177 research outputs found
A novel Doppler backscattering (DBS) system to simultaneously monitor radio frequency plasma fluctuations and low frequency turbulence
A novel quadrature Doppler Backscattering (DBS) system has been developed and
optimized for the E-band (60-90GHz) frequency range using either O-mode or
X-mode polarization in DIII-D plasmas. In general, DBS measures the amplitude
of density fluctuations and their velocity in the lab frame. The system can
simultaneously monitor both low-frequency turbulence (f < 10MHz) and
radiofrequency plasma density fluctuations over a selectable frequency range
(20-500 MHz). Detection of high-frequency fluctuations has been demonstrated
for low harmonics of the ion cyclotron frequency (e.g., 2fci~23MHz) and
externally driven high-frequency helicon waves (f = 476MHz) using an adjustable
frequency down conversion system. Importantly, this extends the application of
DBS to a high-frequency spectral domain while maintaining important turbulence
and flow measurement capabilities. This unique system has low phase noise, good
temporal resolution (sub-millisecond) and excellent wavenumber coverage
(k_{\theta} ~ 1-20cm^{-1} and k_r ~ 20-30cm^{-1}). As a demonstration,
localized internal DIII-D plasma measurements are presented from turbulence (f
= 20MHz) as well
as fluctuations around 476MHz driven by an external high-power 476 MHz helicon
wave antenna. In the future, helicon measurements will be used to validate
GENRAY and AORSA modeling tools for prediction of helicon wave propagation,
absorption and current drive location for the newly installed helicon current
drive system on DIII-D.Comment: 13 pages, 14 figs, journal pape
Molecular cloning of the human nucleotide-excision-repair gene ERCC4.
ERCC4 was previously identified in somatic cell hybrids as a human gene that corrects the nucleotide-excision-repair deficiency in mutant hamster cells. The cloning strategy for ERCC4 involved transfection of the repair-deficient hamster cell line UV41 with a human sCos-1 cosmid library derived from chromosome 16. Enhanced UV resistance was seen with one cosmid-library transformant and two secondary transformants of UV41. Cosmid clones carrying a functional ERCC4 gene were isolated from a library of a second transformant by selecting in Escherichia coli for expression of a linked neomycin-resistance gene that was present in the sCos-1 vector. The cosmids mapped to 16p13.13-p13.2, the location assigned to ERCC4 by using somatic cell hybrids. Upon transfection into UV41, six cosmid clones gave partial correction ranging from 30% to 64%, although all appeared to contain the complete gene. The capacity for in vitro excision of thymine dimers from a plasmid by transformant cell extracts correlated qualitatively with enhanced UV resistance
Kauri Tree-Ring Stable Isotopes Reveal a Centennial Climate Downturn Following the Antarctic Cold Reversal in New Zealand
The dynamics of the Late Glacial have been demonstrated by numerous records from the Northern Hemisphere and far fewer from the Southern Hemisphere (SH). SH paleoclimate records reveal a general warming trend, interrupted by a deglaciation pause Antarctic Cold Reversal (ACR; ā¼14,700ā13,000Ā cal BP). Here, we present decadal tree-ring stable isotope chronologies (Ī“18O, Ī“13C) from New Zealand (NZ) subfossil kauri trees (nĀ =Ā 6) covering the post-ACR millennium from 13,020 to 11,850Ā cal BP. We find a distinct, simultaneous downturn (ā¼12,625ā12,375Ā cal BP) in all tree-ring proxies paralleling regional tree growth declines, suggesting a widespread climate deterioration. This downturn was characterized by sustained high precipitation, low temperatures, and high relative humidity in NZ with incoming weather fronts from the South Ocean. Despite these promising results, questions remain about what drove the Kauri Downturn and how the hydroclimatic conditions were altered during this time period
Transkingdom Networks: A Systems Biology Approach to Identify Causal Members of Host-Microbiota Interactions
Improvements in sequencing technologies and reduced experimental costs have
resulted in a vast number of studies generating high-throughput data. Although
the number of methods to analyze these "omics" data has also increased,
computational complexity and lack of documentation hinder researchers from
analyzing their high-throughput data to its true potential. In this chapter we
detail our data-driven, transkingdom network (TransNet) analysis protocol to
integrate and interrogate multi-omics data. This systems biology approach has
allowed us to successfully identify important causal relationships between
different taxonomic kingdoms (e.g. mammals and microbes) using diverse types of
data
Non-local heat transport in Alcator C-Mod ohmic L-mode plasmas
Non-local heat transport experiments were performed in Alcator C-Mod ohmic L-mode plasmas by inducing edge cooling with laser blow-off impurity (CaF2) injection. The non-local effect, a cooling of the edge electron temperature with a rapid rise of the central electron temperature, which contradicts the assumption of 'local' transport, was observed in low collisionality linear ohmic confinement (LOC) regime plasmas. Transport analysis shows this phenomenon can be explained either by a fast drop of the core diffusivity, or the sudden appearance of a heat pinch. In high collisionality saturated ohmic confinement (SOC) regime plasmas, the thermal transport becomes 'local': the central electron temperature drops on the energy confinement time scale in response to the edge cooling. Measurements from a high resolution imaging x-ray spectrometer show that the ion temperature has a similar behaviour as the electron temperature in response to edge cooling, and that the transition density of non-locality correlates with the rotation reversal critical density. This connection may indicate the possible connection between thermal and momentum transport, which is also linked to a transition in turbulence dominance between trapped electron modes (TEMs) and ion temperature gradient (ITG) modes. Experiments with repetitive cold pulses in one discharge were also performed to allow Fourier analysis and to provide details of cold front propagation. These modulation experiments showed in LOC plasmas that the electron thermal transport is not purely diffusive, while in SOC the electron thermal transport is more diffusive like. Linear gyrokinetic simulations suggest the turbulence outside r/a = 0.75 changes from TEM dominance in LOC plasmas to ITG mode dominance in SOC plasmas.United States. Dept. of Energy (DoE Contract No DE-FC02-99ER54512)Oak Ridge Institute for Science and Education (DOE Fusion Energy Postdoctoral Research Program
Inherent Grading Characteristics of Individual Pathologists Contribute to Clinically and Prognostically Relevant Interobserver Discordance Concerning Broders' Grading of Penile Squamous Cell Carcinomas
Introduction: The aim of our study was to evaluate the significance of transurethral resection of the prostate (TURP) to detect prostate cancer (PCa). A comparison was performed of the TURP specimens of patients undergoing high-intensity focused ultrasound (HIFU) with the core biopsies. Materials and Methods: TURP before undergoing HIFU therapy was performed in 106 patients without neoadjuvant treatment. The resected tissue was subjected to histopathological evaluation and compared to the histological results of transrectal prostate biopsy. Results: Cancer was detected in the resected tissue of 69 patients (65%). A positive correlation of the amount of resected tissue and detection of PCa could be demonstrated in a multivariate analysis. Conclusions: With a rate of 65% PCa detected by TURP, our data provide evidence that TURP might be suitable to detect PCa in a small group of selected patients with continuously rising PSA levels and several negative biopsies. On the other hand, these data underline/reinforce the necessity to treat the whole gland using modern treatment modalities such as HIFU and cryotherapy
Awareness and perception of multidrug-resistant organisms and antimicrobial therapy among internists vs. surgeons of different specialties: Results from the German MR2 Survey
Background: Recently, antibiotic resistance rates have risen substantially and care for patients infected with multidrug-resistant organisms (MDRO) has become a common problem in most in – and outpatient settings. The objectives of the study were to compare the awareness, perception, and knowledge of MDRO and rational antibiotic use between physicians from different medical specialties in German hospitals. Methods: A 35-item questionnaire was sent to specialists in internal medicine (internists), gynecologists, urologists, and general surgeons (non-internists) in 18 German hospitals. Likert-scales were used to evaluate awareness and perception of personal performance regarding care for patients infected with MDRO and rational use of antibiotics. Additionally, two items assessing specific knowledge in antibiotic therapy were included. The impact of medical specialty on four predetermined endpoints was assessed by multivariate logistic regression. Results: 43.0 (456/1061) of recipients responded. Both internists and non-internists had low rates of training in antibiotic stewardship. 50.8 of internists and 58.6 of non-internists had attended special training in rational antibiotic use or care for patients infected with MDRO in the 12 months prior to the study. Internists deemed themselves more confidently to choose the indications for screening patients for colonization with methicillin-resistant Staphylococcus aureus (P=0.004) and to initiate adequate infection control measures (P=0.002) than other specialties. However, there was no significant difference between internists and other specialists regarding the two items assessing specific knowledge in antibiotic therapy and infection control. Conclusion: Among the study participants, a considerable need for advanced training in the study subjects was seen, regardless of the medical specialty
Locating Photography
The specter of global dissemination haunted photography from its very beginning. This chapter explains two aspects of photography's āglobalizationā: its use as a āwesternā technique to document an increasingly colonized world and its dissemination around the world and its adoption by local practitioners. In rural and smallātown central India, the studio retains a central place in most people's encounters with photography. MartĆn Chambi would retain a lifelong adherence to the purity of the photographic image but other indigenista photographers, such as Juan Manuel Figueroa Aznar, would increasingly use paint alongside photography. A World System Photography, seen in networks that fold locally articulated practices into trajectories that fuse technics, history, and culture, can help people think in new ways about the ālocationā of photography. Locations have to be reāimagined as āTerra Infirmaā, unstable and complex positions which may have more of the quality of linking sections of a network than of territories
DNA repair endonuclease ERCC1-XPF as a novel therapeutic target to overcome chemoresistance in cancer therapy
The ERCC1āXPF complex is a structure-specific endonuclease essential for the repair of DNA damage by the nucleotide excision repair pathway. It is also involved in other key cellular processes, including DNA interstrand crosslink (ICL) repair and DNA double-strand break (DSB) repair. New evidence has recently emerged, increasing our understanding of its requirement in these additional roles. In this review, we focus on the proteināprotein and proteināDNA interactions made by the ERCC1 and XPF proteins and discuss how these coordinate ERCC1āXPF in its various roles. In a number of different cancers, high expression of ERCC1 has been linked to a poor response to platinum-based chemotherapy. We discuss prospects for the development of DNA repair inhibitors that target the activity, stability or protein interactions of the ERCC1āXPF complex as a novel therapeutic strategy to overcome chemoresistance
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