Effective Energy Transfer Research Articles

A multifunctional and water-stable Cd (II) coordination polymer: Sensitive detection of roxarsone, Fe3+, CrO42− and Cr2O72− in aqueous media

A two-dimensional (2D) water-stable Cd (II) luminescent coordination polymer (1), namely {[CdLCl2]}n, was obtained through assembly of a new 2-deoxy-d-ribose derivative ligand (L) with CdCl2, 1 showed high stability in water. Further investigation showed that 1 can be used as luminescent probe for the organoarsenic compound Roxarsine (ROX) with high selectivity and sensitivity, high quenching constants (KSV = 2.34 × 104 M−1), low limits of detection (LOD) (0.16 μM) and good recyclability in aqueous media. In addition, this luminescent probe can detect some inorganic harmful ions (Fe3+, Cr2O72− and CrO42−) with excellent versatility. The detection mechanism was proved that the quenching was caused by competitive absorption and resonance energy transfer effect between 1 and analytes. More strikingly, a simple 1-based test strip was developed owing to the quick response and recyclability of 1, which shows visible quenching signals under UV light even when analytes concentrations are as low as 5 μM. This work has provided an effective method for the design of multifunctional CP luminescent sensors for pollutants detections in aqueous media.

Phase transition and luminescence characteristics of dysprosium doped strontium stannate phosphor synthesized using hydrothermal method

A series of strontium stannate (SrSnO3) doped with Dy3+ ions at various wt % concentrations (1, 2, 3 and 5) were synthesized via hydrothermal reaction and analysed using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), environmental electron scanning microscope (ESEM), photoluminescence (PL) and, cathodoluminescence (CL). The XRD results confirmed that all samples were assigned to cubic perovskite-type SrSnO3 structured with the Pm3m‾ space group. The PL emission spectrum of Dy3+ activated samples consisted of some characteristic peaks located at 481 nm, 572 nm, 660 nm and 753 nm, corresponding to (4F9/2 → 6H15/2, blue), (4F9/2 → 6H13/2, yellow), 660 nm (4F9/2 → 6H11/2, red) and 753 nm (4F9/2 → 6H9/2, red) transitions. The PL emission line intensity is gradually enhanced with an increase in doping concentration up to 3 wt %, followed by concentration quenching. The confinement effects of localized resonant energy transfer might cause higher concentration quenching. PL emission spectra were affected by the temperature range from 10 K to 300 K. PL emission anomalies at 270 K in SrSnO3:Dy3+ have been reported to be consistent with a structural phase transition at this temperature. This work confirms Singh et al.'s observation, revealing that SrSnO3 has a phase transition at 270 K.

Applications for data security and latent fingerprint visualization using blue-emitting surface-modified LZO:Ce3+ nanophosphor

The development of technology related to forensic is still beneficial and requires for continued research and the implementation of evaluation procedures. In this context, the current work focuses on the production of blue light emitting La2Zr2O7 nanophosphors (LZO) (NPs) doped with Ce3+ ions and surface modified with oleyl amine (OA) are employed for data security and latent fingerprint imaging applications. The formation of the pure pyrochlore phase is confirmed from powder X-ray diffraction (PXRD). The structural analysis is performed from Rietveld refinement . Scanning electron microscope (SEM) and transmission electron microscopy are used to study the surface morphology and crystallite size estimation respectively. Photoluminescence (PL) emission spectra exhibit all the characteristic emission peaks of Ce3+ ions. The surface modified NPs by OA exhibited 2-fold enhancement in the emission intensity as compared to unmodified NPs, which is due to effective intramolecular energy transfers from coordinated ligands to the activated Ce3+ ions, called the antenna effect. The most trustworthy proof of a person's identity can be found in the ridge characteristics revealed by the observed latent fingerprints employing surface modified nanophosphor. The chemical bonding between the nanophosphor and chemical components contained in the fingerprints, which enables the majority of authenticated sweat pores, further confirmed by high resolution photographs of formed latent fingerprints. The NPs which have OA grafted onto them can be made into security ink that can be used to create hidden inscriptions with a basic brush technique as well as screen print and decoded under 283 nm light illumination. The features of the NPs, which is a real-time option for latent fingerprint formation and anti-counterfeiting technologies are significantly improved by the surface modification technique .

Glutathione Fluorescence Sensing Based on a Co-Doped Carbon Dot/Manganese Dioxide Nanocoral Composite

Glutathione (GSH) is an antioxidant thiol that has a vital role in the pathogenesis of various human diseases such as cardiovascular disease and cancer. Hence, it is necessary to study effective methods of GSH evaluation. In our work, an effective GSH sensor based on a nitrogen and phosphorus co-doped carbon dot (NPCD)-MnO2 nanocoral composite was fabricated. In addition to utilizing the strong fluorescence of the NPCDs, we utilized the reductant ability of the NPCDs themselves to form MnO2 and then the NPCD-MnO2 nanocoral composite from MnO4-. The characteristics of the nanocoral composite were analyzed using various electron microscopy techniques and spectroscopic techniques. The overlap between the absorption spectrum of MnO2 and the fluorescence emission spectrum of the NPCDs led to effective fluorescence resonance energy transfer (FRET) in the nanocoral composite, causing a decrease in the fluorescent intensity of the NPCDs. A linear recovery of the fluorescent intensity of the NPCDs was observed with the GSH level raising from 20 to 250 µM. Moreover, our GSH sensor showed high specificity and sensing potential in real samples with acceptable results.

Synthesis, crystal structure of four 1D to 3D coordination polymers as potential sensor for the detection of ions, antibiotics and pesticides in water media

A series of four 1D to 3D coordination polymers (CPs), namely: [Zn(DTP)SO4(H2O)3]n (CP-1), (DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine); [Co(DTP)2(NO3)2(H2O)2]n (CP-2); [Cu2(DTP)2Cl4(H2O)]n (CP-3) and [Cu4(DTP)2(H2PO4)2(HPO4)3(H2O)]n (CP-4), were synthesized from the reaction of Zn(II), Co(II), Cu(II) ions with the DTP ligand under solvothermal conditions. Structural information on the CPs was obtained from single crystal X-ray diffraction analysis, together with the additional characterization methods of elemental analysis, IR spectroscopy and thermogravimetric analysis (TGA), which were also employed to confirm the purity of the products. In addition, the fluorescence properties of CP-1 were further evaluated and used in a process for the fluorescent sensing of ions, antibiotics and pesticides in an aqueous medium. The results revealed that the sensor displayed extra high sensitivities for ions (Fe3+, MnO4−, Cr2O72−), antibiotics ((1,2-dimethyl-5-nitroimidazole (DMZ), sulfamethazine (SMZ)) and pesticides (imidacloprid (IMI) and metamitron (MMT)). A mechanistic investigation showed that the inner filter effect (IFE) and the fluorescence resonance energy transfer (FRET) effect played dominant roles during the fluorescent quenching process.

Tunable luminescence and improved thermostability via Tm―Dy energy transfer in a tellurooxyphosphate phosphor

Currently, to solve the restrictions of multiple phosphors-converted white light-emitting diodes (w-LED) such as reabsorption and fabricating cost, the single-phase white-emitting phosphor-based w-LED stands a good chance. In this work, we present a type of color-tunable barium tellurooxyphosphate-based phosphor Ba2TeP2O9 (BTP):Tm3+,Dy3+. Under 362 nm excitation, the emitting white color adjustment is realized due to the efficient Tm3+→Dy3+energy transfer. The energy transfer mechanism is ascribed to the dipole-dipole interaction with the 93.3% efficiency. Moreover, the synergistic effect of the Dy3+→Tm3+back-energy transfer and high Debye temperature contributes to the improvement of the luminescent thermostability. For the representative BTP:0.04Tm3+,0.06Dy3+phosphor, the emission at 423 K has only the intensity loss of 9.3%, relative to the initial value, and the chromaticity shifting level is 12.9 × 10–3, verifying that it has comparable luminescence thermostability to the commercial products (such as CaAlSiN3:Eu2+ and BaMgAl10O17:Eu2+). The BTP:0.04Tm3+,0.06Dy3+-based w-LED exhibits the satisfactory parameters of high Ra (88) and low CCT (3227 K). Our work illustrates an effective energy transfer path between Tm3+and Dy3+for developing white-emitting phosphors with high thermostability for lighting application.

Rapid point-of-care detection of SARS-CoV-2 RNA with smartphone-based upconversion luminescence diagnostics

Accurate COVID-19 screening via molecular technologies is still hampered by bulky instrumentation, complicated procedure, high cost, lengthy testing time, and the need for specialized personnel. Herein, we develop point-of-care upconversion luminescence diagnostics (PULD), and a streamlined smartphone-based portable platform facilitated by a ready-to-use assay for rapid SARS-CoV-2 nucleocapsid (N) gene testing. With the complementary oligo-modified upconversion nanoprobes and gold nanoprobes specifically hybridized with the target N gene, the luminescence resonance energy transfer effect leads to a quenching of fluorescence intensity that can be detected by the easy-to-use diagnostic system. A remarkable detection limit of 11.46 fM is achieved in this diagnostic platform without the need of target amplification, demonstrating high sensitivity and signal-to-noise ratio of the assay. The capability of the developed PULD is further assessed by probing 9 RT-qPCR-validated SARS-CoV-2 variant clinical samples (B.1.1.529/Omicron) within 20 min, producing reliable diagnostic results consistent with those obtained from a standard fluorescence spectrometer. Importantly, PULD is capable of identifying the positive COVID-19 samples with superior sensitivity and specificity, making it a promising front-line tool for rapid, high-throughput screening and infection control of COVID-19 or other infectious diseases.

Radiation Type- and Dose-Specific Transcriptional Responses across Healthy and Diseased Mammalian Tissues.

Ionizing radiation (IR) is a genuine genotoxic agent and a major modality in cancer treatment. IR disrupts DNA sequences and exerts mutagenic and/or cytotoxic properties that not only alter critical cellular functions but also impact tissues proximal and distal to the irradiated site. Unveiling the molecular events governing the diverse effects of IR at the cellular and organismal levels is relevant for both radiotherapy and radiation protection. Herein, we address changes in the expression of mammalian genes induced after the exposure of a wide range of tissues to various radiation types with distinct biophysical characteristics. First, we constructed a publicly available database, termed RadBioBase, which will be updated at regular intervals. RadBioBase includes comprehensive transcriptomes of mammalian cells across healthy and diseased tissues that respond to a range of radiation types and doses. Pertinent information was derived from a hybrid analysis based on stringent literature mining and transcriptomic studies. An integrative bioinformatics methodology, including functional enrichment analysis and machine learning techniques, was employed to unveil the characteristic biological pathways related to specific radiation types and their association with various diseases. We found that the effects of high linear energy transfer (LET) radiation on cell transcriptomes significantly differ from those caused by low LET and are consistent with immunomodulation, inflammation, oxidative stress responses and cell death. The transcriptome changes also depend on the dose since low doses up to 0.5 Gy are related with cytokine cascades, while higher doses with ROS metabolism. We additionally identified distinct gene signatures for different types of radiation. Overall, our data suggest that different radiation types and doses can trigger distinct trajectories of cell-intrinsic and cell-extrinsic pathways that hold promise to be manipulated toward improving radiotherapy efficiency and reducing systemic radiotoxicities.

Synergistic dual-mechanism fluorescence quenching immunochromatographic assay based on Fe-polydopamine submicrobeads for sensitive detection of enrofloxacin

A fluorescence quenching immunochromatographic assay (FQ-ICA) was developed in recent years to improve detection sensitivity. However, inefficient fluorescence quenchers and unclear fluorescence quenching mechanisms limit the development of FQ-ICA. Here, Fe-polydopamine submicrobeads (Fe-PDAN) were prepared by integrating Fe(III) and PDAN as a quencher quenching the fluorescence of quantum dot beads (QB) to establish a highly sensitive FQ-ICA. Fe-PDAN not only absorbs the excitation and emission light of QB due to the strong inner filter effect, but also accepts part of the released energy of QB by fluorescence resonance energy transfer, resulting in efficient fluorescence quenching and ensuring ultralow fluorescence background signal. With the synergistic effect of fluorescence resonance energy transfer and inner filter effect, the fluorescence quenching constant of Fe-PDAN was 14.9-fold higher than that of PDAN on the nitrocellulose membrane, indicating the stronger quenching ability of Fe-PDAN. The fluorescence lifetime of QB (25.2 ns) in FQ-ICA decayed by 51.9% after Fe-PDAN quenching (12.1 ns). Enrofloxacin, an abused antibiotic, was specifically recognized by antigen–antibody immunoaffinity reaction and detected by monoclonal antibodies conjugated to Fe-PDAN based on the competitive inhibition principle. The FQ-ICA sensitivity based on Fe-PDAN (limit of detection, LOD = 0.016 ng/mL) improved 5.7-fold more than that based on PDAN (LOD = 0.091 ng/mL). The proposed Fe-PDAN can act as a dual-mechanism quencher to enable highly sensitive FQ-ICA, thereby leading to the innovative design of high-efficiency quenchers in the development of sensitive fluorescence quenching biosensors.

The location of the low-energy states in Lhca1 favors excitation energy transfer to the core in the plant PSI-LHCI supercomplex.

Lhca1 is one of the four pigment-protein complexes composing the outer antenna of plant Photosystem I-light-havesting I supercomplex (PSI-LHCI). It forms a functional dimer with Lhca4 but, differently from this complex, it does not contain 'red-forms,' i.e., pigments absorbing above 700nm. Interestingly, the recent PSI-LHCI structures suggest that Lhca1 is the main point of delivering the energy harvested by the antenna to the core. To identify the excitation energy pathways in Lhca1, we developed a structure-based exciton model based on the simultaneous fit of the low-temperature absorption, linear dichroism, and fluorescence spectra of wild-type Lhca1 and two mutants, lacking chlorophylls contributing to the long-wavelength region of the absorption. The model enables us to define the locations of the lowest energy pigments in Lhca1 and estimate pathways and timescales of energy transfer within the complex and to the PSI core. We found that Lhca1 has a particular energy landscape with an unusual (compared to Lhca4, LHCII, and CP29) configuration of the low-energy states. Remarkably, these states are located near the core, facilitating direct energy transfer to it. Moreover, the low-energy states of Lhca1 are also coupled to the red-most state (red forms) of the neighboring Lhca4 antenna, providing a pathway for effective excitation energy transfer from Lhca4 to the core.

A fluorescence probe based on carbon dots for determination of dopamine utilizing its self-polymerization

A rapid and sensitive strategy for sensing dopamine (DA) was proposed based on the fluorescence quenching effects of polydopamine (PDA) on carbon dots (CDs). The green-emission fluorescence CDs were synthesized via a facile one-pot hydrothermal approach by employing p-phenylenediamine and ethanol as reagents. In alkaline environments, DA would polymerize to form PDA on surface of CDs, resulting in the fluorescence quenching of the detection system owing to the effects of fluorescence resonance energy transfer (FERT) and inner filter effect (IFE). The proposed fluorescence probe exhibits good selectivity and sensitivity to DA in the concentration range of 0.1–15 μM, with a limit of detection (LOD) of 37 nM. Results of detecting DA in serum samples indicate the broad potential of the proposed strategy for future application in diagnosis of DA-related diseases.

Throughput Maximization in Wireless Communication Systems Powered by Hybrid Energy Harvesting

Energy harvesting techniques have been increasingly employed in both consumer and industrial applications to provide clean energy supply. Among the many available energy harvesting techniques, ambient energy harvesting (AEH) is a promising one as it harvests free energy from the environment and, thus, is economically efficient. AEH techniques, however, heavily depend on the dynamic environment and are thus uncontrollable and unstable. More recently, the wireless power transfer (WPT) technique has attracted significant attentions due to its highly controllable feature when powering low-cost devices. Unfortunately, WPT faces strict regulatory limitations to provide high power density and requires charging infrastructures installed to perform effective wireless energy transfer. The pros and cons of the two techniques motivate this work to design a hybrid energy harvesting method by charging a device using a combination of AEH and WPT to maximize the throughput of a wireless system. Specifically, this work first proposes an optimal offline charging scheme to maximize the point-to-point data throughput of a wireless system by fully utilizing the ambient energy and providing extra power supply through WPT to determine the transmission rates. An online heuristic algorithm is further proposed to improve the computational efficiency for practical scenarios when the system has the estimation of future AEH patterns. Our experimental results show that the proposed approaches are effective in maximizing the data throughput when compared to the state of the art.

Interaction between electric field and plasma in inductively coupled discharges

In regard to collisionless heating in inductively coupled discharges, two approaches have been widely adopted to describe the energy transfer between electrons and the radio frequency field. One approach is based on consistent kinetic theory, by which the resulting field can be expressed as the superposition of a series of plane waves and resonant interactions can happen between electrons and each wave, which might dominate the heating. Another approach is based on the single-particle approach, which assumes that the electric field can be approximated as a spatially exponential function. The energy gained by electrons can then be obtained analytically, and effective energy transfer occurs between the electrons and the field due to nonresonant transit time damping. Although the two approaches demonstrated equivalence in some parameter regimes, it is still unclear how to unite the physical picture in the two models. In this work, test particle simulations have been conducted to show how electrons interact with the electric field expressed as a spatially exponential function and as a sum of a series of plane waves. It is found that as an electric field can be approximated by an exponential function, the resonant interaction between electrons and the field is weak and the nonresonant interaction is dominant, so Vahedi’s model is good enough to describe this interaction. When the imaginary part of the surface impedance becomes important, the electric field cannot be well approximated by an exponential function. It is shown that the resonant interaction dominates the power dissipation of the coupled field.

Creation of automatic clamping mechanisms for spindle assemblies of machine tools using a formalized description of structural elements

The characteristics of the functioning of automatic mechanisms for clamping workpieces and cylindrical tools in the spindle assemblies of metalworking machines determine the potential for improving the productivity and quality of processing. The conducted research is aimed at developing new approaches to the creation of automatic clamping mechanisms with qualitatively new and necessary characteristics of their functioning. The formation of new characteristics is achieved by implementing appropriate changes at the structural level of an object. The results obtained provide better opportunities for the development of structures of automatic clamping mechanisms by improving the systematization of a review of an increased number of alternative options for their structural elements. This was achieved by solving the problem of formal description and representation of structural elements operating on the basis of various physical effects within one subject area of the systematization matrix. The results allow strengthening the heuristic potential in the design and involving an extended range of physical effects suitable for effective energy transfer and conversion in the operating conditions of automatic clamping mechanisms. The possibility of describing structural elements as digital codes helps to increase the efficiency of analysis and processing of information of the initial design stages. Using the codes of the selected structural elements, three sequences corresponding to the structures of automatic clamping mechanisms according to the brief descriptions [1.7–2.4]–(1.1–2.3); [1.7–2.6]–(1.1–2.3); [1.7–2.6+1.6/1.7–2.1]–(1.1–2.3) were compiled. On their basis, designs of automatic clamping mechanisms with predictably better characteristics and extended technological capabilities are developed

Study of Linear Energy Transfer Effect on Rib Fracture in Breast Patients Receiving Pencil-Beam-Scanning Proton Therapy

<h3>Purpose/Objective(s)</h3> To study the linear energy transfer (LET) effect upon rib fracture (RF) in breast cancer patients treated with pencil-beam scanning proton therapy (PBS) using dose-linear energy transfer volume histogram (DLVH). <h3>Materials/Methods</h3> After IRB approval, we retrospectively identified RF cases detected after workup of chest wall pain or incidentally on imaging in breast cancer patients treated with PBS to the breast/chest wall and regional nodes from 2015-2020. Control patients were selected to match the RF patients 2:1 considering prescription dose, boost location, reconstruction status, laterality, chest wall thickness, and treatment year. For all plans, a chest wall was contoured, incorporating ribs and intercostal muscles within the 50% prescription isodose line. Both dose and LET were calculated using a planning tool dose engine. DLVH was generated for each patient, using dose and LET as the two axes. The DLVH index, <i>V</i>(<i>d, l</i>), defined as <i>V</i>(% for normalized volume or cc for absolute volume) of the structure with a dose of at least <i>d</i> Gy[RBE] and an LET of at least <i>l</i> keV/µm, was calculated for all combinations of <i>d</i> and <i>l</i>. Conditional logistic regression model was used to establish the relation of <i>V</i>(<i>d, l</i>) and the observed RF at each combination of <i>d</i> and <i>l</i>. The derived <i>p values</i> constitute a <i>p value</i> map in the 2D dose and LET plane. Concordance and its standard error (se) maps were generated to evaluate the performances for all DLVH indices. A correlation coefficient map was obtained to determine the correlation between the featured DLVH indices. <h3>Results</h3> Eight RF cases were identified, and 16 controls were matched. Of RF patients, seven were treated with post-mastectomy (PMRT) and one was treated with post-lumpectomy radiotherapy. Six RF patients treated with PMRT received a dose of 50 Gy[RBE] in 25 fractions to the chest wall and regional lymph nodes; of these, four received a simultaneous integrated boost (SIB) of 56.25 Gy[RBE] to the chest wall (n=2) or axillary nodes (n=2), and one received a sequential boost of 14 Gy[RBE] in 7 fractions to the chest wall. One RF patient that received PMRT was treated with 40.05 Gy[RBE] in fifteen fractions to the chest wall and regional lymphatics. The post-lumpectomy patient received 50 Gy[RBE] in 25 fractions to the whole breast and regional nodes with a SIB of 56.25 Gy[RBE] to the lumpectomy cavity. Two characteristics correlated with RF (<i>p</i><0.2): 1) Smaller <i>V</i>(50-54 Gy[RBE], 0-4.4keV/µm) of the RF patients with a maximum concordance of 0.813 (se 0.114); 2) Larger <i>V</i>(0-36 Gy[RBE], 5.2-6.8keV/µm) of the RF patients with a maximum concordance of 0.875 (se 0.119) compared with controls. These two features were independent from each other with a weak negative correlation (-0.185). <h3>Conclusion</h3> The increase of high LET in moderate dose regions of the chest wall from constraining the adjacent heart and lung dose during PBS treatment planning may result in increased risk of RF.

Technical note: Investigation of dose and LETd effect to rectum and bladder by using non-straight laterals in prostate cancer receiving proton therapy.

Parallel-opposed lateral beams are the conventional beam arrangements in proton therapy for prostate cancer. However, when considering linear energy transfer (LET) and RBE effects, alternative beam arrangements should be investigated. To investigate the dose and dose averaged LET (LETd ) impact of using new beam arrangements rotating beams 5°-15° posteriorly to the laterals in prostate cancer treated with pencil-beam-scanning (PBS) proton therapy. Twenty patients with localized prostate cancer were included in this study. Four proton treatment plans for each patient were generated utilizing 0°, 5°, 10°, and 15° posterior oblique beam pairs relative to parallel-opposed lateral beams. Dose-volume histograms (DVHs) from posterior oblique beams were analyzed. Dose-LETd -volume histogram (DLVH) was employed to study the difference in dose and LETd with each beam arrangement. DLVH indices, , defined as the cumulative absolute volume that has a dose of at least d (Gy[RBE]) and a LETd of at least l (keV/µm), were calculated for both the rectum and bladder to the whole group of patients and two-sub groups with and without hydrogel spacer. These metrics were tested using Wilcoxon signed-rank test. Rotating beam angles from laterals to slightly posterior by 5°-15° reduced high LETd volumes while it increased the dose volume in the rectum and increased LETd in bladders. Beam angles rotated five degrees posteriorly from laterals (i.e., gantry in 95° and 265°) are proposed since they achieved the optimal balance of better LETd sparing and minimal dose increase in the rectum. A reduction of V(50 Gy[RBE], 2.6 keV/µm) from 7.41 to 3.96 cc (p < 0.01), and a slight increase of V(50 Gy[RBE], 0 keV/µm) from 20.1 to 21.6 cc (p < 0.01) were observed for the group without hydrogel spacer. The LETd sparing was less effective for the group with hydrogel spacer, which achieved the reduction of V(50 Gy[RBE], 2.6 keV/µm) from 4.28 to 2.10 cc (p < 0.01). Posterior oblique angle plans improved LETd sparing of the rectum while sacrificing LETd sparing in the bladder in the treatment of prostate cancer with PBS. Beam angle modification from laterals to slightly posterior may be a strategy to redistribute LETd and perhaps reduce rectal toxicity risks in prostate cancer patients treated with PBS. However, the effect is reduced for patients with hydrogel spacer.

Rapid and ultrasensitive detection of SARS-CoV-2 spike protein based on upconversion luminescence biosensor for COVID-19 point-of-care diagnostics

Here, we firstly introduce a detection system consisting of upconversion nanoparticles (UCNPs) and Au nanorods (AuNRs) for an ultrasensitive, rapid, quantitative and on-site detection of SARS-CoV-2 spike (S) protein based on Förster resonance energy transfer (FRET) effect. Briefly, the UCNPs capture the S protein of lysed SARS-CoV-2 in the swabs and subsequently they are bound with the anti-S antibodies modified AuNRs, resulting in significant nonradiative transitions from UCNPs (donors) to AuNRs (acceptors) at 480 nm and 800 nm, respectively. Notably, the specific recognition and quantitation of S protein can be realized in minutes at 800 nm because of the low autofluorescence and high Yb-Tm energy transfer in upconversion process. Inspiringly, the limit of detection (LOD) of the S protein can reach down to 1.06 fg mL−1, while the recognition of nucleocapsid protein is also comparable with a commercial test kit in a shorter time (only 5 min). The established strategy is technically superior to those reported point-of-care biosensors in terms of detection time, cost, and sensitivity, which paves a new avenue for future on-site rapid viral screening and point-of-care diagnostics.

Effects of dose and dose-averaged linear energy transfer on pelvic insufficiency fractures after carbon-ion radiotherapy for uterine carcinoma

Background and PurposeThe correlation between dose-averaged linear energy transfer (LETd) and its therapeutic or adverse effects, especially in carbon-ion radiotherapy (CIRT), remains controversial. This study aimed to investigate the effects of LETd and dose on pelvic insufficiency fractures after CIRT. Material and MethodsAmong patients who underwent CIRT for uterine carcinoma, 101 who were followed up for > 6 months without any other therapy were retrospectively analyzed. The sacrum insufficiency fractures (SIFs) were graded according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity criteria. The correlations between the relative biological effectiveness (RBE)-weighted dose, LETd, physical dose, clinical factors, and SIFs were evaluated. In addition, we analyzed the association of SIF with LETd, physical dose, and clinical factors in cases where the sacrum D50% RBE-weighted dose was above the median dose. ResultsAt the last follow-up, 19 patients developed SIFs. Receiver operating characteristic curve analysis revealed that the sacrum D50% RBE-weighted dose was a valuable predictor of SIF. Univariate analyses suggested that LETd V10 keV/µm, physical dose V5 Gy, and smoking status were associated with SIF. Cox regression analysis in patients over 50 years of age validated that current smoking habit was the sole risk factor for SIF. Therefore, LETd or physical dose parameters were not associated with SIF prediction. ConclusionThe sacrum D50% RBE-weighted dose was identified as a risk factor for SIF. Additionally, neither LETd nor physical dose parameters were associated with SIF prediction.

Perovskite GdAlO3:Dy3+ nanophosphors: A gel-combustion synthesis, phase evaluation and down conversion luminescent characteristics for lighting applications

The single phase Gd1-xAlO3:xDy3+ (x = 1, 3, 5, 7, 9 mol %) nanophosphors that produce cool white light have been synthesized by utilizing urea assisted gel-combustion synthetic method. The prepared nanocrystalline materials are thoroughly investigated using a variety of structural as well as photophysical analyses. According to Rietveld refinement elucidations, pure GdAlO3 and Dy3+ doped GdAlO3 nanomaterials have crystallized into an orthorhombic structure with space group of Pnma. Transmission electron microscopy (TEM) graph validates that agglomerated particle with irregular dimensionality are still in nano-range which corroborate the outcomes of diffraction data. As a result of effective energy transfer between Gd3+ to Dy3+, Dy3+ emission achieved by Gd3+ excitation at 281 nm was substantially greater than that obtained through direct excitation of Dy3+ at 350 nm. The photoluminescence emission spectra recorded at 281 nm excitation wavelength revealed two strong bands i.e. blue and yellow which were accompanying the transitions 4F9/2 → 6H15/2 (481 nm) and 4F9/2 → 6H13/2 (575 nm), separately. The dipole-quadruple interactions are accountable for quenching of concentration in focused nanophosphors. Photometric analysis exposed the luminescence of white color in prepared nanomaterials demonstrating its extensive applications in white light applications.

(Invited, Digital Presentation) Photovoltaic Applications Using Energy Transfer Characteristics from Quantum Dots

Silicon-related materials are most commonly used in solar cells and become now an invaluable material. However, a reported maximum energy conversion efficiency of Si solar cell is close to reaching its theoretical limits. To further improve the cell performance and create new functions, it will become increasingly important to functionalize Si materials using nanostructures. One- and zero-dimensional Si nanostructures called Si nanowires (SiNWs) and Si quantum dots (Si QDs) are increasingly being used as new solar cell materials. Our group has shown that the conversion efficiency of solar cells can be increased by the non-radiation energy transfer (NRET) from Si QDs [1]. Recently, research has been developed on compound semiconductor QDs and perovskite QDs, and the conversion efficiency has been successfully increased [3-7].n-type SiNW arrays were fabricated by electroless etching and Bosch & nanoimprint lithography followed by CVD process. The CVD process was performed to form p-type Si layer for pn homojunction. Hybrid heterojunction cells of PEDOT:PSS and n-SiNWs were also fabricated. Passivation by ozone and hydrogen were applied to improve the solar cell properties [2]. After the cell fabrications, the solar cells were coated with Si QDs, CdZnS/ZnS QDs, CdZnSe/ZnS QDs and perovskite QDs. The fabrication methods and conditions of QDs have been reported elsewhere [1-7]Energy transfer effects such as NRET are new ways of increasing solar cell efficiency. To effectively use the NRET effect, the surface of Si QDs should be fully passivated by ligand molecules. The NRET process is a highly distance-dependent phenomenon, and its dependence on the length of the passivation ligands clearly showed this. NRET efficiency was increased by shortening the ligand length from 1-octadecene to 1-octene, resulting in higher JSC, ultimately providing higher energy conversion efficiency. The efficiency was increased about 1-2 % by adding SiQDs. We also observed the same effect for CdZnS/ZnS QDs, CdZnSe/ZnS QDs and perovskite CsPbCl3 QDs. In these cases, in addition to the NRET effect, the radiative energy transfer (RET) effect also contributes to the increase in conversion efficiency.