be used to obtain interfacial tensions, say of individual emulsion droplets. Experimental problems include accounting for the extent of wetting of the inner lumen of the capillary, rate problems because of the time-dependence of surfactant (if any) adsorption on the capillary and, for narrow capillaries accounting for the work needed to bend the interface. Indeed, this method has also been used to measure bending moduli (sec. 1.15). 

Since the Seralyzer system partly requires the use of diluted serum or plasma, a pipette system or a dilutor unit must be kept ready (Fig. 43). The entire system consists of one each 30 pi and 100 pi air displacement micro-pipette, a... 

Larval bioassays to determine pyrethroid resistance status in the test insects were similar to those recommended by the Entomological Society of America (Anon.. 1970) Technical grade insecticide was dissolved in acetone and five serially diluted concentrations prepared- For each concentration, ien 3rd instar larvae (30-40 mg) were treated with l pL of solution applied by mieroappliea-tor or micro pipette to the dorsal thorax. Each test was replicated three times and every replicate included are tone-treated controls which confirmed no control mortality. Synergists PBO and profenofos were applied 30 minutes before the fen valerate at 10, and 0.1 pg per larva, respectively (Gunning er a/., 1991). After dosage, the larvae were held individually at 25 1DC with adequate food. Mortality was assessed 4ft hours after treatment. Larvae were considered dead if unable to move in a coordinated way when prodded with a blunt probe. The data were analysed by probil, and resistance factors calculated as the ratio of resistant LDW to susceptible LD. ... 

Coat ELISA plate wells overnight at 4°C with 100 pL of the appropriate dilution ofrlgG in CB (see Note 2). Lise adjustable (micro)pipette(s) to prepare antibody dilutions and to coat microwells. 

For the data reported in Table 4, samples of oil in 125 ml bottles were warmed, shaken, and then aliquots were removed using a syringe (LAB 2) or micro-pipette (LABs 1, 3). The temperature at which the aliquot was removed varied between hot (40°C, LAB 1) to an intermediate temperature between 40°C and ambient (warm, LABs 2 and 3). It was thought that procedures used to remove hot aliquots may have provided opportunities for loss of volatile mercury or may have allowed reactions to take place possibly with oxygen in air when bottles were opened for aliquot removal. 

Fig. 2. Filamentous actin structures in cells stimulated by attractant. Cells of D. discoideum migrate toward a micro-pipette filled with cAWlP (first bright-fleld Imag and accumulate there within 8 min (last image). Actin structures are labeled with LimEA-GFP and viewed throughout the entire cell bodies by maximum projection 1, filopodia 2 and 3, macropinocytic cups showing membrane internalization at the front and other sites of the cell surface 4 and 5, actin waves propagating on the substrate-attached cell surface. Time is indicated in seconds, tip position of the pipette by circles. Bar, f 0 p,m. In cooperation with Ulrike Engel at the Nikon Imaging Center, University of Fleidelberg.

Microinjection of living Drosophila embryos is essential in embryonic research and requires precise control of injection location and force [Shen et al. (2007)]. Current practice in microinjection typically involves manual operation by human, which is time-consuming with low yield. It is thus of interest to automate the microinjection process, and the IPMC-PVDF sensori-actuator structure can potentially be used to realize automated microinjection. Here we demonstrate the monitoring of IPMC-actuated microneedle with the integrated PVDF feedback, in penetrating living Drosophila embryos. A micro pipette with a sharp tip (1.685 pm in diameter and 2.65° in angle) was mounted at the free end of the IPMC-PVDF structure, as illustrated in Fig. 8.12. 

Emanuel, C. F. (1973). Delivery precision of micro-pipettes. Anal. Chem. 45 1568-1569. Halpaap, H., and Krebs, K.-F. (1977). Thin layer chromatographic and high performance thin layer chromatographic ready-for-use preparations with concentrating zones. J. Chromatogr. 142 823-853. 

A variety of apertures have been used to deliver nanometer-sized spots of light. While early NSOM tips were fabricated out of etched quartz crystals and micro-pipettes, tapered optical fibers with tip diameters of ca. 100 nm are now typically used. A metallic thin film such as aluminum is usually applied around the sides of the tapered region of the NSOM tip to focus the light toward the sample. For optical fibers, the numerical aperture is related to the difference in the indices of refraction of the cladding and core (Eq. 2) ... 

When was raised by the injection of a minute volume of 0.1 M KCl from a fourth micro-pipette, the integrated antidromic responses to varying intensities of cuneate stimulation were clearly increased (see lower traces. Fig. 10), presumably because the terminals were significantly depolarized. 

B. Integrated antidromic potentials recorded from peripheral forelimb nerve in response to cycles of automatically incremented constant current stimulation of fibre terminals via third micro-electrode attached to K electrode. KCl (0.1 M) injected from fourth micro-pipette 100 ym away during time marked by horizontal black bar. 

TABLE III. Data from intracellular measurements in frog heart muscle made with chloride microelectrodes and KCl filled micro-pipettes. Entries are mean values plus or minus the standard error of the mean. 

---