Spatially heterogeneous dynamics in a thermosensitive soft suspension before and after the glass transition

The microscopic dynamics and aging of a soft thermosensitive suspension was investigated by looking at the thermal fluctuations of tracers in the suspension. Below and above the glass transition, the dense microgel particles suspension was found to develop an heterogeneous dynamics, featured by a non Gaussian Probability Distribution Function (PDF) of the probes' displacements, with an exponential tail. We show that non Gaussian shapes are a characteristic of the ensemble-averaged PDF, while local PDF remain Gaussian. This shows that the scenario behind the non Gaussian van Hove functions is a spatially heterogeneous dynamics, characterized by a spatial distribution of locally homogeneous dynamical environments through the sample, on the considered time scales. We characterize these statistical distributions of dynamical environments, in the liquid, supercooled, and glass states, and show that it can explain the observed exponential tail of the van Hove functions observed in the concentrated states. The intensity of spatial heterogeneities was found to amplify with increasing volume fraction. In the aging regime, it tends to increase as the glass gets more arrested.Comment: 19 pages, 10 figures, Soft Matter accepte

Helical Packings and Phase Transformations of Soft Spheres in Cylinders

The phase behavior of helical packings of thermoresponsive microspheres inside glass capillaries is studied as a function of volume fraction. Stable packings with long-range orientational order appear to evolve abruptly to disordered states as particle volume fraction is reduced, consistent with recent hard sphere simulations. We quantify this transition using correlations and susceptibilities of the orientational order parameter psi_6. The emergence of coexisting metastable packings, as well as coexisting ordered and disordered states, is also observed. These findings support the notion of phase transition-like behavior in quasi-1D systems.Comment: 5 pages, with additional 4 pages of supplemental material, accepted to Physical Review E: Rapid Communication

Two-dimensional freezing criteria for crystallizing colloidal monolayers

Video microscopy was employed to explore crystallization of colloidal monolayers composed of diameter-tunable microgel spheres. Two-dimensional (2D) colloidal liquids were frozen homogenously into polycrystalline solids, and four 2D criteria for freezing were experimentally tested in thermal systems for the first time: the Hansen–Verlet freezing rule, the Löwen–Palberg– Simon dynamical freezing criterion, and two other rules based, respectively, on the split shoulder of the radial distribution function and on the distribution of the shape factor of Voronoi polygons. Importantly, these freezing criteria, usually applied in the context of single crystals, were demonstrated to apply to the formation of polycrystalline solids. At the freezing point, we also observed a peak in the fluctuations of the orientational order parameter and a percolation transition associated with caged particles. Speculation about these percolated clusters of caged particles casts light on solidification mechanisms and dynamic heterogeneity in freezing

Melting of Multilayer Colloidal Crystals Confined Between Two Walls

Video microscopy is employed to study the melting behaviors of multilayer colloidal crystals composed of diameter-tunable microgel spheres confined between two walls.We systematically explore film thickness effects on the melting process and on the phase behaviors of single crystal and polycrystalline films. Thick films (\u3e4 layers) are observed to melt heterogeneously, while thin films ( ≤ 4 layers) melt homogeneously, even for polycrystalline films. Grain-boundary melting dominates other types of melting processes in polycrystalline films thicker than 12 layers. The heterogeneous melting from dislocations is found to coexist with grain-boundary melting in films between 5- and 12-layers. In dislocation melting, liquid nucleates at dislocations and forms lakelike domains embedded in the larger crystalline matrix; the “lakes” are observed to diffuse, interact, merge with each other, and eventually merge with large strips of liquid melted from grain boundaries. Thin film melting is qualitatively different: thin films homogeneously melt by generating many small defects which need not nucleate at grain boundaries or dislocations. For three- and four-layer thin films, different layers are observed to have the same melting point, but surface layers melt faster than bulk layers. Within our resolution, two- to four-layer films appear to melt in one step, while monolayers melt in two steps with an intermediate hexatic phase

Melting of Colloidal Crystal Films

We study melting mechanisms in single and polycrystalline colloidal films composed of diametertunable microgel spheres with short-ranged repulsive interactions and confined between two glass walls. Thick films (\u3e4 layers), thin-films (≤4 layers), and monolayers exhibit different melting behaviors. Thick films melt from grain boundaries in polycrystalline solid films and from film-wall interfaces in single-crystal films; a liquid-solid coexistence regime is observed in thick films but vanishes at a critical thickness of 4 layers. Thin solid films (2 to 4 layers) melt into the liquid phase in one step from both grain boundaries and from within crystalline domains. Monolayers melt in two steps with a middle hexatic phase

Effect of SPIO Nanoparticle Concentrations on Temperature Changes for Hyperthermia via MRI

Magnetic nanoparticles (MNPs) are being developed for a wide range of biomedical applications. In particular, hyperthermia involves heating the MNPs through exposure to an alternating magnetic field (AMF). These materials offer the potential for selectively by heating cancer tissue locally and at the cellular level. This may be a successful method if there are enough particles in a tumor possessing sufficiently high specific absorption rate (SAR) to deposit heat quickly while minimizing thermal damage to surrounding tissue. The current research aim is to study the influence of super paramagnetic iron oxides Fe3O4 (SPIO) NPs concentration on the total heat energy dose and the rate of temperature change in AMF to induce hyperthermia in Ehrlich carcinoma cells implanted in female mice. The results demonstrated a linearly increasing trend between these two factors

Two Features at the Two-Dimensional Freezing Transitions

We studied the two-dimensional freezing transitions in monolayers of microgel colloidal spheres with short-ranged repulsions in video-microscopy experiments, and monolayers of hard disks, and Yukawa particles in simulations. These systems share two common features at the freezing points: (1) the bimodal distribution profile of the local orientational order parameter; (2) the two-body excess entropy, s2, reaches −4.5 ± 0.5 kB. Both features are robust and sensitive to the freezing points, so that they can potentially serve as empirical freezing criteria in two dimensions. Compared with the conventional freezing criteria, the first feature has no finite-size ambiguities and can be resolved adequately with much less statistics; and the second feature can be directly measured in macroscopic experiments without the need for microscopic information

Comparative Study between High Resolution Ultrasound and MRI in Diagnosis of Rotator Cuff Tears

Background: The four muscles that support the humeral head and come from the anterior and posterior sides of the scapula with their tendons situated in the smaller and larger tuberosities are collectively known as the "rotator cuff." The teres minor, supraspinatus, infraspinatus, and subscapularis are among these muscles. Objectives: This study compares dynamic high-resolution ultrasonography to MRI, which was the gold standard to assess the value of each technology in identifying rotator cuff injury. Patients and methods: This was prospective study for fifty patients were sent to the Diagnostic and Interventional Radiology Clinic in Qena City suspected to have rotator cuff injury. . Results: Patients' ages ranged from 19 to 70, with a mean age of 36 years, a standard deviation of 16.35 years. In our study, there were a total of 32 affected males (64%) and 18 affected females (36%) with a male to female ratio of 1.78:1. In identifying complete tears in our patients, in general, we found that USG has 100% overall sensitivity, 92.68% overall specificity, and 94% overall diagnostic accuracy. Positive predictive value was 75%, whereas the negative predictive value was 100%. Conclusion: MRI and ultrasound have similar levels of sensitivity and specificity. When high-resolution imaging is feasible, trained radiologists are on hand, and rotator cuff integrity is the main concern, US may be thought of as the screening method because it is less expensive and more widely available

In Vivo Anti-Inflammatory, Anti-Bacterial and Anti-Diarrhoeal Activity of Ziziphus Jujuba Fruit Extract

BACKGROUND: Ziziphus jujuba belongs to family Rhamnaceae widely distributed in subtropical and tropical countries. It is used traditionally for several pharmacological purposes including anti-inflammation, antidiarrhoeal and antibacterial, as well as tonic and sometimes as hypnotic (sedative).AIM: To determine the in vivo antidiarrhoeal, antibacterial and anti-inflammatory activities of Z. jujuba fruit ethanolic extract.METHOD: The fruit was macerated and extracted by 95% (v/v) ethanol. The antidiarrhoeal activity was evaluated using castor oil and Escherichia coli induced diarrhoea mouse model. The antidiarrhoeal and antibacterial activity was investigated at graded doses (400-1200 mg/kg). The anti-inflammatory effects were tested using the carrageenan-induced paw oedema in female Wistar rats. Rat’s treatment groups received tragacanth, 100 mg/kg diclofenac sodium, 800 mg/kg, 1200 mg/kg or 1600 mg/kg of an ethanolic extract of Z. jujuba (EEZJ). All treatment groups were fed with the compounds one hour before carrageenan injection at of rat’s paw. Also, the EEZJ was further analysed by HPLC-PDA system for identification of the presence of betulinic acid and quercetin.RESULTS: EEZJ different doses did not show inhibitory activity against castor oil induced diarrhoea except for the higher (1200 mg/kg) dose. However, the frequency of defecation of stools and watery stool were reduced significantly when compared to control group (P ≤ 0.05 and P ≤ 0.01 respectively), resulted in overall 67% inhibition of diarrhoea. Our anti-inflammatory results demonstrated that EEZJ was able to inhibit the carrageenan-induced paw oedema in rats to a significant degree (p ≤ 0.05) and the paw volume and thickness of both left and right paw were affected compared to the negative control group.CONCLUSION: EEZJ possesses antidiarrhoeal and antibacterial activity in a dose depending manner and may provide a pharmacological basis for its clinical use in diarrheal diseases. The activity may partially be due to the presence of betulinic acid and quercetin

High Genetic Diversity of Human Rhinovirus among Pilgrims with Acute Respiratory Tract Infections during 2019 Hajj Pilgrimage Season

OBJECTIVES: Acute Respiratory tract infections (ARI) due to Human Rhinoviruses (HRV) are common in pilgrims during the annual Hajj pilgrimage. The objective of this study was to investigate the genetic diversity of HRV among pilgrims with respiratory symptoms during Hajj 2019. METHODS: HRV infection was detected using multiplex real time RT-PCR. Cycle sequencing was performed on positive samples and the sequences were subjected to phylogenetic analysis. RESULTS: 19 HRV-positive respiratory samples were sequenced. All three serotypes of HRV were identified: HRV-A (13; [68.42%)) was more common than HRV-B (2; [10.53%]), and HRV-C (4; [21.05%]). HRV-A species were found to be of genotypes A101, A21, A30, A57, A23, A60 and A11. HRV-B species belonged to genotypes B4 and B84, and HRV-C species were of genotypes C15, C3 and C56. CONCLUSIONS: Sequencing studies of respiratory tract viruses in pilgrims are important. We provide preliminary evidence of high diversity of HRV genotypes circulating in pilgrims in a restricted area during Hajj. This requires further clinical and sequencing studies of viral pathogens in larger consorts of overseas and local pilgrims