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We describe a frequency domain superconducting quantum interference device (SQUID) multiplexer which monitors a row of low-temperature sensors simultaneously with a single SQUID. Each sensor is ac biased with a unique frequency and all the sensor currents are added in a superconducting summing loop. A single SQUID measures the current in the summing loop, and the individual signals are lock-in detected after the room temperature SQUID electronics. The current in the summing loop is nulled by feedback to eliminate direct crosstalk. In order to avoid the accumulation of Johnson noise in the summing loop, a tuned bandpass filter is inserted in series with each sensor. To multiplex 32 Voltage-biased Superconducting Bolometers (VSB) with 1 msec time constants a total bandwidth of 100 kHz is required. The minimum bias frequency is limited to ≳500 kHz by practical limitations in the size of photolithographed inductors and capacitors. The major limitation of our multiplexing scheme is in the slew rate of the read...

In order to obtain a high laser efficiency from Xe pumped Nd laser systems, a novel cavity filter glass doped with Eu3+ and Sm3+ was investigated using a phosphate host. Sm3+, which served to inhibit ASE also was found to strongly transfer its energy to the Eu3+. The Eu3+ emits an efficient red emission from the 5D0 yields 7F1 transition which is located exactly at the Nd3+ absorption band and therein radiatively sensitizes the Nd laser emission. The energy transfer and back transfer of these two rare-earth ions in phosphate will be discussed. This doubly-doped phosphate glass cavity samples produced an increase in output power by 50 percent over undoped filters in a Xe pumped pulsed Nd:glass laser system.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This study validated a polymerase chain reaction-based method for the detection of a specific bovine mitochondrial gene derived from rendered bovine tissues and admixed with complete animal feed. Four laboratories participated in this effort: one state laboratory and three Food and Drug Administration (FDA) laboratories, including one FDA field laboratory. The protocol used a statistical approach of 90% probability, with a 95% confidence interval for determining acceptable rates of false-positive and false-negative samples. Each participating laboratory analyzed 30 samples of feed each containing 0, 0.125, and 2.0% bovine meat and bone meal (BMBM), for a total of 90 feed samples. The samples were randomized such that the analysts were unaware of the true identity of the test samples. The results demonstrated that all laboratories met the acceptance criteria established for this protocol. The overall rates of false-negative results were 0.83% (1/120) at the level of 0.125% BMBM and 1.67% (2/120) at the level of 2% BMBM. The overall rate of false-negative results for all levels of BMBM was 1.25% (3/240). The rate for false-positive results was 0.83%.

High power, high brightness fiber lasers have numerous potential commercial and military applications. Fiber lasers with cladding pump designs represent a new generation of diode pumped configurations that are extremely efficient, have single mode output and may be operated with or without active cooling. Kigre has invented a new family of Er/Yb/Nd phosphate laser glass materials (designated QX) that promise to facilitate a quantum leap in fiber laser technology of this field. The new phosphate glass Rare-Earth doped fiber exhibit many advantages than Silica or Fluoride base fiber, see table.1. Instead of 30 to 50 meters of fused silica with a 50 mm bend radii; Kigre's phosphate glass fiber amplifiers may be designed to be less than 4 meters long .Laser performance and various design parameters, such as the fiber core diameter, NA, inner cladding shape and doping concentration are evaluated. Laser performances was demonstrated for an experimental QX/Er doubled clading fiber commissioned by MIT having 8 micron core, a 240 X 300 micron rectangle shaped inner cladding with 0.4 NA and 500 micron outer clading.. Kigre obtained approximately 2 dB/cm gain from 15cm long fiber under 940nm pumping The same fiber was evaluated by researcher at MIT. They used 975nm pump source. Maximum 270mW output was demonstrated by 30 cm long fiber with Fresnel reflection resonator mirrors. The slope efficiency of absorbed pump power s 47%.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A high repetition rate diode pumped Erbium glass laser was demonstrated at 50Hz with Q-switched outputs up to 15mj by various Q-switch methods.

Summary form only given. Recently, Kigre introduced a new family of rare-earth doped fibers (Wu et al, 2000), based on phosphate laser glass. Due to their phonon energy, erbium-doped phosphate glasses exhibit lower up-conversion losses than silica glass. This, and the high solubility for rare-earth ions, makes phosphate glasses promising candidates for high-gain erbium devices. High doping concentrations enable short devices, and fiber lasers or amplifiers with only a few centimeters of active fiber can be realized. This is to be compared to standard EDFAs that normally contain tens of meters of erbium-doped silica fibers. We have demonstrated a short fiber-laser based on a single-mode Er:Yb codoped phosphate fiber, pumped by a 946 nm Nd:YAG laser.

Passive Q-Switch characteristics of Co 2+ :MgAl 2 O 3 sample were evaluated in a diode pumped QX/Er Erbium glass laser at 1535 nm, a flashlamp pumped Nd:YAG laser at 1.44 micrometers and Nd 3+ :KGd(WO 4 ) 2 laser at 1.34 micrometers .

Rapid identification of bovine materials in animal feedstuffs is essential for effective control of a potential source of bovine spongiform encephalopathy. We have developed a rapid method for the detection of the presence of bovine materials in animal feeds. Animal feed samples were prepared by a Chelex-100 treatment method, then subjected to polymerase chain reaction (PCR) detection. The assay can be completed in 2 h including 30 min for sample preparation, 35-65 min for PCR cycling and 30 min for gel electrophoresis. This method is not only rapid, simple and consistent, but also avoids a hazardous waste disposal issue associated with a previously described guanidine thiocyanate (GuSCN) extraction-PCR method.

Growing (35 kg body weight) and finishing (85 kg body weight) swine challenged with endotoxin (Escherichia coli O55:B5) at a dose of either 2 or 20 microg/kg produced tumor necrosis factor (TNF)alpha in a dose-response relationship as measured by bioassay. Peak TNFalpha plasma levels were observed 1-2 hr post-challenge, returning to basal values 4 hr post-challenge. However, both an enzyme-linked immunosorbent assay specific for swine TNFalpha and total human TNFalpha demonstrated no dose-response relationship; peak plasma levels of immunoreactive TNFalpha were also observed 1-2 hr post-challenge. Maximal plasma interleukin-6 levels occurred 1-2 hr post-challenge and remained elevated through 8 hr post-challenge; there was no effect of lipopolysaccharide dose or metabolic status. Although the metabolic status of the animals also affected glucose levels, with growing animals exhibiting greater sensitivity compared with finishing animals, endotoxin-induced decreases in blood glucose levels were primarily dose-dependent. In contrast, changes in plasma urea nitrogen and free fatty acid (FFA) levels were strictly related to the metabolic status. Urea nitrogen levels were unchanged in growing swine, whereas they were increased in finishing swine and remained elevated 24 hr post-challenge. FFA levels in growing and finishing swine increased 3-6 hr post-challenge. FFA levels returned to basal values for finishing swine 24 hr post challenge, but in growing swine remained elevated 24 hr post-challenge. Plasma aspartate transaminase levels were increased through 24 hr post-challenge; animals given a dose of 20 microg/kg exhibited the greatest increase. Similarly, swine challenged with a dose of 20 microg/kg also exhibited the greatest increase in levels of conjugated bilirubin; there was no effect on unconjugated (free) bilirubin. These results demonstrate that endotoxin challenge of swine result in a pattern of changes that are dependent on both the dose of endotoxin used and the metabolic status of the animal examined.

A high repetition rate diode pumped Erbium glass laser was demonstrated at 50 Hz with Q-switched outputs up to 15 mj by various Q-switch methods.

A high repetition rate diode pumped Erbium glass laser was demonstrated at 50 Hz with Q-switched outputs up to 15 mj by various Q-switch methods.

The effect of concentration of Er 3+ on the upconversion luminescence of the Er:Yb:glass excited by InGaAs laser diode is reported. With different concentration of Er 3+ , the upconversion luminescence intensity, the intensity ration of green and red lights, and the near infrared lights are different. The detailed mechanisms of upconversion luminescence are analyzed.

The absorption spectra and fluorescence spectra of a novel Er:Yb:phosphate glass were measured, and some emission parameters including the intensity parameters, integrated cross-section, emission cross-section, spontaneous emission probability were calculated by J-O theory. Green and red upconversion luminescence were obtained when excited with 966 nm LD, the mechanism of upconversion were analyzed in detail. Laser around 1.54 micrometers were obtained with the glass, the power is 5.2 mW.

This paper summaries our effort to develop new Nd3+, Er3+ and Yb3+ doped phosphate laser glasses, which exhibit high strength and low thermal expansion coefficient as well as acceptable optical athermal behavior. Ion-exchange chemical strengthening processes and laser performances of these glasses are presented.

A new Er 3+ doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO 3 molten salt was developed. Ion-exchange process of this glass was investigated by treating glass samples in a variety of salt bathes with various exposure times. Planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm was demonstrated. Spectral properties of Er 3+ in this glass were characterized by measuring absorption and emission spectra, and fluorescence lifetimes. Emission cross section of Er 3+ in this glass was calculated to be 0.76 X 10 -20 cm 2 using McCumber theory. Our preliminary experimental results indicate this new Er 3+ doped glass is an excellent material for ion-exchanged waveguide lasers and amplifiers.

Barrows were restrictively fed starting at 20 kg BW to determine the effects of endotoxin on growth performance of control and somatotropin-treated pigs. The following treatments were used: 1) daily i.m. vehicle injection until 55 kg BW; 2) daily i.m. injections of 100 micrograms of recombinant porcine somatotropin (pST)/kg BW, until 55 kg; 3) i.v. saline injections for 7 d consecutively starting at 60 kg BW; 4) i.v. injections of 1 microgram of bacterial lipopolysaccharide (LPS)/kg BW for 7 d starting at 60 kg BW; and 5) the combined LPS+pST treatment, with pST injections from 20 kg through the 7 d of LPS treatment. Pigs evaluated for LPS effects were fed to 60 kg anticipating a weight loss. Pigs were bled at 0800 and 1100 at 55 kg and on d 7 of LPS treatment. Rectal temperatures were taken on d 7. Treatment with pST increased ADG by 13 to 20% and improved feed:gain by 17 to 23% before LPS treatment. During the 7 d of LPS injections, ADG and feed:gain did not differ, although feed efficiency was impaired and variable. Rectal temperatures at 1100 were progressively increased: control < LPS < LPS-pST (P < .01). Protein accretion was improved 27% by pST treatment, and lipid accretion was decreased 45% before LPS. Lipid stores decreased (P < .01) after LPS treatment in the pST-treated pigs. Lipopolysaccharide treatment and(or) decreased feed intake reduced the hyperinsulinemia and hyperglycemia (P < .01) associated with pST treatment. These results indicate that LPS induced a simulated septicemia and that the effects were not negated by pST treatment. The observed hyperthermia was additive, possibly due to increased lean body mass induced by pST combined with the pyrogenic effect of LPS.

Physical, spectral and laser properties of a new Yb doped phosphate laser glass, QX/Yb, has been developed. This glassexhibits a low thermal expansion coefficient and a negative temperature coefficient of refractive index, resulting in anacceptable athermal behavior and an excellent thermal loading capability. The peak absorption and emission cross sections ofYb3 were measured to be l.06x102° cm2 and O.9O3x1W2° cm2, respectively. The concentration quenching and the influenceofthe OI-1 content on fluorescence lifetimes were examined. Excellent laser performance with a slope efficient of49% and amaximum output power of400 mW was demonstrated.Keywords: ytterbium-doped glass, laser glasses, phosphate glasses, solid state lasers

By pumping with a cw diode-pumped Nd:YAG laser operating at 946nm laser operation of a new Yb-doped phosphate glass with 440mW cw output power and a slope efficiency of 48% with respect to the absorbed pump power was achieved at room temperature.

We describe the design, fabrication, and testing of a broadband log-periodic antenna coupled to multiple cryogenic bolometers. This detector architecture, optimized here for astrophysical observations, simultaneously receives two linear polarizations with two octaves of bandwidth at millimeter wavelengths. The broad bandwidth signal received by the antenna is divided into sub-bands with integrated in-line frequency-selective filters. We demonstrate two such filter banks: a diplexer with two sub-bands and a log-periodic channelizer with seven contiguous sub-bands. These detectors have receiver efficiencies of 20-40% and percent level polarization isolation. Superconducting transition-edge sensor bolometers detect the power in each sub-band and polarization. We demonstrate circularly symmetric beam patterns, high polarization isolation, accurately positioned bands, and high optical efficiency. The pixel design is applicable to astronomical observations of intensity and polarization at millimeter through sub-millimeter wavelengths. As compared with an imaging array of pixels measuring only one band, simultaneous measurements of multiple bands in each pixel has the potential to result in a higher signal-to-noise measurement while also providing spectral information. This development facilitates compact systems with high mapping speeds for observations that require information in multiple frequency bands., 4 pages, 4 figures, accepted for publication in Applied Physics Letters

The basic research and engineering work for developments of eyesafe radar transmitter are reviewed. The characteristics of two model transmitters are introduced. Laser output at 1.54 micrometers with 5 mJ of energy and a 60 ns pulse width was demonstrated at 15 Hz using a rotating prism Q-switch. The laser media is an experimental Er:Glass, designated QX/ER.

Basic laser performance data for the 4F3/2 - 4I13/2 transition of Nd3+ in phosphate, silicate, and germanate glasses with various doping concentrations are presented. A slope efficiency of 1.1% was achieved in Q-100 phosphate laser glass. The resonator loss analysis indicates that there is no significant excited state absorption at 1.355 micrometer for phosphate glasses. Simultaneous operation of both the 4F3/2 - 4I13/2 and the 4F3/2 - 4I11/2 transitions of Nd3+ in phosphate, silicate, and germanate glasses have been achieved using two different methods. Laser output from these two transitions demonstrate good temporal and spatial overlap under the tested conditions.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Laser emission at 1535 nm from Er3+: glass is interesting due to its eyesafe wavelength and high atmospheric transmission. Diode laser pumping of the Er:Glass laser rod dramatically reduces thermal effects when compared to flashlamp pumping, allowing operation at higher repetition rates with higher average output power. This technology opens new opportunities for use in many applications such as ranging, target designation, laser radar, environmental sensing, collision avoidance, law enforcement and wind shear detection.

Laser operation of a new Yb3+-doped phosphate glass with 440 mW cw output power and a slope efficiency of 49% with respect to the absorbed pump power was achieved at room temperature by pumping with a cw diode-pumped Nd:YAG laser operating at 946 nm.

A flashlamp pumped, 200Hz, Q-Switched, TEM00Nd:YAG laser system with 10W of fundamental average power was developed. Using a nonlinear crystal frequency conversion system, 560mW of fifth harmonic (213nm) output was obtained .

FAP and CaF2 [4]. Intracavity focusing was necessary to raise the intracavity power density in orderto optimize Q-switching in the low absorption cross section Er3 doped glass and crystal 0-switchmaterials. The results typically revealed a Q-switched giant pulse followed by a train of free runningspikes or multiple 0-switched pulses. Passively 0-switched pulses of 3mJ and 6Ons pulse width weresuccessfullyobtainedusingtetravalenturanium doped strontium fluoride (U4 :SrF2), by R. D. Stultzet. a!. [5]. In this paper, we report on the bleaching of divalent uranium doped calcium fluoride

Significant enhancement of the thermal loading capability has been achieved with both Er3+ and Nd3+ doped inherently strong glasses by an ion-exchange chemical strengthening process. A free running laser with an average output power of 6.5 W and a Q-switched single mode laser with an energy of 5 mJ at a repetition rate of 15 Hz have been demonstrated at the 1.54 micrometers eye safe wavelength with strengthened QX/Er glass. An average output power of 110 W at 1.05 micrometers has been obtained employing a strengthened QX/Nd glass rod.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The immunomodulatory effect of oxytetracycline (OTC) on murine splenic lymphocytes (MSL), peritoneal exudate macrophage (PEM) functions and antibody production was examined. In vivo exposure to OTC slightly delayed initiation of antibody formation during the primary response. However, OTC exposure had no effect on either the peak time of antibody response or peak antibody titer. OTC also had no significant effect on the secondary antibody response. Mitogen-induced proliferation of MSL cocultured with OTC and pokeweed mitogen, phytohemagglutinin or concanavalin was equivocal. However, allogeneic stimulation of MSL was inhibited at 100 micrograms/ml OTC. There was also a decrease in the number of cells recovered. OTC had no effect on lymphocyte cytotoxicity in cells cultured in vitro. OTC inhibited the cytotoxic response of Corynebacterium parvum-elicited PEM at 10 micrograms/ml (effector:target of 10:1). Low levels of OTC (1-10 micrograms/ml) augmented the cytotoxic response (effector:target of 5:1). The effect of OTC on induction of PEM cytotoxicity was assessed by coculturing thioglycollate-elicited (TG) PEM in vitro with IFN-gamma and endotoxin along with 0-100 micrograms/ml OTC. Induction of cytotoxicity was inhibited at 0.5 microgram/ml. The effect of OTC on TG-PEM antimicrobial activity was assessed by measuring reduction of nitroblue tetrazolium (NBT) and cytochrome C. OTC inhibited the reduction of NBT at 500 micrograms/ml following PMA stimulation of TG-PEM. OTC had no effect on either NBT or cytochrome C reduction following stimulation with opsonized zymosan. These results demonstrate that OTC-mediated immunosuppression is a multifaceted event, with differing sensitivities both between immune cells and between different pathways within the same cell.

The effect of dietary chromium picolinate (CrP) and recombinant porcine growth hormone, somatotropin (rPST) administration on growth performance and cytokine production in Landrace-Poland China gilts was determined using a 2 by 2 treatment array. Treatments were: (1) control (basal diet), (2) CrP-supplemented diet (basal diet + 300 micrograms Cr3+/kg diet as CrP), (3) rPST (100 pg/kg body weight/day), and (4) rPST+CrP. CrP-supplemented diets were fed beginning at 20 kg body weight through 90 kg. Administration of rPST was begun at 60 kg weight and continued through 90 kg. All rPST treated pigs demonstrated improvements in growth performance versus controls. Pigs given CrP-supplemented diets showed no differences in growth performance. At 90 kg, pigs were challenged with endotoxin (lipopolysaccharide, 0.2 microgram/kg i.v.). Blood samples were collected at 0, 1, and 3 h postchallenge. Plasma IL-6 levels increased from 23 U/ml at time 0 to 1,927 U/ml at 3 h for control swine. Swine from the CrP treatment group had IL-6 levels of 8,130 U/ml at 3 h post-LPS. There were no differences in plasma IL-6 from pigs in the rPST and rPST+CrP treatment groups compared to the controls. Endotoxin challenge had no effect on either blood glucose levels or induction of TNF-alpha in any treatment group. PBMC from CrP-treated animals produced more IL-2 than peripheral blood mononuclear cells from all other groups.

New erbium doped glass base compositions and sensitizer ion concentrations have been investigated. Laser, spectral, and thermo-mechanical properties have been tested. This study has resulted in a new erbium doped phosphate laser glass that exhibits improved thermal shock resistance and superior laser performance.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Inflammatory responses are accompanied by increased expression of hepatocyte-derived proteins collectively known as acute phase reactants (APR). B6C3F1 female mice were exposed intraperitoneally every 24 hr to either vehicle (PBS) or DMN (5 mg/kg) for up to six exposures. Following a single treatment (acute), liver tissues were collected at 3, 6, 12, and 24 hr postexposure. The same collection scheme was repeated following the fourth and sixth exposures (subchronic). Total cellular RNA was isolated and Northern blot analyses were performed using 3′-end radiolabeled oligonucleotides specific for serum amyloid A (SAA), serum amyloid P (SAP), and albumin (ALB). SAA transcripts were detected 3 hr after acute DMN exposure, peaked at 6 hr, and rapidly declined to vehicle control levels by 12 hr. No SAA transcripts were observed in vehicle-treated controls. In contrast, SAP transcripts were constitutively expressed in both vehicle and DMN-treated groups throughout the acute exposure period. However, at 3 and 6 hr after DMN exposure, elevated levels of SAP transcripts were observed before returning to control levels at 12 and 24 hr. Expression of albumin transcripts decreased rapidly following acute DMN exposure and remained suppressed throughout the first 24-hr period measured. Serum levels of complement component-3 (C3) increased 2 hr after a single DMN exposure, whereas decreases in serum albumin levels were first observed at 24 hr post-exposure. After four exposures to DMN, SAA transcripts were detected at all time periods measured. Similarly, SAP transcripts in livers of DMN-exposed animals were consistently elevated above vehicle controls. Results after six exposures to DMN were similar, with SAA and SAP transcripts elevated at all time points tested. By comparison, repeated vehicle exposures resulted in a stress-related transient expression of SAA and SAP transcripts. Thus, acute and subchronic DMN exposure resulted in differential APR transcript expression and may serve as useful biomarkers following chemical exposure.

Faraday rotator glasses with high Verdet constants are used for optical isolators and sensors. Based on the Tb2O3 -B2O3-Al2O3- SiO2 system and the effect of each component on glass formation, glass compositions were selected for development of new Faraday rotator glasses. Devitrification of Tb-glass was studied by microscopic morphology to establish the production process. Dispersion of Verdet constant and the influence of Tb3+ concentration on Verdet constant were investigated. Special technology was utilized for production of platinum-free glass. The quenching process is necessary to obtain crystal-free glass. Three kinds of Faraday rotator glass with higher Verdet constant than that of M16 have been developed. The higher Verdet constant glass is possible to obtain.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Altered immune functions have been demonstrated in mice following exposure to dimethylnitrosamine (DMN). In particular, changes in cell-mediated immune responses resulted from chronic DMN exposure in vivo. Since cytokines are potent immunoregulatory peptides, experiments were performed to determine whether DMN exposure results in the induction of serum-borne inflammatory cytokines. Animals were exposed to either vehicle (PBS) or DMN (5.0 mg/kg) every 24 hr for 14 days. Serum and liver samples were obtained from individual mice at 0, 1, 2, 3, 6, 12, and 24 hr following the first exposure, with additional samples collected every 24 hr preceding the daily DMN exposure. Sera were then analyzed for IL-1 beta, IL-3, IL-6, CSF-1, GM-CSF, and TNF-alpha activities using either biological or immunological assays. In addition, liver total cellular RNA was probed for the induction of IL-1 beta transcripts using the solution hybridization/RNase protection assay. IL-1 beta, IL-6, and TNF-alpha serum activities were observed within 2 hr of DMN exposure and returned to vehicle control levels by 3 days even though DMN exposure was maintained. Chronic expression of cytokine activity (after 72 hr) was only observed for GM-CSF. A rapid induction of IL-1 beta transcripts (within 1 hr) in both vehicle and DMN-treated animals was observed by solution hybridization. However, by 3 hr postexposure, transcript levels decreased in the vehicle-treated animals while remaining elevated in the DMN-treated animals for 6 hr. These results demonstrated that DMN exposure in vivo induced: (1) the expression of serum-borne cytokine activities, and (2) IL-1 beta transcription in liver tissue.

DMN exposure has been shown to increase macrophage cytotoxic activity against tumor targets both in vitro and in vivo. Since the production and expression of the macrophage-derived cytokine tumor necrosis factor-alpha (TNF-alpha) is associated with such anti-tumor activity, studies were performed to determine whether changes in TNF-alpha gene transcription and biosynthesis resulted following DMN exposure. Thioglycollate-elicited macrophages obtained from DMN-exposed animals displayed enhanced levels of constitutively expressed TNF-alpha transcripts compared to vehicle controls. Northern blot analysis of the time course expression of TNF-alpha following endotoxin (1 microgram/ml) stimulation in vitro showed a significantly greater induction of TNF-alpha transcripts in macrophages from DMN-exposed than control animals, with peak levels detected between 30 and 120 min. Maximum endotoxin-induced TNF-alpha secretion occurred later than the accumulation of the transcripts, with greater secretion observed between 120 and 360 min. In contrast to endotoxin, stimulation with IFN-gamma (100 U/ml) produced no changes in the level of TNF-alpha transcripts. However, stimulation of macrophages with IFN-gamma did greatly enhance the surface expression of membrane-bound TNF-alpha in cells from the DMN-treated animals. Supernatants from media and endotoxin stimulated macrophage were tested for TNF-alpha activity against WEHI-164 cells. In media alone, a five-fold increase in TNF-alpha activity was observed at 6 h in supernatants from macrophage obtained from DMN-exposed animals compared to the vehicle group. Treatment of supernatants with either superoxide dismutase (SOD) or catalase to remove reactive oxygen products did not alter their lytic capacity. However, addition of a neutralizing murine-anti-TNF-alpha antibody reduced the lytic capacity of the supernatants by 90% in both treatment groups. Accumulation of IL-1 beta transcripts gradually increased over the 6 h with a concomitant increase in secreted IL-1 beta that was identical in both DMN and vehicle groups. These results demonstrate that DMN exposure: (1) enhances the expression of TNF-alpha in peripheral macrophages by transcriptional regulatory mechanism(s) and, (2) does not alter the expression or secretion of IL-1 beta.

Many applications exist for eye safe laser operating at high repetition rates. This paper will discuss the operation of Q-switched Er:glass lasers at high repetition rates with peak powers in the megawatt range.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We describe the fabrication and testing of antenna-coupled superconducting transition-edge bolometers for use at millimeter wavelengths. The design uses a double-slot dipole antenna connected to superconductingniobium microstrip. Band defining filters are implemented in the microstrip, which is then terminated with a load resistor. The power dissipated in the load resistor is measured by a superconducting transition-edge sensor (TES). The load resistor and TES are thermally well connected and are supported by a silicon nitride substrate. The substrate is suspended by four narrow silicon nitride legs for thermal isolation. The bolometers have been optically characterized and the spectral response is presented. This detector is a prototype element for use in an array designed for studies of the cosmic microwave backgroundpolarization.

A new Er 31 -doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO3 molten salt is developed. The ion-exchange process of this glass is investigated by treating glass samples in a variety of salt baths with various exposure times. A planar waveguide with one mode at 1.54 mm and three modes at 632.8 nm is demonstrated. The spectral properties of Er 31 in this glass are charac- terized by measuring absorption and emission spectra and fluorescence lifetimes. The emission cross section of Er 31 in this glass is calculated to be 0.76310 20 cm 2 using McCumber theory. © 1998 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(98)02012-1)

A flowing water system is described for culture of brachyuran crab larvae. This system, which is suitable for toxicant exposure studies, employs a flow reversal principle, and a minimal area of screen placed low on the side of the culture containers. The design minimizes the problem of larval entrapment in water exit screens. Survival of Cancer magister zoeae in rearing tests lasting up to 60 days compared favorably with survivals obtained previously using static culture methods.

Dimethylnitrosamine (DMN) exposure in vivo affects hematopoiesis at the level of CFU-GM precursor cells. This effect on hematopoiesis has been shown to be an indirect consequence of DMN exposure; therefore, we examined serum from animals exposed to DMN in vivo for the presence of hematopoietic growth factor activity. Serum obtained from animals exposed to DMN in vivo supported colony formation in normal bone marrow stem cells whereas serum obtained from untreated or vehicle-exposed animals failed to support colony formation. Differential staining of the cells which arose following the in vitro culture of normal bone marrow cells with serum from DMN-exposed animals demonstrated the presence of cells of the monocytic and granulocytic lineages. Pre-treatment of serum from DMN-exposed animals with anti-CSF-1 antibodies prior to in vitro culture had no affect on either cell number, cell phenotype or colony-stimulating activity, suggesting the presence of GM-CSF. Administration of serum from DMN-exposed animals to naive recipient animals resulted in increased percentages of both blood-borne monocytes and neutrophils, mimicking the profile observed in DMN-exposed animals. Studies using oligonucleotide-directed PCR demonstrated the presence of GM-CSF transcripts in the livers obtained following DMN exposure. These results demonstrate the presence of a serum-borne activity(ies) following DMN exposure, most likely GM-CSF, which is capable not only of enhancing macrophage and granulocyte hematopoiesis but also of increasing the numbers of these two cell types in the blood.

Estradiol has been reported to suppress numerous cellular immune response. What is not known is how estradiol exerts this effect. In vivo administration of estradiol to male rats caused time-related immunomodulatory effects leading to enhancement of lymphocyte transformation while suppressing a mixed lymphocyte reaction (MLR) response. The suppression of the MLR response was not due to alterations in the ratio of helper and suppressor T cells, nor was it due to alterations in either cell viability or the number of cells in culture. Lymphocytes cultured in vitro with estradiol, however, fail to show any alteration in the resposiveness in either MLR or lymphocyte transformation assays. The suppressive effects of estradiol cannot be transfered from a primary MLR culture to a second MLR culture using the supernatants from the primary MLR culture. Lymphocytes from animals given estradiol in vivo show no alteration in the production of interleukin 2: added in vitro to primary MLR cultures, Interleukin 2 failed to restore full responsiveness to lymphocytes from animals treated in vivo with estradiol. These results suggest that estradiol acts indirectly to cause an alteration in the responsiveness of the regulatory cells of the cellular immune system.

Estradiol has previously been shown to suppress the response of the cellular immune system of the rat while enhancing the production of IgM antibodies. Analysis of the cytosol from rat splenocytes showed saturation of specific binding sites at concentrations of between 80 and 160 nM [3H]-estradiol with an approximate Kd of 12 nM. Competitive binding studies showed a dose-dependent decrease in the binding of [3H]-estradiol to the receptor in the presence of increasing concentrations of unlabeled estradiol. Dexamethasone, progesterone and R1881 (synthetic androgen) had no effect on the binding of [3H]-estradiol. The in vivo administration of estradiol resulted in increased nuclear binding of [3H]-estradiol as compared to vehicle treated controls. These results indicate that rat splenocytes possess specific, translocatable estrogen receptors which may be responsible for the observed modulation of the immune system.

These studies examined the cellular targets of benzo[a]pyrene (BaP)-induced immunomodulation. The immunocompetence of murine mononuclear leukocytes was evaluated following in vivo exposure to BaP. In vitro cell separation and reconstitution techniques were used to evaluate T-dependent antibody (TDAb) production and delineate the immunomodulatory events. Reconstitution of cultures using combinations of adherent and nonadherent cell populations from BaP- and vehicle-treated mice demonstrated that both of these populations were sensitive to the immunomodulatory effects of BaP. Examination of the adherent cell population demonstrated that low numbers of BaP-exposed accessory cells enhanced in vitro TDAb responses. These responses were greater than those observed for analogous cultures containing vehicle-exposed accessory cells. Recombination of separated B cells and T cells from vehicle- or BaP-treated mice in cultures containing normal adherent cells demonstrated that both B cells and T cells were sensitive to the effects of BaP. Cultures containing BaP-exposed cell populations were incapable of supporting control level antibody responses. The results indicate that in vivo BaP exposure induces immunomodulation through effects on macrophages, B cells, and T cells.

Results from our laboratory have demonstrated that the alteration in cellular immunity (CMI) resulting from exposure to dimethylnitrosamine (DMN) in vivo is due to changes in myelopoiesis. Bone marrow stem cells showed no alterations in their capacity to generate CFU-S (pleuripotent stem cells) nor were there any changes in the number of CFU-Mix colonies (IL-3 responsive stem cells) arising from the bone marrow of DMN exposed mice. However, the generation of G/M-CSF and CSF-1 responsive colonies (CFU-G/M and CFU-M) were altered, resulting in an increase in the number of colonies. G/M-CSF colonies generated from the bone marrow stem cells obtained from DMN exposed mice also had increased numbers of cells produced by each colony (total cells/CFU). Indirect immunofluorescence studies demonstrated no changes in the granulocyte/macrophage subsets following G/M-CSF stimulation of bone marrow stem cells obtained from DMN exposed mice. However, there was no change in the total number of cells generated by CSF-1 from the marrows of DMN exposed mice as compared to vehicle treated mice. Marrow cells from DMN exposed mice cultured in vitro with G/M-CSF showed both a shift in their peak proliferative response from 48-72 h to 30-60 h and an increased proliferative response. These same marrow cells showed no shift in their kinetics but a decrease in their proliferative response to CSF-1. Examination of the sera from DMN exposed mice for alterations in the regulatory factors controlling myelopoiesis demonstrated a net decrease of CSF-1 activity but no changes in the concentrations of two inhibitory factors, transferrin and lactoferrin.(ABSTRACT TRUNCATED AT 250 WORDS)

B6C3F1 mice were exposed to the environmental carcinogen benzo(a)pyrene, a well known immunosuppressant. The ability of isolated splenocytes to produce and respond to the immunoregulatory molecules interleukin-2 (IL-2) and interleukin-3 (IL-3) was measured. Significant suppression by BaP of IL-2, but not IL-3, production following BaP exposure was observed. Further, exogenous recombinant IL-2 reconstituted the ability of splenocytes from benzo(a)pyrene treated mice to generate IgM antibody producing cells to the T-dependent antigens of sheep red blood cells. These results indicate that one of the cellular target(s) of BaP induced immunosuppression may be the mechanism(s) responsible for lymphokine production and regulation by activated T cells.