Detection and characterization of viruses as field and vaccine strains in feedlot cattle with bovine respiratory disease.

This study investigated viruses in bovine respiratory disease (BRD) cases in feedlots, including bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronaviruses (BoCV) and parainfluenza-3 virus (PI3V). Nasal swabs were collected from 114 cattle on initial BRD treatment. Processing included modified live virus (MLV) vaccination. Seven BRD necropsy cases were included for 121 total cases. Mean number of days on feed before first sample was 14.9 days. Swabs and tissue homogenates were tested by gel based PCR (G-PCR), quantitative-PCR (qPCR) and quantitative real time reverse transcriptase PCR (qRT-PCR) and viral culture. There were 87/114 (76.3%) swabs positive for at least one virus by at least one test. All necropsy cases were positive for at least one virus. Of 121 cases, positives included 18/121 (14.9%) BoHV-1; 19/121 (15.7%) BVDV; 76/121 (62.8%) BoCV; 11/121 (9.1%) BRSV; and 10/121 (8.3%) PI3V. For nasal swabs, G-PCR (5 viruses) detected 44/114 (38.6%); q-PCR and qRT-PCR (4 viruses) detected 81/114 (71.6%); and virus isolation detected 40/114 (35.1%). Most were positive for only one or two tests, but not all three tests. Necropsy cases had positives: 5/7 G-PCR, 5/7 q-PCR and qRT-PCR, and all were positive by cell culture. In some cases, G-PCR and both real time PCR were negative for BoHV-1, BVDV, and PI3V in samples positive by culture. PCR did not differentiate field from vaccines strains of BoHV-1, BVDV, and PI3V. However based on sequencing and analysis, field and vaccine strains of culture positive BoHV-1, BoCV, BVDV, and PI3V, 11/18 (61.1%) of BoHV-1 isolates, 6/17 (35.3%) BVDV isolates, and 1/10 (10.0%) PI3V identified as vaccine. BRSV was only identified by PCR testing. Interpretation of laboratory tests is appropriate as molecular based tests and virus isolation cannot separate field from vaccine strains. Additional testing using sequencing appears appropriate for identifying vaccine strains.

Time-domain control of ultrahigh-frequency nanomechanical systems.

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.

Guided self-assembly of integrated hollow Bragg waveguides.

We describe the fabrication of integrated hollow waveguides through guided self-assembly of straight-sided, thin film delamination buckles within a multilayer system of chalcogenide glass and polymer. The process is based on silver photodoping, which was used to control both the stress and adhesion of the chalcogenide glass films. Straight, curved, crossing, and tapered microchannels were realized in parallel. The channels are cladded by omnidirectional dielectric reflectors designed for low-loss, air-core guiding of light in the 1550-1700 nm wavelength range. Loss as low as ~15 dB/cm was measured for channels of height ~2.5 mum, in good agreement with both an analytical ray optics model and finite difference numerical simulations. The loss is determined mainly by the reflectivity of the cladding mirrors, which is ~0.995 for the as-fabricated devices.

Nanocluster sensitized erbium-doped silicon monoxide waveguides.

We describe the fabrication and characterization of micron-scale buried strip waveguides with erbium-doped (~ 1 at. %) silicon monoxide (SiO) cores and SiO(2) and polymer claddings. In spite of large core-cladding index offset (Deltan~0.4), propagation loss is as low as ~ 1 dB/cm. The cross-section for the (4)I(13/2) to (4)I(15/2) erbium transition was estimated as ~10(-20) cm(2), a factor of 2 to 3 higher than in silica glass. The annealed core material contains a high density of amorphous silicon nanoclusters, which act as efficient broadband sensitizers for erbium. Both a traditional co-propagating pump (980 nm wavelength) configuration and a transverse pump (532 nm wavelength, < 10 W/cm(2)) configuration were tested. In either case, free carrier absorption loss is the dominant pump-induced mechanism and approximately 15-20 % of the erbium population is invertible.

Percutaneous rotational thrombectomy reduces acute reocclusion in an animal model of acute coronary thrombosis.

This study was designed to compare acute reocclusion rates after treatment of acute coronary thrombosis with a percutaneous thrombectomy device or standard balloon angioplasty. Our group has previously reported on the rationale and development of a mechanical device for the treatment of intra-arterial thrombosis. This device removes fibrin from thrombus, allowing for dissolution of the cellular elements of the thrombus. Theoretically, thrombus removal (as opposed to displacement) might result in a lower rate of acute rethrombosis. The present study utilizes the device percutaneously in the coronary arteries of closed chest swine and compares recanalization and reocclusion rates with standard balloon angioplasty. Twenty-six animals with total thrombotic coronary occlusions were treated; 13 with each device. Reocclusion rates with the thrombectomy device were significantly reduced at 60 min and 120 min after recanalization (p < 0.02), and the mean time to reocclusion was prolonged by 45 min (p = 0.07). Technical problems included poor handling characteristics in early prototypes and stress fractures secondary to improper use. Changes in catheter design and operator protocols have largely eliminated these problems. We conclude that this study demonstrates the feasibility of percutaneous mechanical thrombectomy in the coronary arteries and that reocclusion rates after recanalization of thrombotic occlusions compare favorably to standard angioplasty.

Changes of aldosterone in blood serum of dairy cattle during estrous cycle.

Blood samples were taken daily from five lactating cows and five open heifers beginning with the 1st day postestrus and continuing until the animal was observed in standing estrus. Means of aldosterone in blood serum were 102.6 +/- 5.1 pg/ml for lactating cows and 94.1 +/- 5.1 pg/ml for open heifers. Age and lactation did not appear to be major factors affecting circulating aldosterone in the bovine species. Effect of day of the estrous cycle on aldosterone was quadratic. Concentrations of aldosterone for lactating cows started at 92.3 pg/ml on day 1 of the estrous cycle, peaked at 125.5 pg/ml on day 8, then declined steadily to a low of 43.2 pg/ml on day 20. There was no significant interaction of group by day. During the estrous cycle aldosterone appeared to be related to development of corpus luteum and progesterone. Sodium in blood serum was higher during estrus for lactating cows than open heifers for linear, quadratic, and cubic effects. Although not correlated with aldosterone, sodium exhibited similar cyclic patterns throughout the estrous cycle. Responses between sodium and aldosterone appeared delayed during estrus.

Changes in circulating plasma levels of cortisol in lactating and non-lactating dairy cattle during the estrous cycle.

Plasma cortisol levels were determined by radioimmunoassay for five lactating cows and five open heifers from blood samples collected daily during the course of a complete estrous cycle. Each animal was fitted with an indwelling jugular catheter to minimize stress from bleeding. Mean plasma cortisol levels were 5.67 ng/ml for the lactating cows and 5.87 ng/ml for the open heifers. Mean values for individuals ranged from 3.79 ng/ml to 6.94 ng/ml in the lactating group, and 3.37 ng/ml to 11.69 ng/ml in the open group. These differences, both between and within groups, were not significant. Mean cortisol values during the estrous cycle ranged from 2.26+/-0.93 ng/ml on day one to 9.49+/-2.11 ng/ml on day six for the lactating group, and 2.74+/-0.52 ng/ml on day six to 14.66+/-10.78 ng/ml on day twelve for the open group. Group by day interactions were not significant. Attempts to correlate plasma cortisol with lactation or day of estrus were not significant.