The
Interface Region Imaging Spectrograph
(IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 – ...0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s
−1
velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains spectra in passbands from 1332 – 1358 Å, 1389 – 1407 Å, and 2783 – 2834 Å, including bright spectral lines formed in the chromosphere (Mg
ii
h 2803 Å and Mg
ii
k 2796 Å) and transition region (C
ii
1334/1335 Å and Si
iv
1394/1403 Å). Slit-jaw images in four different passbands (C
ii
1330, Si
iv
1400, Mg
ii
k 2796, and Mg
ii
wing 2830 Å) can be taken simultaneously with spectral rasters that sample regions up to 130 arcsec × 175 arcsec at a variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an
interface region
, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative–MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by IRIS each day and made available for unrestricted use within a few days of the observation.
The Helioseismic and Magnetic Imager (HMI) investigation will study the solar interior using helioseismic techniques as well as the magnetic field near the solar surface. The HMI instrument is part ...of the Solar Dynamics Observatory (SDO) that was launched on 11 February 2010. The instrument is designed to measure the Doppler shift, intensity, and vector magnetic field at the solar photosphere using the 6173 Fe I absorption line. The instrument consists of a front-window filter, a telescope, a set of wave plates for polarimetry, an image-stabilization system, a blocking filter, a five-stage Lyot filter with one tunable element, two wide-field tunable Michelson interferometers, a pair of 4096(exo 2) pixel cameras with independent shutters, and associated electronics. Each camera takes a full-disk image roughly every 3.75 seconds giving an overall cadence of 45 seconds for the Doppler, intensity, and line-of-sight magnetic-field measurements and a slower cadence for the full vector magnetic field. This article describes the design of the HMI instrument and provides an overview of the pre-launch calibration efforts. Overviews of the investigation, details of the calibrations, data handling, and the science analysis are provided in accompanying articles.
Glutathione peroxidase 4 (GPx4) is an antioxidant enzyme reported as an inhibitor of ferroptosis, a recently discovered non-apoptotic form of cell death. This pathway was initially described in ...cancer cells and has since been identified in hippocampal and renal cells. In this Perspective, we propose that inhibition of ferroptosis by GPx4 provides protective mechanisms against neurodegeneration. In addition, we suggest that selenium deficiency enhances susceptibility to ferroptotic processes, as well as other programmed cell death pathways due to a reduction in GPx4 activity. We review recent studies of GPx4 with an emphasis on neuronal protection, and discuss the relevance of selenium levels on its enzymatic activity.
Dementia is a global epidemic with Alzheimer's disease (AD) being the leading cause. Early identification of patients at risk of developing AD is now becoming an international priority. Neocortical ...Aβ (extracellular β-amyloid) burden (NAB), as assessed by positron emission tomography (PET), represents one such marker for early identification. These scans are expensive and are not widely available, thus, there is a need for cheaper and more widely accessible alternatives. Addressing this need, a blood biomarker-based signature having efficacy for the prediction of NAB and which can be easily adapted for population screening is described. Blood data (176 analytes measured in plasma) and Pittsburgh Compound B (PiB)-PET measurements from 273 participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study were utilised. Univariate analysis was conducted to assess the difference of plasma measures between high and low NAB groups, and cross-validated machine-learning models were generated for predicting NAB. These models were applied to 817 non-imaged AIBL subjects and 82 subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) for validation. Five analytes showed significant difference between subjects with high compared to low NAB. A machine-learning model (based on nine markers) achieved sensitivity and specificity of 80 and 82%, respectively, for predicting NAB. Validation using the ADNI cohort yielded similar results (sensitivity 79% and specificity 76%). These results show that a panel of blood-based biomarkers is able to accurately predict NAB, supporting the hypothesis for a relationship between a blood-based signature and Aβ accumulation, therefore, providing a platform for developing a population-based screen.
Background Recurrent abdominal pain is reported by a third of patients with diverticulosis, particularly those with previous episodes of acute diverticulitis. The current understanding of the ...etiology of this pain is poor. Our aim was to assess visceral sensitivity in patients with diverticular disease and its association with markers of previous inflammation and neuropeptides.
Methods Patients with asymptomatic and symptomatic diverticular disease underwent a flexible sigmoidoscopy and biopsy followed 5–10 days later by visceral sensitivity testing with barostat‐mediated rectal distension. Inflammation was assessed by staining of serotonin (5HT) and CD3 positive cells. mRNA levels of tumor necrosis factor alpha (TNF α) and interleukin‐6 (IL‐6) were quantitated using RT‐PCR. Neuropeptide expression was assessed from percentage area staining with substance P (SP) and mRNA levels of the neurokinin 1 & 2 receptors (NK1 & NK2), and galanin 1 receptor (GALR1).
Key Results Thirteen asymptomatic and 12 symptomatic patients were recruited. The symptomatic patients had a lower first reported threshold to pain (28.4 mmHg i.q.r 25.0–36.0) than the asymptomatic patients (47 mmHg i.q.r 36.0–52.5, P < 0.001). Symptomatic patients had a higher median overall pain rating for the stimuli than the asymptomatic patients (P < 0.02). Symptomatic patients had greater median relative expression of NK1 and TNF alpha mRNA compared with asymptomatic patients. There was a significant correlation between barostat VAS pain scores and NK 1 expression (Figure 4, r2 0.54, P < 0.02).
Conclusions & Inferences Patients with symptomatic diverticular disease exhibit visceral hypersensitivity, and this may be mediated by ongoing low grade inflammation and upregulation of tachykinins.
Quantitative criteria for insomnia Lichstein, K.L.; Durrence, H.H.; Taylor, D.J. ...
Behaviour research and therapy,
04/2003, Letnik:
41, Številka:
4
Journal Article
Recenzirano
Formal diagnostic systems (DSM-IV, ICSD, and ICD-10) do not provide adequate quantitative criteria to diagnose insomnia. This may not present a serious problem in clinical settings where extensive ...interviews determine the need for clinical management. However, lack of standard criteria introduce disruptive variability into the insomnia research domain. The present study reviewed two decades of psychology clinical trials for insomnia to determine common practice with regard to frequency, severity, and duration criteria for insomnia. Modal patterns established frequency (≥3 nights a week) and duration (≥6 months) standard criteria. We then applied four versions of severity criteria to a random sample and used sensitivity–specificity analyses to identify the most valid criterion. We found that severity of sleep onset latency or wake time after sleep onset of: (a) ≥31 min; (b) occurring ≥3 nights a week; (c) for ≥6 months are the most defensible quantitative criteria for insomnia.
Chordoid meningiomas are uncommon WHO grade II primary intracranial neoplasms that possess unique chordoid histology and follow an aggressive clinical course. Our aim was to assess the utility of ...qualitative MR imaging features and quantitative apparent diffusion coefficient values as distinguishing preoperative MR imaging metrics to identify and differentiate chordoid histology from other meningioma histologic subtypes.
Twenty-one patients with meningiomas with chordoid histology, which included both chordoid meningiomas (>50% chordoid histology) and meningiomas with focal chordoid histology (<50% chordoid histology) with available preoperative MR imaging examinations, including diffusion-weighted imaging, were identified. Qualitative imaging features and quantitative ADC values were compared between meningiomas with chordoid histology and 42 nonchordoid meningiomas (29 WHO grade I, eleven WHO grade II, and 2 WHO grade III).
The median ADC (10
mm
/s) of meningiomas with chordoid histology was significantly higher than nonchordoid meningiomas (1.16 versus 0.92,
< .001), as was the median normalized ADC (1.60 versus 1.19,
< .001). In subgroup analysis, the median and normalized ADC values of chordoid meningiomas (
= 11) were significantly higher than those in meningiomas with focal chordoid histology (
= 10,
< .001 and
< .001, respectively) or nonchordoid meningiomas (
= 42,
< .001 and <0.001, respectively). Median and normalized ADC values were not significantly different between the meningiomas with focal chordoid histology and nonchordoid meningiomas (
= .816 and .301, respectively). Among the qualitative imaging features, only DWI signal intensity was significantly associated with meningiomas with chordoid histology diagnosis.
ADC values are higher in chordoid compared with nonchordoid meningiomas and may be used to discriminate the degree of chordoid histology in meningiomas. While qualitative MR imaging features do not strongly discriminate chordoid from nonchordoid meningiomas, DWI may allow preoperative identification of chordoid meningiomas.
Criterion A of the AMPD in HiTOP Widiger, Thomas A.; Bach, Bo; Chmielewski, Michael ...
Journal of personality assessment,
07/2019, Letnik:
101, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The categorical model of personality disorder classification in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (5th ed. DSM-5; American Psychiatric ...Association,
2013
) is highly and fundamentally problematic. Proposed for DSM-5 and provided within Section III (for Emerging Measures and Models) was the Alternative Model of Personality Disorder (AMPD) classification, consisting of Criterion A (self-interpersonal deficits) and Criterion B (maladaptive personality traits). A proposed alternative to the DSM-5 more generally is an empirically based dimensional organization of psychopathology identified as the Hierarchical Taxonomy of Psychopathology (HiTOP; Kotov et al.,
2017
). HiTOP currently includes, at the highest level, a general factor of psychopathology. Further down are the five domains of detachment, antagonistic externalizing, disinhibited externalizing, thought disorder, and internalizing (along with a provisional sixth somatoform dimension) that align with Criterion B. The purpose of this article is to discuss the potential inclusion and placement of the self-interpersonal deficits of the DSM-5 Section III Criterion A within HiTOP.
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