CBETA: First Multipass Superconducting Linear Accelerator with Energy Recovery.

Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.

Cotransport of graphene oxide and Cu(II) through saturated porous media.

This study examines the cotransport of graphene oxide (GO) and Cu in porous media. The impacts of GO concentration and ion strength (IS) on Cu transport in laboratory packed columns were investigated. The results indicated that GO had fairly high mobility at a IS of 1mM, and could serve as an effective carrier of Cu(II). The facilitated transport was found to increase with increasing concentration of GO (CGO). The peak effluent concentration (C/C0)max of Cu was 0.57 at CGO of 120mg/L and IS=1mM and 0.13 at 40mg/L and IS=1mM. The Cu appears to be irreversibly adsorbed by the sand because no Cu appeared in the effluent in the absence of GO. However, the GO-facilitated Cu transport was reduced as the IS increased from 1 to 1000mM. In fact, the facilitated transport was zero percent at an IS of 1000mM. Particle size analysis, Zeta potential measurements and DLVO calculations demonstrated that higher IS values made the GO became unstable and it flocculated and attached to the sand. We also fed GO into the column pre-equilibrated by Cu as sequential elution experiments and found that the later introduced GO can complex the pre-adsorbed Cu from the sand surface because GO has a higher adsorption affinity for Cu. An advection-dispersion-retention numerical model was able to describe the Cu and GO transport in the column. Our work provides useful insights into fate, transport and risk assessment of heavy metal contaminants in the presence of engineered nanoparticles.

Expansion of long-acting gas bubbles for intraocular use. Principles and practice.

Expansion of long-acting gas bubbles used in vitreoretinal surgery may lead to increased intraocular pressure and central retinal artery occlusion. To further understand the principles controlling the expansion of long-acting gases, we compared the expansion of perfluoropropane gas bubbles with that of sulfur hexafluoride gas bubbles in an in vitro model, as well as in rabbits. We found that perfluoropropane bubbles expand more rapidly and to a greater extent than do sulfur hexafluoride bubbles in the first 24 hours. The early rate of expansion of a long-acting gas is largely dependent on convection of the surrounding fluid and is independent of the type of long-acting gas. Early postoperative monitoring of intraocular pressure is, therefore, equally important when using any long-acting gas.

Semen analysis in human immunodeficiency virus infection.

OBJECTIVE: To examine the effect of human immunodeficiency virus (HIV) infection on semen quality and to investigate the role of clinical stage of infection, mode of virus acquisition, and azidothymidine (AZT) treatment. DESIGN, PATIENTS, MAIN OUTCOME MEASURES: Ejaculates from 39 HIV-seropositive men and 51 seronegative controls were compared using conventional semen analysis parameters. Centers for Disease Control (Atlanta, GA) classification and peripheral blood CD4 lymphocyte count of seropositive men were recorded at the time of semen analysis. Five patients provided semen before and after AZT treatment. RESULTS: Semen from seropositive men contained significantly fewer motile sperm (48.8% versus 58.8%, P = 0.001), more round cells (62% versus 28% subjects with density greater than 1 x 10(6)/mL, P = 0.003), and was more viscous (1.3 versus 0.5 cm, P less than 0.05) than semen from seronegative controls. The proportion of motile sperm was correlated with absolute number (r = 0.49, P = 0.004) and percentage (r = 0.37, P = 0.03) of CD4-positive lymphocytes in peripheral blood. Total sperm output, however, was preserved and was not correlated with lymphocyte count or symptomatic disease. Administration of AZT had no deleterious effect on sperm output or other semen variables. CONCLUSION: Human immunodeficiency virus infection per se does not significantly reduce sperm production, regardless of clinical stage or mode of acquisition; however, HIV-seropositive men produce more viscous semen containing fewer motile sperm and more round cells.

A model for predicting contaminant removal by adsorption within the International Space Station water processor: 1. Multicomponent equilibrium modeling.

A thermodynamic model is developed to predict adsorption equilibrium in the International Space Station water processor's multifiltration beds. The model predicts multicomponent adsorption equilibrium behavior using single-component isotherm parameters and fictitious components representing the background matrix. The fictitious components are determined by fitting total organic carbon and tracer isotherms with the ideal adsorbed solution theory. Multicomponent isotherms using a wastewater with high surfactant and organic compound concentrations are used to validate the equilibrium description on a coconut-shell-based granular activated carbon (GAC), coal-based GAC, and a polymeric adsorbent.

Catalytic wet oxidation: mathematical modeling of multicompound destruction.

A mathematical model of a three-phase catalytic reactor, CatReac, was developed for analysis and optimization of a catalytic oxidation reactor that is used in the International Space Station potable water processor. The packed-bed catalytic reactor, known as the volatile reactor assembly (VRA), is operated as a three-phase reactor and contains a proprietary catalyst, a pure-oxygen gas phase, and the contaminated water. The contaminated water being fed to the VRA primarily consists of acetic acid, acetone, ethanol, 1-propanol, 2-propanol, and propionic acid ranging in concentration from 1 to 10 mg/L. The Langmuir-Hinshelwood Hougen-Watson (L-H) (Hougen, 1943) expression was used to describe the surface reaction rate for these compounds. Single and multicompound short-column experiments were used to determine the L-H rate parameters and calibrate the model. The model was able to predict steady-state multicomponent effluent profiles for short and full-scale reactor experiments.

Dilatation balloons: polymer selection, balloon design and assembly.

The current status of coronary dilating instruments is presented from the designer's perspective. Catheter shaft design is considered by important features, common catheter materials and types of catheter construction. Among the seven companies manufacturing balloon dilating instruments, only three types of catheter and four materials are offered. Balloon design is presented by important features and by materials selected. Performance comparisons are made between the three materials used to fabricate dilating balloons: PVC, PE and PET.

Density adjustment of software settings minimizes bias in automated sperm motility estimation.

To minimize overestimation of motility, it is recommended that fresh semen be diluted with seminal plasma prior to automated analysis. However, for glycerolated or cryopreserved semen this is impractical, and alternative methods are needed to minimize automated motility bias. In the present study, the proportion of motile spermatozoa was determined in fresh, diluted and cryopreserved semen (n = 25 ejaculates) using visual and automated methods. The effect of software settings on motility was investigated by assessing samples at a range of modified settings. At standard settings, automated motility was biased in fresh semen (+7.2%) after dilution with cryopreservative (-2.9%) and after cryopreservation (-7.8%) (P < 0.0001 versus visual). Automated motility was inversely related to the minimum number of frames for motility sampling (P < 0.0001), with mean estimates of 41.0, 46.1, 52.0 and 58.2% generated at settings of 8, 4, 2 and 1 frame(s) respectively (n = 15 fresh, diluted and cryopreserved samples). Based on an arbitrary ordinal scale, a method was developed whereby motility sampling was adjusted prior to analysis according to sperm density. Analysis of an independent set of semen samples with density-adjusted software settings reduced bias in automated estimates (n = 30) before and after freezing (P < 0.0001). In addition, bias was no longer related to sperm density. In conclusion, modification of software settings is an effective alternative to dilution to minimize bias in automated motility estimates in fresh, diluted and cryopreserved human semen.

Gel shift and UV cross-linking analysis of Tetrahymena telomerase.

Telomerase is an unusual ribonucleoprotein that synthesizes new telomeres onto chromosome ends. The enzyme has been most extensively characterized in ciliates, where the RNA component has been cloned from several species, and its elongation properties have been characterized in detail. To understand the substrate specificity and protein composition of telomerase, we have used gel shift and UV cross-linking to characterize the enzyme from the ciliate Tetrahymena thermophila. In a mobility shift assay, a complex was identified that contained telomerase RNA, co-purified with telomerase activity, and was sensitive to nuclease treatment. The mobility shift complexes specifically formed using several different single-stranded, telomeric sequences but not non-telomeric primers. These results suggest that the specificity of telomerase for G-rich primer sequences occurs at least in part at the level of primer binding. UV cross-linking analysis identified a 100-kDa cross-linked protein that may be a telomerase component.

Outpatient treatment of lumbar disc sciatica.

Of 47 patients with lumbar disc disease and sciatic radiculopathy (L-5 or S-1), 39 were successfully managed at home and as outpatients in an ambulatory care facility designed for the treatment of arthritis and back pain. When these patients were evaluated one to three years following discharge, they maintained their maximum level of activity and functional improvement noted at discharge. The average total cost per patient including physician's fees, x-rays, laboratory and therapy was approximately equivalent to the day rate for 1(1/2) days in hospital.

Long-term clinical and manometric follow-up of patients with nonspecific esophageal motor disorders.

In the manometric evaluation of patients complaining of chest pain, a nonspecific esophageal motor disorder is commonly identified. Yet, the clinical characteristics of these patients and stability of the manometric pattern with time have not been previously described. This study reports a 3.2-yr clinical and manometric follow-up of 23 patients with nonspecific esophageal motor disorder. These subjects were most commonly middle-aged women with long-standing, persistent, and debilitating clinical symptoms. Ninety-six percent (22/23) of our patients complained of chest pain; 65% (15/23) had dysphagia. In addition, 15 (65%) had evidence of reflux during ambulatory pH studies. Symptoms caused such concern that the patients frequently sought medical assistance to exclude serious diseases. Although the symptoms tended to persist, the motility patterns changed in some patients. Follow-up manometric studies were normal in 29%, and nonspecific esophageal motor disorder persisted in 57% of the patients. In three patients (14%), the pattern evolved into diffuse esophageal spasm. When symptoms were compared with these changes in follow-up manometric patterns, the correlation was poor. This observation suggests that additional mechanism(s) other than disturbed esophageal motility may be responsible for the symptoms seen in these individuals.

Lichen planopilaris-like changes arising within an epidermal nevus: does this case suggest clues to the etiology of lichen planopilaris?

BACKGROUND: Lichen planopilaris shows a perifollicular lymphocytic infiltrate at the level of infundibulum and the isthmus of the hair bulge resulting in necrotic changes within keratinocytes and eventually hair loss. OBJECTIVE: We present a 14-year-old black male with a history of a raised epidermal lesion on the scalp that was present at birth. Over the past few years, the patient developed gradual hair loss and increased verrucous changes of the skin within the original lesion. Histologic sections of the area showed features consistent with an epidermal nevus peripherally, with a central area showing some features characteristic of those seen in lichen planopilaris. In addition, there was marked hyperkeratosis with increased yeast and bacteria within the follicles. CONCLUSIONS: Initiating factors in lichen planopilaris are not well defined. Overgrowth of microorganisms with hyperkeratosis results in factors that disrupt the immune privilege of the hair follicle, leading to an immunologic reaction that is limited to the follicle and spares surrounding eccrine structures. This case suggests possible mechanisms involved in the induction of lichen planopilaris.

Adjuvant therapy with hyaluronidase prior to excision of dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) are uncommon, low grade cutaneous malignancies, which rarely metastasize. Although surgery is the main therapy for these tumors, they commonly recur in spite of wide excisions. Hyaluronidase (HD) has been used both intralesionally as well as intravenously as an adjuvant in therapy of both epithelial and mesenchymal malignancies to decrease local spread, to potentiate differentiation induced apoptosis, and to potentiate the tissue penetration of chemotherapeutic agents. In addition, there is a long history of intralesional HD use without significant complications. The biologic characteristics of DFSP including the observation that hyaluronic acid is commonly present and sometimes is increased in these tumors and the known effects of HD therapy in other malignancies suggested to us that HD pretreatment may be a helpful adjuvant in the surgical management of DFSPs. Following diagnostic biopsy of a recurrent DFSP, the patient was treated for 4 weeks with intralesional HD injections. RESULTS: Based on margins necessary for complete excision from past studies, this patient had decreased margin width and thus had a postoperative wound size less than was expected. The patient has had no evidence of recurrence at 24 months follow-up.

Does simplifying transport and exposure yield reliable results? An analysis of four risk assessment methods.

Four approaches for predicting the risk of chemicals to humans and fish under different scenarios were compared to investigate whether it is appropriate to simplify risk evaluations in situations where an individual is making environmentally conscious manufacturing decisions or interpreting toxics release inventory (TRI) data: (1) the relative risk method, that compares only a chemical's relative toxicity; (2) the toxicity persistence method, that considers a chemical's relative toxicity and persistence; (3) the partitioning, persistence toxicity method, that considers a chemical's equilibrium partitioning to air, land, water, and sediment, persistence in each medium, and its relative toxicity; and (4) the detailed chemical fate and toxicity method, that considers the chemical's relative toxicity, and realistic attenuation mechanisms such as advection, mass transfer and reaction in air, land, water, and sediment. In all four methods, the magnitude of the risk was estimated by comparing the risk of the chemical's release to that of a reference chemical. Three comparative scenarios were selected to evaluate the four approaches for making pollution prevention decisions: (1) evaluation of nine dry cleaning solvents, (2) evaluation of four reaction pathways to produce glycerine, and (3) comparison of risks for the chemical manufacturing and petroleum industry. In all three situations, it was concluded that ignoring or simplifying exposure calculations is not appropriate, except in cases where either the toxicity was very great or when comparing chemicals with similar fate. When the toxicity is low to moderate and comparable for chemicals, the chemicals' fate influences the results; therefore, we recommend using a detailed chemical fate and toxicity method because the fate of chemicals in the environment is assessed with consideration of more realistic attenuation mechanisms than the other three methods. In addition, our study shows that evaluating the risk associated with industrial release of chemicals (e.g., the toxics release inventory) may be misleading if only mass emissions are considered.

Efficient isolation and mapping of rad genes of the fungus Coprinus cinereus using chromosome-specific libraries.

We have constructed cosmid libraries from electrophoretically separated chromosomes of the basidiomycete Coprinus cinereus. These libraries greatly facilitate the isolation of genes by complementation of mutant phenotypes and are particularly useful for map-based cloning strategies. From a library constructed from two co-migrating C.cinereus chromosomes, we isolated a clone that complements the C.cinereus rad9-1 mutation. Examination of this clone showed that it complements both the repair and meiotic defects of this mutant. Restriction fragment length polymorphism mapping using a portion of this clone showed that it maps to the rad9 locus. In addition, a single copy of transforming DNA is sufficient to complement the rad9-1 defects. Thus, we believe we have cloned the rad9 gene itself. We also used a chromosome-specific library and backcrossed isolates to rapidly identify a cosmid clone which is tightly linked to the rad11 locus and is therefore a suitable starting point for a chromosome walk. These rapid methods of gene mapping and isolation should be applicable to any organism with separable chromosomes.

Tripartite mushroom body architecture revealed by antigenic markers.

We have explored the organization of the axonal lobes in Drosophila mushroom bodies by using a panel of immunohistochemical markers. These markers consist of antibodies to eight proteins expressed preferentially in the mushroom bodies: DAMB, DCO, DRK, FASII, LEO, OAMB, PKA RII, and RUT. Previous to this work, four axonal lobes, two projecting dorsally (alpha and alpha') and two medially (beta and gamma), had been described in Drosophila mushroom bodies. However, our analysis of immunohistochemically stained frontal and sagittal sections of the brain revealed three medially projecting lobes. The newly distinguished lobe, which we term beta', lies along the dorsal surface of beta, just posterior to gamma. In addition to resolving a fifth lobe, our studies revealed that there are specific lobe sets defined by equivalent marker expression levels. These sets are (1) the alpha and beta lobes, (2) the alpha' and beta' lobes, and (3) the gamma lobe and heel (a lateral projection formed by a hairpin turn of some of the peduncle fibers). All of the markers we have examined are consistent with these three sets. Previous Golgi studies demonstrate that each mushroom body cell projects one axon that branches into a dorsal lobe and a medial lobe, or one unbranched axon that projects medially. Taken together with the lobe sets listed above, we propose that there are three major projection configurations of mushroom body cell axons: (1) one branch in the alpha and one in the beta lobe, (2) one branch in the alpha' and one in the beta' lobe, and (3) one unbranched axon projecting to the heel and the gamma lobe. The fact that these neuron types exhibit differential expression levels of a number of mushroom body genes suggests that they may have corresponding functional differences. These functions may be conserved in the larvae, as several of these genes were expressed in larval and embryonic mushroom bodies as well. The basic mushroom body structure, including the denritic calyx, peduncle, and lobes, was already visible by the late stages of embryogenesis. With new insights into mushroom body organization, and the characterization of markers for developing mushroom bodies, we are beginning to understand how these structures form and function.

Neurocristic cutaneous hamartoma: a distinctive dermal melanocytosis with an unknown malignant potential.

Neurocristic hamartomas (NCHs) result from aberrant development of the neuromesenchyme. In addition to a dermal melanocytic component, these tumors can contain neurosustentacular and fibrogenic components and can undergo malignant transformation. Although NCHs have many features in common with other dermal melanocytic neoplasms, including cellular blue nevi and some congenital nevi, they have distinctive clinical and histologic features. We present a case report of a 27-year-old white woman with an NCH of the scalp. The clinical, histologic, and immunohistochemical features are compared with those of other dermal melanocytic neoplasms. The NCH contained epithelioid pigmented melanocytes positive for S-100 and HMB45, within which there were well-circumscribed nodules of S-100+/Leu 7+/HMB45- cells surrounded by a capsule composed of spindle cells positive for epithelial membrane antigen. The stromal cells throughout the tumor were diffusely CD34 positive, and hair follicles were decreased and dystrophic within the tumor. NCHs represent neoplastic dysplasia that involves not only melanocytic cells but also neurosustentacular and fibrocytic effector cells. The histologic and immunohistochemical features, along with the decreased and dystrophic hair follicles, suggest that the abnormalities in the mesenchyme are significant and result from the contribution of neural crest cells to the cellular and matrix components of the mesenchyme.