Direct simulation Monte Carlo for new regimes in aggregation-fragmentation kinetics

We revisit two basic Direct Simulation Monte Carlo Methods to model aggregation kinetics and extend them for aggregation processes with collisional fragmentation (shattering). We test the performance and accuracy of the extended methods and compare their performance with efficient deterministic finite-difference method applied to the same model. We validate the stochastic methods on the test problems and apply them to verify the existence of oscillating regimes in the aggregation-fragmentation kinetics recently detected in deterministic simulations. We confirm the emergence of steady oscillations of densities in such systems and prove the stability of the oscillations with respect to fluctuations and noise.Comment: 19 pages, 2 figures, 4 table

Nanohyperthermia of malignant tumors. II. In vivo tumor heating with manganese perovskite nanoparticles

Objectives: To evaluate the ability of manganese perovskite nanoparticles (lanthanum-strontium manganite) to heat the tumor tissue in vivo under action of external alternating magnetic field. Materials and Methods: The magnetic fluid on the basis of nanoparticles of perovskite manganite was tested in the heating experiments using of alternating magnetic field of frequency 300 kHz and amplitude 7.7 kA/m. Guerin carcinoma was transplanted into the muscle of rat. Magnetic fluid was injected intramuscularly or intratumorally. Temperature was measured by copper-constantan thermocouple. Results: Temperature of magnetic fluid was increased by 56 °C for 10 min of alternating magnetic field action. Administration of magnetic fluid into the muscle followed by alternating magnetic field resulted in the elevation of muscle temperature by 8 °C after 30 min post injection. Temperature of the tumor injected with magnetic fluid and treated by alternating magnetic field was increased by 13.6 °C on the 30 min of combined influence. Conclusion: In vivo study with rat tissue has demonstrated that magnetic fluid of manganite perovskite injected in the tumor increases the tumor temperature under an alternating magnetic field. Obtained results emphasize that magnetic fluid of manganite perovskite can be considered as effective inducer of tumor hyperthermia

Nanohyperthermia of malignant tumors.i. lanthanum-strontium manganite magnetic fluid as potential inducer of tumor hyperthermia

Objectives: To synthesize magnetic particles of lanthanum-strontium manganite, prepare the magnetic fluid (MF), evaluate the generation of heat by particles and determine their common toxiсity. Methods: Nanoparticles based on the solid solutions of lanthanum-strontium manganite (La1-xSrxMnO3) have been synthesized by a sol-gel method. Conventional methods of experimental oncology were used. Results: Nanoparticles of ferromagnetic materials on the basis of solid solutions of lanthanum strontium manganite by sol-gel method were synthesized. It was shown the possibility to regulate the aggregate form of particles that are formed during the synthesis. Magnetic fluid based on the synthesized nanoparticles and water solutions of agarose have been produced. It was shown the possibility to heat this magnetic fluid up to 42–45 °С in externally applied alternating magnetic field (AMF) operated at 100–400 kHz. It was determined that under long-term influence of AMF nanofluid is heated up to temperature which is not over that of magnetic phase transition. It was detected that magnetic powder as well as fluid have not displayed acute toxicity or side effects (intraperitoneal or intratumoral administration) in animals either intact or with transplanted tumors. Conclusions: Possibility of synthesized magnetic fluid to generate heat in externally applied AMF as well as lack of side effects allow to consider its as a potential mean for tumor hyperthermia (HT)

Migration and luminescence enhancement effects of deuterium in ZnO/ZnCdO quantum wells

ZnO/ZnCdO/ZnO multiple quantum well samples grown on sapphire substrates by molecular beam epitaxy and annealed in situ were exposed to D(2) plasmas at 150 degrees C. The deuterium showed migration depths of similar to 0.8 mu m for 30 min plasma exposures, with accumulation of (2)H in the ZnCdO wells. The photoluminescence (PL) intensity from the samples was increased by factors of 5 at 5 K and similar to 20 at 300 K as a result of the deuteration, most likely due to passivation of competing nonradiative centers. Annealing up to 300 degrees C led to increased migration of (2)H toward the substrate but no loss of deuterium from the sample and little change in the PL intensity. The initial PL intensities were restored by annealing at \u3e = 400 degrees C as (2)H was evolved from the sample (similar to 90% loss by 500 degrees C). By contrast, samples without in situ annealing showed a decrease in PL intensity with deuteration. This suggests that even moderate annealing temperatures lead to degradation of ZnCdO quantum wells. (c) 2008 American Institute of Physics

Identification and manipulation of tumor associated macrophages in human cancers

Evading immune destruction and tumor promoting inflammation are important hallmarks in the development of cancer. Macrophages are present in most human tumors and are often associated with bad prognosis. Tumor associated macrophages come in many functional flavors ranging from what is known as classically activated macrophages (M1) associated with acute inflammation and T-cell immunity to immune suppressive macrophages (M2) associated with the promotion of tumor growth. The role of these functionally different myeloid cells is extensively studied in mice tumor models but dissimilarities in markers and receptors make the direct translation to human cancer difficult. This review focuses on recent reports discriminating the type of infiltrating macrophages in human tumors and the environmental cues present that steer their differentiation. Finally, immunotherapeutic approaches to interfere in this process are discussed

Anomalous aggregation regimes of temperature-dependent Smoluchowski equations

Temperature-dependent Smoluchowski equations describe the ballistic agglomeration. In contrast to the standard Smoluchowski equations for the evolution of cluster densities with constant rate coefficients, the temperature-dependent equations describe both -- the evolution of the densities as well as cluster temperatures, which determine the aggregation rates. To solve these equations, we develop a novel Monte Carlo technique based on the low-rank approximation for the aggregation kernel. Using this highly effective approach, we perform a comprehensive study of the phase diagram of the system and reveal a few surprising regimes, including permanent temperature growth and "density separation", with a large gap in the size distribution for middle-size clusters. We perform classification of the aggregation kernels for the temperature-dependent equations and conjecture the lack of gelation. The results of our scaling analysis agree well with the simulation data.Comment: Submitted to Physical Review

Some technology aspects for quantum enestor through AIIIBV multicomponent nanoepitaxy

For the first time, it has been considered some quantum enestor technology aspects concerning the integration approach for Si-CMOS and site-controlled InGaN/GaN quantum dots, which provides the possibility to realize single photon sources (SPS)/single photon detector (SPD) for quantum processing based on AIIIBV direct bandgap multicomponent heterogeneous nanostructures and their light energy storing capability, by an analogy with the photosynthetic process in plants