Recent advances in selective photothermal therapy of tumor

Photothermal therapy (PTT), which converts light energy to heat energy, has become a new research hotspot in cancer treatment. Although researchers have investigated various ways to improve the efficiency of tumor heat ablation to treat cancer, PTT may cause severe damage to normal tissue due to the systemic distribution of photothermal agents (PTAs) in the body and inaccurate laser exposure during treatment. To further improve the survival rate of cancer patients and reduce possible side effects on other parts of the body, it is still necessary to explore PTAs with high selectivity and precise treatment. In this review, we summarized strategies to improve the treatment selectivity of PTT, such as increasing the accumulation of PTAs at tumor sites and endowing PTAs with a self-regulating photothermal conversion function. The views and challenges of selective PTT were discussed, especially the prospects and challenges of their clinical applications.

ANALYSIS OF THE TECHNOLOGICAL FACTORS INFLUENCE ON RESPONSE FUNCTION OF THE COPLANAR CAPACITIVE SHAFT BEATING SENSOR

In the paper presents results of analysis of the influence of the thickness of the dielectric substrate of a capacitive beating sensor, the electrodes of which are made of foil dielectric type FR4, on the transformation function of the sensor by methods of computer modeling are presented. The results of research by methods of computer modeling of the influence of the thickness of the dielectric substrate of a capacitive beating sensor, the electrodes of which are made of foil dielectric type FR4, on the transformation function of the sensor are presented. The studies were performed in the measurement range of the sensor with a change in the thickness of the dielectric selected from a standard line of material sizes. A comparative analysis method for manufacturing capacitive sensors using PCB technology was done. As a result of the analysis, the dependences of the influence of the thickness of the dielectric substrate on the conversion function of the capacitive sensor are obtained. Bibl. 20, fig. 2, table.

Development of measurement methods and dose evaluating algorithms for electronic personal dosimeter

For personal radiation dose monitoring, electronic personal dosimeters (EPD), also known as active personal dosimeter (APD), using silicon diode detector have the advantage capability of measuring and displaying directly the exposure results of gamma, beta and neutron radiations in real time. They are mainly considered as good complement to passive dosimeters to satisfy ALARA principle in the radiation protection. In this paper, the meansurement methods and algorithms for evaluating personal dose equivalents such as Hp(10) and Hp(0.07) from air-kerma are studied and developed in two directions: the first, named energy correction method based on incident energy determined by the ratio of two detector responses with the different filter configurations; the second new method is carried out in the way that matching the shape of a detector’s energy response curve to the kerma-to-personal dose equivalent conversion function provides an approximate means of determining the dose equivalent without the need to resolve the actual incident energies. The algorithm has also been experimentally verified at Secondary Standards Dosimetry Laboratory (SSDL) of INST by the beam of radiation defined in ISO 4037-1. The obtained results of personal dose equivalents with errors almost less than 30% in energy range from 20 keV to 1.5 MeV are partially met the EPD design requirements according to the IEC 61526 Standard. The work and results of described in this paper are important basics for design and construction of completed electronic personal dosimeter.

Average Absorbed Breast Dose (2ABD) to Mean Glandular Dose (MGD) Conversion Function for Digital Breast Tomosynthesis: A New Approach

Background: In this work a new method for the Mean Glandular Dose evaluation in digital breast tomosynthesis (DBT) is presented. Methods: Starting from the experimental-based dosimetric index, 2ABD, which represents the average absorbed breast dose, the mean glandular dose MGD2ABD was calculated using a conversion function of glandularity f(G), obtained through the use of Monte Carlo simulations.Results: f(G) was computed for a 4.5 cm thick breast: from its value MGD2ABD for different compressed breast thicknesses and glandularities was obtained. The comparison between MGD2ABD estimates and the dosimetric index provided in the current dosimetry protocols, following the Dance's approach, MGDDance, showed a good agreement (<10%) for all the analyzed breast thicknesses and glandularities. Conclusion: The strength of the proposed method can be considered an accurate mean glandular dose assessment starting from few and accessible parameters, reported in the header DICOM of each DBT exam.

3D Printed Multifunctional PEEK Bone Scaffold for Multimodal Treatment of Osteosarcoma and Osteomyelitis

<p>In this work, we developed the first 3D PEEK based bone scaffold with multi-functions targeting challenging bone diseases such as osteosarcoma and osteomyelitis. 3D printed PEEK/graphene nanocomposite scaffold was deposited with drug laden (antibiotics and/or anti-cancer drugs) hydroxyapatite coating. The graphene nanosheets within the scaffold served as effective photothermal agents that endowed the scaffold with on-demand photothermal conversion function under NIR laser irradiation. The bioactive hydroxyapatite coating significantly boosted the stem cell proliferation <i>in vitro</i> and promoted the new bone growth <i>in vivo</i>. The presence of antibiotics and anti-cancer drugs enabled eradication of drug resistant bacteria as well as ablation of osteosarcoma cancer cells, the treatment efficacy of which can be further enhanced by the on-demand laser induced heating. The promising results demonstrate the strong potential of our multi-functional scaffold in applications such as bone defect repair as well as multimodal treatment of osteosarcoma and osteomyelitis.</p>

3D Printed Multifunctional PEEK Bone Scaffold for Multimodal Treatment of Osteosarcoma and Osteomyelitis

<p>In this work, we developed the first 3D PEEK based bone scaffold with multi-functions targeting challenging bone diseases such as osteosarcoma and osteomyelitis. 3D printed PEEK/graphene nanocomposite scaffold was deposited with drug laden (antibiotics and/or anti-cancer drugs) hydroxyapatite coating. The graphene nanosheets within the scaffold served as effective photothermal agents that endowed the scaffold with on-demand photothermal conversion function under NIR laser irradiation. The bioactive hydroxyapatite coating significantly boosted the stem cell proliferation <i>in vitro</i> and promoted the new bone growth <i>in vivo</i>. The presence of antibiotics and anti-cancer drugs enabled eradication of drug resistant bacteria as well as ablation of osteosarcoma cancer cells, the treatment efficacy of which can be further enhanced by the on-demand laser induced heating. The promising results demonstrate the strong potential of our multi-functional scaffold in applications such as bone defect repair as well as multimodal treatment of osteosarcoma and osteomyelitis.</p>

STUDY OF A FREQUENCY OUTPUT TEMPERATURE SENSOR BASED ON A QUANTUM HETEROSTRUCTURE WITH A NEGATIVE DIFFERENTIAL RESISTANCE

Physical processes in a quantum two-barrier heterostructure, which is the basis for the development of tunnel-resonant diodes, are considered. These studies have shown that tunnel resonance diodes can be used as temperature sensors with a frequency output signal. The use of devices with negative differential resistance makes it possible to significantly simplify the design of temperature sensors in the entire radio frequency range, at which, depending on the operating modes of the sensor, an output signal can be obtained both in the form of harmonic oscillations and in the form of impulse oscillations of a special form. The study of the characteristics of the sensor is based on the equivalent circuit of the tunnel-resonant diode, which takes into account its capacitive and inductive properties. The current-voltage characteristic of the sensor has a falling section, which is responsible for the appearance of a negative differential resistance in this section. The descending section arises due to a decrease in the current that flows through the double-barrier quantum heterostructure, with an increase in voltage. A decrease in the current occurs due to a decrease in the transparency coefficient of the potential barriers of the heterostructure. A mathematical model of the temperature sensor has been developed, on the basis of which the analytical dependences of the change in the elements of the equivalent circuit of the sensor on temperature, as well as the transformation function and sensitivity, have been determined. It is shown that the main contribution to changes in the conversion function and sensor sensitivity is made by the change in the negative differential resistance with a change in temperature. This, in turn, results in different readings of the instrument’s output frequency. The sensor sensitivity was varied from 480 kHz/0С to 220 kHz/0С in the temperature range from -150 0С to 50 0С.

Assembly of Natively Synthesized Dual Chromophores Into Functional Actinorhodopsin

Microbial rhodopsin is a simple solar energy-capturing molecule compared to the complex photosynthesis apparatus. Light-driven proton pumping across the cell membrane is a crucial mechanism underlying microbial energy production. Actinobacteria is one of the highly abundant bacterial phyla in freshwater habitats, and members of this lineage are considered to boost heterotrophic growth via phototrophy, as indicated by the presence of actino-opsin (ActR) genes in their genome. However, it is difficult to validate their function under laboratory settings because Actinobacteria are not consistently cultivable. Based on the published genome sequence of Candidatus aquiluna sp. strain IMCC13023, actinorhodopsin from the strain (ActR-13023) was isolated and characterized in this study. Notably, ActR-13023 assembled with natively synthesized carotenoid/retinal (used as a dual chromophore) and functioned as a light-driven outward proton pump. The ActR-13023 gene and putative genes involved in the chromophore (retinal/carotenoid) biosynthetic pathway were detected in the genome, indicating the functional expression ActR-13023 under natural conditions for the utilization of solar energy for proton translocation. Heterologous expressed ActR-13023 exhibited maximum absorption at 565 nm with practical proton pumping ability. Purified ActR-13023 could be reconstituted with actinobacterial carotenoids for additional light-harvesting. The existence of actinorhodopsin and its chromophore synthesis machinery in Actinobacteria indicates the inherent photo-energy conversion function of this microorganism. The assembly of ActR-13023 to its synthesized chromophores validated the microbial community’s importance in the energy cycle.