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A novel short-term high-lactose culture approach combined with a matrix-assisted laser desorption ionization-time of flight mass spectrometry assay for differentiating Escherichia coli and Shigella species using artificial neural networks
摘要： Background Escherichia coli is currently unable to be reliably differentiated from Shigella species by routine matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. In the present study, a reliable and rapid identification method was established for Escherichia coli and Shigella species based on a short-term high-lactose culture using MALDI-TOF MS and artificial neural networks (ANN). Materials and methods The Escherichia coli and Shigella species colonies, treated with (Condition 1)/without (Condition 2) a short-term culture with an in-house developed high-lactose fluid medium, were prepared for MALDI-TOF MS assays. The MS spectra were acquired in linear positive mode, with a mass range from 2000 to 12000 Da and were then compared to discover new biomarkers for identification. Finally, MS spectra data sets 1 and 2, extracted from the two conditions, were used for ANN training to investigate the benefit on bacterial classification produced by the new biomarkers. Results Twenty-seven characteristic MS peaks from the Escherichia coli and Shigella species were summarized. Seven unreported MS peaks, with m/z 2330.745, m/z 2341.299, m/z 2371.581, m/z 2401.038, m/z 3794.851, m/z 3824.839 and m/z 3852.548, were discovered in only the spectra from the E. coli strains after a short-term high-lactose culture and were identified as belonging to acid shock protein. The prediction accuracies of the ANN models, based on data set 1 and 2, were 97.71±0.16% and 74.39±0.34% (n = 5), with an extremely remarkable difference (p < 0.001), and the areas under the curve of the receiver operating characteristic curve were 0.72 and 0.99, respectively. Conclusions In summary, adding a short-term high-lactose culture approach before the analysis enabled a reliable and easy differentiation of Escherichia coli from the Shigella species using MALDI-TOF MS and ANN.
关键词： MALDI-TOF MS,Escherichia coli,high-lactose culture,artificial neural networks,Shigella species
更新于2025-09-16 10:30:52
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Gold Nanoparticle-Mediated Generation of Reactive Oxygen Species During Plasmonic Photothermal Therapy: A Comparative Study for Different Particles Size, Shape, and Surface Conjugation
摘要： Gold nanoparticles (AuNPs)-mediated photothermal therapy represents an alternative to the effective ablation of cancer cells. However, the photothermal response of AuNPs must be tailored to improve the therapeutic efficacy of plasmonic photothermal therapy (PPT) and mitigate its side effects. This study presents an alternative to ease the tuning of photothermal efficiency and target selectivity. We use laser-treated spherical and anisotropic AuNPs with different sizes and biocompatible folic acid (FA)-conjugated AuNPs (FA-AuNPs) in the well-known human epithelial cervical cancer (HeLa) cell line. We show that large AuNPs produce a more significant photothermal heating effect than small ones. The thermal response of spherical AuNPs of 9 nm was found to reach a maximum increase of 3.0 ± 1 °C, whereas, with spherical AuNPs of 14 nm, the temperature increased by over 4.4 ± 1 °C. Anisotropic AuNPs of 15 nm reached a maximum of 4.0 ± 1 °C, whereas anisotropic AuNPs of 20 nm reached a significant increase of 5.3 ± 1 °C in the cell culture medium (MEM). Notably, anisotropic AuNPs of 20 nm successfully demonstrates the potential for use as a photothermal agent by showing reduced viability down to 60% at a concentration of 100 μM. Besides, we reveal that high concentrations of reactive oxygen species (ROS) are formed within the irradiated cells. It is likely to give rise in combination with stress by photothermal heating, resulting in significant cell death through acute necrosis by compromising the plasma membrane integrity. Cell death and ROS overproduction during PPT were characterized and quantified using transmission electron microscopy (TEM) and confocal fluorescence microscopy with different fluorescent markers. In addition, we show that FA-AuNPs induce cell death through apoptosis by internal damage, whereas diminishing ROS formation during PPT treatment. Our findings suggest the ability of plasmon-mediated ROS to sensitize cancer cells and make them vulnerable to photothermal damage, as well as the protective role of FA-AuNPs from excessive ROS formation, whereas reducing the risk of undesired side effects due to necrotic death pathway. It allows an improvement in the efficacy of AuNP-based photothermal therapy and a reduction in the number of exposures to high temperatures required to induce thermal stress.
关键词： Reactive oxygen species,Laser irradiation,Gold nanoparticles,Folic acid,Photothermal effect
更新于2025-09-16 10:30:52
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<p>The Destruction Of Laser-Induced Phase-Transition Nanoparticles Triggered By Low-Intensity Ultrasound: An Innovative Modality To Enhance The Immunological Treatment Of Ovarian Cancer Cells</p>
摘要： Photodynamic therapy (PDT), sonodynamic therapy (SDT), and oxaliplatin (OXP) can induce immunogenic cell death (ICD) following damage-associated molecular patterns (DAMPs) exposure or release and can be united via the use of nanoplatforms to deliver drugs that can impart anti-tumor effects. The aim of this study was to develop phase-transition nanoparticles (OI_NPs) loaded with perfluoropentane (PFP), indocyanine green (ICG), and oxaliplatin (OXP), to augment anti-tumor efficacy and the immunological effects of chemotherapy, photodynamic therapy and sonodynamic therapy (PSDT).
关键词： photo-sonodynamic therapy,multifunctional nanoparticles,immunogenic cell death,reactive oxygen species,ovarian cancer
更新于2025-09-12 10:27:22
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A Method for Estimating the Functionality of TiO2/Quantum Dot Multilayer Hybrid Structures Based on the Generation of Reactive Oxygen Species
摘要： A new technique for estimating the efficiency of electron transfer from a CdSe/ZnS quantum dot (QD) to TiO2 nanoparticles based on the generation of reactive oxygen species by hybrid structures is presented. It was demonstrated that in the formed multilayer hybrid structures of TiO2/QD, photoinduced electron transfer is realized with an efficiency of 26%.
关键词： hybrid structures,photoinduced electron transfer,semiconductor quantum dots,titanium dioxide nanoparticles,reactive oxygen species
更新于2025-09-12 10:27:22
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Near-infrared boosted ROS responsive siRNA delivery and cancer therapy with sequentially peeled upconversion nano-onions
摘要： RNA interference (RNAi) therapy has become an appealing approach for cancer treatment, while the specificity and efficiency of controlled small interference RNA (siRNA) release remain challenging due to the heterogeneity of tumor environment. Herein, upconversion nano-onions (UCNOs) with stacked polymer coating layers are constructed to decompose sequentially in response to extracellular environment and NIR stimulation. The UCNOs (UCNPs-PEIRB-PEISeSe/siRNA-R8-HA) are composed of upconversion nanoparticles (UCNPs) core functionalized with inner coating layer of photosensitizer rose bengal (RB) conjugated PEI 600, middle coating layer of singlet oxygen (1O2) sensitive diselenide linked PEI 600 with therapeutic siRNA loading and cell-penetrating peptide R8 modification, and outer coating layer of negatively charged hyaluronic acid (HA). HA prevents siRNA leakage during delivery process and specifically targets tumor cells with overexpressed CD44 membrane receptors, and digested by cell secreted hyaluronidase (HAase). Upon the subsequent irradiation at 808 nm, UCNPs core generates emissions around 540 nm, which activate RB to boost ROS generation for complete PEI-SeSe decompose. The NIR boosted decompose of UCNOs induces a fast and efficient siRNA release, which effectively improves the gene silencing efficiency in vitro and suppresses tumor growth in vivo. The proposed sequentially responsive UCNOs have promising potential application in precision medicine.
关键词： Sequential response,siRNA delivery,Upconversion nano-onions (UCNOs),Reactive oxygen species (ROS)
更新于2025-09-12 10:27:22
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Influence of External Input Parameters on Species Production in a Dual-Frequency Capacitively Coupled Radio-frequency Oxygen Plasma
摘要： The impact of some external input parameters on electron, ozone O3, negative O? and positive O2+ ions, metastable singlet delta-state O2(a1Δg) molecule and atomic oxygen O formation is investigated using a numerical simulation. A one-dimensional, self-consistent fluid model of a dual radio-frequency capacitively coupled discharge operating on pure oxygen is developed to explore the evolution of the species density profiles as functions of gas pressure pg, driving high-frequency fhf, inter-electrode gap distance d and driving voltage waveform Vhf. The proposed model incorporates five main species and 24 dominant reaction channels. Simulation results show that the time-averaged density profiles of electron, ozone O3, negative O? and positive O2+ ions decrease when the gas pressure increases. However, the density of the metastable singlet delta-state O2(a1Δg) molecule and atomic oxygen O increase when the gas pressure increases. The electron density significantly increases with increased fhf until a maximum peak is reached at 40.68 MHz, and then it drops almost linearly at frequencies greater than 40.68 MHz. However, the negative ions O? density increases over a range of frequencies from 27.12 to 67.80 MHz, then it decreases slightly as fhf increases further. Therefore, when fhf increases, it does enhance the production of the metastable O2(a1Δg) and the oxygen O atoms, whereas the O2+ density is decreased. It is also shown that an increase in the inter-electrode gap distance causes a noticeably decrease in the formation of the various species in the discharge. Furthermore, a significant increase in the atomic oxygen O and the metastable singlet delta-state O2(a1Δg) densities is displayed as Vhf increases. Comparisons are made with recent simulation models and experimental data, and a qualitative agreement is obtained.
关键词： Low-temperature plasma,Dual capacitively coupled oxygen plasma,Species production
更新于2025-09-12 10:27:22
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A protocol for laser microdissection (LMD) followed by transcriptome analysis of plant reproductive tissue in phylogenetically distant angiosperms
摘要： Background: Plant development is controlled by the action of many, often connected gene regulatory networks. Differential gene expression controlled by internal and external cues is a major driver of growth and time specific differentiation in plants. Transcriptome analysis is the state-of-the-art method to detect spatio-temporal changes in gene expression during development. Monitoring changes in gene expression at early stages or in small plant organs and tissues requires an accurate technique of tissue isolation, which subsequently results in RNA of sufficient quality and quantity. Laser-microdissection enables such accurate dissection and collection of desired tissue from sectioned material at a microscopic level for RNA extraction and subsequent downstream analyses, such as transcriptome, proteome, genome or miRNA. Results: A protocol for laser-microdissection, RNA extraction and RNA-seq was optimized and verified for three distant angiosperm species: Arabidopsis thaliana (Brassicaceae), Oryza sativa (Poaceae) and Eschscholzia californica (Papaveraceae). Previously published protocols were improved in processing speed by reducing the vacuum intensity and incubation time during tissue fixation and incubation time and cryoprotection and by applying adhesive tape. The sample preparation and sectioning of complex and heterogenous flowers produced adequate histological quality and subsequent RNA extraction from micro-dissected gynoecia reliably generated samples of sufficient quality and quantity on all species for RNA-seq. Expression analysis of growth stage specific A. thaliana and O. sativa transcriptomes showed distinct patterns of expression of chromatin remodelers on different time points of gynoecium morphogenesis from the initiation of development to post-meiotic stages. Conclusion: Here we describe a protocol for plant tissue preparation, cryoprotection, cryo-sectioning, laser microdissection and RNA sample preparation for Illumina sequencing of complex plant organs from three phyletically distant plant species. We are confident that this approach is widely applicable to other plant species to enable transcriptome analysis with high spatial resolution in non-model plant species. The protocol is rapid, produces high quality sections of complex organs and results in RNA of adequate quality well suited for RNA-seq approaches. We provide detailed description of each stage of sample preparation with the quality and quantity measurements as well as an analysis of generated transcriptomes.
关键词： Non-model species,Cryosectioning,Evo-devo,Development,RNA-seq,Laser microdissection (LMD)
更新于2025-09-12 10:27:22
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Study on the oxidation and release of gases in spontaneous coal combustion using a dual-species sensor employing laser absorption spectroscopy
摘要： Coal spontaneous combustion (CSC) is a common hazard in coal mines and a significant reason for the loss of coal in stockpiles and mines. To investigate the oxidation and release of gas due to of CSC, a miniature purpose-built laser-based sensor system capable of precise gas measurement and data processing was configured. A distributed feedback (DFB) diode laser with a central wavelength of 2.33 μm, in conjunction with a Herriot-type cell and wavelength modulation spectroscopy (WMS), was used for the simultaneous detection of methane (CH4) and carbon monoxide (CO) during coal combustion. The second-harmonic of WMS was applied to ensure sensor robustness and sensitivity with long-term performance for the system being evaluated by calculating the Allan-Werle deviations for the concentrations of CH4 and CO. The limits of detection (LoDs) for CH4 and CO were 0.05 ppm based on integration times of 120 s and 70 s, respectively. The dual-species sensor was employed for real-time and in situ investigations of coal samples for temperatures ranging from 85 °C to 200 °C and was considered suitable for integration into field monitoring equipment, especially for online early warning forecasting applications in CSC.
关键词： Wavelength modulation spectroscopy,Spontaneous coal combustion,Chemical inhibitor,Laser-based dual-species sensor,Self-heating oxidation
更新于2025-09-12 10:27:22
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Infrared photodissociation spectroscopy of di-manganese oxide cluster cations
摘要： Infrared multiple-photon dissociation (IR-MPD) spectroscopy and density functional calculations have been employed to elucidate the geometric structure of a series of di-manganese oxide clusters Mn2Ox+ (x = 4–7). The theoretical exploration predicts that all investigated clusters contain a rhombus-like Mn2O2 core with up to four, terminally bound, oxygen atoms. The short Mn–O bond length of the terminal oxygen atoms of ～1.58 ? indicates triple bond character instead of oxyl radical formation. However, the IR-MPD spectra reveal that higher energy isomers with up to two O2 molecules η2-coordinated to the cluster core can be kinetically trapped under the given experimental conditions. In these complexes, all O2 units are activated to superoxide species. The sequential increase of the oxygen content in the cluster allows for a controlled increase of the positive charge localized on the Mn atoms reaching a maximum for Mn2O7+.
关键词： superoxide species,density functional theory,di-manganese oxide cluster cations,IR-MPD spectroscopy,Infrared photodissociation spectroscopy
更新于2025-09-12 10:27:22
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Determination of copper-based mineral species by laser induced breakdown spectroscopy and chemometric methods
摘要： The direct identification of mineral species in raw rocks was performed using laser induced breakdown spectroscopy (LIBS). A total of 162 sulfide rocks with mineralogical relevance in the copper industry were analyzed. These contained bornite (Cu5FeS4), chalcocite (Cu2S), chalcopyrite (CuFeS2), covellite (CuS), enargite (Cu3AsS4), molybdenite (MoS2), and pyrite (FeS2). The samples were collected from different mining locations to account for sample variability. Unsupervised multivariate methods like principal component analysis (PCA) and dendrogram analysis were explored, while supervised pattern recognition techniques, such as soft independent modelling of class analogy (SIMCA), partial least squares discriminant analysis (PLS-DA), K-nearest neighbor (KNN), decision tree analysis and artificial neural networks (ANNs) were compared. The sensitivity test performed on the LIBS data shows that the models KNN, SIMCA, PLS-DA and ANN achieve an average classification accuracy of 96.2, 98.1, 90.6 and 100%, respectively. In contrast, the robustness test of the models SIMCA and PLS-DA yields accuracies of 97.7 and 98.8%, respectively. The correct identification of very similar species in terms of their elemental composition such as bornite/chalcopyrite and chalcocite/covellite is also achieved.
关键词： mineral species,chemometrics,Laser induced breakdown spectroscopy,LIBS,multivariate methods,copper industry,pattern recognition
更新于2025-09-12 10:27:22