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This study investigates the role of geometrically necessary dislocations (GNDs) and microstructure on void nucleation and growth in wrought and additively manufactured (AM) tantalum subjected to high-strain rate loading. Multi-modal 3D data was collected using TriBeam tomography to calculate GND densities and their spatial relationship to voids. A microstructural comparison between the wrought and AM samples identified distinct void shapes and locations, with intragranular voids and more spherical voids frequently observed in the AM dataset. Results indicate that voids preferentially form at both high-angle grain boundaries and low-angle subgrain boundaries, the latter of which are frequently observed in the AM material. Through a radial distribution analysis of all voids in the datasets, significant GND localization to near-void-surface regions was observed in both samples. 3D crystal plasticity simulations were employed to extend the experimental observations, revealing higher void growth rates in [111] oriented grains when compared to [001] grains. The simulations also suggest that GNDs can be generated as part of the void growth process, with more GND accumulation for growth in a [111] grain than a [001] grain. These findings provide valuable insights into the links between nanoscale void nucleation, mesoscale void growth, and microstructural effects in dynamically loaded tantalum.

As technologies are woven deep into the fabric of our postdigital society and universities, there is a need to devise new research methods, and to seek out new kinds of research material, in order to better understand our complex and changing surroundings. One such approach, I argue in this article, involves creating and analysing music playlists as a way of critically exploring the learning spaces and practices of higher education. To make this argument, I describe and discuss the ways that music playlists contributed towards an ethnographic study of undergraduate courses in Architecture and History at a UK university. This involved inviting students to participate in the creation of ‘study playlists’, as I sought to understand how their learning spaces and practices were affected by digital technologies. This approach initially helped to establish rapport and trust with participants, as well as eliciting conversation and interview discussion which surfaced how students use streamed playlists and other digital technologies to negotiate personalised learning spaces. By helping to reveal these and other rituals, the music playlist was shown to work as an ethnographic artefact, while at the same time exposing the postdigital character of the contemporary university.

IMPORTANCE: Magnetic resonance imaging (MRI) guidance offers multiple theoretical advantages in the context of stereotactic body radiotherapy (SBRT) for prostate cancer. However, to our knowledge, these advantages have yet to be demonstrated in a randomized clinical trial. OBJECTIVE: To determine whether aggressive margin reduction with MRI guidance significantly reduces acute grade 2 or greater genitourinary (GU) toxic effects after prostate SBRT compared with computed tomography (CT) guidance. DESIGN, SETTING, AND PARTICIPANTS: This phase 3 randomized clinical trial (MRI-Guided Stereotactic Body Radiotherapy for Prostate Cancer [MIRAGE]) enrolled men aged 18 years or older who were receiving SBRT for clinically localized prostate adenocarcinoma at a single center between May 5, 2020, and October 1, 2021. Data were analyzed from January 15, 2021, through May 15, 2022. All patients had 3 months or more of follow-up. INTERVENTIONS: Patients were randomized 1:1 to SBRT with CT guidance (control arm) or MRI guidance. Planning margins of 4 mm (CT arm) and 2 mm (MRI arm) were used to deliver 40 Gy in 5 fractions. MAIN OUTCOMES AND MEASURES: The primary end point was the incidence of acute (≤90 days after SBRT) grade 2 or greater GU toxic effects (using Common Terminology Criteria for Adverse Events, version 4.03 [CTCAE v4.03]). Secondary outcomes included CTCAE v4.03–based gastrointestinal toxic effects and International Prostate Symptom Score (IPSS)–based and Expanded Prostate Cancer Index Composite-26 (EPIC-26)–based outcomes. RESULTS: Between May 2020 and October 2021, 156 patients were randomized: 77 to CT (median age, 71 years [IQR, 67-77 years]) and 79 to MRI (median age, 71 years [IQR, 68-75 years]). A prespecified interim futility analysis conducted after 100 patients reached 90 or more days after SBRT was performed October 1, 2021, with the sample size reestimated to 154 patients. Thus, the trial was closed to accrual early. The incidence of acute grade 2 or greater GU toxic effects was significantly lower with MRI vs CT guidance (24.4% [95% CI, 15.4%-35.4%] vs 43.4% [95% CI, 32.1%-55.3%]; P = .01), as was the incidence of acute grade 2 or greater gastrointestinal toxic effects (0.0% [95% CI, 0.0%-4.6%] vs 10.5% [95% CI, 4.7%-19.7%]; P = .003). Magnetic resonance imaging guidance was associated with a significantly smaller percentage of patients with a 15-point or greater increase in IPSS at 1 month (6.8% [5 of 72] vs 19.4% [14 of 74]; P = .01) and a significantly reduced percentage of patients with a clinically significant (≥12-point) decrease in EPIC-26 bowel scores (25.0% [17 of 68] vs 50.0% [34 of 68]; P = .001) at 1 month. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, compared with CT-guidance, MRI-guided SBRT significantly reduced both moderate acute physician-scored toxic effects and decrements in patient-reported quality of life. Longer-term follow-up will confirm whether these notable benefits persist. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04384770

Background: The worldwide usage of [18F]-sodium fluoride in clinical applications has increased the interest in the facility of its production. The development of a new automated method for multi-preparations of [18F]-NaF and [18F]FDG on an Explora FDG4 module is described. Explora FDG4 is one of the most widely used synthesizers for FDG production in daily routine use and is specifically designed to run up to four different productions with a single module. Therefore, slight modifications are carried out in order to increase the potential of the synthesizer to perform more radiopharmaceuticals. Methods: A fully automated method for multi-preparations of [18F]-NaF and [18F]FDG using Explora FDG4 was developed. Slight modifications to the Exploras hardware and software configuration were applied. A new elution vial for NaF preparation was installed and connected to the free position to MVP1. Quality control was carried out using the standard analytical methods applied for GMP production. Results: This modification successfully provides preparation of [18F]-NaF without affecting the daily FDG production using one set preparation. [18F]-NaF was obtained in a high radiochemical yield (>90%, n=100) in 10 min total preparation time. The quality control results for both obtained products, FDG (RCP >95%) and NaF (RCP >98%), showed that the radiopharmaceuticals were in compliance with USP and Ph.Eur. specifications and compatible with clinical applications. Conclusion: A rapid and simple method for multi preparations of [18F]-NaF and [18F]FDG using a single Explora module was designed. Yet, the chemistry module has the potential to generate more radiopharmaceuticals to decrease the cost of preparation of [18F]-NaF compared to the cassette-based synthesizers, reducing radiation exposure resulting from manual preparations and increasing the reproducibility of [18F]-NaF preparation.

The objective was to determine if 3-axis accelerometers could be used to predict daily activity for cattle grazing rangeland. There were 48 Hereford × Angus 2-yr-old low- or high-residual feed intake (LRFI or HRFI) cows used in this 2-yr trial. Cattle grazed in 4 pasture treatments consisting of continuously grazed, control (CCON); continuously grazed, supplemented (CTRT); rotationally grazed, control (RCON); and rotationally grazed, supplemented pastures (RTRT). Three LRFI- and 3 HRFI-collared cows in each treatment had accelerometers mounted for 29 d in 2016 and 45 d in 2017, beginning mid-October. Grazing time (GT), resting time (RT), and walking time (WLK) were obtained for each cow by direct observation over 3 d each year and compared with accelerometer predicted behavior. In 2016, 1.6% of the days were rejected for halter-mounted accelerometers and 3.6% were rejected in 2017 for collar-mounted accelerometers. The GT and RT were more accurately predicted than was WLK with the percentage error of predicted against observed data being 11.94% for RT, 13.51% for GT, and 30.13% for WLK in 2017. Less observation data were available in 2016, but when considering other sampling periods for the same cows and halters, the error rate was 15.1% for RT, 19.3% for GT, and 52.6% for WLK. The accelerometers successfully identified patterns of grazing behavior and differentiated among climatic, grazing system, supplementation status, and residual feed intake classification influences on GT, RT, and WLK. In a more moderate climate year, HRFI cattle appeared to rest less (P< 0.08) and walk more (P< 0.07) than LRFI cattle. Similar patterns were observed for cattle in the CCON versus CTRT treatments, with supplemented cattle resting more (P< 0.05) and walking less (P< 0.05). Accelerometers appear to be effective in determining mechanistic adaptations in grazing behavior by beef cattle on range.

An adjoint-space optimization technique is presented for the large-scale optimization (i.e., optimization with over 104design variables) of PEM fuel cell microstructure. The algorithm is based on evaluation of sensitivity functions of the cell discharge voltage under specified current conditions. The sensitivity functions are found by solving sparse linear systems of equations to find the Gâtaux derivatives of the discharge voltage with respect to the design variables. The optimization technique is applied to electrolyte distribution and carbon distributions within the cathode catalyst layer, to describe a profile of carbon, electrolyte, and porosity of a PEMFC cathode catalyst layer on a point-by-point basis.

We have developed a programmable, fast switching, accurate, and miniaturized calibration load for use in millimeter and submillimeter low-noise amplifier characterization, and Earth/planetary science radiometers. The proposed solution uses a thermally conductive waveguide vane attenuator with low thermal mass, integrated heater, and silicon thermometer. In the present design, we utilize a 125-$\mu$ m-thick z-cut crystal quartz vane due to its low dielectric constant (relative to silicon), high cryogenic thermal conductivity, chemical robustness, and small thermal contraction. To provide adequate attenuation, the bottom side of the quartz fabrication wafer has an nm thick resistive Ti metal layer deposited. On the top of the quartz wafer, a pattern of Au is deposited to allow adhesion of the heater resistor, thermometer, and internal heat strap. The z-cut quartz vane is mounted on three low thermally conductive Torlon posts, centered on the maximum E-field, and positioned across the waveguide. With this approach the quartz vane, protruding all the way into the waveguide, approximates a blackbody with a physical temperature T. The design uniqueness lies in the choice of cryogenically suitable materials coupled with detailed thermal analyses and proper miniaturization. When operated in a proportional$-$integral $-$derivative loop, these properties combine to facilitate a programmable calibration load with a switching speed of $\lesssim$10 s. It will be shown that the W-band design operates overmoded to $\sim$230 GHz and that the concept is in principle scalable to terahertz frequencies.

In this paper the sensitivity of proton exchange membrane fuel cells (PEMFCs) parameters to catalyst variations is analyzed using the adjoint method. The adjoint method is used to compute the catalyst sensitivity functions, which show how much a given parameter of the cell increases by adding one unit mass of Pt at a given location in the catalyst layers. Numerical results are presented for the sensitivity of polarization voltage at different values of the operating current for a 25 um membrane PEMFC. The results show that the catalyst sensitivity functions depend on the operating current and voltage, as well as the catalyst distribution.

An adjoint-space technique is presented for the large-scale optimization (i.e. optimization with over 102 design variables) of the catalyst distribution in fuel cells. The algorithm is based on evaluating the catalyst sensitivity functions of the discharge voltage under specified current conditions. The catalyst sensitivity functions are computed efficiently using a gradient maximization algorithm, which requires solving a small number of sparse linear systems of equations to find the Gataux derivatives of the discharge current of the cell with respect to the design variables. It is shown that the optimum distribution of the catalyst varies with the discharge conditions, with the positions of landings and openings, as well as with the geometry and dimensions of the layers. It should be noted that our numerical algorithm can be used to describe the complete profile of the optimal catalyst by providing the full (mathematically exact) distribution of platinum particles in the catalyst layer.

In this article we present an adjoint method for the optimization of the catalyst distribution in proton exchange membrane fuel cells (PEMFCs). By using the theory of functional analysis we derive analytical equations for the sensitivity functions of the cell voltage with respect to the catalyst distribution in a very general framework, independent on the transport model used to simulate the PEMFC. Then we present an efficient numerical algorithm to calculate the sensitivity functions using the adjoint method. The adjoint method has the advantage that it can be applied to the optimization of systems with a large (>104) number of optimization variables that are computed simultaneously and independently to maximize the objective function. Finally, we apply the method to the optimization of 2-D platinum distribution in PEMFCs. We show that the optimum platinum distribution varies with the operating conditions, position of landings and openings, cell geometry, and dimensions of the catalyst layers. The method presented in this work can be naturally extended to the optimization of other 2-D and 3-D field variables such as the porosity of catalyst and gas diffusion layers, particle size distribution, or microstructure of the cell.

Here we examine photolithography methodologies to improve the efficiency of foundry and ASIC manufactures that have many part numbers with relatively low run volumes. In such cases, a fab must accommodate a large variety of device layers, topography dispersion, and layout parameters. These factors reduce the lithography process margin and limit design freedom and throughput in the lithography module. These factors also increase design complexity, optical proximity correction (OPC) design loops, mask cost, exposure dose, and number of material sets to meet layer requirements. Consequently, these factors impact the fab's overall efficiency. The primary method proposed to improve efficiency is to use a system that includes a planarizing etch transfer layer, an image transfer layer, and an image capture layer. By combining these elements, the lithography process becomes very predictable, simple, and repeatable, independent of the device

We present 0.''15 resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best-fit model corresponds to 0.06 M , which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability.

We present the first sample of 31 GHz selected sources to flux levels of 1 mJy. From late 2005 to mid-2007, the Sunyaev-Zel'dovich Array observed 7.7 deg2 of the sky at 31 GHz to a median rms of 0.18 mJy beam-1. We identify 209 sources at greater than 5s significance in the 31 GHz maps, ranging in flux from 0.7 mJy to [?]200 mJy. Archival NVSS data at 1.4 GHz and observations at 5 GHz with the Very Large Array are used to characterize the sources. We determine the maximum-likelihood integrated source count to be N(>S) = (27.2 +- 2.5)deg-2 x (S mJy)-1.18+-0.12 over the flux range 0.7-15 mJy. This result is significantly higher than predictions based on 1.4 GHz selected samples, a discrepancy which can be explained by a small shift in the spectral index distribution for faint 1.4 GHz sources. From comparison with previous measurements of sources within the central arcminute of massive clusters, we derive an overdensity of 6.8 +- 4.4, relative to field sources.

We present 30 GHz measurements of the angular power spectrum of the cosmic microwave background (CMB) obtained with the Sunyaev-Zel'dovich Array. The measurements are sensitive to arcminute angular scales, where secondary anisotropy from the Sunyaev-Zel'dovich effect (SZE) is expected to dominate. For a broad bin centered at multipole 4066, we find 67+77 -50 mK2; of which 26 +- 5 mK2 is the expected contribution from primary CMB anisotropy and 80 +- 54 mK2 is the expected contribution from undetected radio sources. These results imply an upper limit of 155 mK2 (95% CL) on the secondary contribution to the anisotropy in our maps. This level of SZE anisotropy power is consistent with expectations based on recent determinations of the normalization of the matter power spectrum, i.e., s8 [?] 0.8.

We report on Combined Array for Research in Millimeter-Wave Astronomy and James Clerk Maxwell Telescope observations toward the Einstein source 1E 1740.7-2942, a low-mass X-ray binary commonly known as the "Great Annihilator." The Great Annihilator is known to be near a small, bright molecular cloud in a region largely devoid of emission in 12CO surveys of the Galactic center. This region is of interest because it is interior to the dust lanes which may be the shock zones where atomic gas from the HI nuclear disk is converted into molecular gas. We find that the region is populated with a large number of dense (n [?] 105 cm-3) regions of excited gas with small filling factors. The gas appears to have turbulent support and may be the result of sprays of material from collisions in the shock zone. We estimate that [?](1-3) x 105 M of shocked gas resides in our r [?] 3', Dv LSR = 100 km s-1 field. If this gas has recently shocked and is interior to the inner Lindblad resonance of the dominant bar, it is in transit to the x 2 disk, suggesting that a significant amount of mass may be transported to the disk by a low filling factor population of molecular clouds with low surface brightness in larger surveys.

We investigate the utility of a new, self-similar pressure profile for fitting Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters. Current SZ imaging instruments-such as the Sunyaev-Zel'dovich Array (SZA)-are capable of probing clusters over a large range in a physical scale. A model is therefore required that can accurately describe a cluster's pressure profile over a broad range of radii from the core of the cluster out to a significant fraction of the virial radius. In the analysis presented here, we fit a radial pressure profile derived from simulations and detailed X-ray analysis of relaxed clusters to SZA observations of three clusters with exceptionally high-quality X-ray data: A1835, A1914, and CL J1226.9+3332. From the joint analysis of the SZ and X-ray data, we derive physical properties such as gas mass, total mass, gas fraction and the intrinsic, integrated Compton y-parameter. We find that parameters derived from the joint fit to the SZ and X-ray data agree well with a detailed, independent X-ray-only analysis of the same clusters. In particular, we find that, when combined with X-ray imaging data, this new pressure profile yields an independent electron radial temperature profile that is in good agreement with spectroscopic X-ray measurements.

We report measurements of the Sunyaev-Zel'dovich (SZ) effect in three high-redshift (0.89 [?] z [?] 1.03), X-ray selected galaxy clusters. The observations were obtained at 30 GHz during the commissioning period of a new, eight-element interferometer--the Sunyaev-Zel'dovich Array (SZA)--built for dedicated SZ effect observations. The SZA observations are sensitive to angular scales larger than those subtended by the virial radii of the clusters. Assuming isothermality and hydrostatic equilibrium for the intracluster medium and gas-mass fractions consistent with those for clusters at moderate redshift, we calculate electron temperatures, gas masses, and total cluster masses from the SZ data. The SZ-derived masses, integrated approximately to the virial radii, are 1.9img1.gif x 1014 M for Cl J1415.1+3612, 3.4img2.gif x 1014 M for Cl J1429.0+4241, and 7.2img3.gif x 1014 M for Cl J1226.9+3332. The SZ-derived quantities are in good agreement with the cluster properties derived from X-ray measurements.

Background:The aim of this 9‐month reentry study was to compare the regenerative healing using porous (P) and nonporous (NP) teflon barrier membranes plus demineralized freeze dried bone allografts (DFDBA) in Class II buccal/lingual furcation defects. Methods:Twenty‐four patients, 13 males and 11 females, ages 38 to 75 (mean 54 ± 10), were included in this study. Each patient had adult periodontitis and one Class II furcation defect measuring ≥3 mm open horizontal probing depth. Twelve patients were randomly selected to receive the NP treatment and 12 received the P membrane. All defects received a DFDBA graft. Measurements were performed by a masked examiner. Results:No statistically significant differences (P>0.05) were found between NP and P groups at any time with respect to any open or closed measure. Improvement in mean open horizontal probing depth was significant for both the NP (2.33 ± 0.78 mm) and P (2.75 ± 0.75 mm) groups. Mean clinical attachment level gains at 9 months were significant for both NP (1.50 ± 1.62 mm) and P (2.50 ± 2.11 mm) groups. Seventeen of 24 defects had an intrabony component and ≥50% fill was obtained in 100% of these defects. Conclusions:The results of this 9‐month reentry study comparing the use of porous and non‐porous barrier membranes with a DFDBA graft indicate that there were no statistically significant differences between groups. Both groups showed a statistically significant improvement following the treatment of Class II furcation defects in humans. J Periodontol 2001;72:1580‐1587.

Background:The primary aim of this randomized, controlled, blinded clinical investigation was to determine if orientation of an acellular dermal matrix (ADM) allograft, basement membrane side against the tooth or connective tissue side against the tooth, affected the percent root coverage. Additional aims were to: 1) compare results of this study with results obtained from other root coverage studies; 2) determine if multiple additional sites could be successfully covered with the same surgery; 3) determine the effect of the procedure on keratinized tissue; and 4) evaluate the amount of creeping attachment obtained. Methods:Ten patients with 2 Miller Class I or II buccal recession defects ≥3 mm were treated with a coronally positioned flap plus ADM and followed for 12 months. Test sites received ADM with the basement membrane side against the root (AB), while the control sites received the connective tissue side against the root (AC). Multiple additional recession sites were treated with the same flap procedure. Results:Mean baseline recession for the AB sites was 4.2 mm and for the AC sites, 3.7 mm. Mean root coverage of 95% was obtained for both AB and AC sites. Sixty‐eight additional Class I or II AB and AC sites obtained about 93% root coverage. The mean increase in keratinized tissue for both treatments was 0.80 mm. No additional root coverage was gained due to creeping attachment between 2 and 12 months. Conclusions:Treatment with ADM was an effective and predictable procedure for root coverage. The orientation of the material did not affect the treatment outcome for any of the parameters tested. J Periodontol 2001;72:571‐582.

This paper gives an analysis of the behavior of polarizing grids and reflecting polarizers by solving Maxwell's equations, for arbitrary angles of incidence and grid rotation, for cases where the excitation is provided by an incident plane wave or a beam of radiation. The scattering and impedance matrix representations are derived and used to solve more complicated configurations of grid assemblies. The results are also compared with data obtained in the calibration of reflecting polarizers at the Owens Valley Radio Observatory. From this analysis, we propose a method for choosing the optimum grid parameters (wire radius and spacing). We also provide a study of the effects of two types of errors (in wire separation and radius size) that can be introduced in the fabrication of a grid.

A series of grooved dielectric quarter-wave plates was made for radio astronomical Zeeman splitting observations at millimeter wavelengths. To meet the stringent requirements on reflection and polarization purity, a design method was formulated based on optimization of multiple reflections. The method solves the problem of achieving low reflections for both polarization components while attaining high purity of circular polarization. Several plates have been manufactured, tested, and used successfully for astronomical observations.

The reproductive and developmental toxicity of styrene has been studied in animals and humans. The animal studies on styrene have diverse study designs and conclusions. Developmental or reproductive toxicity studies have been conducted in rats, mice, rabbits, and hamsters. In most cases, high doses are required to elicit effects, and the effects are not unique to reproduction or development. In a number of the reports, either the experimental designs are limited or the descriptions of the designs and the endpoints measured are insufficient to draw conclusions about the toxicity of styrene. The more complete and better-reported studies show that styrene does not cause developmental toxicity at dose levels that are not maternally toxic. Some neurochemical or neurobehavioral effects have been reported at high exposures. Styrene does not affect fertility or reproductive function. Considerable animal toxicity data on styrene support the conclusion that styrene is neither an endocrine-active substance nor an endocrine disrupter. Human studies often suffer from either inadequate exposure data or exposure to a wide variety of materials, so that attribution of effects to styrene exposure is impossible. Furthermore, investigators often have failed to account for other exposures in the workplace or for other potentially confounding factors in their studies. Menstrual cycle irregularities and congenital abnormalities were initially reported; however, the better and more recent reports do not show that styrene causes developmental or reproductive effects in humans. Human studies also support the conclusion that styrene is not an endocrine disrupter. Although some study authors have concluded that styrene is either a human or an animal reproductive or developmental toxicant, careful review demonstrates that such conclusions are not justified.

The Agricultural Health Study (AHS) has approximately 90,000 pesticide applicators and their spouses enrolled in a number of studies to determine whether exposures to specific pesticides are associated with various cancers and other adverse health outcomes. Although the AHS was intended to be an integrated program of studies, some significant difficulties have emerged. In this report, we examine the design of the AHS, identify important program strengths and flaws, suggest various improvements in the program, and recommend ancillary studies that could be undertaken to strengthen the AHS. Overall, the AHS is collecting a large amount of information on potential determinants of health status among farmers and farm families. A promising feature of the AHS is the prospective cohort study of cancers among farmers in which the research design determines exposures prior to the diagnosis of disease. More effort needs to be devoted to reducing selection bias and information bias. Success of the cohort study will depend in part on follow-up surveys of the cohort to determine how exposures and disease states change as the cohort ages. The cross-sectional and case-control studies planned in the AHS are less promising because they will be subject to some of the same criticisms, such as potentially biased and imprecise exposure assessment, that have characterized the existing literature in this field. Important limitations of the AHS include low and variable rates of subject response to administered surveys, concerns about the validity of some self-reported non-cancer health outcomes, limited understanding of the reliability and validity of self-reporting of chemical use, an insufficient program of biological monitoring to validate the exposure surrogates employed in the AHS questionnaires, possible confounding by unmeasured, nonchemical risk factors for disease, and the absence of detailed plans for data analysis and interpretation that include explicit, a priori hypotheses. Although the AHS is already well underway, most of these limitations can be addressed by the investigators if adequate resources are made available. If these limitations are not addressed, the large amounts of data generated in the AHS will be difficult to interpret. If the exposure and health data can be validated, the scientific value of the AHS should be substantial and enduring. A variety of research recommendations are made to strengthen the AHS. They include reliability and validity studies of farmer reporting of chemical use, biological monitoring studies of farmers and members of farm families, and validity studies of positive and negative self-reports of disease status. Both industry and government should consider expanded research programs to strengthen the AHS.

Diisononyl phthalate (DINP) is one of several dialkyl phthalate esters that are widely used as plasticizers to impart softness and flexibility to normally rigid polyvinyl chloride (PVC) products. During the past 2 years, concern has been voiced by public interest groups and regulatory agencies in Europe, Canada, and the United States regarding the potential adverse health effects of DINP migrating from children's toys during mouthing activities. Concern has focused on potential chronic effects on the kidney and liver. In chronic high-dose studies with rodents, DINP causes a dose-related decrease in body weight, an increase in liver weight, and changes in liver cell histopathology (hypertrophy). To a lesser extent, the rodent kidney is also a target for prolonged high-level exposures of DINP. Prolonged high-level exposure of rodents to DINP leads to an increased incidence of liver tumors (adenomas and carcinomas). The chronic cancer and noncancer effects of DINP on rodent liver are consistent with its known action as a peroxisome proliferator. Peroxisome proliferation is a threshold-based effect that is reversible on cessation of exposure to proliferators such as DINP. Because rodents are uniquely responsive and humans and nonhuman primates are particularly nonresponsive to peroxisome proliferators, rodents are very poor animal models for use in human risk assessment of adverse effects mediated through peroxisome proliferation. Because DINP exerts its effects on rodent liver through a known threshold-based mechanism of little, if any, relevance to humans, a highly conservative risk assessment can be conducted using a NOAEL uncertainty factor approach. Chronic rodent no-observed-effect levels (NOELs) based on end points such as increased liver weight and changes in liver pathology that are early indicators of peroxisome proliferation but should not be considered adverse range from about 100 to 400 mg/kg/day. Application of a 100-fold uncertainty factor yields acceptable daily intakes (ADIs) ranging from 1 to 4 mg/kg/day. Estimates of DINP migration from soft PVC materials have been obtained from a variety of in vitromethods (simulated saliva and controlled agitation) as well as in vivomethods (controlled chewing) that more closely resemble child chewing and mouthing activities. Recent estimates by the Consumer Product Safety Commission (CPSC) suggest that maximum exposures occur in infants 3–12 months of age. The geometric mean (50th percentile) exposure is 5.7 μg/kg/day and the 95th percentile is 94.3 μg/kg/day. These exposure values are 17,500–70,000 and 1100–4200 times, respectively, lower than the chronic rodent NOAEL for DINP and 175–700 and 11–42 times lower than the corresponding ADI of 1–4 mg/kg/day. It is concluded, with a high degree of confidence, that the use of DINP in soft PVC toys and other children's products does not present a significant risk to children. The scientific evidence supports the continued use of DINP as a plasticizer in children's products.

Routine processing of testicular tissue through 10% neutral buffered formalin (NBF) into paraffin produces severe cellular shrinkage which obscures most of the morphologic detail. The following studies were performed to compare different combinations of immersion fixatives and embedding media for optimal cellular detail in the final histologic sections. We examined sections of testes from rats, mice, and rabbits fixed in either NBF, Bouin's, Zenker's, or Helly's fixatives, and embedded in either standard paraffin or glycol methacrylate. The results were similar in all 3 species. In paraffin, Bouin's or Helly's fixatives produced the fewest artifacts, while in glycol methacrylate, NBF-fixed tissue showed the greatest intracellular detail and preservation. The merits and limitations of each method are discussed for the rat, with exceptions for the other species noted where appropriate. The use of glycol methacrylate as the support medium for sectioning makes high-quality tissue sections available from formalin-fixed testes.

Exposure in utero to the synthetic estrogen diethylstilbestrol (DES) is associated with reproductive tract lesions in male and female CD-1 mice. The scanning electron microscope was used to evaluate the luminal surface of the vagina, cervix, and uterus following prenatal exposure to DES. Abnormalities that have been observed include urethral openings in the cervicovaginal area, squamous metaplasia of the uterus, glandular elements in the vagina, and abnormal cell surface features in the vaginal epithelium.

Circular grooves are frequently cut in dielectric lenses and windows to form antireflection layers. These induce a phase difference between polarisation components, with consequent loss of power into cross-polarisation and a phase error similar to astigmatism. Expressions derived for these losses show that the losses are generally small compared to the insertion losses of an unmatched surface. For several consecutive surfaces the effects may be quite significant.

Several parameters of various materials, including solid and foam dielectrics, absorbers, and metals, are collected for use in optical design in the millimetre and submillimetre range. Although the list is not exhaustive it covers most of the important materials and parameters, and extensive references are given.

Recently, a major topic of discussion has been the impact of synthetic chemicals that possess the capacity to alter hormonal activity, the so-called "endocrine modulators," with potentially the capacity to alter the reproductive capability of humans. Particularly, various synthetic pesticides and industrial chemicals that persist in the environment and/or bioac-cumulate have been implicated. Further, it has been alleged that the standard tests for pesticide registration as required by the U.S. Environmental Protection Agency (EPA) and other regulatory agencies may be inadequate to detect endocrine modulating effects. To address these shortcomings, it has been proposed that very specific tests for estrogen receptor binding, or in vitro cell response to chemicals, be used to identify potential endocrine modulators. However, such approaches have certain flaws that limit their application as screens. First, very specific tests, like receptor binding, evaluate only a single chemical event per test. Such tests do not measure toxicity or biological response. Isolated systems are very important for studying mechanisms of action or structure activity relationships, but can only provide a preliminary screen for a single mechanism of toxicity. Isolated systems can not be used to regulate a chemical without additional information. Second, they fail to test many other parts of the neuroendocrine control of the reproduc-tive system. Testing for adverse effects in highly specific in vitro systems failed to replace whole-animal models in carcinogenesis and will also fail in reproductive toxicology because this system is too complicated for such as in vitro approach to be accurately predictive. Advanced tests, such as the EPA multigeneration study, are more effective and reliable means for evaluation than any specific and narrowly focused screening tests. Experience has shown that a better approach to testing chemicals is to evaluate their effects on the whole animal. When one part of the system is adversely affected, various processes may be indirectly affected and can be detected in the animal model. For example, a modulation of testosterone synthesis could lead to (1) altered accessory sex organ morphology, size, and function; (2) decreased sperm counts; and (3) even decreased fertility. These and many other effects would be noted in toxicity studies that are already required for the registration of crop protection chemicals. The developmental and reproductive toxicity guidelines were recently reviewed in a hearing that included the representatives from the EPA, the public, and the Scientific Advisory Panel. The EPA kept the basic study design the same, but added a few new endpoints to further assess chemical-induced effects on reproductive development and function. The review presented herein concentrates on the required Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) testing for pesticides, and demonstrates how the massive arrays of sensitive endocrine endpoints that are delineated in FIFRA Subdivision F have been successfully used to detect both weak and potent hormonally modulating chemicals. For example, (1) diethyl-stilbestrol (DES), which is a potent synthetic therapeutic estrogen, (2) DDT, which is weakly estrogenic but persistent and bioaccumulating, and (3) dioxins, which have anti-estrogenic properties, were all found as being hormonally active in tests similar or identical to FIFRA tests. All food-use pesticides have been evaluated using a comprehensive multi-generation reproduction test. Hence, the FIFRA testing procedures have been demonstrated to identify endocrine modulators of sufficient potency to represent a concern to human health.

We present new results from global VLBI observations of the highly active blazar OJ 287 at 7 and 3 mm wavelengths. We show the first map of the mas to sub-mas structure of OJ 287 at 43 GHz and discuss this image in the context with models of the source structure seen at 100 GHz.

Germanium: silver (Ge:Ag) composite thin films having different concentrations of Ag, ranging from 7% to 40%, have been prepared by dc cosputtering of Ge and Ag. The films' surface morphology and optical properties have been characterized using transmission electron microscopy and infrared spectrophotometry. It is seen that, although the films that contain lower concentrations of Ag have islandlike morphology (i.e., Ag particles distributed in a Ge matrix), the higher metallic concentration films tend to have a symmetric distribution of Ag and Ge. The optical constants (i.e., refractive index n and absorption index k) derived from the measured optical properties show a semiconductor behavior even as high as 40% of Ag concentration, beyond which the metallic properties dominate over the entire infrared spectrum. Comparison of the n and k data with the two well-known effective medium theories, namely, the Maxwell-Garnett theory and the Bruggeman theory, shows that both theories have limited scope in predicting the optical properties of semiconductor–metal composite films in the infrared region. However, an empirical polynomial equation can simulate the experimental data at all wave numbers of the IR spectrum.

Filters are required to block infrared radiation from the low temperature regions of cryogenic receivers to reduce thermal loading and temperature gradients. The design and analysis of PTFE filters mounted on the radiation shield of a closed-cycle Joule-Thompson 4 K refrigerator is described. Calculations of the thennal transmission and emission of the filters are compared with measurements. It was found that the filters were not as effective as expected since the heat sinking of the material to the radiation shield was poor, but the overall heat load was less than anticipated since a thermal gradient developed across the polystyrene foam vacuum window, reducing its infrared emission.

During the estrous cycle, the mouse reproductive tract undergoes a number of specific morphological changes. The alterations which occur in the luminal surface of the vagina, cervix and uterus were studied by scanning electron microscopy (SEM). The stage of estrus was identified by vaginal observation, cytology and histology. The lumen of the reproductive tract was observed with the SEM at low powers of magnification as well as at the subcellular level. Surface epithelial alterations associated with mucification and keratinization of vaginal epithelium were identified by SEM; changes in the squamocolumnar junction were studied as were the cyclic variations in the mouse endometrium.This study was done to characterize the morphological appearance of the normal female mouse reproductive tract and thereby establish a normal baseline for the evaluation of samples from subsequent studies of corresponding pathologic tissue. A comparison of the similarity of the epithelial characteristics observed in normal cervix and vagina at diestrus to those in cells described by other investigators in reportedly dysplastic tissue demonstrates the need for this type of systematic approach in SEM studies.