BACKGROUNDQuantitative MR, including T1ρ mapping, has been extensively used to probe early biochemical changes in knee articular cartilage of subjects with osteoarthritis (OA) and others at risk for ...cartilage degeneration, such as those with anterior cruciate ligament (ACL) injury and reconstruction. However, limited studies have been performed aimed to assess the spatial location and patterns of T1ρ. In this study we used a novel voxel-based relaxometry (VBR) technique coupled with principal component analysis (PCA) to extract relevant features so as to describe regional patterns and to investigate their similarities and differences in T1ρ maps in subjects with OA and subjects six months after ACL reconstruction (ACLR). METHODST1ρ quantitative MRI images were collected for 180 subjects from two separate cohorts. The OA cohort included 93 osteoarthritic patients and 25 age-matched controls. The ACLR-6M cohort included 52 patients with unilateral ACL tears who were imaged 6 months after ACL reconstruction, and 10 age-matched controls. Non-rigid registration on a single template and local Z-score conversion were adopted for T1ρ spatial and intensity normalization of all the images in the dataset. PCA was used as a data dimensionality reduction to obtain a description of all subjects in a 10-dimensional feature space. Logistic linear regression was used to identify distinctive features of OA and ACL subjects. RESULTSGlobal prolongation of the Z-score was observed in both OA and ACL subjects compared to controls higher values in 1st principal component (PC1); P=0.01. In addition, relaxation time differences between superficial and deep cartilage layers of the lateral tibia and trochlea were observed to be significant distinctive features between OA and ACL subjects. OA subjects demonstrated similar values between the two cartilage layers higher value in 2nd principal component (PC2); P=0.008, while ACL reconstructed subjects showed T1ρ prolongation specifically in the cartilage superficial layer (lower values in PC2; P<0.0001). T1ρ elevation located outside of the weight-bearing area, located in the posterior and anterior aspects of the lateral femoral compartment, was also observed to be a key feature in distinguishing OA subjects from controls higher value in 6th principal component (PC6); P=0.007. CONCLUSIONSThis study is the first example of T1ρ local/regional pattern analysis and data-driven feature extraction in knees with cartilage degeneration. Our results revealed similarities and differences between OA and ACL relaxation patterns that could be potentially useful to better understand the pathogenesis of post-traumatic cartilage degeneration and the identification of imaging biomarkers for the early stratification of subjects at risk for developing post-traumatic OA.
To examine whether the benzodiazepine antagonist flumazenil can reverse tolerance to benzodiazepines but without precipitating withdrawal seizures, the antiepileptic effect of flumazenil itself and ...its ability to reverse tolerance at a dose that would leave sufficient receptors free for the binding of benzodiazepines were investigated. Electroencephalographic studies in 6 patients with partial and 6 with generalised seizures showed that flumazenil had a short (20 min) non-dose-dependent suppressant effect on epileptic discharges in those with partial seizures. Receptor occupancy studies in 12 patients showed that 1·5 mg flumazenil given intravenously occupied 55% receptors, whereas 15 mg occupied nearly all receptors. When 3 patients with partial seizures who had become tolerant to clonazepam were given 1·5 mg flumazenil, they were seizure-free for 6-21 days after the injection. The value of intermittent therapy with a benzodiazepine antagonist for preventing or reversing tolerance to benzodiazepine agonists ought to be investigated further.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBJE, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The treatment of spent oil-in-water emulsion (SOWE) from a non-ferrous
metal-processing plant by using aluminum sulfate and hydrated lime was
studied to determine the purification efficiency, to ...optimize the operating
conditions and to scale up the treatment process. The purification efficiency
was estimated by comparing the compositions of the SOWE and the processed
wastewater. The treatment efficiency does not depend on the type of mineral
oil and filter aid. The optimum doses of aluminum sulfate and hydrated lime
must be experimentally determined for each batch of SOWEs, but the results
obtained at laboratory level are applicable at pilot level. The processed
wastewater and the filter cake from the process can be safely disposed into
public sewage systems and at municipal waste landfills, respectively. The
purification efficiency was higher than 98% with respect to total suspended
solids, chemical oxygen demand and oil and grease, and was comparable to the
known treatment processes based on coagulation/flocculation followed by
sedimentation.
nema
Single agent extractions of major and trace metals from soil samples were conducted by means of a rotary mixer and an ultrasonic bath with sonication times of 10, 20, 30, 40 and 50 min. The ...sequential extraction was undertaken according to the European Community Bureau of Reference. The obtained soil extracts were analyzed by inductively coupled plasma-optical emission spectrometry and according to the results, the rotary mixer-assisted extraction was more efficient in the case of alkaline earth elements. However, by use of ultrasound, several times higher amounts of matrix elements (Fe, Al and Mn) and heavy metals predominantly associated with Fe, Al and Mn oxyhydroxides were extracted. The increase of the sonication time failed to improve the extraction yields. The changes in the conductivity, pH, redox potential, particle size diameter and zeta potential of colloid particles with increasing sonication time were measured. The extraction mechanism and expressed selectivity of ultrasound is discussed and an explanation is suggested.
Journal of Hydroinformatics 10(2), 113-126 Unfortunately the order of authors was incorrectly listed when this paper was originally published. The correct order is above.
Polyaniline films potentiodynamically synthesised on gold substrates are analysed ex situ by conventional and imaging ellipsometry (at constant wavelength). Polymers grown up to 50 cycles appear to ...be homogeneous, whereas different structures are displayed by thicker layers. The memory effect, induced by the polymer electrochemical characterisation, in subsequent polymer growth, is demonstrated. In the case of thin films, a reliable methodology has been successfully employed to obtain, from the ellipsometric parameters
Δ and
ψ, the refractive index, the extinction coefficient and the thickness of polymer layers. This approach also allowed us to quantitatively evaluate the magnitude of polymer swelling upon oxidation (11–22%). Furthermore, the surface morphology is well evidenced by the results obtained by imaging ellipsometry.
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