Sono-magnetic heating in tumor phantom

There exist various types of hyperthermia therapy such as radiofrequency, infrared, microwave, focused ultrasound or magnetic. Recently, a lot of effort has been put into combining more than one mode of heating into one treatment. The multimodal hyperthermia proves a better alternative in comparison with a single one. In this paper, we show that the application of dual sono-magnetic heating (ultrasound and magnetic together) gives better results than using either of them alone. The advantage of this bimodal treatment lies not only in cumulative heating of target volume (tumor) but also in synergistic interaction between the two mechanisms—the ultrasound sonication can improve the thermal effect of magnetic hyperthermia through the unblocking Brown’s relaxation. Furthermore, the ultrasound and magnetic heating are complementary to each other. The temperature rise caused by ultrasound is fast changing and by magnetic field slow changing. So the parameters of ultrasound can serve as coarse-tuning settings of heating while the parameters of the magnetic field as fine-tuning enabling more precise hyperthermia

Ocena wykorzystan ia maszyn w gospodarstwach rolniczych ze szczególnym uwzględnieniem kosztów użytecznych

Podjęto próbę wprowadzenia do oceny kosztów mechanizacji pojęcia kosztów użytecznych i bezużytecznych (pustych). Koszty bezużyteczne mają charakter kosztów stałych i są związane z utrzymywaniem potencjału eksploatacyjnego maszyn, który jest nie jest w pełni wykorzystywany. Koszty użyteczne są tą częścią kosztów stałych, które są związane (absorbowane) w trakcie wykonywanej pracy (eksploatacji). Jako racjonalny roczny próg wykorzystania maszyn przyjęto stosunek racjonalnego progu wykorzystania danego środka trwałego w całym okresie jego użytkowania, wyrażony w jednostkach pracy (h, ha, km, t, szt., zwoje, l itd.), do jego ekonomicznego (moralnego) potencjału pracy wyrażonego w latach. Uznano, że koszty niewykorzystanego potencjału produkcyjnego należy rozpatrywać w aspekcie kosztów zarządzania (kosztów okresu) i nie należy nimi obciążać kosztów poszczególnych działalności produkcyjnych

WYKORZYSTANIE METODYKI BEP DO ANALIZY KOSZTÓW MECHANIZACJI W GOSPODARSTWIE ROLNICZYM

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)

Cyclodextrine vs D-glucose in the solutions of the derivative of 1,4-DHP

Hydrophilic and hydrophobic cyclodextrins (CDs) have found a lot of applications in medicine pharmacology, food processing and cosmetology. They can function as a drug carrier material and parent host molecules, increasing drug biocompatibility, optimizing the efficiency of drug activity, and controlling drug release at the desired level. The effectiveness of CD complexation depends on many factors such as the type and the size of both the CD molecule itself and the guest molecule, pH of the solution, and temperature. In aqueous solution of glucose the aggregation of molecules can occur leading to the formation of CD-like structures. In the paper the possibility of the formation of the inclusion complexes of CD and glucose with Nimodipine was investigated with the aid of ultrasonic spectroscopy. By comparing the efficiency of industrial saccharides and glucose in the formation of the inclusion complexes the cost effectiveness of the use of glucose as a substitute for CD can be determined

Denaturation and aggregation of lysozyme in water-ethanol solution

We have applied rheological methods for the analysis of ethanol-lysozyme interaction during the process of denaturation and aggregation of the protein. At low concentration of ethanol a destruction of the hydration shell of lysozyme is observed. With the increase in the ethanol concentration a structural transformation takes place. It leads to the formation of a protein aggregate with an elongated structure. The rheological characteristics of lysozyme-water-ethanol solution changes from Newtonian to pseudoplastic

Influence of Magnetic Nanoparticles on the Focused Ultrasound Hyperthermia

Ultrasound hyperthermia is a medical treatment used to increase temperature of tissues. It can be used independently or as a supportive method for an anticancer treatment. The therapeutic efficacy of focused ultrasound hyperthermia can be improved using sonosensitizers, nanoparticles enhancing the attenuation and dissipation of acoustic energy. As sonosensitizers, we propose magnetic nanoparticles owing to their biodegradability, biocompatibility, and simple positioning in tissues using a magnetic field. Focused ultrasound hyperthermia studies were performed using tissue-mimicking phantoms. Temperature changes were measured at various ultrasound powers and distances from the center of the ultrasound focus. Specific absorption rate (SAR) values, describing the power deposition in the tissues during the hyperthermia treatment, were evaluated for the center of the focus point and for various distances from it. The results show that the addition of nanoparticles increases the SAR almost two times compared to that for the pure phantom. The highest SAR is obtained in the ultrasound focus; it decreases with the increase of the distance from the focus

Ultrasound Study of Magnetic and Non-Magnetic Nanoparticle Agglomeration in High Viscous Media

Ultrasound attenuation spectroscopy has found wide application in the study of colloidal dispersions such as emulsions or suspensions. The main advantage of this technique is that it can be applied to relatively high concentration systems without sample preparation. In particular, the use of Epstein-Carhart-Allegra-Hawley’s (ECAH) ultrasound scattering theory, along with experimental data of ultrasound velocity or attenuation, provide the method of estimation for the particle or droplet size from nanometers to millimeters. In this study, suspensions of magnetite and silica nanoparticles in high viscous media (i.e., castor oil) were characterized by ultrasound spectroscopy. Both theoretical and experimental results showed a significant difference in ultrasound attenuation coefficients between the suspensions of magnetite and silica nanoparticles. The fitting of theoretical model to experimental ultrasound spectra was used to determine the real size of objects suspended in a high viscous medium that differed from the size distributions provided by electron microscopy imaging. The ultrasound spectroscopy technique demonstrated a greater tendency of magnetic particles toward agglomeration when compared with silica particles whose sizes were obtained from the combination of experimental and theoretical ultrasonic data and were more consistent with the electron microscopy images

The Effect of Tissue-Mimicking Phantom Compressibility on Magnetic Hyperthermia

During hyperthermia, magnetite nanoparticles placed in an AC magnetic field become a source of heat. It has been shown that in fluid suspensions, magnetic particles move freely and generate heat easily. However, in tissues of different mechanical properties, nanoparticle movement is limited and leads to a small temperature rise in tissue. Therefore, it is crucial to conduct magnetic hyperthermia experiments in similar conditions to the human body. The effect of tissue-mimicking phantom compressibility on the effectiveness of magnetic hyperthermia was investigated on agar phantoms. Single and cluster nanoparticles were synthesized and used as magnetic materials. The prepared magnetic materials were characterized by transmission electron microscopy (TEM), and zeta potential measurements. Results show that tissue-mimicking phantom compressibility decreases with the concentration of agar. Moreover, the lower the compressibility, the lower the thermal effect of magnetic hyperthermia. Specific absorption rate (SAR) values also proved our assumption that tissue-mimicking phantom compressibility affects magnetic losses in the alternating magnetic field (AMF)