BACKGROUNDThe influence of extensive coronary calcifications on the diagnostic and prognostic value of coronary computed tomography angiography-derived fractional flow reserve (FFRCT) has been ...scantily investigated. OBJECTIVESThe purpose of this study was to investigate the diagnostic and short-term role of FFRCT in chest pain patients with Agatston score (AS) >399. METHODSThis was a prospective multicenter study of 260 stable patients with suspected coronary artery disease (CAD) and AS >399. FFRCT was measured blinded by an independent core laboratory. All patients underwent invasive coronary angiography (ICA) and FFR if indicated. The agreement of FFRCT ≤0.80 with hemodynamically significant CAD on ICA/FFR (≥50% left main or ≥70% epicardial artery stenosis and/or FFR ≤0.80) was assessed. Patients undergoing FFR had colocation FFRCT measured, and the lowest per-patient FFRCT was registered in all patients. The association among per-patient FFRCT, coronary revascularization, and major clinical events (all-cause mortality, myocardial infarction, or unstable angina hospitalization) at 90-day follow-up was evaluated. RESULTSMedian age and AS were 68.5 years (IQR: 63-74 years) and 895 (IQR: 587-1,513), respectively. FFRCT was ≤0.80 in 204 patients (78%). Colocation FFRCT (n = 112) showed diagnostic accuracy, sensitivity, and specificity to identify hemodynamically significant CAD of 71%, 87%, and 54%. The area under the receiver-operating characteristics curve (AUC) was 0.75. When using the lowest FFRCT (n = 260), per-patient accuracy, sensitivity, and specificity were 57%, 95%, and 32%, respectively. The AUC was 0.84. A total of 85 patients underwent revascularization, and FFRCT was ≤0.80 in 96% of these. During follow-up, major clinical events occurred in 3 patients (1.2%), all with FFRCT ≤0.80. CONCLUSIONSMost patients with AS >399 had FFRCT ≤0.80. Using ICA/FFR as the reference revealed a moderate diagnostic accuracy of colocation FFRCT. Compared with the lowest per-patient FFRCT, colocation FFRCT measurement improved diagnostic accuracy and specificity. The 90-day follow-up was favorable with few coronary revascularizations and no major clinical events occurring in patients with FFRCT >0.80. (Use of FFR-CT in Stable Intermediate Chest Pain Patients With Severe Coronary Calcium Score FACC; NCT03548753).
Heparin, a major anticoagulant drug, comprises a complex mixture of motifs. Heparin is isolated from natural sources while being subjected to a variety of conditions but the detailed effects of these ...on heparin structure have not been studied in depth. Therefore, the result of exposing heparin to a range of buffered environments, ranging pH values from 7 to 12, and temperatures of 40, 60 and 80 °C were examined. There was no evidence of significant N-desulfation or 6-O-desulfation in glucosamine residues, nor of chain scission, however, stereochemical re-arrangement of α-L-iduronate 2-O-sulfate to α-L-galacturonate residues occurred in 0.1 M phosphate buffer at pH 12/80 °C. The results confirm the relative stability of heparin in environments like those during extraction and purification processes; on the other hand, the sensitivity of heparin to pH 12 in buffered solution at high temperature is highlighted, providing an important insight for heparin manufacturers.
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Thiol groups of cysteine (Cys) residues in proteins react with quinones, oxidation products of polyphenols, to form protein–polyphenol adducts. The aim of the present work was to quantify the amount ...of adduct formed between Cys residues and 4-methylcatechol (4MC) in minced beef. A Cys–4MC adduct standard was electrochemically synthesized and characterized by liquid chromatography–mass spectrometry (LC–MS) as well as NMR spectroscopy. Cys–4MC adducts were quantified after acidic hydrolysis of myofibrillar protein isolates (MPIs) and LC–MS/MS analysis of meat containing either 500 or 1500 ppm 4MC and stored at 4 °C for 7 days under a nitrogen or oxygen atmosphere. The concentrations of Cys–4MC were found to be 2.2 ± 0.3 nmol/mg MPI and 8.1 ± 0.9 nmol/mg MPI in meat containing 500 and 1500 ppm 4MC, respectively, and stored for 7 days under oxygen. The formation of the Cys–4MC adduct resulted in protein thiol loss, and ca. 62% of the thiol loss was estimated to account for the formation of the Cys–4MC adduct for meat containing 1500 ppm 4MC. Furthermore, protein polymerization increased in samples containing 4MC as evaluated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), and the polymerization was found to originate from protein–polyphenol interactions as evaluated by a blotting assay with staining by nitroblue tetrazolium.
There is a growing interest in lignin valorization to biofuels and chemicals. Here, we propose a novel and simple noncatalytic process to directly liquefy lignin rich solid residual from second ...generation bioethanol production by solvolysis with ethanol. Through an extensive parameter study in batch autoclaves assessing the effects of varying reaction temperature, reaction time, and solvent:lignin ratio, it is shown that hydrothermally pretreated enzymatic hydrolysis lignin solvolysis in supercritical ethanol can produce a heptane soluble bio-oil without the need for exhaustive deoxygenation. The process does not require addition of catalyst or a reducing agent such as hydrogen. The process is advantageously carried out with a low reaction period (<1 h) and with a reduced amount of solvent to lignin feedstock (ethanol:lignin (w/w) ratio of 2:1) which is a previously unexplored domain for lignin solvolysis. The resulting bio-oil product is mainly a mixture of di- and monomeric lignin species where the original lignin unit linkages have been broken. The oxygen content is lowered to <10 wt % (corresponding to an HHV of 36 MJ/kg) and the bio-oil is stable and acid free (verified by NMR), and due to the use of sulfur free lignin rich residual as feedstock, the resulting oil product is equally sulfur free. The residual solid product (char) has a reduced oxygen content relative to the lignin feed and equally increased higher heating value, making it a candidate for use as a biochar.
Solid-state, natural-abundance
95
Mo NMR experiments of four different MoS
2
materials have been performed on a magnet
B
0
= 19.6 T and on a new Series Connected Hybrid (SCH) magnet at 35.2 T. ...Employing two different 2H-MoS
2
(2H phase) materials, a “pseudo-amorphous” MoS
2
nano-material, and a MoS
2
layer on the Al
2
O
3
support of a hydrodesulphurization (HDS) catalyst have enabled introduction of solid-state
95
Mo NMR as an important analytical tool in studies of MoS
2
nano-materials.
95
Mo spin-lattice relaxation time (
T
1
) studies of 160- and 4-layer 2H-MoS
2
samples at 19.6 and 35.2 T show their relaxation rates (1/
T
1
) increase in proportion to
B
0
2
. This is in accord with chemical shift anisotropy (CSA) relaxation being the dominant
T
1
(
95
Mo) mechanism, with a large
95
Mo CSA = 1025 ppm determined for all four MoS
2
nano-materials. The dominant CSA mechanism suggests the MoS
2
band-gap electrons are delocalized throughout the lattice-layer structures, thereby acting as a fast modulation source (
ω
o
τ
c
<< 1) for
95
Mo CSA in 2H-MoS
2
. A decrease in
T
1
(
95
Mo) is observed for an increase in
B
0
field and for a decrease in the number of 2H-MoS
2
layers. All four nano-materials exhibit identical
95
Mo electric field gradient (EFG) parameters. The
T
1
results account for the several failures to retrieve
95
Mo spectral EFG and CSA parameters for multilayer 2H-MoS
2
samples in the pioneering solid-state
95
Mo NMR studies performed during the past two decades (1990–2010), because of the extremely long
T
1
(
95
Mo) = ~200–250 s observed at low
B
0
(~9.4 T) used at that time. Much shorter
T
1
(
95
Mo) values are observed even at 19.6 T for the “pseudo-amorphous” and the HDS catalyst (MoS
2
-Al
2
O
3
support) MoS
2
nano-materials. These allowed useful solid-state
95
Mo NMR spectra for these two samples to be obtained at 19.6 T in a few to < 24 h. Most importantly, this research led to observation of an impressive
95
Mo MAS spectrum for an average of 1–4 thick MoS
2
-layers on a Al
2
O
3
support, i.e., the first MAS NMR spectrum of a low natural-abundance, low-γ quadrupole-nucleus species layered on a catalyst support. While a huge gain in NMR sensitivity, factor ~ 60, is observed for the
95
Mo MAS spectrum of the 160-layer sample at 35.2 T compared to 14.1 T, the MAS spectrum for the 4-layer sample is almost completely wiped out at 35.2 T. This unusual observation for the 4-layer sample (crumpled, rose-like and defective Mo-edge structures) is due to an increased distribution of the isotropic
95
Mo shifts in the
95
Mo MAS spectra at
B
0
up to 35.2 T upon reduction of the number of sample layers.
ABSTRACT
Purpose
To understand the transformation pathways amongst anhydrate/hydrate solid forms of sodium naproxen and to highlight the importance of a polymorphic dihydrate within this context.
...Methods
Multi-temperature dynamic vapour sorption (DVS) analysis combined with variable-humidity X-ray powder diffraction (XRPD) to establish the transformation pathways as a function of temperature and humidity. XRPD and thermogravimetric analysis (TGA) to characterise bulk samples. Monitoring of
in-situ
dehydration using solid-state
13
C CP/MAS spectroscopy.
Results
At 25°C, anhydrous sodium naproxen (AH) transforms directly to one dihydrate polymorph (DH-II). At 50°C, AH transforms stepwise to a monohydrate (MH) then to the other dihydrate polymorph (DH-I). DH-II transforms to a tetrahydrate (TH) more readily than DH-I transforms to TH. Both dihydrate polymorphs transform to the same MH.
Conclusions
The properties of the polymorphic dihydrate control the transformation pathways of sodium naproxen.
Microorganisms in membrane systems tend to adhere to surfaces and to form a gel layer called biofilm, which participates in the separation process as a secondary membrane. On the raw water side, it ...causes an increase of fluid friction resistance which increases
Δp
feed/brine. Also, overall hydraulic resistance of the membrane
Δp
membrane can increase due to the biofilm. If these effects exceed a certain threshold of interference, they are addressed as biofouling. Countermeasures require a three step protocol: (1) detection, (2) sanitation, and (3) prevention. Detection has to be performed on the surface as planctonic cell numbers released randomly from the biofilm do reflect neither site nor extent of biofilm growth. The analysis includes microbiological and biochemical parameters; the differentiation between other kinds of fouling such as scaling or organic fouling can be performed by FTIR-ATR spectroscopical analysis. Sanitation should be focused on removal of the biomass rather than on killing the microorganisms attached to the surface. First, the slime matrix, consisting mainly of polysaccharides and proteins, must be weakened. This requires interference with the binding forces, which are weak physico-chemical interactions such as hydrogen bonds, van der Waals and electrostatical interactions. Then, increased shear forces can remove the biomass. A preventive concept should acknowledge the fact that biodegradable substances in the water represent the biofouling potential. Biofouling can be regarded as a “biofilm reactor in the wrong place”. Reduction of the nutrient content of the raw water can be achieved by a “biofilm reactor in the right place”, i.e., a biofilter on which microorganisms form biofilms and sequester the nutrients from the water phase. Mandatory for any optimized antifouling strategy is monitoring of biofilm development; a fiber optical device which provides real-time, on-line,
in situ information non-destructively is proposed which can be adjusted to membrane modules.
The mechanical properties of biofilms and in particular their mechanical strength is of great importance for both biofilm reactors and for the removal of undesired biofilms as in cases of biofouling ...and biocorrosion. By uniaxial compression measurements, it is possible to determine the apparent elastic or Young's modulus and the yield stress as parameters for mechanical stability. This was performed with a recently developed device, using model biofilms of mucoid strain Pseudomonas aeruginosa SG81. The biofilms were grown on membrane filters placed on nutrient agar medium with different concentrations of calcium ions. The compressive stress-strain behaviour up to failure was recorded at a compression speed of 1 micron s-1. The apparent Young's modulus, representing the stiffness of the biofilm, and the yield stress obtained from the stress--strain diagram were used for the description of mechanical properties of biofilms. A certain critical concentration of calcium ions was found where the Young's modulus of the P. aeruginosa biofilms increases strongly and subsequently remains constant for higher calcium concentrations. This behaviour is explained by the presence of calcium ions crosslinking alginate, which is the major component of the extracellular polymeric substances produced by the mucoid P. aeruginosa strain used in this investigation.
The aim of this work was to evaluate the prognostic impact of statin therapy in symptomatic patients without obstructive CAD.
Information on the prognostic impact of post–coronary computed ...tomographic angiography (CTA) statin use in patients with no or nonobstructive coronary artery disease (CAD) is sparse.
Patients undergoing CTA with suspected CAD in western Denmark from 2008 to 2017 with <50% coronary stenoses were identified. Information on post-CTA use of statin therapy and cardiovascular events were obtained from national registries.
The study included 33,552 patients, median aged 56 years, 58% female, with no (n = 19,669) or nonobstructive (n = 13,883) CAD and a median follow-up of 3.5 years. The absolute risk of the combined end point of myocardial infarction (MI) or all-cause mortality was directly associated with the CAD burden with an event rate/1,000 patient-years of 4.13 (95% CI: 3.69-4.61) in no, 7.74 (95% CI: 6.88-8.71) in mild (coronary artery calcium score CACS 0-99), 13.72 (95% CI: 11.61-16.23) in moderate (CACS 100-399), and 32.47 (95% CI: 26.25-40.16) in severe (CACS ≥400) nonobstructive CAD. Statin therapy was associated with a multivariable adjusted HR for MI and death of 0.52 (95% CI: 0.36-0.75) in no, 0.44 (95% CI: 0.32-0.62) in mild, 0.51 (95% CI: 0.34-0.75) in moderate, and 0.52 (95% CI: 0.32-0.86) in severe nonobstructive CAD. The estimated numbers needed to treat to prevent the primary end point were 92 (95% CI: 61-182) in no, 36 (95% CI: 26-58) in mild, 24 (95% CI: 15-61) in moderate, and 13 (95% CI: 7-86) in severe nonobstructive CAD. Residual confounding may persist, but not to an extent explaining all of the observed risk reduction associated with statin treatment.
The risk of MI and all-cause mortality in patients without obstructive CAD is directly associated with the CAD burden. Statin therapy is associated with a reduction of MI and all-cause death across the spectrum of CAD, however, the absolute benefit of treatment is directionally proportional with the CAD burden.
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