Ultrafast optical ranging using microresonator soliton frequency combs.

Light detection and ranging is widely used in science and industry. Over the past decade, optical frequency combs were shown to offer advantages in optical ranging, enabling fast distance acquisition with high accuracy. Driven by emerging high-volume applications such as industrial sensing, drone navigation, or autonomous driving, there is now a growing demand for compact ranging systems. Here, we show that soliton Kerr comb generation in integrated silicon nitride microresonators provides a route to high-performance chip-scale ranging systems. We demonstrate dual-comb distance measurements with Allan deviations down to 12 nanometers at averaging times of 13 microseconds along with ultrafast ranging at acquisition rates of 100 megahertz, allowing for in-flight sampling of gun projectiles moving at 150 meters per second. Combining integrated soliton-comb ranging systems with chip-scale nanophotonic phased arrays could enable compact ultrafast ranging systems for emerging mass applications.

Spin-dependent thermoelectric properties of a Kondo-correlated quantum dot with Rashba spin-orbit coupling.

Thermoelectric transport phenomena in a single-level quantum dot coupled to ferromagnetic leads are considered theoretically in the Kondo regime. The dot is described by the Anderson model with Rashba type spin-orbit interactions. The finite-U mean field slave boson technique is used to describe transport characteristics, such as the heat conductance, thermopower and thermoelectric efficiency (figure of merit). The role of quantum interference effects in the thermoelectric parameters is also analyzed.

Effect of radioprotectant WR 2721 on cyclic nucleotides, prostaglandins, and lysosomes.

Within 1 hr after ip injection of the radioprotectant WR 2721 into rats, splenic cGMP levels dropped and remained suppressed for 6 hr before returning to normal. However, if rats were exposed to ionizing radiation 30-40 min after WR 2721 treatment, they had higher cGMP levels at 3 hr postirradiation than the nonirradiated, drug-treated controls, but the cGMP content was still found to be lower than that of the irradiated nondrug-treated controls. Radiation exposure of animals pretreated with WR 2721 also resulted in higher liver and spleen levels of cAMP and additional elevations in spleen prostaglandin content, compared with irradiated controls at 3-6 hr after radiation treatment. The secondary fluctuations of lysosomal enzyme activities, prostaglandin content, and cyclic nucleotide levels were also altered in irradiated rats pretreated with WR 2721 when compared with irradiated controls. Liver and spleen lysosomal beta-glucuronidase activities, spleen cAMP and cGMP levels, and spleen prostaglandin concentrations were closer to physiological levels at 3 days postirradiation in rats given WR 2721 before the radiation treatment.

Effects of WR 2721 on cyclic nucleotide levels and lysosomal enzyme activities.

The radioprotectant WR 2721 administered intraperitoneally to rats at 30--40 min before exposure to 1000 rad of 60Co caused a reduction in spleen lysosomal enzyme activity and fluctuations in cyclic nucleotide levels. Liver and spleen cAMP levels from drug-treated animals were higher at 3--6 hr postirradiation whereas spleen cGMP levels were lower at 1--4 hr postirradiation than irradiated controls not given the radioprotectant. At 3 days after radiation exposure, spleen cyclic nucleotide levels and lysosomal enzyme activities in rats given WR 2721 were closer to the level of nonirradiated control rats than of irradiated rats receiving saline.

Prostaglandin levels and lysosomal enzyme activities in irradiated rats.

Whole-body irradiation of rats results in the release of hydrolases from lysosomes, an increase in lysosomal enzyme activities, and changes in the prostaglandin levels in spleen and liver tissues. A transient increase in the concentration of prostaglandins E and F and leakage of lysosomal hydrolases occurred in both spleen and liver tissues 3-6 hours after the animals were irradiated. Maximal values for hydrolase activities, prostaglandin E and F content, and release of lysosomal enzymes were found 4 days postirradiation in rat spleens whereas in the liver only slight increases were observed at this time period for prostaglandin F levels. On day 7 there was a final rise in the spleen's prostaglandin E and F concentrations and leakage of hydrolases from the lysosomes before returning to near normal values on day 11. The prostaglandin F concentration in liver was also slightly elevated on the 7th day after irradiation and then decreased to control levels.

Method for screening urinary steroids by gas chromatography.

Numerous methods are available for measuring urinary steroids in evaluating endocrine dysfunctions. Measurements of these particular steroids, or groups of them, usually involve tedious isolation methods, corrections for interferences and losses of the steroid, and (or) expensive reagents. We show how gas-liquid chromatography provides a rapid, sensitive, and direct method for several steroid metabolites in urine. Androstanol, androsterone, etiocholanolone, dehydroisoandrosterone, pregnanediol, pregnanetriol, 11-keto-17-ketosteroids, and the 11beta-hydroxy-17-ketosteroids can be identified and quantified.

Yeast mutants blocked in removing the methyl group of lanosterol at C-14. Separation of sterols by high-pressure liquid chromatography.

Sterols of a nystatin resistant mutant of the wild type parent of Saccharomyces cerevisiae were separated by a newly developed procedure involving high-pressure liquid chromatography and were identified. The mutant contained larger amounts of squalene and lanosterol (I) than the wild type, as well as 4,14-dimethylcholesta-8,24-dien-3beta-ol (II), 4,14-dimethylergosta-8,24(28)-dien-3beta-ol (III), and 14-methylergosta-8,24(28)-dien-3beta-ol (IV), which were not hitherto found in yeast. These results indicated a block in removal of the methyl group at C-14 of lanosterol. An ergosterol requiring derivative of the mutant which carried in addition a mutation in heme biosynthesis had the same sterols as the parent, but at one-third the concentration. The low level of sterols may be due to a requirement for a heme or cytochrome in oxygenation reactions between lanosterol and ergosterol.

Lactate dehydrogenase isoenzymes linked to beta-lipoproteins and immunoglobulin A.

A clinically asymptomatic individual had an abnormal electrophoretic pattern for lactate dehydrogenase, seven isoenzyme bands being present. This atypical pattern was a result of an interaction of lactate dehydrogenase with immunoglobulin A and beta-lipoprotein. Lactate dehydrogenase enzymes LD2 and LD3 were the isoenzymes responsible for the formation of the complexes.

Cell walls of germinating uredospores: I. Amino Acid and carbohydrate constituents.

Synthesis of germ tube wall is a major quantitative event during germination penetration of fungi on host plants, but little is known of germ tube composition or metabolic regulation. Sonic oscillation was used to separate germ tubes from germinating uredospores of Uromyces phaseoli var. typica. Uniformly (14)C-labeled wall fractions from both structures were prepared by repeated low speed centrifugation and extraction with polar and nonpolar solvents. Based on amino acid analysis, approximately 6 and 16% of the carbon from uredospore and germ tube walls, respectively, was present in amino acids readily accessible to protease. Covalent linkages between amino acid and carbohydrate of walls was indicated by analysis of fragments prepared by mild hydrolytic procedures and separated by column chromatography and paper electrophoresis. The existence of protein in wall structures may resolve some previous uncertainty about the occurrence of protein biosynthesis during germination of rust fungi. Glucose, mannose, and glucosamine were the only carbohydrate components identified in both germ tubes and uredospore walls but different percentages were observed (germ tubes 28: 16: 16; uredospore 6: 36: 6). In germ tubes, most of the glucosamine was present in linkages hydrolyzed only by strong acid treatment, suggesting chitin-like polymers. In uredospore walls, glucosamine appears to be associated with red uredospore pigment which has properties similar to those of a melanin. Approximately 20% of the carbon in walls could not be identified with known compounds, partially because of degradation during the analytical procedures.

Cell Walls of Germinating Uredospores: II. Carbohydrate Polymers.

Polymeric carbohydrates in (14)C-labeled germ tube and uredospore walls of Uromyces phaseoli var. typica were studied by permethylation and by enzymatic hydrolysis. The native structure of the uredospore wall limited the effectiveness of both techniques with this wall, but evidence for two distinct polysaccharides was obtained. A linear (1-->3) glucan, containing minor quantities of (1-->6) linkages, may account for most of the glucose in the uredospore wall. A second uredospore polymer was a glucomannan similar to one reported for other rust fungi in that it consisted of approximately equal numbers of beta(1-->3) and beta(1-->4) mannosidic linkages with glucose as a minor component at the nonreducing end. Branching, most likely by (1-->6) mannose links, was low. In contrast to uredospore wall, considerably more germ tube polysaccharide was accessible to enzymes and to methylation. Methylation studies indicate that (1-->3) glucose and mannose bonds occur predominantly. Evidence from hydrolysis with exo- (beta)-(1-->3) glucanase suggests distinct wall regions of beta(1-->3) glycan, highly branched by (1-->6) bonds, as well as wall regions of a glucomannan with alternating (1-->3) glucose and (1-->3) mannose residues. Polymer heterogeneity was indicated by differences in the proportions of mannose, glucose, and galactose as reducing end groups in different solubility fractions. In germ tube walls, but not in uredospore walls, glucosamine apparently existed as part of chitin polymer as evidenced by the isolation of N,N-diacetylchitobiose from chitinase digestion.

Protein and Ribonucleic Acid Synthesis during Germination of Uredospores.

Existing evidence suggests that there is no net synthesis of protein during germination of spores of some obligate parasites. The problem was reinvestigated with enzymatic hydrolysis, rather than acid hydrolysis or solubility properties, to estimate changes in protein and RNA. Procedures are detailed for the use of uniformly labeled (14)C-uredospores for the isolation and quantitative assay of amino acids and nucleosides resulting from hydrolysis.During early stages of germination in the absence of exogenous substrates, nucleosides derived enzymatically from RNA do not increase nor does the base composition vary. The bases of the free nucleotide pool, although varying in concentration from the RNA bases, also remain constant during this time. After 16 or 24 hours, bases from both sources decrease appreciably, and the decline is correlated with leakages to the external medium.In contrast to previous reports, amino acids released by proteases increased 20 to 25% during the first 3 to 5 hours of germination but decreased after 16 to 24 hours. The results suggest that spores of obligate parasites have a functional protein synthetic system which is involved in germination. Previous negative findings may have resulted from a lack of specificity in the analytic procedures employed, coupled with the possibility that protein or amino acid is associated with the walls of spores and the walls of germ tubes.