588 research outputs found
Vanishing largest Lyapunov exponent and Tsallis entropy
We present a geometric argument that explains why some systems having
vanishing largest Lyapunov exponent have underlying dynamics aspects of which
can be effectively described by the Tsallis entropy. We rely on a comparison of
the generalised additivity of the Tsallis entropy versus the ordinary
additivity of the BGS entropy. We translate this comparison in metric terms by
using an effective hyperbolic metric on the configuration/phase space for the
Tsallis entropy versus the Euclidean one in the case of the BGS entropy.
Solving the Jacobi equation for such hyperbolic metrics effectively sets the
largest Lyapunov exponent computed with respect to the corresponding Euclidean
metric to zero. This conclusion is in agreement with all currently known
results about systems that have a simple asymptotic behaviour and are described
by the Tsallis entropy.Comment: 15 pages, No figures. LaTex2e. Some overlap with arXiv:1104.4869
Additional references and clarifications in this version. To be published in
QScience Connec
A qualitative test for the determination of isoniazid acetylator phenotype
A qualitative test procedure for phenotyping isoniazid acetylators is described. It is
based on a colour reaction which depends on the free sulphadimidine content in the total
urine excreted over any one-hour period between 21 and 26 hours following a dose of
sulphadimidine 1.0 or 1.5 g. depending on body-weight. The test correctly classified
96 per cent of 109 slow and 96 per cent of 68 rapid inactivators. Storage of urine
samples at room-temperature up to 14 days did not affect the accuracy of the results
Determination of Acetylator Phenotype Based on the Ratio of Acetylisoniazid to Isoniazid in Urine Following an Oral Dose of Ordinary Isoniazid
A simple method for classifying subjects as slow or rapid inactivators of isoniazid has been
described. A uniform dose of 300 mg. of ordinary isoniazid was administered orally
to 150 patients with pulmonary tuberculosis. The ratio of acetylisoniazid to isoniazid
was determined in urine collected at hourly intervals from 4 to 8 h. At each
hour the distribution of the ratios was clearly bimodal. The test based on the 5-6 h.
urine collection is recommended for its convenience and excellent discrimination
between slow and rapid inactivators. The agreement between this method and a
‘standard method was of the order of 97 per cent
Clinical response to primary letrozole therapy in elderly patients with early breast cancer : possible role for p53 as a biomarker
Primary tamoxifen therapy has been widely used to treat elderly women with ER-positive breast cancer in the past. Aromatase inhibitors may be more beneficial than tamoxifen when used as primary endocrine therapy in elderly patients. We aimed to retrospectively evaluate a series of elderly women with ER-positive breast cancer treated with primary letrozole therapy as sole therapy with a minimum of 5 years follow up. To identify possible predictive biomarkers a pilot immunohistochemical analysis was performed to assess the expression of PR, HER2, EGFR, BCL2 and p53. A total of 45 women, aged more than 70 years with a diagnosis of ER-positive breast cancer that was treated with primary letrozole therapy were identified. A case note review was undertaken to obtain clinical information. Formalin fixed paraffin embedded tumour tissue from diagnostic core biopsies was available for all patients. Immunohistochemical analysis was performed to establish the protein expression status of p53, PR, HER2, EGFR and BCL2. The mean age of the 45 patients was 87 years (range 70–101). Clinical benefit was seen in 60% of the patients. Median progression free survival was 53 months (95% CI – 34–72) and the median time to progression was 43 months (95% CI – 22–64). BCL2 was expressed in 45/45 (100%); PR in 38/45 (84%); EGFR in 13/45 (28%); HER2 in 9/45 (20%) and p53 in 5/45 (11%) of tissue samples. Positive expression of p53 was associated with poor progression free survival (p = 0.03) in this pilot study. This study demonstrates that letrozole as sole treatment appears to be a suitable treatment option for elderly patients with ER-positive breast cancer who are not fit for, or decline, surgery. The analysis of p53 in a larger study is warranted in order to assess its role as a biomarker in this patient group
The Virulence in the Guinea-pig of Tubercle Bacilli Isolated before Treatment from South Indian Patients with Pulmonary Tuberculosis: 1. Homogeneity of the Investigation and a Critique of the Virulence Test
A series of studies on the virulence in the guinea-pig of tubercle bacilli isolated before
treatment from Indian tuberculous patients admitted to a controlled comparison of different
regimens of domiciliary chemotherapy has recently been undertaken by the Tuberculosis
Chemotherapy Centre, Madras. The main object of these studies was to determine whether
the differences in virulence of the tubercle bacilli obtained from Indian patients before the
start of chemotherapy were related to the severtiy or type of the patients’ disease at that
time and to the subsequent response to treatment. Before these relationships could be‘
investigated, however, it was necessary to find out whether the results of the virulence tests,
which were carried out over a period of two-and-a-half years at the Centre and at the
Microbiological Research Establishment, Porton, England, could be considered as a unified
whole-that, is, as if they had all been done on the same day in the same laboratory.
A proportion of the cultures was stored at – 20°C for 44-78 weeks, but this did not
affect their virulence. Inter-experimental variation was found to be small in the Porton
series of tests and undetectable in the Madras series, and the results in the latter series could
be successfully adjusted to those in the former by allowing for differences in the means and
standard deviations of the distributions for the two series. The measure of virulence used
was found to be reasonably acceptable for the analysis of variance technique. Suggestions
are made as to ways of improving the efficiency of the experimental design in future studies
Robust nanopatterning by laser-induced dewetting of metal nanofilms
We have observed nanopattern formation with robust and controllable spatial
ordering by laser-induced dewetting in nanoscopic metal films. Pattern
evolution in Co film of thickness 1\leq h\leq8 nm on SiO_{2} was achieved under
multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the
formation of cellular patterns which evolve into polygons that eventually break
up into nanoparticles with monomodal size distribution and short range ordering
in nearest-neighbour spacing R. Spatial ordering was attributed to a
hydrodynamic thin film instability and resulted in a predictable variation of R
and particle diameter D with h. The length scales R and D were found to be
independent of the laser energy. These results suggest that spatially ordered
metal nanoparticles can be robustly assembled by laser-induced dewetting
Silicon-induced changes in antifungal phenolic acids, flavonoids, and key phenylpropanoid pathway genes during the interaction between miniature roses and the biotrophic pathogen <em>Podosphaera pannosa</em>
Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection
Sequence and Entropy-Based Control of Complex Coacervates
Biomacromolecules rely on the precise placement of monomers to encode information for structure, function, and physiology. Efforts to emulate this complexity via the synthetic control of chemical sequence in polymers are finding success; however, there is little understanding of how to translate monomer sequence to physical material properties. Here we establish design rules for implementing this sequence-control in materials known as complex coacervates. These materials are formed by the associative phase separation of oppositely charged polyelectrolytes into polyelectrolyte dense (coacervate) and polyelectrolyte dilute (supernatant) phases. We demonstrate that patterns of charges can profoundly affect the charge–charge associations that drive this process. Furthermore, we establish the physical origin of this pattern-dependent interaction: there is a nuanced combination of structural changes in the dense coacervate phase and a 1D confinement of counterions due to patterns along polymers in the supernatant phase
Dietetic hepatic lesions: influence of protein level and vitamin B<SUB>2</SUB> complex deficiency on the liver of rats
1. Attempts have been made to induce hepatic lesions in albino rats by varying the quantity of the protein (casein) and by withholding the supply of the vitamins of the B2 complex. 2. On the vitamin B2 complex deficient diets, the average life-span of the rats was largely influenced by the casein content of the diet, while those which received similar casein diets with yeast as supplement lived longer. 3. Fatty infiltration of the liver with progressive fibrosis (akin to human portal cirrhosis) can be more easily produced in rats by prolonged feeding of diets low in protein (casein) content and deficient in the vitamins of the B2 complex. 4. Increasing the level of protein (casein) in the diet or supplementing low protein diets with yeast has a marked corrective effect on fatty infiltration of the liver and this is attributed to their respective methionine and choline content. 5. In general, the vitamins of the B2 complex have a marked beneficial effect on the fatty livers when given early enough as a supplement
The Virulence in the Guinea-pig of Tubercle Bacilli Isolated before Treatment from South Indian Patients with Pulmonary Tuberculosis 3. Virulence related to Pretreatment Status of Disease and to Response to Chemotherapy
This is the last of a series of three reports from the Tuberculosis Chemotherapy Centre
Madras, on a study undertaken with the object of finding out whether differences in the
virulence in the guinea-pig of tubercle bacilli isolated from South Indian tuberculous patients
before the start of chemotherapy are related to the severity of the patients’ disease on
admission to treatment and to the subsequent response to chemotherapy. The 281 patients in
this study were drawn from the patients admitted to a l-year comparison of four domiciliary
chemotherapeutic regimens : (a) 3.9-5.5 mg/kg isoniazid plus 0.2-0.3 g/kg sodium PAS daily,
divided into two doses (PH series) ; (b) 7.8-9.6 mg/kg isoniazid alone daily in one dose
(HI-I series) ; (c) 7.8-9.6 mg/kg isoniazid alone daily, divided into two doses (HI-2 series) ;
(d) 3.9-5.5 mg/kg isoniazid alone daily, divided into two doses (H series).
No evidence was found of an association between the virulence of the organisms and
any pretreatment condition of known prognostic importance. There was no association
between pretreatment virulence and progress during treatment in the PH series (the most
effective regimen). In the other series, however, the progress was more satisfactory in
patients infected with organisms of low virulence than in those infected with organisms of
high virulence, the association between virulence and progress attaining statistical significance
in the combined HI-2 and H series (the least effective regimens) and only just
failing to do so in the smaller HI-1 series.
Possible explanations are put forward both for the absence of an association between
virulence and severity of disease on admission and for the presence of an association
between virulence and response in the patients treated with isoniazid alone
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