ABSTRACT
In this paper, we investigate, both analytically and numerically, the emergence of a kinetic glass transition in two different model systems: a uniformly heated granular gas and a molecular fluid with nonlinear drag. Despite the profound differences between these two physical systems, their behavior in thermal cycles share strong similarities, which stem from the relaxation time diverging algebraically at low temperatures for both systems. When the driving intensity--for the granular gas-or the bath temperature-for the molecular fluid-is decreased to sufficiently low values, the kinetic temperature of both systems becomes "frozen" at a value that depends on the cooling rate through a power law with the same exponent. Interestingly, this frozen glassy state is universal in the following sense: for a suitable rescaling of the relevant variables, its velocity distribution function becomes independent of the cooling rate. Upon reheating, i.e., when either the driving intensity or the bath temperature is increased from this frozen state, hysteresis cycles arise and the apparent heat capacity displays a maximum. The numerical results obtained from the simulations are well described by a perturbative approach.
ABSTRACT
We analyze the dynamical evolution of a fluid with nonlinear drag, for which binary collisions are elastic, described at the kinetic level by the Enskog-Fokker-Planck equation. This model system, rooted in the theory of nonlinear Brownian motion, displays a really complex behavior when quenched to low temperatures. Its glassy response is controlled by a long-lived nonequilibrium state, independent of the degree of nonlinearity and also of the Brownian-Brownian collisions rate. The latter property entails that this behavior persists in the collisionless case, where the fluid is described by the nonlinear Fokker-Planck equation. The observed response, which includes nonexponential, algebraic, relaxation, and strong memory effects, presents scaling properties: the time evolution of the temperature-for both relaxation and memory effects-falls onto a master curve, regardless of the details of the experiment. To account for the observed behavior in simulations, it is necessary to develop an extended Sonine approximation for the kinetic equation-which considers not only the fourth cumulant but also the sixth one.
ABSTRACT
In influenza A H1 virus, amino acids at position 190 and 225 of HA affect replication and transmission. In this study, we show that the mutation D190Y in the HA of influenza AH1N1pdm09 virus reduces the affinity of the virus for sialic acid receptors expressed at the surface of red blood cells from different species without affecting virus replication in MDCK cells.
Subject(s)
Hemagglutinins/metabolism , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/metabolism , Receptors, Cell Surface/metabolism , Sialic Acids/metabolism , Gene Expression Regulation, Viral/physiology , Hemagglutinins/genetics , MutationABSTRACT
The synthesis of caged NADP analogues 18, 19, and 20 has been accomplished by utilizing the transglycosidase activity of solubilized NAD glycohydrolase (porcine brain) to incorporate caged nicotinamides 2, 3, and 4 into NADP. The synthesis of several nicotinamides modified at the carboxamide with o-nitrobenzyl photolabile groups is demonstrated as well as their potential for enzymatic transglycosidation. These results further demonstrate the feasibility of direct enzymatic transglycosidation of sterically hindered substrates into NAD(P), although high nicotinamide analogue water solubility was found to be a necessary trait for yield enhancement with certain analogues. Caged analogues were surveyed under aqueous conditions for net NADP photorelease, while the UV and fluorescent properties of both analogues and their photobyproducts were assessed for compatibility with systems that rely on optical monitoring of enzyme activity. A highly water-soluble alpha-methyl-o-nitrobenzyl group 8 was developed for the synthesis of 20 in order to enhance net NADP photorelease. Compound 20 demonstrated a high 75% net NADP photoreleased without substantial UV optical blackening or fluorescent byproducts. Analogues 18 and 19 were shown by ESI/MALDI-MS to photogenerate primarily adducts of NADP with deleterious UV and fluorescent properties. Our work stresses the superior release properties conferred by alpha-methyl substitution on aqueous carboxamide photorelease from o-nitrobenzyl compounds.
Subject(s)
NAD+ Nucleosidase , NADP/analogs & derivatives , NADP/chemical synthesis , Animals , Brain/enzymology , Indicators and Reagents , Molecular Structure , NADP/analysis , NADP/chemistry , Spectrophotometry, Ultraviolet , Structure-Activity Relationship , SwineABSTRACT
Whereas estimates of percent deviation of body weight from ideal (F delta weight) are corrected for amputation, those of body mass index (BMI) are not, creating discrepancies in evaluating obesity. A correction of the BMI formula for amputation is proposed. The formula for BMI was corrected for amputation mathematically. The mathematical model predicts that the uncorrected BMI formula underestimates body fat in unilateral amputees and overestimates body fat in subjects with bilateral amputations at the same length of the legs. F delta weight and corrected and uncorrected BMI estimates were computed in 15 subjects with unilateral leg amputation and in 8 subjects with multiple amputations. BMI estimates were as follows: in unilateral amputees, corrected 24.1 +/- 4.1 kg/m2, uncorrected 22.2 +/- 3.9 kg/m2 (p < .001); and in multiple amputees, corrected 21.6 +/- 2.4 kg/m2, uncorrected 32.6 +/- 11.8 kg/m2 (p = .043). Linear regressions of F delta weight obtained from standard nutrition assessment on F delta weight computed from uncorrected and corrected BMI values were as follows: in unilateral amputees, uncorrected F delta weight = -0.079 + 0.932 x actual F delta weight, r = .974, p < .01, and corrected F delta weight = 0.002 + 1.005 x actual F delta weight, r = .997, p < .01; in multiple amputees, uncorrected F delta weight = 0.528 + 1.930 x actual F delta weight, r = .607, p is not significant, and corrected F delta weight = -0.010 + 0.920 x actual F delta weight, r = .936, p < .01.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Amputees , Body Mass Index , Aged , Diabetes Complications , Female , Humans , Male , Mathematics , Middle AgedABSTRACT
Body composition can have a significant effect on methods for estimating urea volume (V) and fractional clearance (KT/V) in patients with renal failure. These effects were examined in 27 men on continuous ambulatory peritoneal dialysis (CAPD). Urea volume was calculated as 0.6% of body weight (V.6), by the Watson formula (VW) and by the Hume formula (VH). Patients were classified as obese (> 120% of ideal body weight), normal (90%-120% of ideal weight), or wasted (< 90% of ideal weight). A patient was considered adequately dialyzed if his weekly KT/V urea exceeded 1.70. Only 75% of subjects were classified as adequately or inadequately dialyzed by all three methods. Six subjects had KT/V0.6 < 1.70 and KT/VW > 1.70; five subjects had KT/VH < 1.70 and KT/VW > 1.70; and two subjects had KT/V0.6 < 1.70 and KT/VH > 1.70. In the obese group, KT/V0.6 (1.62 +/- 0.67) was significantly less than KT/VW (1.93 +/- 0.76; p < 0.001) and KT/VH (1.92 +/- 0.78; p < 0.001). Fractional errors in V and KT/V between any two methods were highly correlated with percent deviation from ideal body weight (r = 0.81 or higher). In peritoneal dialysis patients, excessive body weight affects the estimates of V and KT/V urea by certain methods, and may lead to erroneous impressions about the adequacy of CAPD.
Subject(s)
Body Composition/physiology , Peritoneal Dialysis, Continuous Ambulatory , Urea/blood , Adult , Aged , Aged, 80 and over , Dialysis Solutions/analysis , Female , Humans , Male , Metabolic Clearance Rate/physiology , Middle Aged , Obesity/blood , Reference ValuesABSTRACT
Se presenta un caso de epitelioma espinocelular surgido sobre acné conglobata, en un hombre que fue examinado hace treinta años por esta última y que con posterioridad concurre a la consulta presentando una lesión tumoral en región lateral derecha del cuello, donde existían gran cantidad de cicatrices. Se debe poner especial énfasis en el seguimiento de los pacientes con esta rara afección por su probable degeneración tumoral. Se efectuó tratamiento con buen resultado (AU)
Subject(s)
Middle Aged , Humans , Male , Carcinoma, Squamous Cell/etiology , Skin Neoplasms/etiology , Carcinoma, Squamous Cell/pathology , Skin Neoplasms/pathologyABSTRACT
Se presenta un caso de epitelioma espinocelular surgido sobre acné conglobata, en un hombre que fue examinado hace treinta años por esta última y que con posterioridad concurre a la consulta presentando una lesión tumoral en región lateral derecha del cuello, donde existían gran cantidad de cicatrices. Se debe poner especial énfasis en el seguimiento de los pacientes con esta rara afección por su probable degeneración tumoral. Se efectuó tratamiento con buen resultado
Subject(s)
Middle Aged , Humans , Male , Carcinoma, Squamous Cell/etiology , Skin Neoplasms/etiology , Carcinoma, Squamous Cell/pathology , Skin Neoplasms/pathologyABSTRACT
Se presenta un paciente de 26 años, con una fibromatosis circunscripta cerebriforme congénita en planta de pie izquierdo, hipertrofia del cuarto dedo del mismo y cicatriz en mano derecha resultante quirúrgica de una lesión semejante. Encontramos dos casos descriptos en la bibliografía con idénticas características. Proponemos la denominación de la entidad como fibromatosis congénita acral con alteraciones esqueléticas. Consideramos que existe un amplio espectro de este tipo de lesiones y su publicación y consideración conducirán a una clasificación más completa del tema (AU)
Subject(s)
Adult , Humans , Male , Fibroma/congenital , Skin Neoplasms/congenital , Fingers/pathology , Foot Diseases/pathology , Monoamine Oxidase/pathologyABSTRACT
El síndrome de Klippel-Trenaunay (1900) consta de angioma plano, hipertrofia y várices de miembro inferior. Parkes Weber (1918) aportó el hallazgo de fístulas arteriovenosas. Se presentaron cuatro casos de síndrome de Klippel-Trenaunay-Parkes Weber que fueron estudiados con diversos métodos diagnósticos: Doppler, arteriografía, flebografía y más ultimamente ecografía. Se comprobó en todos ellos la presencia de fístulas arteriovenosas. Se resalta la importancia de la ecografía como método diagnóstico incruento (AU)
Subject(s)
Adult , Middle Aged , Humans , Male , Female , Klippel-Trenaunay-Weber Syndrome/diagnosis , UltrasonographyABSTRACT
Se presenta un paciente de 26 años, con una fibromatosis circunscripta cerebriforme congénita en planta de pie izquierdo, hipertrofia del cuarto dedo del mismo y cicatriz en mano derecha resultante quirúrgica de una lesión semejante. Encontramos dos casos descriptos en la bibliografía con idénticas características. Proponemos la denominación de la entidad como fibromatosis congénita acral con alteraciones esqueléticas. Consideramos que existe un amplio espectro de este tipo de lesiones y su publicación y consideración conducirán a una clasificación más completa del tema
Subject(s)
Adult , Humans , Male , Fibroma/congenital , Skin Neoplasms/congenital , Foot Diseases/pathology , Fingers/pathology , Monoamine Oxidase/pathologyABSTRACT
El síndrome de Klippel-Trenaunay (1900) consta de angioma plano, hipertrofia y várices de miembro inferior. Parkes Weber (1918) aportó el hallazgo de fístulas arteriovenosas. Se presentaron cuatro casos de síndrome de Klippel-Trenaunay-Parkes Weber que fueron estudiados con diversos métodos diagnósticos: Doppler, arteriografía, flebografía y más ultimamente ecografía. Se comprobó en todos ellos la presencia de fístulas arteriovenosas. Se resalta la importancia de la ecografía como método diagnóstico incruento
