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2.
Eur J Radiol ; 156: 110492, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36108480

RESUMO

OBJECTIVES: Septic shock is a potentially fatal condition. This study aims to assess whether iodine uptake and iodine density of abdominal organs on dual-layer spectral detector computed tomography (SDCT) could serve as a new imaging biomarker for patients in septic shock. METHODS: Here, 95 patients who received contrast-enhanced abdominal CT examinations were included and separated into two groups: group A - septic shock; group B - no shock condition. Preselected abdominal (right and left adrenal gland, right and left kidney, infrarenal inferior vena cava (IVC), pancreas, spleen, and liver) localizations were independently evaluated by two radiologists, who measured iodine concentrations (mg/ml) and Hounsfield units (HU). RESULTS: In all, 1520 measurements of iodine concentrations in mg/ml and HU were performed, with 27 patients in group A and 68 in group B. Iodine concentrations in mg/ml and HU correlated significantly in all organs measured. The corresponding correlation coefficient (r) ranged from 0.809 (pancreas) to 0.963 (right kidney). Inter-rater reliability (IRR) was very good for mg/ml (κ = 0.8; p < 0.01) and good for HU (κ = 0.773; p < 0.01) measurements. The mean iodine concentration and HU of the adrenal glands in septic and nonseptic patients was 4.88 ± 1.16 mg/ml/153 ± 36 HU and 2.67 ± 1.07 mg/ml/112 ± 41 HU, respectively. Iodine concentrations in the adrenal glands were significantly higher in group A than in group B patients (p < 0.01). The other organs remained unaffected and no significant difference was observed between patients in group A and B. Patients in group A presented significantly more often with an iodine uptake of >3.5 mg/ml of one adrenal gland (sensitivity = 0.926, specificity = 0.849, AUC = 0.951) or/and a combined concentration of >7 mg/ml of both adrenal glands (sensitivity = 0.889, specificity = 0.836, AUC = 0.928). CONCLUSION: SDCT-derived iodine concentration of the adrenal glands could serve as a novel imaging biomarker for patients in acute septic shock. Our data suggest that an iodine uptake of >3.5 mg/ml of at least one adrenal gland or a combined iodine uptake of >7 mg/ml in both adrenal glands identifies patients in this condition.

3.
Magn Reson Imaging ; 93: 11-14, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35914655

RESUMO

BACKGROUND: The central vein sign (CVS) has been described in vivo in patients with MS but also in other inflammatory lesion of the brain such as neuromyelits optica spectrum disease and others. Recently, it has been used to differentiate patients with MS from other inflammatory lesions of the brain. OBJECTIVE: It was the goal of this study to demonstrate the feasibility of the depiction of the CVS in patients with inflammatory lesion of the upper cervical spinal cord using susceptibility weighted imaging (SWI). METHODS: Consecutive patients with inflammatory lesions of the upper cervical spinal cord were included. Patients were scanned using a 3 T Philips Ingenia CX. The presence of the CVS was assessed by two raters. Demographic and clinical parameters were compared between patients with and those without a CVS. RESULTS: 20 patients could be included. 15 patients had a diagnosis of MS. A CVS was present in 8 patients (40%). Agreement between the two raters was substantial (κ = 0.79). Time from first manifestation was significantly different (14 vs. 2 years, p = 0.021) between patients with CVS and without CVS. CONCLUSION: The depiction of the CVS in the upper cervical spine is feasible. More research is necessary to evaluate these preliminary results and the value of the CVS in the spinal cord.


Assuntos
Medula Cervical , Esclerose Múltipla , Encéfalo/patologia , Medula Cervical/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/patologia , Medula Espinal/diagnóstico por imagem , Medula Espinal/patologia
4.
Osteoarthritis Cartilage ; 30(2): 249-259, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34757027

RESUMO

OBJECTIVE: Patients with advanced knee osteoarthritis (KOA) frequently alter their gait patterns in an attempt to alleviate symptoms. Understanding the underlying pathomechanics and identifying KOA phenotypes are essential to improve treatments. We investigated kinematics in patients with KOA to identify subgroups of homogeneous knee joint kinematics. METHOD: A total of 66 patients with symptomatic KOA scheduled for total knee arthroplasty and 15 age-matched healthy volunteers with asymptomatic, non-arthritic knees were included. We used k-means clustering to divide patients into subgroups based on dynamic radiostereometry-assessed tibiofemoral joint kinematics. Clinical characteristics such as knee ligament lesions and KOA scores were graded by magnetic resonance imaging and radiographs, respectively. RESULTS: We identified four clusters that were supported by clinical characteristics. The flexion group (n = 20) consisted primarily of patients with medial KOA. The abduction group (n = 17) consisted primarily of patients with lateral KOA. The anterior draw group (n = 10) was composed of patients with medial KOA, some degree of anterior cruciate ligament lesion and the highest KOA score. The external rotation group (n = 19) primarily included patients with medial collateral and posterior cruciate ligament lesions. CONCLUSION: Based on tibiofemoral gait patterns, patients with advanced KOA can be divided into four subgroups with specific clinical characteristics and different KOA-affected compartments. The findings add to our understanding of how knee kinematics may affect the patient's development of different types of KOA. This may inspire improved and more patient-specific treatment strategies in the future.


Assuntos
Marcha , Articulação do Joelho/fisiopatologia , Osteoartrite do Joelho/classificação , Osteoartrite do Joelho/fisiopatologia , Idoso , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/diagnóstico por imagem , Análise Radioestereométrica
5.
Radiography (Lond) ; 27(2): 279-283, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32919898

RESUMO

INTRODUCTION: For patients with dementia, behaviour and reactions to stimuli can change and an X-ray examination in the hospital can have be a frightening experience. The aim of this study was to identify the experiences and perspectives of patients with dementia and their caregivers on receiving a mobile x-ray examination in nursing homes. METHODS: This study was designed as a qualitative study using patient observation and semi structured interviews, with a phenomenology-hermeneutic approach. In total, 23 patients were observed during X-ray examinations in nursing homes, and six semi structured interviews were conducted with the caregivers who participated in the examination. RESULTS: The observations and interviews indicated that a known environment, a recognizable framework and calmness were central for a patient with dementia. The patients appeared calm and relaxed during the examination in their usual environment (nursing homes) where there are less stimuli and impressions based of the observations. CONCLUSION: Mobile X-ray examinations for patients with dementia living in nursing homes had a positive impact on patients' reactions towards the X-ray examination. The examinations were performed in the patients' usual and safe environments, where impressions and stimuli were less disturbing for patients with dementia. IMPLICATIONS FOR PRACTICE: The mobile x-ray unit can be of benefit for patients suffering from dementia and result in less impact. The patients living in nursing homes have the opportunity to be examined in their familiar environment, because of the mobile x-ray unit.


Assuntos
Casas de Saúde , Humanos , Projetos Piloto , Pesquisa Qualitativa , Radiografia , Raios X
6.
J Appl Microbiol ; 129(2): 278-286, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32097516

RESUMO

AIMS: The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage moulds Penicillium expansum and Penicillium nordicum. METHODS AND RESULTS: Conidial germination of the tested Penicillium spp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4·4-16·7% at 7·5 mmol l-1 and completely inhibited at 15 mmol l-1 2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63·5 - 75·7% membrane damage upon treatment with 15 mmol l-1 2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth of P. expansum and P. nordicum was additionally confirmed. CONCLUSIONS: 2-phenylethanol inhibits conidial germination and growth of P. expansum and P. nordicum in a nonlethal, reversible and concentration-dependent manner. SIGNIFICANCE AND IMPACT OF THE STUDY: The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.


Assuntos
Antifúngicos/farmacologia , Penicillium/efeitos dos fármacos , Álcool Feniletílico/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Hifas/efeitos dos fármacos , Penicillium/crescimento & desenvolvimento , Percepção de Quorum , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
7.
Data Brief ; 28: 104836, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31871984

RESUMO

The present data article is based on the research work which investigates the influence of blends of diesel and renewable fuels on compression ignition engine emissions. In this experimental work, a 2.4 L, turbocharged, direct injection compression ignition engine and water brake dynamometer were used. Different ternary blends were created by mixing diesel, biodiesel and ethanol together in accordance with a mixture design of experiments. The homogeneity of each ternary blend was qualitatively checked by observing the samples for 24 hours for visible separation. The engine was run over the WLTP drive cycle for each individual ternary blend and the exhaust emissions were recorded. NOVA 7466K and TESTO 350 gas analysers were used to record the exhaust emissions. A factory standard MAF sensor was used to record the inlet air mass flow and an aftermarket ECU was used to determine the fuel flow. The ternary blends were blended using standard laboratory measuring equipment.

8.
AJNR Am J Neuroradiol ; 40(9): 1529-1537, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31395666

RESUMO

BACKGROUND AND PURPOSE: Non-contrast-enhanced MRA techniques have experienced a renaissance due to the known correlation between the use of gadolinium-based contrast agents and the development of nephrogenic systemic fibrosis and the deposition of gadolinium in some brain regions. The purpose of this study was to assess the diagnostic performance of ungated non-contrast-enhanced radial quiescent-interval slice-selective MRA of the extracranial supra-aortic arteries in comparison with conventional contrast-enhanced MRA in patients with clinical suspicion of carotid stenosis. MATERIALS AND METHODS: In this prospective study, both MRA pulse sequences were performed in 31 consecutive patients (median age, 68.8 years; 19 men). For the evaluation, the cervical arterial system was divided into 35 segments (right and left side). Three blinded reviewers separately evaluated these segments. An ordinal scoring system was used to assess the image quality of arterial segments and the stenosis grading of carotid arteries. RESULTS: Overall venous contamination in quiescent-interval slice-selective MRA was rated as "none" by all readers in 84.9% of cases and in 8.1% of cases in contrast-enhanced MRA (P < .0001). The visualization quality of arterial segments was considered good to excellent in 40.2% for the quiescent-interval slice-selective MRA and in 52.2% for the contrast-enhanced MRA (P < .0001). The diagnostic accuracy of ungated quiescent-interval slice-selective MRA concerning the stenosis grading showed a total sensitivity and specificity of 85.7% and 90.0%, respectively. CONCLUSIONS: Ungated quiescent-interval slice-selective MRA can be used clinically as an alternative to contrast-enhanced MRA without a significantly different image quality or diagnostic accuracy for the detection of carotid stenosis at 1.5T.


Assuntos
Estenose das Carótidas/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
9.
Phys Rev Lett ; 121(22): 221301, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30547645

RESUMO

We present results from an analysis of all data taken by the bicep2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at 95 and 150 GHz. The Q and U maps reach depths of 5.2, 2.9, and 26 µK_{CMB} arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈400 square degrees. The 220 GHz maps achieve a signal to noise on polarized dust emission approximately equal to that of Planck at 353 GHz. We take auto and cross spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz. We evaluate the joint likelihood of the spectra versus a multicomponent model of lensed-ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and we impose priors on some of these using external information from Planck and WMAP derived from larger regions of sky. The model is shown to be an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_{0.05}<0.07 at 95% confidence, which tightens to r_{0.05}<0.06 in conjunction with Planck temperature measurements and other data. The lensing signal is detected at 8.8σ significance. Running a maximum likelihood search on simulations we obtain unbiased results and find that σ(r)=0.020. These are the strongest constraints to date on primordial gravitational waves.

11.
AJNR Am J Neuroradiol ; 39(9): 1617-1621, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30026386

RESUMO

BACKGROUND AND PURPOSE: Recent studies have suggested that wall enhancement of unruptured intracranial aneurysms in high-resolution MR imaging might serve as an imaging biomarker for higher risk of rupture. Histologic studies have revealed a possible association among inflammatory processes, degeneration, and destabilization of the aneurysm wall preceding rupture. Understanding the histologic condition underlying aneurysm wall enhancement could be an important step toward assessing the value of this method for risk stratification. We present our observations of aneurysm wall enhancement in MR vessel wall imaging and underlying histologic changes. MATERIALS AND METHODS: We reviewed records of patients with an unruptured middle cerebral artery aneurysm who underwent MR vessel wall imaging before aneurysm clipping. Contrast enhancement of the aneurysm wall was dichotomized into either none/faint or strong. Histologic analysis included myeloperoxidase stain for detection of inflammatory cell invasion and CD34 stain for assessment of neovascularization and vasa vasorum. RESULTS: Thirteen aneurysms were included. Five aneurysms showed strong wall enhancement. Among these, myeloperoxidase staining revealed inflammatory cell infiltration in 4. Three showed neovascularization. In 2 aneurysms, vasa vasorum were present. Seven aneurysms did not show wall enhancement; 1 had only mild enhancement. None of these bore evidence of inflammatory cell invasion or neovascularization, and they all lacked vasa vasorum. CONCLUSIONS: Wall enhancement in MR vessel wall imaging is associated with inflammatory cell invasion, neovascularization, and the presence of vasa vasorum. Enhancement does not occur when histologic signs of inflammation are absent. Our results support the hypothesis that MR vessel wall imaging could provide valuable information for risk stratification.


Assuntos
Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/patologia , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Adulto , Idoso , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/patologia , Feminino , Humanos , Inflamação/diagnóstico por imagem , Inflamação/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
12.
J Eur Acad Dermatol Venereol ; 32(1): 125-128, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28833590

RESUMO

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease defined by recurrent nodules, tunnels and scarring involving the intertriginous skin. Patients with HS often report an array of systemic symptoms such as fatigue and malaise. The aetiology of these symptoms remains unclear. Previously, various bacteria have been associated with mature HS lesions, and bacteraemia has been reported in patients with HS using traditional culturing methods. Thus, we hypothesized that a low-grade bacteraemia contributes to the symptomatology in patients with HS. OBJECTIVE: To explore the potential presence of bacteraemia in patients with HS and healthy controls. METHOD: A case-control study. Compositions of bacteria in the blood of 27 moderate to severe HS patients and 26 healthy controls were investigated using next-generation 16S ribosomal RNA gene sequencing (NGS) and routine anaerobic and aerobic blood culturing. None of the participants received any antibiotics (systemic or topical therapy) within 1 month prior to the study. HS patients with a recent flare were randomly selected by consecutive recruitment of eligible patients from the Department of Dermatology, Zealand University Hospital, Denmark. Healthy controls were recruited from the University of Copenhagen as well as from the healthcare staff. RESULTS: The different bacterial compositions were investigated using NGS and traditional anaerobic and aerobic blood culturing. Our NGS analysis provided a previously unreported characterization of the bacterial composition in peripheral blood from patients with HS and healthy controls. Overall, our data demonstrated that patients with HS do not have a different bacterial composition in their peripheral blood than healthy controls. CONCLUSION: The study suggests that the self-reported symptoms in HS such as malaise and fatigue may not be linked to bacteraemia.


Assuntos
Bacteriemia/microbiologia , Hidradenite Supurativa/sangue , Hidradenite Supurativa/microbiologia , RNA Ribossômico 16S/sangue , Adulto , Hemocultura , Estudos de Casos e Controles , Fadiga/etiologia , Feminino , Hidradenite Supurativa/complicações , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Exacerbação dos Sintomas , Adulto Jovem
13.
Sci Rep ; 7(1): 11030, 2017 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-28887473

RESUMO

We demonstrate on-chip, differential DNA and RNA extraction from a single cell using a microfluidic chip and a two-stage lysis protocol. This method enables direct use of the whole extract, without additional washing steps, reducing sample loss. Using this method, the tumor driving pathway in individual cells from a colorectal cancer cell line was determined by applying a Bayesian computational pathway model to sequences obtained from the RNA fraction of a single cell and, the mutations driving the pathway were determined by analyzing sequences obtained from the DNA fraction of the same single cell. This combined functional and mutational pathway assessment of a single cell could be of significant value for dissecting cellular heterogeneity in tumors and analyzing single circulating tumor cells.


Assuntos
DNA/isolamento & purificação , Redes Reguladoras de Genes , Microfluídica/métodos , RNA/isolamento & purificação , Análise de Célula Única/métodos , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Misturas Complexas/análise , Misturas Complexas/isolamento & purificação , DNA/análise , Humanos , RNA/análise
14.
Phys Rev Lett ; 118(26): 261301, 2017 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-28707937

RESUMO

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118 kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6 eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16 keV/c^{2}. These are the most stringent constraints to date for these interactions.

15.
Phys Rev Lett ; 118(25): 251302, 2017 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-28696768

RESUMO

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41} cm^{2} (σ_{p}=5×10^{-40} cm^{2}) at 35 GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

16.
Phys Rev Lett ; 118(2): 021303, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-28128598

RESUMO

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4} kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46} cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46} cm^{2} at 50 GeV c^{-2}.

18.
Lett Appl Microbiol ; 63(2): 117-23, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27234372

RESUMO

UNLABELLED: Milk acidification and metabolic activity of the starter cultures are affected by oxygen; however, molecular factors related to the redox changes are poorly defined. The objective of the study was to investigate transcriptional responses in Lactococcus lactis subsp. cremoris CHCCO2 grown in milk to the shifts of oxygen and redox potential (Eh7 ). Transcriptomic studies were performed with the use of Illumina HiSeq 2000 mRNA sequencing and validated by the real-time quantitative PCR. In total 105 differentially expressed genes were assigned functional gene names. Most of the differentially expressed genes were detected during aerobic reduction phase. Upregulated genes were implicated in lactose utilization, glycogen biosynthesis, amino sugar metabolism, oxidation-reduction, pyrimidine biosynthesis and DNA integration processes. Genes of purine nucleotide biosynthesis and genes encoding amino acid, multidrug resistance and ion ABC transporters were mostly downregulated, while oligopeptide transporter genes were reduced during oxygen depletion and induced at minimum Eh7 . SIGNIFICANCE AND IMPACT OF THE STUDY: Understanding of gene responses in starter cultures to the changes of oxidation-reduction state is important for the better control and reproducibility of dairy fermentations. We applied mRNA sequencing by Illumina HiSeq 2000 to investigate gene expression profile in a dairy strain of Lactococcus lactis subsp. cremoris during milk acidification. Novelty of this study lies in linking transcriptional responses to oxygen depletion and the changes of redox potential with the fermentation kinetics and clarification of molecular factors specifically expressed in milk which might be essential for bacterial performance and the final quality of cheeses.


Assuntos
Fermentação/genética , Regulação Bacteriana da Expressão Gênica/genética , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Leite/metabolismo , Animais , Sequência de Bases , Queijo/microbiologia , Perfilação da Expressão Gênica , Ácido Láctico/metabolismo , Lactose/metabolismo , Leite/microbiologia , Oxirredução , Oxigênio/metabolismo , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Transcriptoma
19.
Phys Rev Lett ; 116(16): 161301, 2016 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-27152785

RESUMO

We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4} kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium ß source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33 GeV c^{-2} WIMP mass.

20.
Phys Rev Lett ; 116(16): 161302, 2016 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-27152786

RESUMO

We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4} kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41} cm^{2} (σ_{p}=2.9×10^{-39} cm^{2}) at 33 GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

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