We describe a
3
He magnetometer capable to measure high magnetic fields (
B
> 0.1 T) with a relative accuracy of better than 10
-12
. Our approach is based on the measurement of the free induction ...decay of gaseous, nuclear spin polarized
3
He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T
2
∗
being of order minutes which is achieved for spherical sample cells in the regime of “motional narrowing” where the disturbing influence of field inhomogeneities is strongly suppressed. The
3
He gas is spin polarized in situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T
2
∗
further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10
-4
.
Under fast MAS conditions, techniques for
1H signal selection and suppression, which have originally been developed for solution-state NMR, become applicable to solids. In this work, we describe how ...WATERGATE and DANTE pulse sequences can be used under MAS to selectively excite or suppress peaks in
1H solid-state spectra. As known from the liquid-state analogues, signal selection and/or suppression is supported by pulsed-field gradients which selectively dephase and rephase transverse magnetisation. Under MAS, the required field gradients are provided by a simple pair of coils which have been built into a standard fast-MAS probe. PFG-assisted techniques enable efficient selection or suppression of
1H peaks in a single transient of the pulse sequence without the need for phase cycles. Therefore, these tools can readily be incorporated into solid-state MAS NMR experiments, which is demonstrated here for
1H–
1H double-quantum NMR spectra of supramolecular systems. In the examples presented here, the
1H signals of interest are relatively weak and need to be observed despite the presence of the strong
1H signal of long alkyl sidechains. PFG-assisted suppression of this strong perturbing signal is shown to be particularly useful for obtaining unambiguous results.
The properties of poly(
p-phenylene vinylene) (PPV) films depend on the degree of orientational order present in the films. Recently, Dermaut
et al. reported a novel cold-stretching technique (
...Macromolecules
33, 5634–5637 (2000)) in which chain alignment can be introduced into PPV precursor films by uniaxially stretching them prior to the thermal elimination reaction that forms PPV. The two-dimensional direction exchange with correlation for orientation-distribution evaluation and reconstruction (DECODER)
13C NMR technique was applied to both unstretched PPV films and PPV films that were uniaxially cold stretched to a draw ratio λ=l/l
0=5. The unstretched films were found to be moderately ordered, comprised of a component present at 80% with a Gaussian distribution of
60° fwhm, while the remaining 20% is isotropically distributed. A distribution of 9°±3° fwhm was measured by NMR in good agreement with IR dichroism measurements for the uniaxially cold-stretched films, establishing that a high degree of orientational order can be introduced by cold stretching PPV films.
We present a study of the structural effects of hydrogen adsorption on Ru14 – investigated by a combination of trapped ion electron diffraction and density functional computations. While the bare ...Ru14 – forms a double layer hexagonal structure, the adsorption of hydrogen initiates an evolution of the metal core toward an icosahedral structure. The structural rearrangement is driven by the difference in mean hydrogen adsorption energies, gradually stabilizing the icosahedral cluster core structure for higher hydrogen coverage. Detailed temperature dependent measurements reveal a crossover between the two structure motifs and indicate a structural phase equilibrium. Accompanying free energy computations confirm the chemical equilibrium and identify a hydrogen coverage instability region where the cluster hydrides decompose into the two core isomers with different hydrogen coverage.
Background
Inflammation drives atherosclerosis and its complications. Anti-inflammatory therapy with interleukin 1 beta (IL-1β) antibody reduces cardiovascular events in patients with elevated ...high-sensitive C-reactive protein (hsCRP). This study aims to identify the share of patients with coronary heart disease (CHD) and residual inflammation who may benefit from anti-inflammatory therapy.
Methods
hsCRP and low-density lipoprotein (LDL) levels were determined in 2741 all-comers admitted to the cardiological ward of our tertiary referral hospital between June 2016 and June 2018. Patients without CHD, with acute coronary syndrome, chronic or recurrent systemic infection, use of immunosuppressant or anti-inflammatory agents, chronic inflammatory diseases, chemotherapy, terminal organ failure, traumatic injury and pregnancy were excluded.
Results
856 patients with stable CHD were included. 42.7% of those had elevated hsCRP ≥ 2 mg/l. Within the group of patients with LDL-cholesterol < 70 mg/dl, 30.9% shared increased hsCRP indicating residual inflammation. After multivariate adjusted backward selection elevated Lipoprotein (a) (OR 1.61,
p
= 0.048), elevated proBNP (OR 2.57,
p
< 0.0001), smoking (OR 1.70,
p
= 0.022), and obesity (OR 2.28,
p
= 0.007) were associated with elevated hsCRP. In contrast, the use of ezetimibe was associated with normal hsCRP (OR 0.51,
p
= 0.014). In the subgroup of patients with on-target LDL-cholesterol < 70 mg/dl, backward selection identified elevated proBNP (OR 3.49,
p
= 0.007) as independent predictor of elevated hsCRP in patients with LDL-cholesterol < 70 mg/dl.
Conclusion
One-third of all-comers patients with CHD showed increased levels of hsCRP despite a LDL-cholesterol < 70 mg/dl potentially qualifying for an anti-inflammatory therapy. Elevated proBNP is an independent risk factor for hsCRP elevation.
Graphic abstract
We elaborate on the possibilities and needs to integrate design thinking into requirements engineering, drawing from our research and project experiences. We suggest three approaches for tailoring ...and integrating design thinking and requirements engineering with complementary synergies and point at open challenges for research and practice.
The effect of hydrogenation on the structure of Ru19 – has been studied using a combination of trapped ion electron diffraction and density functional computations. While the bare Ru19 – cluster has ...a closed-shell octahedral geometry, hydrogenation of the cluster changes the structure type of the ruthenium core toward an icosahedral motif. The experiments show a gradual structural transition depending on the number of adsorbed hydrogen atoms. Density functional theory computations reveal the driving force behind this process to be the larger hydrogen adsorption energies for the bi-icosahedral structure and predict a corresponding structural rearrangement at around 20 adsorbed hydrogen atoms, which is consistent with the experimental findings. Additionally, the computations provide insight into the hydrogen-binding situation. They show that hydrogen is preferentially atomically bound only to surface Ru atoms. H2 binding is predicted only at high hydrogen loadings.
Aims. Literature on percutaneous coronary intervention (PCI) stated an inverse relationship between hospital volume and mortality, but the effects on other characteristics are unclear. Methods. Using ...German national records, all coronary angiographies with coronary artery disease in 2017 were identified. We applied risk-adjustment to account for differences in population characteristics. Results. Of overall 528,188 patients, 55.22% received at least one stent, with on average 1.01 stents implanted in all patients. Based on those patients who received at least one stent, this corresponds to an average number of 1.82 stents. In-hospital mortality across all patients was 2.93%, length of hospital stay was 6.46 days, and mean reimbursement was €5,531. There were comparatively more emergency admissions in low volume centers and more complex cases (3-vessel disease, left main stenosis, and in-stent stenosis) in high volume centers. In multivariable regression analysis, volume and likelihood of stent implantation (p=0.003) as well as number of stents (p=0.020) were positively correlated. No relationship was seen for in-hospital mortality (p=0.105), length of stay (p=0.201), and reimbursement (p=0.108). Nonlinear influence of volume suggests a ceiling effect: In hospitals with ≤100 interventions, likelihood and number of implanted stents are lowest (∼34% and 0.6). After that, both rise steadily until a volume of 500 interventions. Finally, both remain stable in the categories of over 500 interventions (∼60% and 1.1). Conclusion. In PCI, lower volume centers contribute to emergency care. Higher volume centers treat more complex cases and show a higher likelihood of stent implantations, with a stable safety.
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