Magnetic nanoparticles for enhancing the effectiveness of ultrasonic hyperthermia

Ultrasonic hyperthermia is a method of cancer treatment in which tumors are exposed to an elevated cytotoxic temperature using ultrasound (US). In conventional ultrasonic hyperthermia, the ultrasound-induced heating in the tumor is achieved through the absorption of wave energy. However, to obtain appropriate temperature in reasonable time, high US intensities, which can have a negative impact on healthy tissues, are required. The effectiveness of US for medical purposes can be significantly improved by using the so-called sonosensitizers, which can enhance the thermal effect of US on the tissue by increasing US absorption. One possible candidate for such sonosensitizers is magnetic nanoparticles with mean sizes of 10–300 nm, which can be efficiently heated because of additional attenuation and scattering of US. Additionally, magnetic nanoparticles are able to produce heat in the alternating magnetic field (magnetic hyperthermia). The synergetic application of ultrasonic and magnetic hyperthermia can lead to a promising treatment modality

Comparison of magnetic and non-magnetic nanoparticles as sonosensitizers in ultrasonic hyperthermia

Nanoparticles have attracted a great interest in scientific world because of the new applications they offer. They are commonly used in medical procedures such as hyperthermia and thermal ablation. Here, we propose, using magnetic and non-magnetic nanoparticles, as sonosensitizers which are the materials that improve the efficiency of heating induced by ultrasound. A comparison between various types of nanomaterials, such as magnetite, silicon dioxide, and Laponite nanoparticles, was done. The results show that both magnetic and non-magnetic nanomaterials can be utilized in ultrasonic heating. However, magnetite nanoparticles without surface modification can strongly interact with each other and are prone to agglomeration that can deteriorate thermal effect in tissuemimicking phantoms

Ultrasonic Absorption Coefficient and Propagation Velocity in Critical Benzonitrile-Isooctane Mixture

Measurements of the absorption coefficient and propagation velocity of ultrasonic waves in critical benzonitrile and isooctane mixture are reported for the frequency range of 5-25 MHz and temperatures ΔT = T - T$\text{}_{c}$ from 0.15 to 20 K. The analysis of the experimental results is based on dynamic scaling theory leading to good agreement with the theoretical predictions, especially in the reduced frequency range 1 < ω* < 100. The adiabatic coupling constant g is calculated and compared to the experimental value

Use methodology of BEP to analyze mechanization costs on farm

Podjęto próbę adaptacji metodyki analizy BEP do oceny rentowności użytkowania maszyn rolniczych. Przyjęto traktowanie kosztu amortyzacji maszyny jako kosztu stałego, ale tylko do progu racjonalnego wykorzystania. Powyżej tego progu, uznano, że amortyzacja powinna być liczona metodą czynną i traktowana jako koszt zmienny. W tym przypadku to potencjał techniczny i jego zużycie staje się „wąskim gardłem”. Dodatkowo uznano za zasadne uwzględnianie kosztu oprocentowania zaangażowanego kapitału, który będzie miał charakter kosztu stałego. Dotychczas badania nad efektywnością wykorzystania maszyn skupiały się nad ilościową analizą ich wykorzystania, pomijano zaś aspekty finansowe. Proponowane wykorzystanie metodyki BEP pozwala nie tylko na określenie progu rentowności ilościowego i wartościowego dla analizowanej maszyny, ale również na obliczenie granicznych wartości poszczególnych składowych kosztów zmiennych (cen paliwa, remontów) oraz stałych (garażowania, konserwacji, oprocentowania).The article attempts to adapt the BEP analysis methodology to assess the viability of agricultural machinery. It was assumed to treat the machine depreciation cost as a fixed cost, but only to the rational use threshold. Above this threshold, it was considered that depreciation should be calculated using the active method and treated as a variable cost. In this case it’s a technical potential and its wear becomes a bottleneck. In addition, it was considered reasonable to take into account the cost of interest on the capital employed, which would be a fixed cost. So far research on the efficiency of machinery utilization has focused on the quantitative analysis of their use, and the financial aspects are ignored. The proposed use of the BEP methodology allows not only quantitative and qualitative yield thresholds for the analyzed machine, but also the calculation of the limit values of the variable component costs (fuel prices, repairs) and fixed costs (garage, maintenance, interest rates)

Absorption and Dispersion of Ultrasonic Waves in n-Amylic Alcohol-Nitromethane Critical Mixture

Measurement of absorption and propagation velocity of ultrasonic waves as well as shear viscosity in n-amylic alcohol-nitromethane critical mixture are reported. Acoustic measurements were performed in the frequency range from 5 to 25 MHz and temperatures ΔT = T - T$\text{}_{c}$ from 0.1 to 12.3 K. An analysis of the results was carried out on the basis of a modified version of mode-coupling theory [10], which led to good agreement with experiment. The correlation length ξ$\text{}_{0}$ = 0.94 Ǻ is in agreement with the value obtained from optical measurements