Background
Depression and anxiety may unfavorably impact on cardiac autonomic dysregulation. However, it is unclear whether this relationship results from a causal effect or may be attributable to ...confounding factors. We tested the relationship between depression and anxiety with heart rate (HR) and heart rate variability (HRV) across a 9‐year follow‐up (FU) period and investigated possible confounding by antidepressant use and genetic pleiotropy.
Methods
Data (no. of observations = 6,994, 65% female) were obtained from the longitudinal Netherlands Study of Depression and Anxiety, with repeated waves of data collection of HR, HRV, depression, anxiety, and antidepressant use. Summary statistics from meta‐analyses of genome‐wide association studies were used to derive polygenic risk scores of depression, HR, and HRV.
Results
Across the 9‐year FU, generalized estimating equations analyses showed that the relationship between cardiac autonomic dysregulation and depression/anxiety rendered nonsignificant after adjusting for antidepressant use. A robust association was found between antidepressant use (especially tricyclic antidepressants, selective serotonin, and noradrenalin reuptake inhibitors) and unfavorable cardiac autonomic activity across all waves. However, no evidence was found for a genetic correlation of depression with HR and HRV, indicating that confounding by genetic pleiotropy is minimal.
Conclusions
Our results indicate that the association between depression/anxiety and cardiac autonomic dysregulation does not result from a causal pathway or genetic pleiotropy, and these traits might therefore not be inevitably linked. Previously reported associations were likely confounded by the use of certain classes of antidepressants.
MCNPX-PoliMi for nuclear nonproliferation applications Pozzi, S.A.; Clarke, S.D.; Walsh, W.J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2012, Letnik:
694
Journal Article
Recenzirano
This paper describes the use of the Monte Carlo code MCNPX-PoliMi for nuclear-nonproliferation applications, with particular emphasis on the simulation of spontaneous and neutron-induced nuclear ...fission. New models for the outgoing neutrons and gamma rays emitted in spontaneous and induced fission are described. For spontaneous fission, the models include prompt neutron energy distributions that depend on the number of neutrons emitted in the individual fission events. For neutron-induced fission, due to lack of data, the prompt neutron energy distributions are independent of the number of neutrons emitted in the individual fission events. Gamma rays are sampled independently of the neutrons. Code validation is performed on well-characterized mixed-oxide fuel and plutonium-oxide samples.
In reversed-phase chromatography (RPC), the restricted retention of “bulky” solutes can occur in one of two ways, giving rise to either “shape selectivity” or “steric interaction.” Starting with data ...for 150 solutes and 167 monomeric type-B alkylsilica columns, the present study examines the steric interaction process further and compares it with shape selectivity. The dependence of column hydrophobicity and steric interaction on column properties (ligand length and concentration, pore diameter, end-capping) was determined and compared. The role of the solute in steric interaction was found to be primarily a function of solute molecular length, with longer solutes giving increased steric interaction. We find that there are several distinct differences in the way shape selectivity and steric interaction are affected by separation conditions and the nature of the sample. Of particular interest, steric interaction exhibits a maximum effect for monomeric C
18 columns, and becomes less important for either a C
1 or C
30 column; shape selectivity appears unimportant for monomeric C
1–C
18 columns at ambient and higher temperatures, but becomes pronounced for C
30 – as well as polymeric columns with ligands ≥C
8. One hypothesis is that shape selectivity involves the presence or creation of cavities within the stationary phase that can accommodate a retained solute (a primarily enthalpic process), while steric interaction mainly makes greater use of spaces that pre-exist the retention of the solute (a primarily entropic process). The related dependence of hydrophobic interaction on column properties was also examined.
A recently developed treatment of reversed-phase column selectivity (the hydrophobic-subtraction model) is reviewed and extended, including its characterization of the selectivity of different column ...types (e.g., C
1–C
30, cyano, phenyl, etc.). The application of this model to retention data for various solutes and columns has provided new insights into the nature of different solute–column interactions and their relative importance in affecting sample retention and separation. Reversed-phase columns can be characterized by five selectivity parameters (
H
,
S
*,
A
,
B
and
C
), values of which are summarized here for more than 300 different columns. The selection of columns of either equivalent or different selectivity is readily achievable on the basis of their values of
H
,
S
*, etc. The development of the hydrophobic-subtraction model, its use in characterizing the selectivity of different reversed-phase liquid chromatography (RP-LC) columns, and its application to various practical problems as described here began in 1998. The original inspiration for this project owes much to Jack Kirkland, who also contributed actively to the initial studies that laid the foundation of this model; he has since provided other important support to this project. Jack and one of the authors (LRS) have enjoyed a strong professional relationship and personal friendship for the past 35 years, and it is the privilege of the authors to dedicate this paper and the work that it represents to Jack. His contributions to HPLC column technology have extended from the mid-1960s into the present century, and it is impossible to conceive of present day HPLC practice without Jack's contributions over the years. In this and other ways, his position as a pioneer and key implementer of HPLC is widely recognized. We wish Jack well in the years to come.
Gastric infection with Helicobacter pylori is a cosmopolitan problem, and is especially common in developing regions where there is also a high prevalence of gastric cancer. These infections are ...known to cause gastritis and peptic ulcers, and dramatically enhance the risk of gastric cancer. Eradication of this organism is an important medical goal that is complicated by the development of resistance to conventional antimicrobial agents and by the persistence of a low level reservoir of H. pylori within gastric epithelial cells. Moreover, economic and practical problems preclude widespread and intensive use of antibiotics in most developing regions. We have found that sulforaphane (-)-1-isothiocyanato-(4R)-(methylsulfinyl)butane, an isothiocyanate abundant as its glucosinolate precursor in certain varieties of broccoli and broccoli sprouts, is a potent bacteriostatic agent against 3 reference strains and 45 clinical isolates of H. pylori minimal inhibitory concentration (MIC) for 90% of the strains is ≤4µg/ml, irrespective of their resistance to conventional antibiotics. Further, brief exposure to sulforaphane was bactericidal, and eliminated intracellular H. pylori from a human epithelial cell line (HEp-2). In complementary experiments, sulforaphane blocked benzoapyrene-evoked fore-stomach tumors in ICR mice. This protection resulted from induction of phase 2 detoxication and antioxidant enzymes, and was abrogated in mice lacking the nrf2 gene, which regulates phase 2 enzymes. Thus, the dual actions of sulforaphane in inhibiting Helicobacter infections and blocking gastric tumor formation offer hope that these mechanisms might function synergistically to provide diet-based protection against gastric cancer in humans.
Root hairs are fast growing, ephemeral tubular extensions of the root epidermis. They arise in the unsuberized maturation zone of the root, effectively increasing the root surface area in the region ...over which nutrient and water uptake occur. Variation in root hair length (RHL) between varieties has been shown to be genetically determined, and could, therefore, have consequences for nutrient capture and yield potential in crops. We describe the development of a medium-to-high throughput screening method for assessing RHL in wheat at the seedling stage. This method was used to screen a number of wheat mapping population parental lines for variation in RHL. Parents of two populations derived from inter-varietal crosses differed for RHL: Spark vs Rialto and Charger vs Badger. We identified quantitative trait loci (QTLs) for RHL in the populations derived from these crosses. In Spark × Rialto, QTLs on chromosomes 1A, 2A and 6A were associated with variation in RHL, whilst in Charger × Badger, a QTL for RHL was identified on 2BL. The QTLs on 2A and 6A co-localized with previously described QTLs for yield components. Longer root hairs may confer an advantage by exploiting limiting mineral and water resources. This first QTL analysis of root hair length in wheat identifies loci that could usefully be further investigated for their role in tolerance to limiting conditions.
ABSTRACT
Stellar activity and planetary effects induce radial velocity (RV) offsets and cause temporal distortions in the shape of the stellar line profile. Hence, accurately probing the stellar line ...profile offers a wealth of information on both the star itself and any orbiting planets. Typically, cross-correlation functions (CCFs) are used as a proxy for the stellar line profile. The shape of CCFs, however, can be distorted by line blending and aliasing limiting the stellar and planetary physics that can be probed from them. Least-squares deconvolution (LSD) offers an alternative that directly fits the mean line profile of the spectrum to produce a high-precision profile. In this paper, we introduce our novel method ACID (Accurate Continuum fItting and Deconvolution) that builds on LSD techniques by simultaneously fitting the spectral continuum and line profile as well as performing LSD in effective optical depth. Tests on model data revealed ACID can accurately identify and correct the spectral continuum to retrieve an injected line profile. ACID was also applied to archival High Accuracy Radial-velocity Planet Searcher (HARPS) data obtained during the transit of HD189733b. The application of the Reloaded Rossiter–McLaughlin technique to both ACID profiles and HARPS CCFs shows ACID residual profiles improved the out-of-line root mean square (RMS) by over 5 per cent compared to CCFs. Furthermore, ACID profiles are shown to exhibit a Voigt profile shape that better describes the expected profile shape of the stellar line profile. This improved representation shows that ACID better preserves the stellar and planetary physics encoded in the stellar line profile shape for slow rotating stars.
Retention factors
k have been measured for 67 neutral, acidic and basic solutes of highly diverse molecular structure (size, shape, polarity, hydrogen bonding, p
K
a, etc.) on 10 different C
18 ...columns (other conditions constant). These data have been combined with
k values from a previous study (86 solutes, five different C
8 and C
18 columns) to develop a six-term equation for the correlation of retention as a function of solute and column. Values of
k can be correlated with an accuracy of ±1–2% (1 standard deviation). This suggests that all significant contributions to column selectivity have been identified (and can be measured) for individual alkyl-silica columns which do not have an embedded polar group. That is, columns of the latter kind can be quantitatively characterized in terms of selectivity for use in the separation of any sample.
A previous model of column selectivity for reversed-phase liquid chromatography (RP-LC) has been applied to an additional 21 columns with embedded or end-capping polar groups (EPGs). ...Embedded-polar-group columns exhibit a significantly different selectivity
vs. non-EPG, type-B columns, generally showing preferential retention of hydrogen-bond donors, as well as decreased retention for hydrogen-bond acceptors or ionized bases. EPG-columns are also generally less hydrophobic (more polar) than are non-EPG-columns. Interestingly, columns with polar end-capping tend to more closely resemble non-EPG columns, suggesting that the polar group has less effect on column selectivity when used to end-cap the column versus the case of an embedded polar group. Column selectivity data reported here for EPG-columns can be combined with previously reported values for non-EPG columns to provide a database of 154 different columns. This enables a comparison of any two of these columns in terms of selectivity. However, comparisons that involve EPG columns are more approximate.
The isocratic retention of 67 widely-different solutes in reversed-phase liquid chromatography (RP-LC) has been investigated as a function of temperature and mobile phase composition (%
B) for three ...different C
18 columns. Similar studies were also carried out in a gradient mode, where temperature, gradient time and solvent type were varied. These results show that changes in retention with these conditions are similar for each of these three columns. This suggests that relative column selectivity as defined by experiments for one set of experimental conditions will be approximately applicable for other conditions, with the exception of changes in mobile phase pH—which can affect values of the column parameter
C
(a measure of silanol ionization). Column selectivity as a function of pH was explored for several columns.
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