Model of automobile emission checking by wireless technology.

Air contains a lot of pollutants and most of these pollutants are toxic. Carbon monoxide (CO) is one of the five primary pollutants, which together contributes more than 90% of global atmospheric pollution. Therefore, CO has been chosen for this analytical study. The main source of CO is the exhaust from automobiles only. In the present situation, the usage of motor vehicles rapidly expanded. The number of vehicles cannot be reduced but their emission (which is a cause for pollution) can be effectively controlled. In this direction, a model has been developed in this study to sense the level of carbon monoxide emitted from the automobiles. When the exhaust reaches a harmful level it sends the data about the vehicle number and the concentration of CO to the emission-testing centre (PC). As a result the government can take necessary action to seize the particular vehicle emitting more carbon monoxide than the permitted level.

In vitro cytotoxicities of ionic liquids: effect of cation rings, functional groups, and anions.

In vitro cytotoxicities were measured for ionic liquids (ILs) containing various cations and anions using the MCF7 human breast cancer cell line. We measured the cytotoxicities of ionic liquids containing the cations pyridinium, pyrrolidinium, piperidinium, or imidazolium with various alkyl chain lengths, and the anions bromide, bis(trifluoromethanesulfone)imide (Tf(2)N), trifluoromethylsulfonate (TfO), or nonafluoromethylsulfonate (NfO). Three new hydrophobic, task-specific ionic liquids (TSILs), namely, [MBCNPip](+)[Tf(2)N](-), [MPS(2)Pip](+)[Tf(2)N](-), and [MPS(2)Pyrro](+)[Tf(2)N](-) designed for metal-ion extraction were also evaluated. IC(50) values of the ionic liquids toward the MCF7 cells ranged from 8 microM to 44 mM. The toxicity depended significantly on the nature of the cations and anions, especially when the cations contained a long side chain. TSILs studied in this work were less toxic than the classical ILs.

Three-dimensional cellular microarray for high-throughput toxicology assays.

We have developed a miniaturized 3D cell-culture array (the Data Analysis Toxicology Assay Chip or DataChip) for high-throughput toxicity screening of drug candidates and their cytochrome P450-generated metabolites. The DataChip consists of human cells encapsulated in collagen or alginate gels (as small as 20 nl) arrayed on a functionalized glass slide for spatially addressable screening against multiple compounds. A single DataChip containing 1,080 individual cell cultures, used in conjunction with the complementary human P450-containing microarray (the Metabolizing Enzyme Toxicology Assay Chip or MetaChip), simultaneously provided IC(50) values for nine compounds and their metabolites from CYP1A2, CYP2D6, and CYP3A4 and a mixture of the three P450s designed to emulate the human liver. Similar responses were obtained with the DataChip and conventional 96-well plate assays, demonstrating that the near 2,000-fold miniaturization does not influence the cytotoxicity response. The DataChip may therefore enable toxicity analyses of drug candidates and their metabolites at throughputs compatible with the availability of compounds at early-stage drug discovery.

Enhanced platelet adhesion and aggregation by endothelial cell-derived unusually large multimers of von Willebrand factor.

Endothelial cells synthesize and secrete von Willebrand factor (VWF) multimers, including unusually large forms (ULVWF), which are usually cleaved into smaller multimers found in normal plasma (P-VWF). Thrombotic thrombocytopenic purpura (TTP) is a microangiopathic disorder characterized by systemic attachment of platelets to inadequately cleaved ULVWF multimers. We have compared ULVWF and P-VWF in their capacity to become immobilized onto surfaces in vitro and their ability to mediate platelet adhesion. We have also used functional assays to directly compare ULVWF forms with purified P-VWF in mediating platelet aggregation in solution. At comparable concentrations, ULVWF is more effectively adsorbed onto glass surfaces than P-VWF and supports increased platelet adhesion. ULVWF is also significantly more potent than P-VWF in mediating both shear-induced platelet aggregation and ristocetin-mediated platelet agglutination.

High-throughput screening of biocatalytic activity: applications in drug discovery.

Enzymes catalyze a diverse set of reactions that propel life's processes and hence serve as valuable therapeutic targets. High-throughput screening methods have become essential for sifting through large chemical libraries in search of drug candidates, and several sensitive and reliable analytical techniques have been specifically adapted to high-throughput measurements of biocatalytic activity. High-throughput biocatalytic assay platforms thus enable rapid screening against enzymatic targets, and have vast potential to impact various stages of the drug discovery process, including lead identification and optimization, and ADME/Tox assessment. These advances are paving the way for the adoption of high-throughput biocatalytic assays as an indispensable tool for the pharmaceutical industry.

Kinetics of GPIbalpha-vWF-A1 tether bond under flow: effect of GPIbalpha mutations on the association and dissociation rates.

The interaction between platelet glycoprotein (GP) Ib-IX-V complex and von Willebrand factor (vWF) is the first step of the hemostatic response to vessel injury. In platelet-type von Willebrand disease, two mutations, G233V and M239V, have been described within the Cys209-Cys248 disulfide loop of GPIbalpha that compromise hemostasis by increasing the affinity for vWF. We have earlier shown that converting other residues in this region to valine alters the affinity of GPIbalpha for vWF, with mutations K237V and Q232V, respectively, showing the greatest increase and decrease in affinity. Here, we investigated further the effect of these two mutations on the kinetics of the GPIbalpha interaction with the vWF-A1 domain under dynamic flow conditions. We measured the cellular on- and off-rate constants of Chinese hamster ovary cells expressing GPIb-IX complexes containing wild-type or mutant GPIbalpha interacting with vWF-A1-coated surfaces at different shear stresses. We found that the gain-of-function mutant, K237V, rolled very slowly and continuously on vWF-A1 surface while the loss-of-function mutant, Q232V, showed fast, saltatory movement compared to the wild-type (WT). The off-rate constants, calculated based on the analysis of lifetimes of transient tethers formed on surfaces coated with limiting densities of vWF-A1, revealed that the Q232V and K237V dissociated 1.25-fold faster and 2.2-fold slower than the WT. The cellular on-rate constant of WT, measured in terms of tethering frequency, was threefold more and threefold less than Q232V and K237V, respectively. Thus, the gain- and loss-of-function mutations in GPIbalpha affect both the association and dissociation kinetics of the GPIbalpha-vWF-A1 bond. These findings are in contrast to the functionally similar selectin bonds where some of the mutations have been reported to affect only the dissociation rate.