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Objective To determine the effects of ultrasound stimulated microbubble (USMB) by different ultrasound combinations of pulse length (PL) and pulse repetition frequency (PRF) under fixed mechanical index and duty cycle on tumor perfusion and drug delivery in C57BL/6 mice. Methods Twenty-four female C57BL/6 mice (6~8 weeks old, average body weight 17.74±0.43 g) were randomly divided into 3 groups (n=8): control group (group A), DOX+PL3.0+PRF2000 group (group B) and DOX+PL30.5+PRF200 group (group C) after being carried with MC38 xenograft tumor. Contrast-enhanced ultrasound (CEUS) was performed before and after USMB treatment to compare the peak intensity (PI), area under the curve (AUC) and tumor perfusion percentage. Doxorubicin (DOX) was injected slowly after USMB treatment, and then the concentration of DOX in the tumor was detected with high-performance liquid chromatography (HPLC). Microstructure of the tumor was observed pathologically. Results The values of PI and AUC after treatment had no significant differences when compared with those before treatment in group A (P>0.05), the values were increased by 19.3% and 18.0%, respectively in group B (P0.05), and the area increased by 21.0% in group B (P0.05). The pathological results showed that the tumor microvessels in group A and B were slightly and moderately dilated, while those in group C were ruptured and bleeding. Conclusion Under the fixed mechanical index and duty cycle, USMB with higher PRF and lower PL can enhance tumor blood perfusion and promote drug delivery. However, higher PL and lower PRF can block tumor blood perfusion.

Accurate measurement of thermal properties in thin films is crucial for optimizing devices and deepening our understanding of heat transfer at nano and micro scales. This study presents a combined experimental and computational investigation on a chip-integrated technique for the assessment of in-plane thermal properties of thin films. This method stands out by incorporating inherent error cancelation to lessen the impact of radiative heat loss and allows simultaneous, independent determination of both thermal conductivity and diffusivity through straightforward linear fittings from the same dataset, reducing error propagation. We examine an 84 nm thick SiNx membrane over a temperature range from 100 K to nearly 500 K, aligning with previous studies. Further investigations into a conducting polymer film post-doping demonstrate a notable increase in both thermal conductivity and diffusivity, corroborating scanning thermal microscopy observations, confirming the technique's efficacy and reliability. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the appropriate combination of pulse length (PL) and pulse repetition frequency (PRF) when performing ultrasound stimulated microbubble (USMB) to enhance doxorubicin (DOX) delivery to tumors. Methods: A total of 48 tumor‐bearing mice were divided into four groups, namely groups A–D. The mice in groups B–D were treated with chemotherapy and USMB treatment with different combinations of PL and PRF, and group A was control. Contrast‐enhanced ultrasound imaging was conducted to analyze tumor blood perfusion. Fluorescence microscopy and high‐performance liquid chromatography were used to qualitatively and quantitatively analyse DOX release. The structural changes of tumors were observed under light microscope and transmission electron microscope. Furthermore, another 24 tumor‐bearing mice were treated with sonochemotherapy and some related inflammatory factors were measured to explore the underlying mechanism. Results: With PL of three cycles and PRF of 2 kHz, the tumor perfusion area ratio increased by 26.67%, and the DOX concentration was 4.69 times higher than the control (P <.001). With PL of 34.5 cycles and PRF of 200 Hz, the tumor perfusion area ratio decreased by 12.7% and DOX did not exhibit increased extravasation compared with the control. Microvascular rupture and hemorrhage were observed after long PL and low PRF treatment. While vasodilation and higher levels of some vasodilator inflammatory factors were found after treatment with short PL and high PRF. Conclusions: USMB treatment using short PL and high PRF could enhance tumor blood perfusion and increase DOX delivery, whereas long PL and low PRF could not serve the same purpose. [ABSTRACT FROM AUTHOR]

π‐Conjugated polymers can be manipulated at the molecular and thin‐film levels to strengthen thermoelectric performance. Herein, two distinctive polymers—PBDP‐T and PBDB‐T with respective outstanding Seebeck coefficient (S) and electrical conductivity (σ) are selected and their functional units are integrated to synthesize random terpolymers via the ′backbone sequence′ strategy. The resulting disordered π‐backbones of terpolymers however lead to an unsuccessful acquisition of high power factor (PF). Alternately, the ′film sequence′ strategy is utilized and representative high‐σ P2F and high‐S PTB7‐Th polymers are blended. Note that 3D conductive paths are generated in the blend films when the PTB7‐Th content falls between 35–80 wt%, which favors charge transportation and yields high σ. At an optimal 65 wt% PTB7‐Th, a maximum PF of 145.5 µW m−1 K−2 is obtained, far surpassing that of each parent polymer, which marks a breakthrough of the ′two‐phase combination′ rule. The peak PF achieved in medium PTB7‐Th content is attributed to the coexistence of bilayered and mixed morphologies, the former of which delivers slowly declining σ while the latter results in greatly elevated S with increasing PTB7‐Th. Given the notably lower thermal conductivity acquired in blend than neat polymers, the room‐temperature thermoelectric figure‐of‐merit as high as 0.15 is achieved. [ABSTRACT FROM AUTHOR]

As the worldwide energy crisis is worsened, thermoelectric materials that can harvest low‐grade waste heat and directly convert it into electricity provide promising alternative energy sources. Emerging ionic thermoelectrics (iTEs) have recently attracted widespread attention thanks to their impressively high thermopower that can reach hundreds of times more than conventional electronic thermoelectrics (eTEs). Based on the Soret effect, the performances of iTEs depend on the thermo‐diffusion of mobile ions in electrolytes, resulting in electrical characteristics distinct from eTE materials and opening up additional potential applications of thermoelectrics. Among these materials, organics‐based iTEs (i‐OTEs) provide unique advantages such as low‐cost, light‐weight, and eco‐friendliness, thereby offering more promising application scenarios that can utilize dissipated heat, for example, from human bodies or mobile devices. This concise review begins with the comparison of iTE and eTE, and then discusses their different mechanisms and applied devices in detail. Next, the recent advances of i‐OTEs will be in‐depth highlighted, including the merits and weaknesses of representative types of materials, effects of additives, and effective strategies for performance optimization. Finally, the state‐of‐the‐art achievements of i‐OTEs are summarized, and an overview is provided of the existing challenges and an outlook of prospective development and applications in future efforts. [ABSTRACT FROM AUTHOR]

π‐Conjugated donor (D)−acceptor (A) copolymers have been extensively studied as organic photovoltaic (OPV) donors yet remain largely unexplored in organic thermoelectrics (OTEs) despite their outstanding mechanical bendability, solution processability and flexible molecular design. Importantly, they feature high Seebeck coefficient (S) that are desirable in room‐temperature wearable application scenarios under small temperature gradients. In this work, the authors have systematically investigated a series of D−A semiconducting copolymers possessing various electron‐deficient A‐units (e.g., BDD, TT, DPP) towards efficient OTEs. Upon p‐type ferric chloride (FeCl3) doping, the relationship between the thermoelectric characteristics and the electron‐withdrawing ability of A‐unit is largely elucidated. It is revealed that a strong D−A nature tends to induce an energetic disorder along the π‐backbone, leading to an enlarged separation of the transport and Fermi levels, and consequently an increase of S. Meanwhile, the highly electron‐deficient A‐unit would impair electron transfer from D‐unit to p‐type dopants, thus decreasing the doping efficiency and electrical conductivity (σ). Ultimately, the peak power factor (PF) at room‐temperature is obtained as high as 105.5 µW m−1 K−2 with an outstanding S of 247 µV K−1 in a paradigm OPV donor PBDB‐T, which holds great potential in wearable electronics driven by a small temperature gradient. [ABSTRACT FROM AUTHOR]

Many studies have shown that tumor cells that survive radiotherapy are more likely to metastasize, but the underlying mechanism remains unclear. Here we aimed to identify epithelial-mesenchymal transition (EMT)-related key genes, which associated with prognosis and radiosensitivity in rectal cancer. First, we obtained differentially expressed genes by analyzing the RNA expression profiles of rectal cancer retrieved from The Cancer Genome Atlas database, EMT-related genes, and radiotherapy-related databases, respectively. Then, Lasso and Cox regression analyses were used to establish an EMT-related prognosis model (EMTPM) based on the identified independent protective factor Fibulin5 (FBLN5) and independent risk gene EHMT2. The high-EMTPM group exhibited significantly poorer prognosis. Then, we evaluated the signature in an external clinical validation cohort. Through in vivo experiments, we further demonstrated that EMTPM effectively distinguishes radioresistant from radiosensitive patients with rectal cancer. Moreover, individuals in the high-EMTPM group showed increased expression of immune checkpoints compared to their counterparts. Finally, pan-cancer analysis of the EMTPM model also indicated its potential for predicting the prognosis of lung squamous cell carcinoma and breast cancer patients undergoing radiotherapy. In summary, we established a novel predictive model for rectal cancer prognosis and radioresistance based on FBLN5 and EHMT2 expressions, and suggested that immune microenvironment may be involved in the process of radioresistance. This predictive model could be used to select management strategies for rectal cancer., (© 2024 Wiley Periodicals LLC.)

In this work, the combination of cold rolling with post-aging treatment is developed to achieve the optimal strength-ductility for the in situ nano TiB 2 /Al-Cu-Mg composite. The microstructure and mechanical properties of the composite subjected to 20% thickness reduction of cold rolling at room temperature and their evolutions upon post-aging at different temperatures were investigated by means of a tensile test, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. It was found that the TiB 2 particles were effective in dislocation pinning and accumulation during the cold-rolling process. The tensile tests indicated that both the yield and ultimate tensile strengths of the cold-rolling sample increased a lot due to the dislocation strengthening and precipitation strengthening generated by dynamic precipitation during cold rolling in comparison with the conventional T6 sample. After aging at 100 °C/12 h, the elongation to failure reached ~8.4%, which was higher than the conventional T6 sample. Meanwhile, there was also a dramatic increase of strength. The yield and ultimate tensile strengths are ~644 MPa and ~726 MPa, respectively. This remarkable strength-ductility combination was due to the modified microstructure caused prior to artificial aging by the cold-rolling method and the formation of nanosized Guinier-Preston-Bagaryatsky (GPB) zones. The underlying mechanisms related to the superior strength-ductility combination were discussed regarding the microstructural characteristics in the composite.