Hydroxy fatty acids (FAs) in fresh snow from Sapporo, one of the heaviest snowfall regions in the world, have been studied to ascertain the airborne bacterial endotoxin concentrations and their ...biomass. The presence of β-hydroxy FAs (C9–C28), constituents of the Gram-negative bacterium (GNB), suggests long-range transport of soil microbes. Likewise, the occurrence of α- and ω-hydroxy FAs (C9–C30 and C9–C28, respectively) in snow reveals their contribution from epicuticular waxes and soil microorganisms. Estimated endotoxin and GNB mass can aid in assessing their possible impacts on the diversity and functioning of aquatic and terrestrial ecosystems, as well as lethal effects on pedestrians through dispersal of microbes. Air mass back trajectories together with hydroxy FAs reveal their sources from Siberia, the Russian Far East and northern China by the Asian monsoon. This study highlights the role of fresh snow that reduces the human health risk of GNB and endotoxin by the scavenging from air.
To utilize natural language processing (NLP) of MRI reports and various clinical variables to develop a preliminary model predictive of the need for surgery in patients with low back and neck pain. ...Such a model would be beneficial for informing clinical practice decisions and help reduce the number of unnecessary surgical referrals, streamlining the surgical process.
A historical cohort study was conducted using de-identified data from patients referred to a spine assessment clinic. Various demographic, clinical, and radiological variables were included as potential predictors. Full-text radiology reports of patients' MRI findings were vectorized using NLP before applying machine learning algorithms to develop models predicting who underwent surgery. Outputs from these models were then entered into a logistic regression model with clinical variables to develop a preliminary model predictive of surgical recommendations.
Of the 398 patients assessed, 71 underwent spine surgery. NLP variables were significant predictors in univariate analysis but did not remain in the final logistic regression model. An outcome of receiving surgery was predicted by a primary symptom of low back and leg pain (adjusted odds ratio 2.81), distal pain indicated by a pain diagram (adjusted odds ratio 2.49) and self-reported difficulties walking (adjusted odds ratio 2.73).
A logistic regression model was created to predict which patients may require spine surgery. Simple clinical variables appeared more predictive than variables created using NLP. However, additional research with more data samples is needed to validate this model and fully evaluate the usefulness of NLP for this task.
ABSTRACT
The ALMA (Atacama Large Millimeter Array) interferometer, with its unprecedented combination of high sensitivity and high angular resolution, allows for (sub-)mm wavelength mapping of ...protostellar systems at Solar system scales. Astrochemistry has benefitted from imaging interstellar complex organic molecules in these jet–disc systems. Here, we report the first detection of methanol (CH3OH) and methyl formate (HCOOCH3) emission towards the triple protostellar system VLA1623−2417 A1+A2+B, obtained in the context of the ALMA Large Programme FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). Compact methanol emission is detected in lines from Eu = 45 K up to 61 K and 537 K towards components A1 and B, respectively. Large velocity gradient analysis of the CH3OH lines towards VLA1623−2417 B indicates a size of 0.11–0.34 arcsec (14–45 au), a column density $N_{\rm CH_3OH}$ = 1016–1017 cm−2, kinetic temperature ≥ 170 K, and volume density ≥ 108 cm−3. A local thermodynamic equilibrium approach is used for VLA1623−2417 A1, given the limited Eu range, and yields Trot ≤ 135 K. The methanol emission around both VLA1623−2417 A1 and B shows velocity gradients along the main axis of each disc. Although the axial geometry of the two discs is similar, the observed velocity gradients are reversed. The CH3OH spectra from B show two broad (4–5 km s−1) peaks, which are red- and blueshifted by ∼ 6–7 km s−1 from the systemic velocity. Assuming a chemically enriched ring within the accretion disc, close to the centrifugal barrier, its radius is calculated to be 33 au. The methanol spectra towards A1 are somewhat narrower (∼ 4 km s−1), implying a radius of 12–24 au.
Chemical models predict that the deuterated fraction (the column density ratio between a molecule containing D and its counterpart containing H) of N2H+, D
frac(N2H+), high in massive ...pre-protostellar cores, is expected to rapidly drop by an order of magnitude after the protostar birth, while that of HNC, D
frac(HNC), remains constant for much longer. We tested these predictions by deriving D
frac(HNC) in 22 high-mass star-forming cores divided in three different evolutionary stages, from high-mass starless core candidates (HMSCs, eight) to high-mass protostellar objects (HMPOs, seven) to ultracompact H ii regions (UCHIIs, seven). For all of them, D
frac(N2H+) was already determined through IRAM 30 m Telescope observations, which confirmed the theoretical rapid decrease of D
frac(N2H+) after protostar birth. Therefore, our comparative study is not affected by biases introduced by the source selection. We have found average D
frac(HNC) of 0.012, 0.009 and 0.008 in HMSCs, HMPOs and UCHIIs, respectively, with no statistically significant differences among the three evolutionary groups. These findings confirm the predictions of the chemical models, and indicate that large values of D
frac(N2H+) are more suitable than large values of D
frac(HNC) to identify cores on the verge of forming high-mass stars, likewise what was found in the low-mass regime.
PCR-Restriction Fragment Length Polymorphism (RFLP) analyses targeting multiple nuclear genes were established for the simple and practical identification of Leishmania species without using ...expensive equipment. This method was applied to 92 clinical samples collected at 33 sites in 14 provinces of Ecuador, which have been identified at the species level by the kinetoplast cytochrome b (cyt b) gene sequence analysis, and the results obtained by the two analyses were compared. Although most results corresponded between the two analyses, PCR-RFLP analyses revealed distribution of hybrid strains between Leishmania (Viannia) guyanensis and L. (V.) braziliensis and between L. (V.) guyanensis and L. (V.) panamensis, of which the latter was firstly identified in Ecuador. Moreover, unexpected parasite strains having the kinetoplast cyt b gene of L. (V.) braziliensis and nuclear genes of L. (V.) guyanensis, L. (V.) panamensis, or a hybrid between L. (V.) guyanensis and L. (V.) panamensis were identified. This is the first report of the distribution of a protozoan parasite having mismatches between kinetoplast and nuclear genes, known as mito-nuclear discordance. The result demonstrated that genetically complex Leishmania strains are present in Ecuador. Since genetic exchanges such as hybrid formation were suggested to cause higher pathogenicity in Leishmania and may be transmitted by more species of sand flies, further country-wide epidemiological studies on clinical symptoms, as well as transmissible vectors, will be necessary.
Abstract To develop an effective neuroprotective strategy against ischemic injury, it is important to identify the key molecules involved in the progression of injury. Direct molecular analysis of ...tissue using mass spectrometry (MS) is a subject of much interest in the field of metabolomics. Most notably, imaging mass spectrometry (IMS) allows visualization of molecular distributions on the tissue surface. To understand lipid dynamics during ischemic injury, we performed IMS analysis on rat brain tissue sections with focal cerebral ischemia. Sprague–Dawley rats were sacrificed at 24 h after middle cerebral artery occlusion, and brain sections were prepared. IMS analyses were conducted using matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) in positive ion mode. To determine the molecular structures, the detected ions were subjected to tandem MS. The intensity counts of the ion signals of m/z 798.5 and m/z 760.5 that are revealed to be a phosphatidylcholine, PC (16:0/18:1) are reduced in the area of focal cerebral ischemia as compared to the normal cerebral area. In contrast, the signal of m/z 496.3, identified as a lyso-phosphatidylcholine, LPC (16:0), was clearly increased in the area of focal cerebral ischemia. In IMS analyses, changes of PC (16:0/18:1) and LPC (16:0) are observed beyond the border of the injured area. Together with previous reports—that PCs are hydrolyzed by phospholipase A2 (PLA2 ) and produce LPCs,—our present results suggest that LPC (16:0) is generated during the injury process after cerebral ischemia, presumably via PLA2 activation, and that PC (16:0/18:1) is one of its precursor molecules.
Abstract
This study reports that high fluence fullerene ion (C
60
+
) irradiation of 1–6 MeV, which was made possible by a new-type of high-flux ion source, elongates metal nanoparticles (NPs) in ...amorphous SiO
2
as efficiently as swift heavy ions (SHIs) of 200 MeV Xe
14+
, i.e., two orders of the magnitude higher energy ions. Comparing the irradiation effects induced by both the beams, the stopping processes of C
60
ions in SiO
2
are discussed in this paper. Despite of having almost the same elongation efficiency, the C
60
+
irradiation induced ~10 times more efficient sputtering due to the clustering enhancement and/or the synergy effect. Ion tracks of ~10.4 nm in diameter and 60–80 nm in length were observed in crystalline SiO
2
under 4 MeV C
60
irradiation
.
While the track diameter was comparable to those by SHIs of the same electronic stopping, much shorter track lengths than those predicted by a rigid C
60
molecule model indicates that the fragmentation occurred due to nuclear collisions. The elongation of the metal NPs was induced only down to the depth where the tracks were observed but not beyond.
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