The identification of anhydrous and hydrated forms of pharmaceutical substances is of great importance in pharmaceutical science and industry. We report the use of THz time-domain spectroscopy ...(THz-TDS) for pseudopolymorph investigation. The anhydrous forms of pharmaceutical substances including caffeine, theophylline, D-glucose, and ampicillin exhibit different THz absorption spectra from their hydrated forms, presumably due to their different intermolecular vibrational modes mediated by hydrogen-bonding. The data from X-ray powder diffractometry (XRPD) confirm the crystallinity differences between the anhydrous and hydrated forms. The temperature-dependent THz spectra of caffeine hydrate were also recorded, and it demonstrates that THz-TDS can be used to monitor the dehydration process of drug hydrates. We conclude that THz-TDS is an advantageous technique for the pseudopolymorph identification and study, and has great potential to become a process analytical technology (PAT) in pharmaceutical production and quality control.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A survey of C
2
H
N
= 1 − 0 and N
2
H
+
J
= 1 − 0 toward
Planck
Galactic cold clumps (PGCCs) was performed using the Purple Mountain Observatory’s 13.7 m telescope. C
2
H and N
2
H
+
were chosen to ...study the chemical evolutionary states of PGCCs. Among 121 observed molecular cores associated with PGCCs, 71 and 58 are detected with C
2
H
N
= 1 − 0 and N
2
H
+
J
= 1 − 0, respectively. The detected lines of most sources can be fitted with a single component with compatible
V
LSR
and line widths, which confirms that these PGCC cores are very cold (with gas temperatures 9–21 K) and quiescent while still dominanted by turbulence. The ratio between the column densities of C
2
H and N
2
H
+
(
N
(C
2
H)/
N
(N
2
H
+
)) is found to be a good tracer for the evolutionary states of PGCC cores. Gas-grain chemical model can reproduce the decreasing trend of
N
(C
2
H)/
N
(N
2
H
+
) as a function of time. The cores with the lowest abundances of N
2
H
+
(
X
N
2
H
+
< 10
−10
) are the youngest, and have nearly constant abundances of C
2
H. In evolved cores with
X
N
2
H
+
~10
−9
, abundances of C
2
H drop quickly as the exhaustion of carbon atoms. Although these PGCC cores are in different evolutionary states, they are all quite young (< 5 × 10
5
yr) with
N
(C
2
H) >
N
(N
2
H
+
). Mapping observations are carried out toward 20 PGCC cores. The PGCC cores in Cepheus have lower
N
(C
2
H)/
N
(N
2
H
+
) and larger line widths compared with those in Taurus. This implies that PGCC cores in Taurus are less chemically evolved than those in Cepheus.
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FMFMET, NUK, UL, UM, UPUK
Clostridioides difficile is considered an urgent threat to human health by the US Centers for Disease Control and Prevention. In recent years, C. difficile has been reported increasingly as a cause ...of gastrointestinal disease in children, and the prevalence of hospital-acquired C. difficile infection and community-acquired CDI in children is increasing.
To perform a systematic review and meta-analysis of risk factors for CDI in children.
MEDLINE/PubMed, EMBASE, Web of Science, Scopus, OVID, China National Knowledge Infrastructure, Wanfang (Chinese), SinoMed (Chinese) and Weipu (Chinese) were searched from inception to 12th January 2022. Observational studies (cohort, case–control and cross-sectional) on CDI in children were included in the analysis. Data were pooled using a fixed or random-effects model, and odds ratios (OR) were calculated.
In total, 25 observational studies were included in the analysis. Prior antibiotic exposure OR 1.93, 95% confidence interval (CI) 1.25–2.97, prolonged hospitalization (OR 14.68, 95% CI 13.24–16.28), history of hospitalization (OR 3.67, 95% CI 1.91–7.06), gastric acid suppressants (OR 1.96, 95% CI 1.41–2.73), male gender (OR 1.18, 95% CI 1.05–1.32), neoplastic disease (OR 3.40, 95% CI, 2.85–4.07), immunodeficiency (OR 4.18, 95% CI 3.25–5.37), solid organ transplantation (OR 4.56, 95% CI 3.95–5.27) and enteral feeding (OR 2.21, 95% CI 1.05–4.62) were associated with increased risk of CDI.
This systematic review and meta-analysis provides further evidence for the susceptibility factors of CDI to improve clinicians' awareness of CDI, and prevent C. difficile-associated diarrhoea in children.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Magnetic flux leakage (MFL) sensors, with their compact configuration and high sensitivity to small defects, have attracted much attention in recent years for the non-destructive testing of ...ferromagnetic structures. Tunnel magneto-resistive (TMR) devices have superior performances in sensitivity and linear operation range over conventional magneto-resistive devices. In this paper, a commercial TMR device is employed for developing an electromagnet-based MFL sensor. The electromagnet magnetizer includes Helmholtz-like coils together with a custom-made magnetic shield. The orthogonal test method is applied to aid the structural parameter optimization to the magnetizer based on the finite element analysis results of magnetic field distribution. In this study a prototype of a TMR-based MFL sensor is developed, and its performances on detecting various types of defects are tested on a scanning apparatus. The experimental results show that the MFL signal induced by a blind hole with dimensions of 0.3 mm in both depth and diameter is detectable. In addition, two adjacent notches located more than 2.0 mm from each other can be clearly distinguished from the received MFL signal. The detectable angular detection range for a single TMR device is estimated as 52° in the tested linear shaft rod. The consistency between the simulated and received MFL signal induced by a row of notches inspires confidence in the proposed sensor design method, which in the future can be transplanted for TMR-based sensor array design. Finally, the TMR-based MFL sensor is used for detecting a flaw of a single broken wire with a diameter of 0.5 mm, and the induced MFL signal can be clearly recognized from the oscillation signal that is generated by the twisted rope surface. Therefore, the presented TMR-based MFL sensor has great potential for steel wire rope inspection with enhanced sensitivity to small defects, and it is capable of being integrated into production lines due to its compact configuration.
The Qinling‐Tongbai‐Dabie‐Sulu orogenic belt comprises a Palaeozoic accretion‐dominated system in the north and a Mesozoic collision‐dominated system in the south. A combined petrological and ...geochronological study of the medium‐to‐high grade metamorphic rocks from the diverse Palaeozoic tectonic units in the Tongbai orogen was undertaken to help elucidate the origins of Triassic ultrahigh‐pressure metamorphism and collision dynamics between the Sino‐Korean and Yangtze cratons. Peak metamorphic conditions are 570–610 °C and 9.3–11.2 kbar for the lower unit of the Kuanping Group, 630–650 °C and 6.6–8.9 kbar for the upper unit of the Kuanping Group, 550–600 °C and 6.3–7.7 kbar for the Erlangping Group, 770–830 °C and 6.9–8.5 kbar for the Qinling Group and 660–720 °C and 9.1–11.5 kbar for the Guishan complex. Reaction textures and garnet compositions indicate clockwise P–T paths for the amphibolite facies rocks of the Kuanping Group and Guishan complex, and an anticlockwise P–T path for the granulite facies rocks of the Qinling Group. Sensitive high‐resolution ion microprobe U–Pb zircon dating on metamorphic rocks and deformed granite/pegmatites revealed two major Palaeozoic tectonometamorphic events. (i) During the Silurian‐Devonian (c. 440–400 Ma), the Qinling continental arc and Erlangping intra‐oceanic arc collided with the Sino‐Korean craton. The emplacement of the Huanggang diorite complex resulted in an inverted thermal gradient in the underlying Kuanping Group and subsequent thermal relaxation during the exhumation. Meanwhile, the oceanic subduction beneath the Qinling continental arc produced magmatic underplating and intrusion, leading to granulite facies metamorphism followed by a near‐isobaric cooling path. (ii) During the Carboniferous (c. 340–310 Ma), the northward subduction of the Palaeo‐Tethyan ocean generated a medium P/T Guishan complex in the hangingwall and a high P/T Xiongdian eclogite belt in the footwall. The Guishan complex and Xiongdian eclogite belt are therefore considered to be paired metamorphic belts. Subsequent separation of the paired belts is inferred to be related to the juxtaposition of the Carboniferous eclogites with the Triassic HP metamorphic complex during continental subduction and exhumation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present systematic studies of the transient dynamics of GaAs by ultrafast time-resolved reflectivity. In photoexcited non-equilibrium states, we found a sign reverse in reflectivity change ΔR/R, ...from positive around room temperature to negative at cryogenic temperatures. The former corresponds to a free carrier metallic state, while the latter is attributed to an exciton insulating state, in which the transient electronic properties is mostly dominated by excitons, resulting in a transient metal-insulator transition (MIT). Two transition temperatures (T1 and T2) are well identified by analyzing the intensity change of the transient reflectivity. We found that photoexcited MIT starts emerging at T1 as high as ∼ 230 K, in terms of a dip feature at 0.4 ps, and becomes stabilized below T2 that is up to ∼ 180 K, associated with a negative constant after 40 ps. Our results address a phase diagram that provides a framework for the inducing of MIT through temperature and photoexcitation, and may shed light on the understanding of light-semiconductor interaction and exciton physics.
A modified indirect algorithm for extracting real permittivities from measured resonant frequencies has been developed. It is based on the perturbation theory along with the Newton iteration method, ...and improves the speed of the calculation with a factor of 2-4. It is superior, especially when system matrices under calculation are large. Based on the complementary advantages of the modified algorithm and a direct algorithm, a mixed algorithm of high speed and accuracy has been described. A real measurement system incorporating the linear fractional curve-fitting method and the mixed algorithm has been built to measure complex permittivities of high-Q materials.
This study was conducted to determine the effect of dietary CLA (Conjugated linoleic acid) levels on growth performance, fatty acid profiles and lipid metabolism of liver in Synechogobius hasta. Fish ...were fed six diets with fish oil replaced by 0 (control), 5, 10, 15, 20 and 25 g kg⁻¹ CLA for 8 weeks. Weight gain, WG, and SGR (specific growth rate) tended to increase when dietary CLA levels increased from 0 to 10 g kg⁻¹ and then decline with further increasing dietary CLA levels to 25 g kg⁻¹. FCR (feed conversion ratio) showed contrary trend with WG and SGR. The reduced VSI (vicero somatic index) and increased HSI (hepatosomatic index) were observed in fish fed increasing dietary CLA levels. Whole‐body lipid content declined, but hepatic lipid content increased with increasing dietary CLA levels. Dietary CLA modified total percentages of the main groups of fatty acids in liver. Hepatic 6PGD, ME and ICDH activities increased with increasing dietary CLA levels. FAS and G6PD were very variable and not related to dietary treatments. CPT I activities showed no significant differences among the treatments. Based on second‐order polynomial regression analysis of WG and FCR against dietary CLA level, 8.7–10.1 g kg⁻¹ was indicated to be the optimal dietary CLA range for maximum growth and feed utilization for S. hasta.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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