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On the absence of triplet exciton loss pathways in non-fullerene acceptor based organic solar cells
摘要： We investigate the viability of highly efficient organic solar cells (OSCs) based on non-fullerene acceptors (NFA) by taking into consideration efficiency loss channels and stability issues caused by triplet excitons (TE) formation. OSCs based on a blend of the conjugated donor polymer PBDB-T and ITIC as acceptor were fabricated and investigated with electrical, optical and spin-sensitive methods. The spin-Hamiltonian parameters of molecular TEs and charge transfer TEs in ITIC e.g., zero-field splitting and charge distribution, were calculated by Density Functional Theory (DFT) modelling. In addition, the energetic model describing the photophysical processes in the donor-acceptor blend was derived. Spin-sensitive photoluminescence measurements prove the formation of charge transfer (CT) states in the blend and the formation of TEs in the pure materials and the blend. However, no molecular TE signal is observed in the completed devices under working conditions by spin-sensitive electrical measurements. The absence of a molecular triplet state population allows to eliminate a charge carrier loss channel and irreversible photooxidation facilitated by long-lived triplet states. These results correlate well with the high power conversion efficiency of the PBDB-T:ITIC-based OSCs and their high stability.
关键词： triplet excitons,Density Functional Theory,organic solar cells,non-fullerene acceptors,photoluminescence detected magnetic resonance,electrically detected magnetic resonance
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Indoor and Outdoor Test Results for "DUSST", a Low-Cost, Low-Maintenance PV Soiling Sensor
摘要： Pneumatic devices require tight tolerances to keep them leak-free. Specialized companies offer various off-the-shelf devices, while these work well for many applications, there are also situations where custom design and production of pneumatic parts are desired. Cost efficiency, design flexibility, rapid prototyping, and MRI compatibility requirements are reasons why we investigated a method to design and produce different pneumatic devices using a laser cutter from acrylic, acetal, and rubber-like materials. The properties of the developed valves, pneumatic cylinders, and stepper motors were investigated. At 4-bar working pressure, the 4/3-way valves are capable of 5-Hz switching frequency and provide at most 22-L/min airflow. The pneumatic cylinder delivers 48 N of force, the acrylic stepper motor 30 N. The maximum switching frequency over 6-m long transmission lines is 4.5 Hz, using 2-mm tubing. A MRI-compatible robotic biopsy system driven by the pneumatic stepper motors is also demonstrated. We have shown that it is possible to construct pneumatic devices using laser-cutting techniques. This way, plastic MRI-compatible cylinders, stepper motors, and valves can be developed. Provided that a laser-cutting machine is available, the described pneumatic devices can be fabricated within hours at relatively low cost, making it suitable for rapid prototyping applications.
关键词： pneumatic systems,Biopsy,magnetic resonance imaging,medical robotics,pneumatic actuators
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Strong voltage-boost effect in two-step photon-up conversion solar cells
摘要： Single-image super resolution is a process of obtaining a high-resolution image from a set of low-resolution observations by signal processing. While super resolution has been demonstrated to improve image quality in scaled down images in the image domain, its effects on the Fourier-based image acquisition technique, such as MRI, remains unknown. We performed high-resolution ex vivo late gadolinium enhancement (LGE) magnetic resonance imaging (0.4 × 0.4 × 0.4 mm3) in postinfarction swine hearts (n = 24). The swine hearts were divided into the training set (n = 14) and the test set (n = 10), and in all hearts, low-resolution images were simulated from the high-resolution images. In the training set, super-resolution dictionaries with pairs of small matching patches of the high- and low-resolution images were created. In the test set, super resolution recovered high-resolution images from low-resolution images using the dictionaries. The same algorithm was also applied to patient LGE (n = 4) to assess its effects. Compared with interpolated images, super resolution significantly improved basic image quality indices (P < 0.001). Super resolution using Fourier-based zero padding achieved the best image quality. However, the magnitude of improvement was small in images with zero padding. Super resolution substantially improved the spatial resolution of the patient LGE images by sharpening the edges of the heart and the scar. In conclusion, single-image super resolution significantly improves image errors. However, the magnitude of improvement was relatively small in images with Fourier-based zero padding. These findings provide evidence to support its potential use in myocardial scar imaging.
关键词： magnetic resonance imaging,Image processing,image quality,myocardial scar
更新于2025-09-19 17:13:59
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All-in-one theranostic nanoplatform with controlled drug release and activated MRI tracking functions for synergistic NIR-II hyperthermia-chemotherapy of tumors
摘要： Real-time tracking drug release behavior is fundamentally important for avoiding adverse effects or unsuccessful treatment in personalize medical treatment. However, the development of a non-invasive drug reporting platform still remains challenging. Herein the design of a novel synthetic magnetic resonance imaging (MRI) agent for drug release tracking (SMART) is reported, which integrates photothermal core and paramagnetic ion/drug loading shell with a thermal valve in a hybrid structure. Through near-infrared (NIR)-II photothermal effect originating from inner Au-Cu9S5 nanohybrid core, burst release of drugs loaded in the mesoporous silica shell is achieved. The concomitant use of a phase change material not only prevents premature drug release, but also regulates heating effect, keeping local temperature below 45 oC, enabling synergistic chemotherapy and mild hyperthermia in vitro and in vivo. Furthermore, the drug release from SMART facilitates proton accessibility to the paramagnetic ions anchored inside mesopores channels, enhancing longitudinal T1 relaxation rate and displaying positive signal correlation to the amount of released drug, thus allowing non-invasive real-time monitoring of drug release event. The current study highlights the potential of designed MRI nanophores such as SMART for real-time and in-situ monitoring of drug delivery for precision theranostic applications.
关键词： drug delivery,chemotherapy,NIR-II window,magnetic resonance,hyperthermia
更新于2025-09-19 17:13:59
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Her2-Functionalized Gold-Nanoshelled Magnetic Hybrid Nanoparticles: a Theranostic Agent for Dual-Modal Imaging and Photothermal Therapy of Breast Cancer
摘要： Targeted theranostic platform that integrates multi-modal imaging and therapeutic function is emerging as a promising strategy for earlier detection and precise treatment of cancer. Herein, we designed targeted gold-nanoshelled poly (lactic-co-glycolic acid) (PLGA) magnetic hybrid nanoparticles carrying anti-human epidermal growth factor receptor 2 (Her2) antibodies (Her2-GPH NPs) for dual-modal ultrasound (US)/magnetic resonance (MR) imaging and photothermal therapy of breast cancer. The agent was fabricated by coating gold nanoshell around PLGA nanoparticles co-loaded with perfluorooctyl bromide (PFOB) and superparamagnetic iron oxide nanoparticles (SPIOs), followed by conjugating with anti-Her2 antibodies. Cell-targeting studies demonstrated receptor-mediated specific binding of the agent to Her2-positive human breast cancer SKBR3 cells, and its binding rate was significantly higher than that of Her2-negative cells (P < 0.001). In vitro, the agent had capabilities for contrast-enhanced US imaging as well as T2-weighted MR imaging with a relatively high relaxivity (r2 = 441.47 mM?1 s?1). Furthermore, the Her2 functionalization of the agent prominently enhanced the US/MR molecular imaging effect of targeted cells by cell-specific binding. Live/dead cell assay and targeted photothermal cytotoxicity experiments confirmed that Her2-GPH NPs could serve as effective photoabsorbers to specifically induce SKBR3 cell death upon near-infrared laser irradiation. In summary, Her2-GPH NPs were demonstrated to be novel targeted theranostic agents with great potential to facilitate early non-invasive diagnosis and adjuvant therapy of breast cancer.
关键词： Anti-Her2 antibody,Photothermal therapy,Ultrasound imaging,Magnetic resonance imaging,Theranostic agent,Breast cancer
更新于2025-09-16 10:30:52
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Cobalt/Manganese Oxides as Theragnosis Nanoplatforms With Magnetic Resonance/Near-Infrared Imaging for Efficient Photothermal Therapy of Tumors
摘要： The combination of near-infrared (NIR) response and imaging response is a hot research area in which the functions of nanomaterials are maximized. However, the types of such materials reported so far present problems such as requiring complex synthesis. In this study, hydrophilic, porous, and hollow cobalt/manganese oxide (CMO) nanocrystals (NCs) were successfully prepared via a facile and green hydrothermal route. The CMO NCs show strong near-infrared (NIR) absorption, which results from their defect structure due to the coexistence of Co2+ and Co3+ in the as-prepared CMO NCs. Thus, the CMO NCs exhibit excellent photothermal performance, showing photothermal efficiency of up to 43.2%. In addition, the CMO NCs possess good magnetic resonance (MR) imaging performance, with longitudinal relaxivity (r1) of up to 3.48 mM?1 s?1. Finally, for the first time, we prove that the CMO nanocrystals are a promising photothermal agent. Our work provides insights into the application of Mn-based control agents and photothermal agents for photothermal theragnosis therapy.
关键词： cobalt/manganese oxides,photothermal agents,magnetic resonance imaging,photothermal theragnosis therapy,near-infrared absorption
更新于2025-09-16 10:30:52
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Table-top nuclear magnetic resonance system for high-pressure studies with <i>in situ</i> laser heating
摘要： High pressure Nuclear Magnetic Resonance (NMR) is known to reveal the behavior of matter under extreme conditions. However, until now, significant maintenance demands, space requirements, and high costs of superconducting magnets render its application unfeasible for regular modern high pressure laboratories. Here, we present a table-top NMR system based on permanent Halbach magnet arrays with a diameter of 25 cm and height of 4 cm. At the highest field of 1013 mT, 1H-NMR spectra of ice VII have been recorded at 25 GPa and ambient temperature. The table-top NMR system can be used together with double sided laser heating setups. Feasibility of high-pressure high-temperature NMR was demonstrated by collecting 1H-NMR spectra of H2O at 25 GPa and 1063(50) K. The change in the signal intensity in a laser-heated NMR diamond anvil cell has been found to yield a convenient way for temperature measurements.
关键词： diamond anvil cell,laser heating,Halbach magnet,Nuclear Magnetic Resonance,high-pressure
更新于2025-09-16 10:30:52
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[Methods in Molecular Biology] || Multifunctional Magnetic Nanoparticles-Labeled Mesenchymal Stem Cells for Hyperthermia and Bioimaging Applications
摘要： Magnetic nanoparticles have demonstrated considerable capacity for theranosis purposes due to their unique characteristics, including magnetic properties, comparable size to biomolecules, favorable conjugations of drugs and biomolecules, ability to labeling, and capability of sensing, separation, detection, and targeted drug delivery. They could be exploited in magnetic resonance imaging as the contrast agents and also warmed as exposed to an external magnetic AC ?eld that could be applied in hyperthermia. Here, progresses and advances in the strategy and assembly of ?uorescent magnetic nanoparticles are presented for stem cell tracing and drugs/biomolecules targeting into cells.
关键词： Conjugation,Fluorescent probe,Stem cell tracing,Magnetic resonance imaging,Magnetic nanoparticles,Hyperthermia
更新于2025-09-12 10:27:22
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Multiple Iterations of Magnetic Resonance-Guided Laser Interstitial Thermal Ablation of Brain Metastases: Single Surgeon's Experience and Review of the Literature
摘要： BACKGROUND: Prior treatment with magnetic resonance-guided, laser-induced thermal therapy (LITT) is widely assumed not to be a contraindication for further treatment of brain lesions, including further iterations of LITT. However, the safety and efficacy of repeat LITT treatments have never been formally investigated. OBJECTIVE: To evaluate treatment with multiple iterations of LITT. METHODS: All patients treated with LITT at least twice at our institution were included in the study. Outcomes and neurological examinations from before and after surgery were retrospectively examined from clinic notes. Perilesonal edema was determined at various timepoints using volumetric data derived from manual tracings of fluid-attenuated inversion recovery (FLAIR) enhancement on magnetic resonance imaging (MRI). Finally, a literature review of prior cases of repeat LITT was performed. RESULTS: A total of 9 patients underwent 18 treatments with LITT; all but 1 of whom were treated for metastatic brain lesions. One patient had a transient cerebrospinal fluid leak, whereas a second patient had a superficial wound infection, both of which resolved with standard medical care. The remaining 7 patients tolerated all LITT procedures without complication. Analysis of perilesional edema volume demonstrated a correlation with the amount of energy delivered during LITT. Literature review found 5 published papers describing 9 patients who underwent LITT more than once, the majority of whom tolerated repeat LITT well. CONCLUSION: LITT is a safe and promising treatment modality and may be used multiple times without issue. There appears to be an association between the amount of energy delivered during a LITT session and the degree of postoperative perilesional edema.
关键词： Brain tumor,Metastasis,Magnetic resonance laser-induced thermal therapy,Minimally invasive surgery,Tumor recurrence
更新于2025-09-12 10:27:22
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Light-Emitting Diode Photobiomodulation After Cerebral Ischemia
摘要： Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm2) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm2 at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.
关键词： magnetic resonance imaging,intracerebral hemorrhage,photobiomodulation therapy,ischemic stroke,functional recovery,animal model
更新于2025-09-12 10:27:22