Scalable stable comb-to-tone integrated RF photonic drive for superconducting qubits.

The recent advent of quantum computing has the potential to overhaul security, communications, and scientific modeling. Superconducting qubits are a leading platform that is advancing noise-tolerant intermediate-scale quantum processors. The implementation requires scaling to large numbers of superconducting qubits, circuit depths, and gate speeds, wherein high-purity RF signal generation and effective cabling transport are desirable. Fiber photonic-enhanced RF signal generation has demonstrated the principle of addressing both signal generation and transport requirements, supporting intermediate qubit numbers and robust packaging efforts; however, fiber-based approaches to RF signal distribution are often bounded by their phase instability. Here, we present a silicon photonic integrated circuit-based version of a photonic-enhanced RF signal generator that demonstrates the requisite stability, as well as a path towards the necessary signal fidelity.

Evaluation of commercial insect repellents on human skin against Aedes aegypti (Diptera: Culicidae).

An olfactometer was used to evaluate the efficacy of selected commercial insect repellent products against Aedes aegypti (L.). A comparison of 12 commercial repellent products was made on human skin. The products tested included 2 natural oil insect repellent formulations (Buzz Away and Green Ban) containing plant extracts, 2 proprietary products (Skin-So-Soft lotion and bath oil), and 8 commercial deet preparations in various concentrations and forms of spray, aerosol, stick, cream, and lotion. Behavioral responses and time to probe were determined in triplicate using 10 female mosquito challenges per replicate for each product. Generally, products with higher concentrations of deet were found to have longer repellence times. OFF spray and Muskol lotion offered the longest repellence times. However, there was no significant difference in time for mosquitoes to probe among the formulations. Skin-So-Soft lotion and bath oil were not as effective as deet in repelling Ae. aegypti. Natural oil insect repellent formulations offered essentially no repellency against Ae. aegypti. This is a simple and reproducible method to evaluate the efficacy of insect repellents and is recommended for preliminary screening of new insect repellents or formulations.

Succinate dehydrogenase and mitochondria in the hair cells in the organ of Corti of mature and old shaker-1 mice.

The activity of succinate dehydrogenase in the sensory hair cells in the organ of Corti of mature and old shaker-1 mice described as the animals grew older, the outer hair cells being the most effected. The decrease inactivity of this enzyme was closely linked with the degeneration of the mitochondria. When mitochondria were absent or grossly degenerated there was no enzyme activity. It is possible that this defect is linked with the deafness in these mice.

A study of otoconia of normal mice and shaker mice.

Otoconia from the maculae of the utricule and the saccule of normal mice and shaker mice have been examined by means of polarizing microscopy and scanning electron microscopy. X-ray dispersive analysis was used to determine the elements present in the crystals. The otoconia were found to be negative birefringent crystals. They are among the largest crystals found in mammalian tissues, many being 30-50 microns in length and 109-20 microns in diameter. The majority were calcite (calcium carbonate) crystals. Some crystals had a different morphological appearance and contained phosphorus (phosphate compound) as well as calcium. The phosphate content was much less and sometimes absent from utricular otoconia of shaker mice.

Computer assisted structure-activity studies of chemical carcinogens. An N-nitroso compound data set.

N-nitroso compounds, consisting of nitrosamines and nitrosamides, are potentially important in the etiology of human cancer. An attempt to study the molecular structure-carcinogenicity relations of these compounds is reported. A pattern-recognition approach was used to develop predictive ability for carcinogenic potential. A set of 15 calculated molecular structure descriptors that supported a linear discriminant function able to successfully separate 116 carcinogens from 28 noncarcinogens was identified. Predictive ability of an overall of 91%--93% for carcinogens and 85% for noncarcinogens--was obtained in the randomized testing. This relatively high predictability demonstrates that pattern-recognition methods can be useful in analyzing these compounds for carcinogenic activity. The inclusion of two electronic descriptors implicitly supports the alpha-hydroxylation hypothesis. The relations of descriptors used and possible mechanism of action are discussed.

Computer-assisted structure-activity studies of chemical carcinogens. A heterogeneous data set.

A structure-activity relations study has been performed on a heterogeneous set of organic compounds to develop predictive ability for carcinogenic potential. The compounds employed came from more than 12 structural classes and numbered 130 carcinogens and 79 noncarcinogens. A set of 28 calculated molecular structure descriptors was identified that supported a linear discriminant function able to completely separate 192 compounds into the carcinogenic and noncarcinogenic classes. A predictive ability of 90% for carcinogens and 78% for noncarcinogens was obtained in randomized testing. The results demonstrate that pattern-recognition methods can be used to analyze a diverse set of compounds each represented by calculated molecular structure descriptors for a common biological activity.

Further studies of the membrane potential of the stria cells of the guinea pig in vitro.

Negative membrane potentials from the stria vascularis of the guinea pig have been recorded in vivo. Stable negative membrane potentials from the stria cells have also been recorded for as long as 2 minutes in vitro. They varied from -20 mV to -49 mV, irrespective of whether the stria vascularis was immersed in Ringer's solution for in K-Ringer's solution (approximately to the composition of an endolymph). Labelling of the inserted stria cells from which the membrane potential had been recorded demonstrated that the microelectrode tip was inside the cell. These cells will continue to show electrical activity for some time when immersed in suitable media.

Synthesis and anticancer activity of novel cyclic N-hydroxyureas.

To overcome the disadvantages of hydroxyurea in anticancer therapy such as fast biotransformation and low potency, five cyclic N-hydroxyureas were synthesized. A new reaction was developed to prepare the desired products from the appropriate alkyl omega-haloalkylcarbamates with hydroxylamine. This reaction probably involves a two-step mechanism: nucleophilic substitution and intramolecular cyclization. The anticancer screening tests of these compounds were done both in vitro using tissue culture and in vivo. One compound, 1-hydroxy-1,3-diazacylohexan-2-one, had anticancer activity comparable to hydroxyurea both in vivo and in vitro.