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1.
Sci Adv ; 9(35): eadh5586, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37656797

RESUMO

Jammed granular media and glasses exhibit spatial long-range correlations as a result of mechanical equilibrium. However, the existence of such correlations in the flowing matter, where the mechanical equilibrium is unattainable, has remained elusive. Here, we investigate this problem in the context of the percolation of interparticle forces in flowing granular media. We find that the flow rate introduces an effective long-range correlation, which plays the role of a relevant perturbation giving rise to a spectrum of varying exponents on a critical line as a function of the flow rate. Our numerical simulations along with analytical arguments predict a crossover flow rate [Formula: see text] below which the effect of induced disorder is weak and the universality of the force chain structure is shown to be given by the standard rigidity percolation. We also find a power-law behavior for the critical exponents with the flow rate [Formula: see text].

2.
Soft Matter ; 17(20): 5162-5169, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34036970

RESUMO

Owing to the local/heterogeneous structures in supercooled liquids, after several decades of research, it is now clear that supercooled liquids are structurally different from their conventional liquid counterparts. Accordingly, an approach based on a local probe should provide a better understanding about the local mechanical properties as well as heterogeneous structures. Recently, the superiority of active microrheology over global rheology has been demonstrated [Yu et al., Sci. Adv., 2020, 6, 8766]. Here, we elaborate this new avenue of research and provide more evidence for such superiority. We report on the results of an extensive molecular dynamics simulation of active microrheology of a model glass. We identify several time scales in time series of friction, and detect a transition in dynamical behavior of friction. We discuss the possible relation to structural heterogeneities-a subject of considerable interest in glass physics.

3.
Soft Matter ; 17(20): 5259, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34037065

RESUMO

Correction for 'Dynamical time scales of friction dynamics in active microrheology of a model glass' by A. Madanchi et al., Soft Matter, 2021, DOI: 10.1039/d0sm02039g.

4.
Sci Adv ; 6(29): eaba8766, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32832632

RESUMO

The glass transition remains unclarified in condensed matter physics. Investigating the mechanical properties of glass is challenging because any global deformation that might result in shear rejuvenation would require a prohibitively long relaxation time. Moreover, glass is well known to be heterogeneous, and a global perturbation would prevent exploration of local mechanical/transport properties. However, investigation based on a local probe, i.e., microrheology, may overcome these problems. Here, we establish active microrheology of a bulk metallic glass, via a probe particle driven into host medium glass. This technique is amenable to experimental investigations via nanoindentation tests. We provide distinct evidence of a strong relationship between the microscopic dynamics of the probe particle and the macroscopic properties of the host medium glass. These findings establish active microrheology as a promising technique for investigating the local properties of bulk metallic glass.

5.
Phys Rev E ; 100(6-1): 060101, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31962542

RESUMO

We present a random-interface representation of the three-dimensional (3D) Ising model based on thermal fluctuations of a uniquely defined geometric spin cluster in the 3D model and its 2D cross section. Extensive simulations have been carried out to measure the global interfacial width as a function of temperature for different lattice sizes which is shown to signal the criticality of the model at T_{c} by forming a size-independent cusp in 3D, along with an emergent super-roughening at its 2D cross section. We find that the super-rough state is accompanied by an intrinsic anomalous scaling behavior in the local properties characterized by a set of geometric exponents which are the same as those for a pure 2D Ising model.

6.
Nat Commun ; 8(1): 11, 2017 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-28396590

RESUMO

Soft particulate media include a wide range of systems involving athermal dissipative particles both in non-living and biological materials. Characterization of flows of particulate media is of great practical and theoretical importance. A fascinating feature of these systems is the existence of a critical rigidity transition in the dense regime dominated by highly intermittent fluctuations that severely affects the flow properties. Here, we unveil the underlying mechanisms of rare fluctuations in soft particulate flows. We find that rare fluctuations have different origins above and below the critical jamming density and become suppressed near the jamming transition. We then conjecture a time-independent local fluctuation relation, which we verify numerically, and that gives rise to an effective temperature. We discuss similarities and differences between our proposed effective temperature with the conventional kinetic temperature in the system by means of a universal scaling collapse.Soft particulate flows such as granular media are prone to fluctuations like jamming and avalanches. Here Rahbari et al. consider the statistics of rare fluctuations to identify an effective temperature which, unlike previous ones, is valid for packing fractions both near and far from the jamming point.

7.
Arch Razi Inst ; 72(3): 189-195, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-30341940

RESUMO

Bovine theileriosis is an important tick-borne disease caused by intraerythrocytic parasites from genus Theileria. This study sought to detect the theileriosis among cattle and buffaloes using molecular and microscopic tests in West Azerbaijan, Iran. For this purpose, 484 blood samples from 193 cattle and 291 buffaloes were collected during March to July 2014. The breed, gender, age, and habitat of these animals were recorded. These animals were native and apparently healthy, living in four different cities of the province. The blood films were stained with Giemsa’s for microscopic examinations. Direct cell semi-nested polymerase chain reaction (PCR) assay was performed to detect T.annulata DNA with Tbs-S/Tbs-A and To-S/Tbs-A primer pairs targeted to 18S ribosomal RNA gene for Theileria spp. and T.orientalis amplification, respectively. The molecular assays revealed that 36 cattle (18.65%) were infected, in which 15 cattle were infected by both T.annulata and T.orientalis. Out of 291 buffaloes, four samples (1.4%) were infected by Theileria genotypes, and two buffaloes (0.7%) were infected only by T.orientalis. The observational results of the gender, age, and habitat of the studied animals were similar to animals of the other parts of Iran. The present study indicated that T.orientalis may be prevalent in native cattle and buffaloes throughout the northern parts of Iran. This study assessed the infection of buffaloes with T.orientalis for the first time.


Assuntos
Búfalos , Doenças dos Bovinos/epidemiologia , Theileria/isolamento & purificação , Theileriose/epidemiologia , Animais , Corantes Azur/química , Bovinos , Doenças dos Bovinos/sangue , Doenças dos Bovinos/parasitologia , Feminino , Irã (Geográfico)/epidemiologia , Masculino , Reação em Cadeia da Polimerase/veterinária , Prevalência , Theileriose/sangue , Theileriose/parasitologia
9.
Sci Rep ; 6: 21110, 2016 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-26899304

RESUMO

We report on universality in boundary domain growth in cluster aggregation in the limit of maximum concentration. Maximal concentration means that the diffusivity of the clusters is effectively zero and, instead, clusters merge successively in a percolation process, which leads to a sudden growth of the boundary domains. For two-dimensional square lattices of linear dimension L, independent of the models studied here, we find that the maximum of the boundary interface width, the susceptibility χ, exhibits the scaling χ ~ L(γ) with the universal exponent γ = 1. The rapid growth of the boundary domain at the percolation threshold, which is guaranteed to occur for almost any cluster percolation process, underlies the the universal scaling of χ.

10.
Artigo em Inglês | MEDLINE | ID: mdl-26172699

RESUMO

We conduct extensive independent numerical experiments considering frictionless disks without internal degrees of freedom (rotation, etc.) in two dimensions. We report here that for a large range of the packing fractions below random-close packing, all components of the stress tensor of wet granular materials remain finite in the limit of zero shear rate. This is direct evidence for a fluid-to-solid arrest transition. The offset value of the shear stress characterizes plastic deformation of the arrested state which corresponds to dynamic yield stress of the system. Based on an analytical line of argument, we propose that the mean number of capillary bridges per particle, ν, follows a nontrivial dependence on the packing fraction, ϕ, and the capillary energy, ɛ. Most noticeably, we show that ν is a generic and universal quantity which does not depend on the driving protocol. Using this universal quantity, we calculate the arrest stress, σ(a), analytically based on a balance of the energy injection rate due to the external force driving the flow and the dissipation rate accounting for the rupture of capillary bridges. The resulting prediction of σ(a) is a nonlinear function of the packing fraction, ϕ, and the capillary energy, ɛ. This formula provides an excellent, parameter-free prediction of the numerical data. Corrections to the theory for small and large packing fractions are connected to the emergence of shear bands and of contributions to the stress from repulsive particle interactions, respectively.

11.
Artigo em Inglês | MEDLINE | ID: mdl-24229163

RESUMO

We investigate the influence of the shape of a particle on the structure of the jamming phase diagram of wet granular materials. We compute the jamming phase diagram of wet dimers (two fused disks) and compare it with that of the wet disks. Amplitude of the external force at solidification, i.e., the jamming force F(s), is computed as a function of the packing fraction ϕ, the capillary bridge energy ɛ, and the aspect ratio of dimers α. Based on data collapse, an equation for amplitude of the external force at solidification F(s)(ϕ,ɛ,α) is derived. F(s) has scaling and logarithmic relations with ϕ and ɛ, respectively, exactly the same type reported for wet disks earlier. Interestingly, F(s) does not depend on the aspect ratio of dimers α. The only difference is that wet dimers are found to be more stiffer than wet disks. However, the similarities of the equations describing F(s)(ϕ,ɛ,α) of wet dimers and disks imply that there exists, yet unknown, universal aspects of mechanical response of wet granular materials to the external forces, independent from the particle shape. In addition, we study local orientation of particles and its statistical properties.

12.
Nat Commun ; 4: 2222, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23887743

RESUMO

Crackling noise is a common feature in many systems that are pushed slowly, the most familiar instance of which is the sound made by a sheet of paper when crumpled. In percolation and regular aggregation, clusters of any size merge until a giant component dominates the entire system. Here we establish 'fractional percolation', in which the coalescence of clusters that substantially differ in size is systematically suppressed. We identify and study percolation models that exhibit multiple jumps in the order parameter where the position and magnitude of the jumps are randomly distributed--characteristic of crackling noise. This enables us to express crackling noise as a result of the simple concept of fractional percolation. In particular, the framework allows us to link percolation with phenomena exhibiting non-self-averaging and power law fluctuations such as Barkhausen noise in ferromagnets.

13.
Phys Rev E Stat Nonlin Soft Matter Phys ; 86(1 Pt 1): 011407, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23005417

RESUMO

In this paper we present results of extensive Monte Carlo simulations of diffusion-limited aggregation (DLA) with a seed placed on an attractive plane as a simple model in connection with the electrical double layers. We compute the fractal dimension of the aggregated patterns as a function of the attraction strength α. For the patterns grown in both two and three dimensions, the fractal dimension shows a significant dependence on the attraction strength for small values of α and approaches that of the ordinary two-dimensional (2D) DLA in the limit of large α. For the nonattracting case with α = 1, our results in three dimensions reproduce the patterns of 3D ordinary DLA, while in two dimensions our model leads to the formation of a compact cluster with dimension 2. For intermediate α, the 3D clusters have a quasi-2D structure with a fractal dimension very close to that of the ordinary 2D DLA. This allows one to control the morphology of a growing cluster by tuning a single external parameter α.


Assuntos
Coloides/química , Modelos Químicos , Modelos Moleculares , Reologia/métodos , Simulação por Computador , Difusão , Transição de Fase
14.
Iran J Parasitol ; 7(4): 91-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23323097

RESUMO

BACKGROUND: Anaplasma ovis infections can cause clinical symptoms in acute phase and lead to huge economic losses in flocks. The aim of the present study was to investigate the hematological and parasitological changes in experimental anaplasmosis in sheep with Iranian strain of A. ovis. METHOD: Five male sheep without any blood parasite infection were selected. One hundred ml heparinized blood was collected from splenectomised sheep that showed 6% A. ovis parasitemia. Inoculums of 20 ml blood were administered intravenously to each test animal. Hematological, parasitological and clinical changes of experimental anaplasmosis were studied in 0-38 days post infection. RESULT: Parasitemia was detected 3 days post infection and reached its maximum level on the day 12 of experiment in test animals. Then the parasitemia was declined, but the organism could be found persistently until the last day of study. The red cell counts, packed cell volume and hemoglobin concentration were decreased and mean corpuscular volume was increased significantly during the infection period. Reticulocytosis and basophilic stippling were also detected. No significant changes were observed in total and differential leukocyte count and animal body temperature. CONCLUSION: Experimental A. ovis infection in sheep resulted in marked normocytic normochromic anemia at the beginning of the infection which became macrocytic normochromic by the development of the disease. There were negative correlations between parasitemia and RBC, PCV and Hb values, therefore hematological assessment can be considered as a practical diagnostic tool in ovine anaplasmosis.

15.
Iran J Parasitol ; 6(4): 23-32, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22347310

RESUMO

BACKGROUND: Coccidiosis of domestic fowl, caused by species of the Genus Eimeria, is responsible for important economic losses in poultry production. Because different species and/or strains can vary in pathogenicity and other biological parameters, their precise characterization is important for epizootiological studies. METHODS: Fifty samples from litter, whole intestinal tract and feces were collected from poultry houses located in different provinces of Iran. One hundred twenty male day-old broiler chicks were challenged with three selected isolates. Data on weight gain, Food Conversion Ratio (FCR), food intake, lesion scoring and shedding of oocysts per gram of feces were recorded and analyzed by the Duncan's test. RESULTS: In all treatments, the challenged groups had statistically significant lower weight gain than that of unchallenged control group. Isolate three caused the lowest weight gain and food intake and the worst lesion score as well as FCR. Despite originating from close geographical regions for isolates 1 and 2, the difference in biopathologic factors may be either due to different proportion of identified species or the different pathogenicity of the species present in the isolates. CONCLUSION: The results highlight the importance of considering various species of Eimeria in designing the preventive, control and treatment strategies to prevent coccidiosis in different regions of Iran. Further characterization of each isolate would be the next step to provide a basis for coccidiosis research with well-characterized local isolates.

16.
Med Vet Entomol ; 24(1): 88-90, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20377736

RESUMO

Newcastle disease (Paramyxoviridae) is a highly infectious virus shed in the faeces of infected birds. Non-biting Muscid flies characteristically visit manure and decaying organic material to feed and oviposit, and may contribute to disease transmission. The housefly, Musca domestica (Linnaeus, 1758) (Diptera: Muscidae), has been implicated as a mechanical vector of numerous pathogens. In this study 2000 aerial net-captured houseflies were examined for their ability to harbour Newcastle disease virus (NDV). In an adjacent study, laboratory-reared flies were experimentally exposed to NDV La Sota strain. The virus was detected in the dissected gastrointestinal tract of laboratory-exposed flies for up to 72 h post-exposure, whereas the untreated control flies were negative.


Assuntos
Moscas Domésticas/virologia , Insetos Vetores/virologia , Doença de Newcastle/transmissão , Vírus da Doença de Newcastle/crescimento & desenvolvimento , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais/sangue , Testes de Hemaglutinação , Doença de Newcastle/virologia , Aves Domésticas , Doenças das Aves Domésticas/transmissão
17.
Phys Rev E Stat Nonlin Soft Matter Phys ; 82(6 Pt 1): 061305, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21230670

RESUMO

Small amounts of a wetting liquid render sand a stiff and moldable material. The cohesive forces between the sand grains are caused by capillary bridges at the points of contact. Due to the finite strength of these bridges wet sand undergoes a transition from an arrested (i.e., solidified) to a fluidized state under an externally applied shear force. The transition between these two dynamic states is studied in a MD-type simulation of a two-dimensional assembly of bidisperse frictionless disks under the action of a cosine force profile. In addition to soft core repulsion the disks interact through a hysteretic and short ranged attractive force modeling the effect of the capillary bridges. In this model the transition between the fluidized and the arrested state is discontinuous and hysteretic. The parameter dependence of the critical force for solidification is modeled by combining theoretical arguments with a detailed numerical exploration of the transition. We address a range of densities from slightly below close packing until slightly above densities where the system approaches a shear-banded state. Differences and similarities of the transition in wet granulates to the jamming transition are also addressed.

18.
Iran J Parasitol ; 5(4): 21-30, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22347262

RESUMO

BACKGROUND: Ovine babesiosis is the most important haemoparasitic tick-borne disease of small ruminants in Iran caused by Babesia ovis, B. motasi, and B. crassa. The aim of this study was to characterize the species of ovine Babesia species isolated from different geographical region of Iran. METHODS: One hundred fifty four blood samples collected from animals, which demonstrated the pale mucous membranes or hyperthermia. The specimens were transferred to the laboratory and the blood smears stained with Geimsa, the morphological and biometrical data of parasite in any infected erythrocyte have been considered. Extracted DNA from each blood samples were used in PCR and semi nested- PCR in order to confirm the presence of the species. RESULTS: Microscopical observation on 154 blood smears determined 38 (24.67%) and 40 (26%) samples were infected by Babesia and Theileria respectively. The mixed infections occurred in four (2.6%) samples. The results of the PCR assays showed nine (5.85%), 81 (53%) and 18 (11.7%) were distinguished as Babesia, Theileria and mixed infection, respectively. Semi nested- PCR did not confirm the presence of B. motasi. CONCLUSION: The causative organism of many cases of haemoprotozoal diseases, which recorded in previous studies, could be B. ovis or Theileria lestoquardi. The result confirmed that B. ovis was only species which causes babesiosis in the study areas. It seems that the biometrical polymorphisms could exist in B. ovis in Iran. This polymorphism could be a main problem in differentiation between B. ovis and B. motasi and it could be dissolved by specific PCR analysis.

19.
Trop Biomed ; 27(3): 504-8, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21399592

RESUMO

Hexamita sp. was identified in 8 cases of sixty (13.3%) stunted diarrhoeic 1- 12- week old native turkey poults. Large numbers of the flagellated parasites were found within the dilated crypts of Lieberkuhn of ileum and jejunum. In TEM studies on the parasagittal section of the parasite, elongated flagellated binuclear parasite was found. The morphological characteristics of the seen protozoan are similar with those described for Hexamita meleagridis. The parasite could be considered as an intestinal pathogenic protozoan parasite, causing stunting and diarrhoea in turkeys in Iran.


Assuntos
Diplomonadida/citologia , Doenças das Aves Domésticas/patologia , Infecções Protozoárias em Animais/patologia , Animais , Diarreia/parasitologia , Diarreia/patologia , Histocitoquímica , Íleo/parasitologia , Íleo/patologia , Mucosa Intestinal/parasitologia , Mucosa Intestinal/patologia , Irã (Geográfico) , Jejuno/parasitologia , Jejuno/patologia , Microscopia Eletrônica de Transmissão , Doenças das Aves Domésticas/parasitologia , Infecções Protozoárias em Animais/parasitologia , Perus
20.
Med Vet Entomol ; 23(3): 281-3, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19712158

RESUMO

The distribution of Hyalomma species on domestic animals was studied in four zoogeoghraphical zones. Nine hundred and ninety-two Hyalomma ticks were collected from sheep, goats, cattle and camels. A total of seven tick species consisting of: Hyalomma anatolicum Koch, 1844 (28.93%), H. excavatum Koch, 1844 (12.5%), H. asiaticum Schulze & Schlottke, 1930 (13.5%), H. marginatum Koch, 1844 (27.01%), H. detritum Schulze, 1919 (9.67%), H. schulzei Olenev, 1931 (4.03%) and H. dromedary Koch, 1844 (4.33%) were recorded. The results indicated that H. anatolicum, H. asiaticum, H. marginatum and H. detritum were present in all zones whereas H. excavatum was absent in Zone I. The result also showed that H. dromedari was presented in Zones III and IV whereas H. schulzei was present in Zones II and III. During this study, the tick species collected are candidates for investigation as vectors of pathogenic organisms in Iran.


Assuntos
Ixodidae , Ruminantes/parasitologia , Infestações por Carrapato/veterinária , Animais , Camelus/parasitologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Geografia , Irã (Geográfico)/epidemiologia , Ixodidae/classificação , Ovinos/parasitologia , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologia , Infestações por Carrapato/epidemiologia
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