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1.
Phys Rev Lett ; 133(12): 121004, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39373410

RESUMO

We report results from an analysis aimed at detecting the trispectrum of the kinematic Sunyaev-Zel'dovich (kSZ) effect by combining data from the South Pole Telescope (SPT) and Herschel-SPIRE experiments over a 100 deg^{2} field. The SPT observations combine data from the previous and current surveys, namely SPTpol and SPT-3G, to achieve depths of 4.5, 3, and 16 µK-arcmin in bands centered at 95, 150, and 220 GHz. For SPIRE, we include data from the 600 and 857 GHz bands. We reconstruct the velocity-induced large-scale correlation of the small-scale kSZ signal with a quadratic estimator that uses two cosmic microwave background (CMB) temperature maps, constructed by optimally combining data from all the frequency bands. We reject the null hypothesis of a zero trispectrum at 10.3σ level. However, the measured trispectrum contains contributions from both the kSZ and other undesired components, such as CMB lensing and astrophysical foregrounds, with kSZ being sub-dominant. We use the agora simulations to estimate the expected signal from CMB lensing and astrophysical foregrounds. After accounting for the contributions from CMB lensing and foreground signals, we do not detect an excess kSZ-only trispectrum and use this nondetection to set constraints on reionization. By applying a prior based on observations of the Gunn-Peterson trough, we obtain an upper limit on the duration of reionization of Δz_{re,50}<4.5 (95% confidence level). We find these constraints are fairly robust to foregrounds assumptions. This trispectrum measurement is independent of, but consistent with, Planck's optical depth measurement. This result is the first constraint on the epoch of reionization using the non-Gaussian nature of the kSZ signal.

2.
J Low Temp Phys ; 199(3-4)2020.
Artigo em Inglês | MEDLINE | ID: mdl-33487736

RESUMO

We describe the design and measurement of feedhorn-coupled, transition-edge sensor (TES) polarimeters with two passbands centered at 220 GHz and 280 GHz, intended for observations of the cosmic microwave background. Each pixel couples polarized light in two linear polarizations by use of a planar orthomode transducer and senses power via four TES bolometers, one for each band in each linear polarization. Previous designs of this detector architecture incorporated passbands from 27 to 220 GHz; we now demonstrate this technology at frequencies up to 315 GHz. Observational passbands are defined with an on-chip diplexer, and Fourier-transform-spectrometer measurements are in excellent agreement with simulations. We find coupling from feedhorn to TES bolometer using a cryogenic, temperature-controlled thermal source. We determine the optical efficiency of our device is η = 77% ± 6% (75% ± 5%) for 220 (280) GHz, relative to the designed passband shapes. Lastly, we compare two power-termination schemes commonly used in wide-bandwidth millimeter-wave polarimeters and find equal performance in terms of optical efficiency and passband shape.

3.
Phys Rev Lett ; 123(18): 181301, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31763885

RESUMO

We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500 deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

4.
J Low Temp Phys ; 193(3-4)2018.
Artigo em Inglês | MEDLINE | ID: mdl-34815585

RESUMO

Microwave Kinetic Inductance Detectors (MKIDs) provide a compelling path forward to the large-format polarimeter, imaging, and spectrometer arrays needed for next-generation experiments in millimeter-wave cosmology and astronomy. We describe the development of feedhorn-coupled MKID detectors for the TolTEC millimeter-wave imaging polarimeter being constructed for the 50-meter Large Millimeter Telescope (LMT). Observations with TolTEC are planned to begin in early 2019. TolTEC will comprise ∼7,000 polarization sensitive MKIDs and will represent the first MKID arrays fabricated and deployed on monolithic 150 mm diameter silicon wafers - a critical step towards future large-scale experiments with over 105 detectors. TolTEC will operate in observational bands at 1.1, 1.4, and 2.0 mm and will use dichroic filters to define a physically independent focal plane for each passband, thus allowing the polarimeters to use simple, direct-absorption inductive structures that are impedance matched to incident radiation. This work is part of a larger program at NIST-Boulder to develop MKID-based detector technologies for use over a wide range of photon energies spanning millimeter-waves to X-rays. We present the detailed pixel layout and describe the methods, tools, and flexible design parameters that allow this solution to be optimized for use anywhere in the millimeter and sub-millimeter bands. We also present measurements of prototype devices operating in the 1.1 mm band and compare the observed optical performance to that predicted from models and simulations.

5.
Phys Rev Lett ; 111(14): 141301, 2013 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-24138230

RESUMO

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

6.
Rev Sci Instrum ; 83(9): 093113, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23020368

RESUMO

Improvements in superconductor device fabrication, detector hybridization techniques, and superconducting quantum interference device readout have made square-centimeter-sized arrays of gamma-ray microcalorimeters, based on transition-edge sensors (TESs), possible. At these collecting areas, gamma microcalorimeters can utilize their unprecedented energy resolution to perform spectroscopy in a number of applications that are limited by closely-spaced spectral peaks, for example, the nondestructive analysis of nuclear materials. We have built a 256 pixel spectrometer with an average full-width-at-half-maximum energy resolution of 53 eV at 97 keV, a useable dynamic range above 400 keV, and a collecting area of 5 cm(2). We have demonstrated multiplexed readout of the full 256 pixel array with 236 of the pixels (91%) giving spectroscopic data. This is the largest multiplexed array of TES microcalorimeters to date. This paper will review the spectrometer, highlighting the instrument design, detector fabrication, readout, operation of the instrument, and data processing. Further, we describe the characterization and performance of the newest 256 pixel array.

7.
Cytotechnology ; 5(3): 223-31, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1367549

RESUMO

A model mammalian cell system for the production of recombinant proteins was investigated. Murine myeloma cells which had lost the ability to produce both heavy and light chain immunoglobulin molecules were transfected with a vector containing the immunoglobulin heavy chain promoter and enhancer elements linked to the human growth hormone gene. The growth kinetics of G32, a clonal isolate, were found to be similar to both the parent myeloma and hybridomas. However, production of hGH by G32 was growth associated, rather than as a secondary metabolite as is the case for hybridomas. In addition, G32 produced hGH at molar levels greater than most hybridomas.


Assuntos
Hormônio do Crescimento/genética , Proteínas Recombinantes/genética , Transfecção , Células Tumorais Cultivadas , Animais , Divisão Celular , Glucose/metabolismo , Hormônio do Crescimento/biossíntese , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Leves de Imunoglobulina/genética , Cinética , Lactatos/metabolismo , Camundongos , Regiões Promotoras Genéticas , Proteínas Recombinantes/biossíntese
8.
Parasite Immunol ; 9(5): 615-26, 1987 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3684328

RESUMO

The proteins and antigens of different life stages of Trichostrongylus colubriformis were compared with those of Ostertagia circumcincta in an attempt to identify the subset of parasite molecules that is genus-specific and that may therefore be involved in the induction of genus-specific, host-protective immunity. Novel short-term culture techniques were instituted to label biosynthetically the proteins of the infective larval and adult stages of the parasites using 35S-methionine. High resolution, two-dimensional electrophoretic profiles of the labelled proteins indicated that the majority of proteins synthesized by adults were also present in the larval stages. Qualitative differences in the levels of these common proteins were observed, indicating differences in protein expression or turnover. There was extensive homology between larvae from the different species, with only eight major differences apparent in their profiles of biosynthetically-labelled proteins. Western blot analysis using immune sheep sera indicated that extensive homology also existed between the antigens of T. colubriformis and O. circumcincta larvae.


Assuntos
Antígenos de Helmintos/análise , Ostertagia/imunologia , Proteínas/análise , Trichostrongylus/imunologia , Animais , Reações Cruzadas , Eletroforese em Gel de Poliacrilamida , Imunoensaio , Marcação por Isótopo , Larva/imunologia , Ostertagia/análise , Especificidade da Espécie , Trichostrongylus/análise
9.
Cell ; 45(2): 269-80, 1986 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-2421919

RESUMO

Evidence is presented that the IIb-IIIa glycoprotein complex, which functions as the receptor for fibrinogen on platelets and is central to platelet aggregation, is expressed on the surface of leukocytes where it may function as a receptor for fibronectin. F(ab')2 fragments of a monoclonal antibody, 25E11, raised against activated large granular lymphocytes, inhibited killing by natural killer cells, blocked the binding of fibronectin-coated particles by monocytes, and stimulated neutrophils to exhibit increased antibody-dependent killing. Immunoprecipitation studies of leukocytes and platelets, and the ability of 25E11 to inhibit platelet aggregation, identified the antigen as an epitope on the IIb-IIIa complex. This glycoprotein thus constitutes the first example of a receptor mediating both platelet aggregation and leukocyte adhesion.


Assuntos
Adesão Celular , Leucócitos/citologia , Agregação Plaquetária , Receptores de Superfície Celular/fisiologia , Adulto , Anticorpos Monoclonais/imunologia , Criança , Citotoxicidade Imunológica , Epitopos/imunologia , Fibronectinas/metabolismo , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Células Matadoras Naturais/imunologia , Glicoproteínas da Membrana de Plaquetas , Receptores de Fibronectina , Receptores Imunológicos/metabolismo , Trombastenia/imunologia , Trombastenia/patologia
10.
Mol Biochem Parasitol ; 18(3): 333-42, 1986 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3515179

RESUMO

A cloned library of DNA complementary to the mRNA of adult Schistosoma japonicum has been prepared and expressed as fusion proteins with Escherichia coli beta-galactosidase. Colonies expressing the S. japonicum cDNA clones were screened both with antibodies from individuals with a history of schistosomiasis and with antibodies obtained from a rabbit immunized with whole adult worms. In both cases colonies were detected which bound antibody, although the frequency of antigen-positive clones was much higher with the rabbit antiserum than with human sera. In both cases the proportion of colonies reacting with antibodies was markedly lower than that published for equivalent screens of Plasmodium falciparum cDNA with sera from individuals with a history of falciparum malaria. Several major S. japonicum antigens were identified by the affinity purification of antibodies using immobilised fusion proteins produced during lytic growth of the recombinant bacteriophage.


Assuntos
Antígenos de Helmintos/genética , Proteínas Recombinantes/genética , Schistosoma japonicum/imunologia , Anticorpos/isolamento & purificação , Cromatografia de Afinidade , Clonagem Molecular , DNA/genética , Escherichia coli/genética , Regulação da Expressão Gênica , Vetores Genéticos , Schistosoma japonicum/genética
11.
J Immunol Methods ; 86(2): 217-23, 1986 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-3511153

RESUMO

Portions of nitrocellulose filters containing blotted electrophoresed antigens of Schistosoma japonicum adult worms were reacted with polyclonal rabbit antisera raised to this human parasite. Eluted antibodies were used as probes for detection of antigen-positive clones in an Escherichia coli lambda gt11 amp3 expression library of adult worm cDNA. Several cloned antigens corresponding to a S. japonicum antigen of Mr 26 000, being sought as a candidate vaccine molecule in a mouse model of schistosomiasis japonica, were identified using this approach. The method provides an antibody reagent that is an attractive alternative to other more tedious means of producing oligospecific antibodies, including monoclonal antibodies, for screening of expression libraries.


Assuntos
Antígenos de Helmintos/genética , Schistosoma japonicum/imunologia , Animais , Anticorpos/imunologia , Antígenos de Helmintos/imunologia , Precipitação Química , Clonagem Molecular , DNA/genética , Técnicas de Imunoadsorção , Schistosoma japonicum/genética
12.
Parasite Immunol ; 7(2): 165-78, 1985 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-4000700

RESUMO

Serum antibody responses of mice exposed to Philippine isolates of Schistosoma japonicum have been analysed by immunoprecipitation of exogenously radiolabelled antigens extracted from adult worms. Attention was focused on labelled protein antigens differentially recognized by sera of mice that differ genetically in their resistance status. Mice of the inbred strain 129/J can show high level resistance to first or repeated infection with S. japonicum. Even after six percutaneous administrations of 25 cercariae, approximately 50% of 129/J mice remain healthy with no or very few worms present in the portal system. Sera from 129/J mice exposed to S. japonicum consistently and differentially recognise an antigen of adult worms of mol. wt. 26,000. This antigen, termed Sj26, is not immunoprecipitated from S. mansoni adult worms by sera from resistant 129/J mice. Serum antibodies to Sj26 are present in at least some patients with a history of schistosomiasis japonica. Whether immune responses to Sj26 are involved directly in expression of resistance to S. japonicum remains to be determined. However, this antigen produced by cloned DNA in expression vectors, or isolated from adult worms, is an obvious candidate to be tested for vaccination efficacy in mice.


Assuntos
Antígenos de Helmintos/imunologia , Schistosoma japonicum/imunologia , Esquistossomose/imunologia , Animais , Formação de Anticorpos , Antígenos de Helmintos/análise , Precipitação Química , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Soros Imunes , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos/genética , Proteínas/análise
13.
JAMA ; 249(21): 2883, 1983 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-6842798

RESUMO

KIE: A physician whose daughter died of cancer outlines the progress of her illness and the aggressive treatment regimen that prolonged her suffering. Citing E. Cassell's article, "The nature of suffering and the goals of medicine," which appeared in the 16 March 1982 issue of the New England Journal of Medicine, Beall reminds physicians of the need to understand suffering and exercise mercy when deciding between aggressive treatment and palliative care for terminally ill patients.^ieng


Assuntos
Cuidados para Prolongar a Vida/psicologia , Neoplasias/terapia , Estresse Psicológico , Assistência Terminal , Adulto , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/terapia , Feminino , Humanos , Neoplasias/psicologia , Assistência Terminal/psicologia , Revelação da Verdade
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