Enhanced Photoactivity on Ag/Ag3PO4 Composites by Plasmonic Effect

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Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology

Purpose: Microbeam radiation therapy (MRT) is an experimental radiotherapy technique that has shown potent antitumor effects with minimal damage to normal tissue in animal studies. This unique form of radiation is currently only produced in a few large synchrotron accelerator research facilities in the world. To promote widespread translational research on this promising treatment technology we have proposed and are in the initial development stages of a compact MRT system that is based on carbon nanotube field emission x-ray technology. We report on a Monte Carlo based feasibility study of the compact MRT system design

Photocatalytic decomposition of 4-t-octylphenol over NaBiO 3 driven by visible light: Catalytic kinetics and corrosion products characterization

The photocatalytic decomposition of 4-t-octylphenol (4-t-OP) by NaBiO 3 photocatalyst and the catalyst stability in aqueous solution were investigated systematically for the first time. The results showed that some parameters such as catalyst dosage, initial 4-t-OP concentration and pH value of the solution had great effects on the photocatalytic activity. The NaBiO 3 photocatalyst maintained considerable catalytic performance under visible light (λ > 400 nm) irradiation and exhibited a higher photocatalytic activity compared to the commercialized photocatalyst P25. In addition, the corrosion products of NaBiO 3 catalyst under acid condition (HCl aqueous solution contained) were characterized by X-ray diffraction (XRD), transmittance electronic microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and UV-vis transmittance spectrum analysis. The results showed that NaBiO 3 was unstable under the acidic condition and the catalyst could convert into Bi 3+-containing compounds such as Bi 2O 3, etc. The experiment demonstrates that NaBiO 3 can be corroded to nano-sized BiOCl crystal in the presence of hydrogen chloride, the band gap of which was estimated to be 3.28 eV by Tauc's approach. © 2009 Elsevier B.V. All rights reserved.postprin

Early Assessment of Tumor Response to Radiation Therapy using High-Resolution Quantitative Microvascular Ultrasound Imaging

Measuring changes in tumor volume using anatomical imaging weeks to months post radiation therapy (RT) is currently the clinical standard for indicating treatment response to RT. For patients whose tumors do not respond successfully to treatment, this approach is suboptimal as timely modification of the treatment approach may lead to better clinical outcomes. We propose to use tumor microvasculature as a biomarker for early assessment of tumor response to RT. Acoustic angiography is a novel contrast ultrasound imaging technique that enables high-resolution microvascular imaging and has been shown to detect changes in microvascular structure due to cancer growth. Data suggest that acoustic angiography can detect longitudinal changes in the tumor microvascular environment that correlate with RT response

BiOX (X = Cl, Br, I) photocatalysts prepared using NaBiO 3 as the Bi source: Characterization and catalytic performance

The Bismuth oxyhalides, crystalline BiOX (X = Cl, Br, I) were prepared via a facile method, using NaBiO 3 and HX aqueous solutions as the raw materials for the first time. The systematic microstructure and optical property characterizations of the BiOX photocatalysts demonstrated the reliability of this new and facile preparation approach. The photocatalytic activity on the degradation of typical phenolic endocrine disrupting chemicals over BiOX and P25 were evaluated under Xenon-light irradiation and the initial photocatalytic mechanism was discussed based on the band edge potential analysis. © 2009.postprin

Direct aperture optimization using an inverse form of back-projection

Direct aperture optimization (DAO) has been used to produce high dosimetric quality intensity-modulated radiotherapy (IMRT) treatment plans with fast treatment delivery by directly modeling the multileaf collimator segment shapes and weights. To improve plan quality and reduce treatment time for our in-house treatment planning system, we implemented a new DAO approach without using a global objective function (GFO). An index concept is introduced as an inverse form of back-projection used in the CT multiplicative algebraic reconstruction technique (MART). The index, introduced for IMRT optimization in this work, is analogous to the multiplicand in MART. The index is defined as the ratio of the optima over the current. It is assigned to each voxel and beamlet to optimize the fluence map. The indices for beamlets and segments are used to optimize multileaf collimator (MLC) segment shapes and segment weights, respectively. Preliminary data show that without sacrificing dosimetric quality, the implementation of the DAO reduced average IMRT treatment time from 13 min to 8 min for the prostate, and from 15 min to 9 min for the head and neck using our in-house treatment planning system PlanUNC. The DAO approach has also shown promise in optimizing rotational IMRT with burst mode in a head and neck test case

Radiation Sensitivity in a Preclinical Mouse Model of Medulloblastoma Relies on the Function of the Intrinsic Apoptotic Pathway

While treatments that induce DNA damage are commonly used as anti-cancer therapies, the mechanisms through which DNA damage produces a therapeutic response are incompletely understood. Here we have tested whether medulloblastomas must be competent for apoptosis to be sensitive to radiation therapy. Whether apoptosis is required for radiation sensitivity has been controversial. Medulloblastoma, the most common malignant brain tumor in children, is a biologically heterogeneous set of tumors typically sensitive to radiation and chemotherapy; 80% of medulloblastoma patients survive long-term after treatment. We used functional genetic studies to determine if the intrinsic apoptotic pathway is required for radiation to produce a therapeutic response in mice with primary, Shh-driven medulloblastoma. We found that cranial radiation extended the survival of medulloblastoma-bearing mice and induced widespread apoptosis. Expression analysis and conditional deletion studies showed that p53 was the predominant transcriptional regulator activated by radiation and was strictly required for treatment response. Deletion of Bax, which blocked apoptosis downstream of p53, was sufficient to render tumors radiation resistant. In apoptosis-incompetent, Bax-deleted tumors, radiation activated p53-dependent transcription without provoking cell death and caused two discrete populations to emerge. Most radiated tumor cells underwent terminal differentiation. Perivascular cells, however, quickly resumed proliferation despite p53 activation, behaved as stem cells, and rapidly drove recurrence. These data show that radiation must induce apoptosis in tumor stem cells to be effective. Mutations that disable the intrinsic apoptotic pathways are sufficient to impart radiation resistance. We suggest that medulloblastomas are typically sensitive to DNA-damaging therapies because they retain apoptosis competence

Epidemiology, causes, clinical manifestation and diagnosis, prevention and control of coronavirus disease (COVID-19) during the early outbreak period

__Background:__ The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 31 January 2020, this epidemic had spread to 19 countries with 11 791 confirmed cases, including 213 deaths. The World Health Organization has declared it a Public Health Emergency of International Concern. __Methods:__ A scoping review was conducted following the methodological framework suggested by Arksey and O'Malley. In this scoping review, 65 research articles published before 31 January 2020 were analyzed and discussed to better understand the epidemiology, causes, clinical diagnosis, prevention and control of this virus. The research domains, dates of publication, journal language, authors' affiliations, and methodological characteristics were included in the analysis. All the findings and statements in this review regarding the outbreak are based on published information as listed in the references. __Results:__ Most of the publications were written using the English language (89.2%). The largest proportion of published articles were related to causes (38.5%) and a majority (67.7%) were published by Chinese scholars. Research articles initially focused on causes, but over time there was an increase of the articles related to prevention and control. Studies thus far have shown that the virus' origination is in connection to a seafood market in Wuhan, but specific animal associations have not been confirmed. Reported symptoms include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. Preventive measures such as masks, hand hygiene practices, avoidance of public contact, case detection, contact tracing, and quarantines have been discussed as

Cryptococcus neoformans induces IL-8 secretion and CXCL1 expression by human bronchial epithelial cells

<p>Abstract</p> <p>Background</p> <p><it>Cryptococcus neoformans </it>(<it>C. neoformans</it>) is a globally distributed fungal pathogen with the potential to cause serious disease, particularly among immune compromised hosts. Exposure to this organism is believed to occur by inhalation and may result in pneumonia and/or disseminated infection of the brain as well as other organs. Little is known about the role of airway epithelial cells in cryptococcal recognition or their ability to induce an inflammatory response.</p> <p>Methods</p> <p>Immortalized BEAS-2B bronchial epithelial cells and primary normal human bronchial epithelium (NHBE) were stimulated <it>in vitro </it>with encapsulated or acapsular <it>C. neoformans </it>cultivated at room temperature or 37°C. Activation of bronchial epithelial cells was characterized by analysis of inflammatory cytokine and chemokine expression, transcription factor activation, fungal-host cell association, and host cell damage.</p> <p>Results</p> <p>Viable <it>C. neoformans </it>is a strong activator of BEAS-2B cells, resulting in the production of the neutrophil chemokine Interleukin (IL)-8 in a time- and dose-dependent manner. IL-8 production was observed only in response to acapsular <it>C. neoformans </it>that was grown at 37°C. <it>C. neoformans </it>was also able to induce the expression of the chemokine CXCL1 and the transcription factor CAAT/enhancer-binding protein beta (CEBP/β) in BEAS-2B cells. NHBE was highly responsive to stimulation with <it>C. neoformans</it>; in addition to transcriptional up regulation of CXCL1, these primary cells exhibited the greatest IL-8 secretion and cell damage in response to stimulation with an acapsular strain of <it>C. neoformans</it>.</p> <p>Conclusion</p> <p>This study demonstrates that human bronchial epithelial cells mediate an acute inflammatory response to <it>C. neoformans </it>and are susceptible to damage by this fungal pathogen. The presence of capsular polysaccharide and <it>in vitro </it>fungal culture conditions modulate the host inflammatory response to <it>C. neoformans</it>. Human bronchial epithelial cells are likely to contribute to the initial stages of pulmonary host defense <it>in vivo</it>.</p

MicroRNA-211 Expression Promotes Colorectal Cancer Cell Growth In Vitro and In Vivo by Targeting Tumor Suppressor CHD5

Background: Chromodomain-helicase-DNA-binding protein 5 (CHD5) is a newly identified tumor suppressor that is frequently downregulated in a variety of human cancers. Our previous work revealed that the low expression of CHD5 in colorectal cancer is correlated with CHD5 promoter CpG island hypermethylation. In this study, we investigated the effect of microRNA-211 (miR-211)-regulated CHD5 expression on colorectal tumorigenesis. Methodology/Principal Findings: miR-211 was predicted to target CHD5 by TargetScan software analysis. A stably expressing exogenous miR-211 colorectal cancer cell line (HCT-116 miR-211) was generated using lentiviral transduction and used as a model for in vitro and in vivo studies. The expression level of miR-211 in HCT-116 miR-211 cells was upregulated by 16-fold compared to vector control cells (HCT-116 vector). Exogenous miR-211 directly binds to the 39-untranslated region (39-UTR) of CHD5 mRNA, resulting in a 50 % decrease in CHD5 protein level in HCT-116 miR-211 cells. The levels of cell proliferation, tumor growth, and cell migration of HCT-116 miR-211 cells were significantly higher than HCT-116 vector cells under both in vitro and in vivo conditions, as determined using the methods of MTT, colony formation, flow cytometry, scratch assay, and tumor xenografts, respectively. In addition, we found that enforced expression of miR-211 in HCT-116 cells was able to alter p53 pathway-associated regulatory proteins, such as MDM2, Bcl-2, Bcl-xL, and Bax. Conclusion/Significance: Our results demonstrate that CHD5 is a direct target of miR-211 regulation. Enforced expression o