Abstract-This paper reports on cell and microparticle manipulation using optically induced dielectrophoresis. Our novel optoelectronic tweezers (OET) device enables optically controlled trapping, transportation, and sorting via dielectrophoretic forces. By integrating a spatial light modulator and using direct imaging, arbitrary dynamic manipulation patterns are obtained. Here, we demonstrate manipulation functions, including particle collectors, single-particle traps, individually addressable single-particle arrays, light-defined particle channels, and size-based particle sorting. OET-induced particle manipulation velocities are analyzed as a function of the applied voltage, optical pattern linewidth, and single-particle trap dimensions.[ 2006-0210]Index Terms-Dielectrophoresis (DEP), optical tweezers, optically induced DEP, optoelectronic tweezers (OET).

Since the 1960s, combination chemotherapy has been widely utilized as a standard method to treat cancer. However, because of the potentially enormous number of drug candidates and combinations, conventional identification methods of the effective drug combinations are usually associated with significantly high operational costs, low throughput screening, laborious and time-consuming procedures, and ethical concerns. In this paper, we present a low-cost, high-efficiency microfluidic print-to-screen (P2S) platform, which integrates combinatorial screening with biomolecular printing for high-throughput screening of anticancer drug combinations. This P2S platform provides several distinct advantages and features, including automatic combinatorial printing, high-throughput parallel drug screening, modular disposable cartridge, and biocompatibility, which can potentially speed up the entire discovery cycle of potent drug combinations. Microfluidic impact printing utilizing plug-and-play microfluidic cartridges is experimentally characterized with controllable droplet volume and accurate positioning. Furthermore, the combinatorial print-to-screen assay is demonstrated in a proof-of-concept biological experiment which can identify the positive hits among the entire drug combination library in a parallel and rapid manner. Overall, this microfluidic print-to-screen platform offers a simple, low-cost, high-efficiency solution for high-throughput large-scale combinatorial screening and can be applicable for various emerging applications in drug cocktail discovery.

b-Thalassemia is a serious health problem in the United States, especially in California, due to increased Asian immigration. Neonatal screening by using high-performance liquid chromatography (HPLC) or isoelectric focusing (IEF) may lead to confusion due to interactions of various hemoglobinopathies with b-thalassemia. Our purpose was to develop single-tube multiplexed PCR assays using original neonatal screening specimens to identify the mutations responsible for b-thalassemia in order to expedite diagnostic confirmation. Primers were designed for two to six common ethnic-specific mutations using the amplification refractory mutation system (ARMS). This multiplex ARMS approach was standardized using DNA samples with known mutations for b-thalassemia in those of Asian (Southeast Asian, Chinese, and Asian Indian) and African-American descent. Specimens from African-American neonates were tested for two mutations (À88 and À29); Asian Indians for five mutations (IVSI-1, IVSI-5, codons (Cd) 41/42, Cd 8/9, and 619-bp deletion); Chinese, Taiwanese, and Southeast Asians for seven mutations (Cd 41/42, Cd 17, À28, IVSII-654, Cd 71/72, IVSI-5, and IVSI-1). We identified each of these b-thalassemia mutations in multiplexed ARMS from positive control samples. We tested 25 anonymized dried blood specimens from neonates who had been diagnosed with b-thalassemia and who also belonged to these ethnic groups. We detected a mutation specific to the neonate's ethnic group using the ARMS approach in nearly all specimens, and the results were confirmed by sequencing. Multiplexed ARMS for ethnic-specific b-thalassemia mutations from the original newborn screening dried blood specimens is a rapid and efficient approach for diagnostic confirmation. Am.

In the present study, Dill (Anethum graveolens) seed essential oil, its nonpolar and polar fractions, compounds isolated and derivatized were evaluated for their antioxidant potential using different in vitro assays. The major compounds carvone, limonene, and camphor were isolated from dill seed essential oil using column chromatography and characterized using spectroscopic techniques. Among all the tested components for antioxidant activity, carveol and perillyl alcohol were most effective (IC50 values < 0.16 mg/ml), whereas camphor was least effective (IC50 values > 10 mg/ml). All the tested compounds exhibited lower antioxidant potential than the standard. Practical applications Oxidation of food products was delayed by compounds known as antioxidants. The use of synthetic antioxidant is restricted because of carcinogenicity in human servings and plant‐based natural antioxidant are preferred due to safety and less toxicity. The aim of this in vitro study was to assess the antioxidant activity of the different constituents of dill seed essential oil. The present study revealed that carvone and its derivatives are potent scavengers of free radicals which might be due to the presence of unsaturated hydroxyl group. Thus, natural antioxidants are the important source of alternative medicines and natural therapy in the pharmaceutical industry.

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The ability to generate strong magnetic field gradients is a prerequisite for efficient magnetic-based cell/bio-particle separation or concentration. Creating these gradients is difficult under microscale fluidic devices. Conventional MEMS magnetic-based microfluidic devices involve the use of non-trivial and expensive multi-layer fabrication processes in order to produce magnetic field generators/concentrators (e.g. metal coil/ferromagnetic structures) around the microfluidic channels. A microfluidic device with simplified fabrication procedures while achieving the same functional purposes of magnetic separation/concentration of particles is highly desirable. Here, we propose a simple single-layer, single-mask fabrication technique for magnetic MEMS fluidic device construction, where nickel microparticles can be monolithographically integrated into any configurations. We constructed the microfluidic device through conventional PDMS replicate molding, with injection of nickel microparticles into a side channel 25 µm apart from the main separation channel. The nickel microparticles are responsible for bending and concentrating the external magnetic field for gradient generation. This magnetic field gradient induced magnetic forces on the particles present in the main channel. The force generated by the presence of the nickel particles is 3.31 times greater than that without the use of a magnetic field concentrator (i.e. nickel particles). The proposed methodology can be extended for the development of automated high-throughput microfluidic cell separation devices. The simplicity of fabrication and enhanced magnetic separation efficiency shows great promise for future microfluidic systems.

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Following single application of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) on wheat crop @ 300 and 600 g ha(-1), resulting in active application of trifloxystrobin @ 75.0 and 150.0 g a.i. ha(-1) and tebuconazole @ 150 and 300 g a.i. ha(-1), the average initial deposits of trifloxystrobin on wheat leaves were 5.54 and 8.30 mg kg(-1), and that of tebuconazole were 14.66 and 27.94 mg kg(-1), respectively. Half-life values for trifloxystrobin were observed to be 2.80 and 2.51 days whereas those for tebuconazole were found to be 2.46 and 1.85 days at recommended and double the recommended dosages, respectively. The residues of trifloxystrobin and tebuconazole dissipated to the extent of >89% at both the dosages after 7 days. Wheat grain samples at harvest having pre harvest interval of 140 days did not show the presence of trifloxystrobin and tebuconazole at their determination limit of 0.01 mg kg(-1).