Ultra-sharp asymmetric Fano-like resonance spectrum on Si photonic platform.

In this paper, we report the generation of an ultra-sharp asymmetric resonance spectrum through Fano-like interference. This generation is accomplished by weakly coupling a high-quality factor (Q factor) Fabry-Pérot (FP) cavity and a low-Q factor FP cavity through evanescent waves. The high-Q FP cavity is formed by Sagnac loop mirrors, whilst the low-Q one is built by partially transmitting Sagnac loop reflectors. The working principle has been analytically established and numerically modelled by using temporal coupled-mode-theory (CMT), and verified using a prototype device fabricated on the 340 nm silicon-on-insulator (SOI) platform, patterned by deep ultraviolet (DUV) lithography. Pronounced asymmetric resonances with slopes up to 0.77 dB/pm have been successfully measured, which, to the best of our knowledge, is higher than the results reported in state-of-the-art devices in on-chip integrated Si photonic studies. The established theoretical analysis method can provide excellent design guidelines for devices with Fano-like resonances. The design principle can be applied to ultra-sensitive sensing, ultra-high extinction ratio switching, and more applications.

Lipoxin-induced migration of fish leukocytes.

The migration-inducing abilities of both synthetic lipoxin A4 (LXA4) and leukotriene B4 (LTB4) for rainbow trout neutrophils were examined with an in vitro assay. LXA4 caused enhanced migration of these cells with a three- to fourfold greater response than that observed toward LTB4 at most concentrations tested. Checkerboard assays showed that synthetic LXA4 was chemokinetic for trout leukocytes, while LTB4 was chemotactic. The chemokinetic ability of LX synthesized by rainbow trout macrophages maintained in short-term culture was also determined. These cells produced both 4-and 5-series LX, namely LXA4, LXA5, 11-trans-LXA4, 11-trans-LXA5, 7-cis-11-trans-LXA4 and 6(S)-LXA4. Although greater migration was found to LXA4 than to most of the other 4-series positional isomers, at least at some concentrations, this did not exhibit the degree of stereospecificity previously reported in some studies for mammalian leukocytes. Little difference was found between the chemokinetic responses of rainbow trout leukocytes to 4- and 5-series LX. These findings suggest that LXs are important migration-inducing molecules in trout and have a relatively long evolutionary history.

Leucocyte migration in rainbow trout (Oncorhynchus mykiss [Walbaum]): optimization of migration conditions and responses to host and pathogen (Diphyllobothrium dendriticum [Nitzsch]) derived chemoattractants.

A rainbow trout leucocyte-derived chemoattractant(s) was prepared and tested as a stimulant of leucocyte migration. It was used to optimize an in vitro leucocyte migration assay using a 48-well micro chemotaxis chamber. This assay has subsequently been used to test the chemoattractant activity of antigen extracts from the tegument of Diphyllobothrium dendriticum plerocercoids and conditioned medium obtained after in vitro maintenance of live plerocercoids. Leucocytes were found to have an increased directional motility (chemotactic response) to the host-derived chemoattractant(s) but a random increased motility (chemokinetic response) following stimulation/contact with parasite-derived antigens.

NADPH oxidase-like activity in rainbow trout Oncorhynchus mykiss (Walbaum) macrophages.

Evidence for the existence of an NADPH oxidase-like enzyme in rainbow trout macrophages is given. Reduced-minus-oxidised difference spectroscopy revealed the presence of a cytochrome b with three absorbance peaks, at 430, 533, and 558 nm. The low midpoint potential of the latter peak suggests this cytochrome is the same as the terminal component of NADPH oxidase (i.e., cytochrome b-245). Subcellular fractionation of macrophages revealed two peaks of cytochrome b activity, in accord with the concept of a plasma membrane localisation of cytochrome b activity in addition to a mitochondrial localisation. Finally, that the rainbow trout oxidase is a multicomponent enzyme was suggested by inhibitor studies, where specific inhibitors of the flavin and cytochrome b-245 components of NADPH oxidase induced significant reduction in superoxide anion production.

The effect of ondansetron on atracurium-induced neuromuscular blockade.

STUDY OBJECTIVE: To determine whether treatment with ondansetron, a new antiemetic drug, affects nondepolarizing neuromuscular blockade. DESIGN: Randomized, double-blind, prospective study. SETTING: Operating room at a university medical center. PATIENTS: 30 ASA physical status I and II patients scheduled for elective surgery. INTERVENTIONS: After the induction of anesthesia with midazolam 2 to 4 mg/kg, sodium thiopental 6 to 8 mg/kg, and fentanyl 4 to 8 micrograms/kg, the ulnar nerve was stimulated at the wrist through subcutaneous needle electrodes at a frequency of 0.15 Hz. The response to stimulation was measured and recorded with a force-displacement transducer applied to the thumb. Patients were randomized to one of three treatment groups. A steady baseline to ulnar nerve stimulation with nitrous oxide-oxygen-opioid-thiopental anesthesia was established. The first study group (Group 1) received a placebo, the second group (Group 2) received 8 mg of ondansetron, and the third group (Group 3) received 16 mg of ondansetron as an intravenous infusion over 5 minutes. Patients were then given incremental doses of atracurium 0.05 mg/kg at 3-minute intervals to establish approximately 95% twitch inhibition so as to construct a dose-response curve. An atracurium infusion was then begun to maintain a constant degree of neuromuscular blockade. At the end of surgery, patients were allowed to recover spontaneously, or pharmacologic antagonism of residual neuromuscular blockade was achieved with neostigmine 0.05 mg/kg and glycopyrrolate 0.01 mg/kg. Mechanomyographic response to train-of-four stimuli (2 Hz for 2 seconds) every 20 seconds was monitored during the atracurium infusion and recovery from neuromuscular blockade. MEASUREMENTS AND MAIN RESULTS: Log dose-response curves were determined for the study groups and compared using analysis of variance (ANOVA). The 50%, 75%, and 95% effective doses (ED50, ED75, and ED95) were calculated from the equation describing the log dose-response. Maintenance infusion rates were determined, and the neostigmine-accelerated recovery index of 25% to 75% was measured for each group. The results were compared using ANOVA. There were no significant differences among the treatment groups with respect to maintenance infusion rate (7.8 +/- 1.8 micrograms/kg/min for Group 1, 7.7 +/- 2.5 micrograms/kg/min for Group 2, and 7.3 +/- 2.3 micrograms/kg/min for Group 3) or neostigmine-accelerated recovery interval of 25% to 75% (4.5 +/- 2.3 minutes, 4.4 +/- 3.1 minutes, 6.6 +/- 3.9 minutes in Groups 1, 2, and 3, respectively). The log dose-response data for Groups 1, 2, and 3 did not differ significantly (p = 0.068), and the calculated ED95 in each treatment group demonstrated no dose-related change (0.254 +/- 0.022, 0.279 +/- 0.033, and 0.240 +/- 0.022 for Groups 1, 2, and 3, respectively). CONCLUSIONS: Ondansetron is an antiemetic drug that can be used in the perioperative period without concern for potentiation of nondepolarizing neuromuscular blockade, change in atracurium maintenance dose, or change in rate of neostigmine-induced recovery from neuromuscular blockade with atracurium.

Statistical analysis of decay of organophosphorus and pyrethroid insecticides and carbaryl on paddy rice, maize, sunflowers and field peas.

A model is developed to describe the decay of seven insecticides on stored paddy rice, maize, sunflowers and peas, and is shown to be more precise than each of six literature models on pesticide decay. It relates residues (R), as a ratio of applied concentration (R(0)), to time after insecticide application (t), modifying the usual first-order kinetics equation lnR=lnR(0)-kt by assuming that the rate constant k has a mixture of values according to a gamma distribution with mean K. The resulting equation is lnR=lnR(0)-Kcln(1+t/c), where c is a constant determined empirically. For large c, this model reduces to the first-order model with K=k. The parameter K is further modelled as linear in temperature for maize and rice. The rate of loss of protectants was found not to be seriously affected by co-application with other insecticides, and this is a useful finding for future studies on rates of loss of grain protectants. The apparent rate of loss was also not seriously affected by the method of analysis, whether by gas chromatography or high-performance liquid chromatography, and this finding supports previous validation of the methods.

The laboratory maintenance of Diphyllobothrium dendriticum (Nitzsch, 1824).

A protocol for the routine laboratory maintenance of the life-cycle of Diphyllobothrium dendriticum, using herring gulls (Larus argentatus), Cyclops abyssorum and rainbow trout Oncorhynchus mykiss ( = Salmo gairdneri) as the definitive, first and second intermediate hosts respectively, is described.

Sequential development of the immune response in rainbow trout [Oncorhynchus mykiss (Walbaum, 1792)] to experimental plerocercoid infections of Diphyllobothrium dendriticum (Nitzsch, 1824).

Development of the inflammatory response of rainbow trout to experimental infections with Diphyllobothrium dendriticum plerocercoids is described using light and electron microscopy. The cellular response to plerocercoids occurred within 2 weeks post-infection (p.i.). This was followed by an increase in leucocyte numbers during weeks 3-6 p.i., with full encapsulation of plerocercoids by week 6 p.i. Neutrophils were the first leucocytes to engage the developing plerocercoid, followed by large influxes of macrophages which transformed into epithelioid cells. With longer times p.i. the accumulation of different leucocyte types increased, and a blood vascular network developed. Full development of the composite cyst was characterized by fibroplasia, particularly at the periphery of the cyst, and the subsequent deposition of a collagenous tissue matrix. Enzyme-linked immunosorbent assay (ELISA) examination of serum samples taken over the 20 week period showed that specific anti-D. dendriticum antibody titres were first detected at 5 weeks p.i. and increased to a maximum by 11 weeks p.i.

Determination of pyrethroid residues on paddy rice by reversed-phase high-performance liquid chromatography.

Several synthetic pyrethroids and the synergist piperonyl butoxide have been determined as aged residues on paddy rice by reversed-phase high-performance liquid chromatography with detection at 225 nm. These compounds are commonly used as protectants for stored grains. Studies on the comparative rates of extraction of both the pesticides and interfering material from the grain were conducted with acetone, methanol, and hexane as extracting solvents. Acetone was the best of these solvents because it provided quantitative extraction of the pesticides over a 48-h period, and did not give high levels of ballast material. Pyrethroids present in the extract at levels in excess of 0.5 microgram/ml could be determined by direct injection, but at lower concentrations, clean-up and preconcentration were required. Clean-up of acetone extracts was accomplished with either Florisil or alumina pre-columns, and up to a tenfold preconcentration was achieved by adsorption of the pesticide on a C18 pre-column, or by concentrating the extract through evaporation of the solvent. These approaches gave good recoveries and linear calibration plots. Detection limits were of the order of 0.05 microgram/ml.

Intra nasal administration of poly-lactic acid microsphere co-encapsulated Yersinia pestis subunits confers protection from pneumonic plague in the mouse.

Equivocal doses of soluble, or high molecular weight poly (lactic acid) microsphere co-encapsulated, F1 and V subunit antigens of Yersinia pestis were used to immunize mice intra-nasally. Animals were dosed on day 1 and 7 with 2.724 micrograms V plus 0.956 micrograms F1. Co-encapsulated antigens induced superior systemic and mucosal immunity in comparison with free F1 and V. All of the mice immunized with soluble antigens died shortly after an aerosol challenge consisting of 1 x 10(5) colony-forming units of plague bacteria. In contrast, 66% of the co-encapsulated subunit vaccinees survived this lethal challenge. Humoral immunity to plague was improved further, resulting in 80% protection from challenge, if a relatively high dose (10 micrograms) of cholera toxin B subunit was added to the microsphere suspension prior to intra-nasal delivery. Significantly, by adding 10 micrograms cholera toxin B subunit to the free antigen solution, a 100% post-challenge survival rate was attained. We conclude that in this animal model of pneumonic plague, intra-nasal administration of microgram quantities of Yersinia pestis subunits confers protective immunity, provided the vaccines are microencapsulated or admixed with a strong mucosal adjuvant, such as the cholera toxin B subunit.

Local and systemic immune response to a microencapsulated sub-unit vaccine for plague.

Microencapsulated Fl and V sub-unit antigens of Yersinia pestis were used to immunize mice intraperitoneally with a combination of 25 micrograms of each of the microencapsulated sub-units. The combined microsphere formulation induced both mucosal and systemic immunity. There was an additive effect in combining sub-units and the protection afforded by the combined microencapsulated antigens was superior to that provided by the administration of any single encapsulated antigen and by the existing whole cell vaccine. The protective efficacy of the combined microencapsulated sub-units was further enhanced by co-administering cholera toxin B sub-unit. Microencapsulation of the sub-units offered advantages which included depot release of the vaccine in vivo and the facilitation of oral, intranasal or inhalational delivery. Therefore, immunization with microencapsulated sub-unit antigens was an effective means of generating humoral and cellular responses which endowed protective immunity.