Display omitted
•EADSA and LC–MS allows the differentiation of sterol diastereoisomers.•24S- and 24R-hydroxycholesterol are present in human plasma.•Four diastereoisomers of ...3β,7-dihydroxycholest-5-enoic acid are found in human plasma.•3β,7α- and 3β,7β-dihydroxychol-5-enoic acids are found in human plasma.•7α- and 7β- epimers give distinguishable MS3 spectra.
The introduction of a hydroxy group to the cholesterol skeleton introduces not only the possibility for positional isomers but also diastereoisomers, where two or more isomers have different configurations at one or more of the stereocentres but are not mirror images. The differentiation of diastereoisomers is important as differing isomers can have differing biochemical properties and are formed via different biochemical pathways. Separation of diasterioisomers is not always easy by chromatographic methods Here we demonstrate, by application of charge-tagging and derivatisation with the Girard P reagent, the separation and detection of biologically relevant diastereoisomers using liquid chromatography − mass spectrometry with multistage fragmentation.
Dihydroxyoxocholestenoic acids are intermediates in bile acid biosynthesis. Here, using liquid chromatography – mass spectrometry, we confirm the identification of ...7α,24-dihydroxy-3-oxocholest-4-en-26-oic and 7α,25-dihydroxy-3-oxocholest-4-en-26-oic acids in cerebrospinal fluid (CSF) based on comparisons to authentic standards and of 7α,12α-dihydroxy-3-oxocholest-4-en-26-oic and 7α,x-dihydroxy-3-oxocholest-4-en-26-oic (where hydroxylation is likely on C-22 or C-23) based on exact mass measurement and multistage fragmentation. Surprisingly, patients suffering from the inborn error of metabolism cerebrotendinous xanthomatosis, where the enzyme CYP27A1, which normally introduces the (25 R)26-carboxylic acid group to the sterol side-chain, is defective still synthesise 7α,24-dihydroxy-3-oxocholest-4-en-26-oic acid and also both 25 R- and 25 S-epimers of 7α,12α-dihydroxy-3-oxocholest-4-en-26-oic acid. We speculate that the enzymes CYP46A1 and CYP3A4 may have C-26 carboxylase activity to generate these acids. In patients suffering from hereditary spastic paraplegia type 5 the CSF concentrations of the 7α,24- and 7α,25-dihydroxy acids are reduced, suggesting an involvement of CYP7B1 in their biosynthesis in brain.
Display omitted
•Dihydroxy-3-oxocholest-5-en-26-oic are found in human CSF and plasma.•Hydroxy groups may be at 7α,24, 7α,25, or 7α,12α.•Another acid is hydroxylated at 7α and in the side-chain probably at C-22 or C-23.•In patients with CTX acids with 25 R or 25 S stereochemistry are found.•In patients with SPG5 the concentrations of acids in CSF are reduced.
Computational capability has been developed to adjust multigroup neutron cross sections, including self-shielding correction factors, to improve the fidelity of boiling water reactor (BWR) core ...modeling and simulation. The method involves propagating multigroup neutron cross-section uncertainties through various BWR computational models to evaluate uncertainties in key core attributes such as core k
eff
, nodal power distributions, thermal margins, and in-core detector readings. Uncertainty-based inverse theory methods are then employed to adjust multigroup cross sections to minimize the disagreement between BWR core modeling predictions and observed (i.e., measured) plant data. For this paper, observed plant data are virtually simulated in the form of perturbed three-dimensional nodal power distributions with the perturbations sized to represent actual discrepancies between predictions and real plant data. The major focus of this work is to efficiently propagate multigroup neutron cross-section uncertainty through BWR lattice physics and core simulator calculations. The data adjustment equations are developed using a subspace approach that exploits the ill-conditioning of the multigroup cross-section covariance matrix to minimize computation and storage burden. Tikhonov regularization is also employed to improve the conditioning of the data adjustment equations. Expressions are also provided for posterior covariance matrices of both the multigroup cross-section and core attributes uncertainties.
The onset of flow instability (OFI) and critical heat flux (CHF) in heated thin horizontal annular flow passages cooled by subcooled water were investigated.
For OFI, six different test sections, ...with inner diameter of 6.4 mm, annular gap widths of 0.724–1.001 mm, and heated lengths of 174–197 mm were used. The test parameter ranges were: 85–
1428
kg/m
2
s
mass flux, 0.344–1.034 MPa exit pressure, 50–150 °C inlet temperature, 0.124–
1.0
MW/m
2
surface heat flux and 0–∞ inner-to-outer surface heat flux ratio. In addition, the effect of dissolved non-condensables on OFI was examined by performing similar experiments with degassed water and water saturated with air at test section inlet temperature and exit pressure. A total of 138 OFI test were run addressing important parametric trends. A theoretical model based on the solution of one-dimensional fluid conservation equations, which assumes no voidage upstream the onset of significant void (OSV) point, and accounts for thermodynamic non-equilibrium beyond the OSV point using an empirical quality profile fit, was shown to predict the conditions leading to OFI reasonably well.
For CHF, the test section was an annulus with 6.45 and 7.77 mm inner and outer diameters, respectively (0.66 mm gap width), and an 18.5-cm long heated section. The experimental parameters investigated covered the following ranges: test section exit pressure: 0.344–1.034 MPa; coolant (water) mass flux: 100–
380
kg/m
2
s
; wall heat flux: 0.231–
1.068
MW/m
2
; water inlet temperature: 30–65 °C. The measured CHF values were considerably lower than the expected CHF values for vertical test section configuration. In all the tests CHF occurred at relatively high equilibrium qualities, and was preceded by flow stratification which caused dry-out of the upper surface of the flow channel. The data were correlated in two ways: by introducing empirical correction multipliers into three widely used correlations for vertical channels; and based on the compensated distortions method.
Abstract
Purpose
This systematic review summarizes the existing evidence on treatment options and outcomes for partial scapholunate interosseous ligament (pSLIL) injuries.
Methods
A systematic ...electronic search of Medline, Embase, and CINAHL was performed from inception through to February 13, 2022. All primary research articles addressing the treatment of pSLIL tears were eligible for inclusion regardless of timing of surgery, surgical technique, or rehabilitation. The PRISMA Checklist guided the reporting and data abstraction. Descriptive statistics and forest plots are presented.
Results
A total of 14 studies with 342 patients were included for analysis. Treatments were categorized into four groups: electrothermal shrinkage (ES), arthroscopic capsuloplasty (AC), open capsulodesis (OC), and no treatment (NT). There were five studies in the ES group (
N
= 69, mean age = 34.3 ± 3.3 years), three studies in the AC group (
N
= 138, mean age = 32.2 ± 3.8 years), five studies in the OC group (
N
= 123, mean age of 30.7 ± 7.8 years), and one study in the NT group (
N
= 12, mean age = 43 years, range = 28–67 years). The average postintervention visual analog scale pain score for the ES group was 1.4 ± 0.5 (from 5.7 ± 1.8), for the AC group was 3.2 ± 1.3 (from 6.6 ± 0), for the OC group was 2.3 ± 2.1 (from 5.6 ± 1.6), and for the NT group was 3.2 (from 7.6). The wrist extension range of motion improved postoperatively for all intervention groups (ES = 66.3°–70.7°; AC = 67°–74.5°; and OC = 48.9°–63.5°), whereas it remained unchanged for the NT group (46°–45°). Grip strength also improved in all intervention groups (ES = 17.9–29.9 kg; AC = 24.0–32.2 kg; and OC = 15.8–26.6 kg), while the NT group remained unchanged (25–24 kg). The radiographic scapholunate gap improved postoperatively in all groups that reported pre- and postintervention (ES = 2.2–1.9 mm; OC = 2.5–1.8 mm) and slightly worsened in the NT group (2.5–2.7 mm). In the ES group, there were three complications (11.5%, no major complications), in the AC group there was one major complication (0.9%, complex regional pain syndrome CRPS), and in the OC group there were six complications (15.4%, four major complications—CRPS).
Conclusion
All interventional treatment options (ES, AC, and OC) provided significant improvements in patient-reported pain, range of motion, grip strength, and radiographic parameters, with low complication rates. In comparison, no improvement in range of motion or grip strength was noted in the NT group. Therefore, surgical management of pSLIL injuries is an effective and relatively safe treatment option. Further studies comparing the outcomes of specific surgical treatments are warranted to further elucidate the optimal management option for pSLIL tears.
Level of Evidence
Level III, systematic review of Level III–IV studies.
Genetic diversity and phylogenetic analyses of 24 species, representing nine sections of the genus Galium (Rubiaceae), have been made using the Inter Simple Sequence Repeats (ISSR), Randomly ...Amplified Polymorphic DNA (RAPD), and combined ISSR and RAPD markers. Four ISSR primers and three RAPD primers generated 250 polymorphic amplified fragments. The results of this study showed that the level of genetic variation in Galium is relatively high. RAPD markers revealed a higher level of polymorphism (158 bands) than ISSR (92 bands). Clustering of genotypes within groups was not similar when RAPD and ISSR derived dendrograms were compared. Six clades can be recognized within Galium, which mostly corroborate, but also partly contradict, traditional groupings. UPGMA-based dendrogram showed a close relationship between members of section Leiogalium with G. verum and G. humifusum (sect. Galium), and G. angustifolium (sect. Lophogalium). Principal coordinated analysis, however, showed some minor differences with UPGMA-based dendrograms. The more apomorphic groups of Galium form the section Leiogalium clade including the perennial sections Galium, Lophogalium, Jubogalium, Hylaea and Leptogalium as well as the annual section Kolgyda. The remaining taxa of Galium are monophyletic.
PDF
