135 research outputs found
Heavy-Fermions in LiV2O4: Kondo-Compensation vs. Spin-Liquid Behavior?
7Li NMR measurements were performed in the metallic spinel LiV2O4. The
temperature dependencies of the line width, the Knight shift and the
spin-lattice relaxation rate were investigated in the temperature range 30 mK <
T < 280 K. For temperatures T < 1 K we observe a spin-lattice relaxation rate
which slows down exponentially. The NMR results can be explained by a
spin-liquid behavior and the opening of a spin gap of the order 0.6 K
Dynamical effects induced by long range activation in a nonequilibrium reaction-diffusion system
We both show experimentally and numerically that the time scales separation
introduced by long range activation can induce oscillations and excitability in
nonequilibrium reaction-diffusion systems that would otherwise only exhibit
bistability. Namely, we show that the Chlorite-Tetrathionate reaction, where
autocatalytic species diffuses faster than the substrates, the spatial
bistability domain in the nonequilibrium phase diagram is extended with
oscillatory and excitability domains. A simple model and a more realistic model
qualitatively account for the observed behavior. The latter model provides
quantitative agreement with the experiments.Comment: 19 pages + 9 figure
Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach
We investigate the infinite-dimensional two-orbital Hubbard model at
arbitrary band fillings. By means of the self-energy functional approach, we
discuss the stability of the metallic state in the systems with same and
different bandwidths. It is found that the Mott insulating phases are realized
at commensurate band fillings. Furthermore, it is clarified that the orbital
selective Mott phase with one orbital localized and the other itinerant is
stabilized even at fractional band fillings in the system with different
bandwidths.Comment: 7 pages, 10 figure
Factors associated with shunt dynamic in patients with cryptogenic stroke and patent foramen ovale: an observational cohort study
<p>Abstract</p> <p>Background</p> <p>As previously reported there is evidence for a reduction in right to left shunt (RLS) in stroke patients with patent foramen ovale (PFO). This occurs predominantly in patients with cryptogenic stroke (CS). We therefore analysed factors associated with a shunt reduction on follow-up in stroke patients suffering of CS.</p> <p>Methods</p> <p>On index event PFO and RLS were proven by transesophageal echocardiography and contrast-enhanced transcranial Doppler-sonography (ce-TCD). Silent PE was proved by ventilation perfusion scintigraphy (V/Q) within the stroke work-up on index event; all scans were re-evaluated in a blinded manner by two experts. The RLS was re-assessed on follow-up by ce-TCD. A reduction in shunt volume was defined as a difference of ≥20 microembolic signals (MES) or the lack of evidence of RLS on follow-up. For subsequent analyses patients with CS were considered; parameters such as deep vein thrombosis (DVT) and silent pulmonary embolism (PE) were analysed.</p> <p>Results</p> <p>In 39 PFO patients suffering of a CS the RLS was re-assessed on follow-up. In all patients (n = 39) with CS a V/Q was performed; the median age was 40 years, 24 (61.5%) patients were female. In 27 patients a reduction in RLS was evident. Silent PE was evident in 18/39 patients (46.2%). Factors such as atrial septum aneurysm, DVT or even silent PE were not associated with RLS dynamics. A greater time delay from index event to follow-up assessment was associated with a decrease in shunt volume (median 12 vs. 6 months, <it>p </it>= 0.013).</p> <p>Conclusions</p> <p>In patients with CS a reduction in RLS is not associated with the presence of a venous embolic event such as DVT or silent PE. A greater time delay between the initial and the follow-up investigation increases the likelihood for the detection of a reduction in RLS.</p
A cartilage tissue engineering approach combining starch-polycaprolactone fibre mesh scaffolds with bovine articular chondrocytes
In the present work we originally tested the suitability
of corn starch-polycaprolactone (SPCL) scaffolds for
pursuing a cartilage tissue engineering approach. Bovine articular
chondrocytes were seeded on SPCL scaffolds under
dynamic conditions using spinner flasks (total of 4 scaffolds
per spinner flask using cell suspensions of 0.5×106 cells/ml)
and cultured under orbital agitation for a total of 6 weeks.
Poly(glycolic acid) (PGA) non-woven scaffolds and bovine
native articular cartilage were used as standard controls for
the conducted experiments. PGA is a kind of standard in
tissue engineering approaches and it was used as a control
in that sense. The tissue engineered constructs were characterized
at different time periods by scanning electron microscopy
(SEM), hematoxylin-eosin (H&E) and toluidine
blue stainings, immunolocalisation of collagen types I and II,
and dimethylmethylene blue (DMB) assay for glycosaminoglycans
(GAG) quantification assay. SEM results for SPCL
constructs showed that the chondrocytes presented normal
morphological features, with extensive cells presence at the
surface of the support structures, and penetrating the scaffolds
pores. These observations were further corroborated
by H&E staining. Toluidine blue and immunohistochemistry
exhibited extracellular matrix deposition throughout the 3D structure. Glycosaminoglycans, and collagen types I and II
were detected. However, stronger staining for collagen type
II was observed when compared to collagen type I. The PGA
constructs presented similar features toSPCLat the end of the
6 weeks. PGA constructs exhibited higher amounts of matrix
glycosaminoglycans when compared to the SPCL scaffolds.
However, we also observed a lack of tissue in the central
area of the PGA scaffolds. Reasons for these occurrences
may include inefficient cells penetration, necrosis due to high
cell densities, or necrosis related with acidic by-products
degradation. Such situation was not detected in the SPCL
scaffolds, indicating the much better biocompatibility of the
starch based scaffolds
Transcranial sonography for diagnosis of Parkinson's disease
<p>Abstract</p> <p>Background</p> <p>In idiopathic Parkinson's disease (IPD) transcranial sonography (TCS) represents an alternative diagnostic method to verify clinical diagnosis. Although the phenomenon of an increased echogenicity of the Substantia nigra (SN) is well known this method is still not widly used in the diagnostic workup. Until now reliability of this method is still a matter of debate, partly because data only existed from a few laboratories using the same ultrasound machine. Therefore our study was conducted to test the reliability of this method by using a different ultrasound device and examining a large population of control and IPD subjects by two examiners to calculate interobserver reliability.</p> <p>Method</p> <p>In this study echogenicity of SN was examined in 199 IPD patients and 201 control subjects. All individuals underwent a neurological assessment including Perdue pegboard test and Webster gait test. Using a Sonos 5500 ultrasound device area of SN was measured, echogenicity of raphe, red nuclei, thalamus, caudate and lenticular nuclei, width of third and lateral ventricle were documented.</p> <p>Results</p> <p>We found a highly characteristic enlargement of the SN echogenic signal in IPD. The cut-off value for the SN area was established using a ROC curve with a sensitivity of 95% corresponding to an area of SN of 0.2 cm<sup>2 </sup>and was found to be equivalent to the cut-off values of other studies using different ultrasound devices.</p> <p>Conclusions</p> <p>Our study shows that TCS is a reliable and highly sensitive tool for differentiation of IPD patients from individuals without CNS disorders.</p
Fruit crops, 1986: a summary of research
Influence of treatments at planting on trellised apple tree performance / David C. Ferree -- Influence of growth regulators on branching of young apple trees / David C. Ferree and John C. Schmid -- Influence of growth regulators on scarf skin of Rome Beauty apples / David C. Ferree and John C. Schmid -- Influence of fungicides on scarf skin on Gallia Beauty / David C. Ferree and Michael A. Ellis -- Little relationship between root pruning and winter injury / James R. Schupp and David C. Ferree -- Performance of two apple cultivars on MS and M9 interstems on Antonovka / D. C. Ferree, R. M. McConnell, and J. C. Schmid -- Air sprayer jet deflection by travel or wind: as predicted by computer / R. D. Fox, R. D. Brazee, and D. L. Reichard -- Measuring atmospheric water vapor / R. D. Brazee and R. D. Fox -- A prototypic pollination unit made from expanded polystyrene / James E. Tew and Dewey M. Caron -- Effects of gibberellic acid (GA3) and daminozide (Alar) on growth and fruiting of Himrod grapes / G. A. Cahoon, M. L. Kaps, and S. P. Pathak -- Development of an action threshold for meadow spittlebug on strawberries / Mark A. Zajac and Franklin R. Hall -- Long-term yield of selected blackberry cultivars and selections in southern Ohio / Craig K. Chandler, Donald A. Chandler, and Greg L. Brenneman -- Electronic information transfer / R. C. Funt. -- A summary of research on synthetic pyrethroids and mites in the apple orchard ecosystem / Franklin R. Hall -- Controlling apple collar rot: effects of fungicides, soil amendments, and depth of planting / M. A. Ellis, D. C. Ferree, and L. V. Madden -- Validation of an electronic unit for predicting apple scab infection periods / M. A. Ellis, L. V. Madden, and L. L. Wilson -- Epidemiology and control of strawberry leather rot / G. G. Grove, M. A. Ellis, and L. V. Madden -- Research on cane diseases of thornless blackberry in Ohio / M. A. Ellis, G. A. Kuter, and L. L. Wilso
Decrease in shunt volume in patients with cryptogenic stroke and patent foramen ovale
<p>Abstract</p> <p>Background</p> <p>In patients with patent foramen ovale (PFO) there is evidence supporting the hypothesis of a change in right-to-left shunt (RLS) over time. Proven, this could have implications for the care of patients with PFO and a history of stroke. The following study addressed this hypothesis in a cohort of patients with stroke and PFO.</p> <p>Methods</p> <p>The RLS volume assessed during hospitalisation for stroke (index event/T0) was compared with the RLS volume on follow-up (T1) (median time between T0 and T1 was 10 months). In 102 patients with a history of stroke and PFO the RLS volume was re-assessed on follow-up using contrast-enhanced transcranial Doppler/duplex (ce-TCD) ultrasound. A change in RLS volume was defined as a difference of ≥20 microembolic signals (MES) or no evidence of RLS during ce-TCD ultrasound on follow-up.</p> <p>Results</p> <p>There was evidence of a marked reduction in RLS volume in 31/102 patients; in 14/31 patients a PFO was no longer detectable. An index event classified as cryptogenic stroke (P < 0.001; OD = 39.2, 95% confidence interval 6.0 to 258.2) and the time interval to the follow-up visit (P = 0.03) were independently associated with a change in RLS volume over time.</p> <p>Conclusions</p> <p>RLS volume across a PFO decreases over time, especially in patients with cryptogenic stroke. These may determine the development of new strategies for the management in the secondary stroke prevention.</p
Metabolic Engineering of Cofactor F420 Production in Mycobacterium smegmatis
Cofactor F420 is a unique electron carrier in a number of microorganisms including Archaea and Mycobacteria. It has been shown that F420 has a direct and important role in archaeal energy metabolism whereas the role of F420 in mycobacterial metabolism has only begun to be uncovered in the last few years. It has been suggested that cofactor F420 has a role in the pathogenesis of M. tuberculosis, the causative agent of tuberculosis. In the absence of a commercial source for F420, M. smegmatis has previously been used to provide this cofactor for studies of the F420-dependent proteins from mycobacterial species. Three proteins have been shown to be involved in the F420 biosynthesis in Mycobacteria and three other proteins have been demonstrated to be involved in F420 metabolism. Here we report the over-expression of all of these proteins in M. smegmatis and testing of their importance for F420 production. The results indicate that co–expression of the F420 biosynthetic proteins can give rise to a much higher F420 production level. This was achieved by designing and preparing a new T7 promoter–based co-expression shuttle vector. A combination of co–expression of the F420 biosynthetic proteins and fine-tuning of the culture media has enabled us to achieve F420 production levels of up to 10 times higher compared with the wild type M. smegmatis strain. The high levels of the F420 produced in this study provide a suitable source of this cofactor for studies of F420-dependent proteins from other microorganisms and for possible biotechnological applications
The role of platelet rich plasma in musculoskeletal science
The idea of using platelet rich plasma (PRP) in medicine has been around since the 1970s. It is only more recently that its use has been employed in the area of musculoskeletal science. Platelet rich plasma in this area has received much media attention being used by many celebrity sports athletes for musculoskeletal injuries. Therefore it is important for the musculoskeletal practitioner to be aware of the concepts surrounding its use and application. In this article we cover what platelet rich plasma is, how it is prepared and administered, its potential clinical application, and what the current literature discusses in the various areas of musculoskeletal science
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