Keyhole

Aluminum, the most common material used for contacts, is easy to use, has low resistivity, and reduces surface Si02 to form interfacial metal-oxide bonds that promote adhesion to the substrate. However, as designs reach submicrometer dimensions, aluminum, Al, has been found to be a poor choice for metallization of contacts and via holes. Al has relatively poor step coverage, which is nonuniform layer thickness when deposited over right-angled geometric features. This leads to keyhole void formation when spaces between features are smaller than 0.7 p.m. New collimated sputtering techniques can extend the lower limit of Al use to 0.5-p.m appHcations. 

Prior to an anticipated air release of a hazardous material, a circular evacuation strategy may be appropriate. Evacuation might also be initiated for a keyhole-shaped area baised on prevailing wind conditions. These strategies are illustrated below. When a large number of people aie involved, the evacuation should be staged, that is, arc ls closest to the site should be evacuated first and the evacuation zone gradually expanded. 

Fixed riser with retaining plate and keyhole slot in cap. 

FIGURE 27.20 (a) Top and edge views of quartz crystal with keyhole-shaped vapor-... 

Ki Antagonist binding affinity Ki67 Nuclear membrane antigen KLH Keyhole limpet haemocyanin K , Michaelis constant KOS KOS strain of herpes simplex... 

Dissolve the protein to be modified at a concentration of 1-10 mg/ml in 0.1 M sodium phosphate, pH 7.4. NaCl may be added to this buffer if desired. For the modification of keyhole limpet hemocyanin (KLH Thermo Fisher) as described by Staros et al., 1986, include 0.9 M NaCl to maintain the solubility of this high-molecular-weight protein. If lower or higher concentrations of the protein are used, adjust the amounts of the other reactants as necessary to maintain the correct molar ratios. 

The most common carrier proteins in use today are keyhole limpet hemocyanin (KLH MW 4.5 X 105 to 1.3 X 107), BSA (MW 67,000), aminoethylated (or cationized) BSA (cBSA), thyroglobulin (MW 660,000), ovalbumin (OVA MW 43,000), and various toxoid proteins, including tetanus toxoid and diphtheria toxoid. Other proteins occasionally used include myoglobin, rabbit serum albumin, immunoglobulin molecules (particularly IgG) from bovine or mouse sera, tuberculin purified protein derivative, and synthetic polypeptides such as poly-L-lysine and poly-L-glutamic acid. 

In rodents, sheep red blood cells (SRBC) are routinely used for immunization. The antibody response is determined using the plaque forming cells assay (PFC) or by plasma SRBC-specific antibody titer [21, 22], As an alternative to SRBC, other T-cell-dependent antigen may be used, including keyhole limpet hemocyanin (KLH), tetanus toxoid (TT), or pneumococcal antigen. 

Niewola et al. [183, 185] have described a rapid, convenient and accurate method, based upon an enzyme-based immunosorbent assay (ELISA) for the determination of Paraquat residues in soil. Polystyrene plates, coated with paraquat-keyhole limpet haemocyanin (KLH) conjugate, are incubated with the test samples and a known amount of monoclonal antibody. Residual antibody that has not reacted with free Paraquat in the sample combines with paraquat-KLH on the plate. The determination of the fixed antibody is achieved by the addition of peroxidase labelled rabbit antimouse immunoglobulin G followed by reaction with a chromogenic substrate. The enzyme activity of the solid phase is determined from the absorbance measurements, which are inversely proportional to the concentration of Paraquat. The method shows high specificity and correlates well with the traditional ion exchange-spectrophotometric method for the determination of Paraquat [178]. 

In this method the keyhole limpet haemoglobin conjugate was prepared as follows Keyhole limpet haemocyanin (KLH, Calbiochem, La Jolia, CA) and bovine serum albumin (BSA, BDH Chemicals) were coupled to the adduct (2), derived from 6-bromohexanoic acid and monoquat (3), via a carbodiimide reaction, as reported previously by Niewola et al. [184], The resulting conjugates contained 662mol of Paraquat per mole of KLH and 15mol of Paraquat per mole of 6-bromohexanoic acid. The amount of Paraquat bound to the protein was determined by spectrophotometric dithionite assay for Paraquat and the protein concentration was established by a standard Lowry test. 

KLH Keyhole limpet haemocyanin, used for its excellent antigenic properties. It is used as a carrier protein in order to bestow immunogenicity in small haptens. 

Serum antibody responses of B lymphocytes can be assessed either by vaccination with a potent primary antigen such as keyhole limpet hemocyanin (KLH), or by boosting with a recall antigen such as tetanus toxoid. This results in either a primary or secondary antibody response in normal individuals, which is often reduced or absent in AIDS patients. 

Since small haptens are not immunogenic -i.e. do not usually stimulate the formation of antibodies-, they must be coupled to a carrier protein. For instance, Schultz [22b] described the coupling of the hapten to the carrier proteins bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH), in order to generate antibodies for his specific studies. 

I went to the door and opened it slowly in case he had his ear to the keyhole and needed to skedaddle, but he was leaning against the wall on the far side of the corridor, arms folded and eyes hot with anger. I winked and stepped aside. 

Lymphocytes Streptokinase Phytohemoagglutin Tuberculin (PPD) Keyhole limpet Hemocyanine Human y-globulin Tuberculin... 

For keyhole limpet hemocyanine (KLH) both antibody responses and delayed type hypersensitivity (DTH) reactions can be determined [43—45]. In addition several infectious models, including bacterial, viral and parasitic infections may be used to challenge the immune system [18,46]. As survival and eradication of the infections is the primary function of the immune system, these models provide direct information on the functional status of the immune system. Direct immunotoxic compounds will induce immunosuppression and thus an increase in infection rate and/or severity of the infection. The number of infectious agents (bacteria, parasites, or viral colonyforming units), increased morbidity and mortality are indications for an immunotoxic effect. Also a reduction in specific antibody levels in animals treated with the test compound compared to nontreated controls indicates immunosuppression. 

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