Critical Behavior of Sandpile Models with Sticky Grains

We revisit the question whether the critical behavior of sandpile models with sticky grains is in the directed percolation universality class. Our earlier theoretical arguments in favor, supported by evidence from numerical simulations [ Phys. Rev. Lett., {\bf 89} (2002) 104303], have been disputed by Bonachela et al. [Phys. Rev. E {\bf 74} (2004) 050102] for sandpiles with no preferred direction. We discuss possible reasons for the discrepancy. Our new results of longer simulations of the one-dimensional undirected model fully support our earlier conclusions.Comment: 8 pages, 3 eps figures, accepted in Physica A, elsart.cls attache

Physicochemical and biological studies of a new erythromycin derivate - erythromycin folate

Se preparó un derivado nuevo de la eritromicina, el folato de eritromicina, y se evaluaron sus propiedades fisicoquímicas y biológicas. El derivado presenta una buena solubilidad en metanol, etanol y propileno glicol. Los valores de los coeficientes de partición, que fueron 1,12 y 1,10 en sistemas de cloroformo/agua y octanol/agua respectivamente, indican que probablemente se distribuya bien in vivo. La potencia in vitro del derivado, 716 μg/mg, es mayor que la de derivados existentes como el estolato de eritromicina, el estearato de eritromicina, el etil sucinato de eritromicina, el gluceptato de eritromicina y el lactobionato de eritromicina. Las concentraciones inhibitorias mínimas in vitro del derivado son menores que las de la base frente a Klebsiella pneumonia, Pseudomonas aeruginasa, Bacillus pumilis y Escherichia coli. Los parámetros farmacocinéticos in vivo del derivado en conejos son los siguientes: la vida media de eliminación, t½ es de 117,45 min. para el derivado y de 150,45 min. para la base de eritromicina utilizada como estándar de referencia. El volumen de distribución Vd del derivado y de la base de eritromicina es de 177,56 % y 352,20 % respectivamente. Los resultados de la investigación indican que el folato de eritromicina tiene un gran potencial en aplicaciones clínicas posibles.A new derivative of erythromycin, Erythromycin folate was prepared and its physicochemical and biological properties were evaluated. The derivative has good solubility in methanol, ethanol and propylene glycol. The partition coefficient values of 1.12 and 1.10 in chloroform/water and octanol/water systems respectively indicate that the derivative will probably distribute well in vivo. The in vitro potency of the derivative, 716 μg/mg, is higher than the existing derivatives like erythromycin estolate, erythromycin stearate, erythromycin ethyl succinate, erythromycin gluceptate, and erythromycin lactobionate. The in vitro Minimum Inhibitory Concentrations are less for the derivative than the base against Klebsiella pneumonia, Pseudomonas aeruginasa, Bacillus pumilis and Escherichia coli. The in vivo pharmacokinetic parameters of the derivative in rabbits are as follows: the elimination half life, t½ is 117.45 min for the derivative while it is 150.45 min for erythromycin base the reference standard. The volume of distribution Vd is 177.56% and 352.20% for the derivative and erythromycin base respectively. The results of the present investigations indicate that erythromycin folate has a high potential for possible clinical application.La University Grants Commission (UGC) de la India ha financiado este proyect

Revisiting Absorbing Phase Transition in Energy Exchange Models

A recent study of conserved Manna model, with both discrete and continuous variable, indicates that absorbing phase transitions therein belong to the directed percolation (DP) universality class. In this context we revisit critical behaviour in energy exchange models with a threshold. Contrary to the previous claims [PRE 83, 061130 (2011), arXiv:1102.1631], our results indicate that both the maximal and minimal versions of this model belong to the DP class.Comment: 8 pages, 7 eps figure

Solid-phase preparation and characterization of albendazole solid dispersion

La dispersión sólida de albenzadol (ABZ) se preparó mediante el método de mezclado de polvos utilizando Eudragit E-100 (EGT) como transporte. Los patrones de difracción de rayos X y los termogramas calorimétricos diferenciales de barrido demostraron que la cristalinidad del fármaco en la mezcla física disminuían con el tiempo de almacenamiento. Al aumentar la temperatura de almacenamiento, la humedad relativa y la proporción en peso de polímero de la mezcla, se reducía el calor de fusión de la mezcla almacenada. La interacción específi ca de ABZ y EGT en el estado sólido se investigó mediante espectroscopia de infrarrojos y resonancia magnética nuclear. Se dedujo que el EGT experimenta una protonación N, formando un enlace de hidrógeno en el nitrógeno terciario, con preferencia respecto de una protonación O. En el estudio de solubilidad de fase se observó un aumento lineal de la solubilidad con la concentración de polímero. La mejora de la velocidad y la efi ciencia de disolución dependió del valor del calor de fusión, así como de la proporción de mezcla del polímero. La mezcla almacenada presentó una mejora signifi cativa de la biodisponibilidad en conejos, en comparación con la de la mezcla recién preparada.Solid dispersion of albendazole (ABZ) was prepared by powder mixing method using Eudragit E-100 (EGT) as a carrier. The X-ray diffraction patterns and differential scanning calorimetric thermograms demonstrated that the crystallinity of the drug in the physical mixture decreased with the storage time. The higher the storage temperature and the higher the relative humidity, and the higher the weight ratio of polymer in the mixture, the lower was the heat of fusion of the stored mixture. The specifi c interaction of ABZ with EGT in the solid state was investigated by infrared spectroscopy, and nuclear magnetic resonance. It was understood that EGT undergoes N-protonation, forming hydrogen bond at the tertiary nitrogen, in preference to O-protonation. Phase solubility study showed a linear increase in the solubility with the polymer concentration. The enhancement of dissolution rate and the dissolution effi ciency depended on the heat of fusion value as well as mixing ratio of the polymer. The stored mixture showed a signifi cantly enhanced bioavailability in rabbits compared to the freshly prepared one.Consejo Indio de Investigación Médica (Indian Council of Medical Research, ICMR), Nueva Delhi

Techniques for measuring the thermal conductivity of nanofluids: A review

There has been a rapid progress in research activities concerning nanofluids since a large enhancement in their thermal conductivity has been reported a decade ago. While this extraordinary thermal conductivity of nanofluids deserves scientific investigation, the inconsistency and controversy of the results reported by different groups for identical nanofluids across the world raises fundamental doubts and poses a hindrance in the potential applications of nanofluids. This paper presents a critical review of the several techniques for the measurement of thermal conductivity of nanofluids employed by the researchers. Additionally, a detailed description of a unique thermal conductivity measurement device based on the thermal comparator principle, developed by the present authors has been described. Besides the principle of this measurement device, the constructional details have been elaborated. Finally, some suggestions have been made for improving the reliability of the measurement of thermal conductivity.Nanofluid Measurement techniques Thermal conductivity Thermal comparator

Giant magnetodielectric and enhanced multiferroic properties of Sm doped bismuth ferrite nanoparticles

Improvements in magnetodielectric and multiferroic properties are essential for visualizing the real application of multiferroics, precisely, BiFeO3 (BFO). An enhancement of multiferroic and magnetodielectric properties has been achieved for chemically prepared nanocrystalline BFO by virtue of Sm doping. The X-ray diffraction study confirms the growth of single phase nanocrystalline BFO which corroborates TEM observation. The magnetic study delineates the ferromagnetic behavior of nanocrystalline Sm-doped BFO samples even at room temperature, which is absent in pristine samples. Surprisingly, a few orders of magnitude increase in resistivity is observed in Sm doped samples. Room temperature ferroelectric measurement showed that Sm doping improves the polarization significantly. In addition, we have achieved a giant change in the magnetodielectric properties of Sm doped samples which has not been reported so far. Large lattice strain arising due to the mismatch of ionic radii and the decrease of oxygen vacancies combined could play an important role in the enhancement of multiferroic properties of nanocrystalline Sm-doped BFO which is a promising multiferroic material

Enhancement of multiferroic properties of nanocrystalline BiFeO3 powder by Gd-doping

Large leakage current and a very low magnetic moment are the two most disadvantages of BiFeO3 (BFO), which hinder the possibilities of its application in modern devices. An enhancement of the multiferroic properties of BFO is a real challenge to the scientific community. We are able to achieve improve magnetic, electric and magneto-dielectric (MD) properties of sol–gel prepared nanocrystalline BFO by virtue of the beneficial effect of gadolinium doping. The phase purity and nanocrystalline nature of the samples have been confirmed by the X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. Both dc and ac electrical properties were measured to understand the detail charge transport mechanism. The dc electrical resistivity was found to arise due to a variable range hopping conduction mechanism. The variation of ac-conductivity, as a function of frequency in the range (20 Hz–1 MHz) and temperature (298–523 K), was explained on the basis of the correlated barrier hoping (CBH) conduction mechanism. The origin of the improved magnetic and electrical properties have been attributed to a possible suppression of the inhomogeneous magnetic spin structure and/or broken periodicity of the spin cycloid of BFO due to smaller crystallite size, and a decrease of the oxygen vacancies. Our findings demonstrate the fundamental importance of doping in enhancing the multiferroic properties, which would open up the possibility of using BFO in designing spintronic devices

Diglycolamide-functionalized task specific ionic liquids for nuclear waste remediation: extraction, luminescence, theoretical and EPR investigations

A 3.6 × 10−2 M solution of a diglycolamide-functionalized task specific ionic liquid (DGA-TSIL) in [C4mim][NTf2] was used for the extraction of actinides (mainly Am) and other elements present in high level nuclear waste. The extraction of Eu3+ was relatively higher than that of Am3+ conforming to the mechanism displayed by other diglycolamide extractants such as TODGA (tetraoctyl diglycolamide). The distribution ratio values decreased in the presence of simulated high level waste (SHLW) as compared to those obtained with pure tracers. The nature of the extracted species was established by the slope analysis method which suggested 1:2 species for the extraction of Am3+ and Eu3+. Calculation of the Judd–Ofelt parameters from the luminescence data of the Eu3+ complexes indicated that the structure of the extracted complexes exhibits S4 symmetry. Theoretical calculations showed virtually no difference between the structures of the complexes of Am3+ and Eu3+. The nature of the radiolytic degradation products was analyzed by electron paramagnetic resonance (EPR) spectroscopic measurements revealing the presence of alkyl imidazolium and methyl radicals

Assessment of economic loss due to fish diseases in Assam, India: Implication of farming practices

Not AvailableExtensive surveys were conducted in 60fish farms in Cachar and Nagaon districts of Assam, India to assess economic loss due to aquatic animal diseases and contribution of fish farming practices thereon. Epizootic Ulcerative Syndrome (EUS), also known as mycotic granulomatosis or red spot disease was the most common disease that affected most fish species during winter months. Other disease conditions reported were dropsy, fin/tail rot and Argulus infestation. Overall disease prevalence was less in Cachar district compared to that in Nagaon district. Estimated loss of fish production (as percentage of total production) and total economic loss (in Rs.) were estimated to be 10.8% & 67,500.0 per farm (30,770.0 per ha) in Cachar and 5% &55,300.0 per farm (14,900.0 per ha) in Nagaon district. The average farm area, water area and number of ponds (per farmer) were lessin Cachar compared to that in Nagaon district. Average fish production was also lower (1870 kg/ha) in Cachar compared to Nagaon (2470 kg/ha). Majority of fish farms in Cachar (60%) operated as nursery(N) and grow-out(G) systems whereas those in Nagaon operated as nursery˗fingerling˗growout(N-F-G)system (63.33%). Overwhelming majority of farmers (93.33%) in Cachar practiced polyculture, but 30% farmers practiced integrated farming in Nagaon district. N-F-G farming system and integrated culture practice adopted by majority of Nagaon farmers apparently led to higher fish productivity and less economic loss. Poor pre-stocking management of fish ponds was found to be the main contributory factor for higher disease prevalence in Nagaon compared to that in Cachar district. However, the farmers in Nagaon district were more aware of disease control measures that resulted in moderate economic loss.All India Network Project on Fish Healt

Modifying exchange bias effects of Mn/NiFe bilayers by in-situ Ar+ bombardment

In this work, we present a procedure to modify the exchange bias (EB) properties of antiferromagnetic Mn/ferromagnetic NiFe bilayers by in-situ low energy Ar+ bombardment of the Mn layer during sample deposition. We present structural and magnetic results for unassisted and Ar+ assisted Mn/NiFe bilayers. X-ray diffraction, transmission electron microscopy and electron diffraction results establish different preferred Mn orientation directions between the two samples as a result of the Ar+ bombardment process. Hysteresis loops taken over several temperatures reveal that samples assisted with Ar+ ions during the Mn layer deposition had suppressed EB properties at low temperature as compared to samples grown without Ar+ assistance