FocusDet: an efficient object detector for small object.

The object scale of a small object scene changes greatly, and the object is easily disturbed by a complex background. Generic object detectors do not perform well on small object detection tasks. In this paper, we focus on small object detection based on FocusDet. FocusDet refers to the small object detector proposed in this paper. It consists of three parts: backbone, feature fusion structure, and detection head. STCF-EANet was used as the backbone for feature extraction, the Bottom Focus-PAN for feature fusion, and the detection head for object localization and recognition.To maintain sufficient global context information and extract multi-scale features, the STCF-EANet network backbone is used as the feature extraction network.PAN is a feature fusion module used in general object detectors. It is used to perform feature fusion on the extracted feature maps to supplement feature information.In the feature fusion network, FocusDet uses Bottom Focus-PAN to capture a wider range of locations and lower-level feature information of small objects.SIOU-SoftNMS is the proposed algorithm for removing redundant prediction boxes in the post-processing stage. SIOU multi-dimension accurately locates the prediction box, and SoftNMS uses the Gaussian algorithm to remove redundant prediction boxes. FocusDet uses SIOU-SoftNMS to address the missed detection problem common in dense tiny objects.The VisDrone2021-DET and CCTSDB2021 object detection datasets are used as benchmarks, and tests are carried out on VisDrone2021-det-test-dev and CCTSDB-val datasets. Experimental results show that FocusDet improves mAP@.5% from 33.6% to 46.7% on the VisDrone dataset. mAP@.5% on the CCTSDB2021 dataset is improved from 81.6% to 87.8%. It is shown that the model has good performance for small object detection, and the research is innovative.

Ultra-Broadband Ultraviolet-Visible Light-Short Wavelength Infrared InGaAs Focal Plane Arrays via n-InP Contact Layer Removal.

PIN InGaAs short wavelength infrared (SWIR) focal plane array (FPA) detectors have attracted extensive attention due to their high detectivity, high quantum efficiency, room temperature operation, low dark current, and good radiation resistance. Furthermore, InGaAs FPA detectors have wide applications in many fields, such as aviation safety, biomedicine, camouflage recognition, and infrared night vision. Recently, extensive research has been conducted on the extension of the response spectrum from short wavelength infrared (SWIR) to visible light (VIS) through InP substrate removal and reserving the n-InP contact layer. However, there is little research on the absorption of InGaAs detectors in the ultraviolet (UV) band. In this paper, we present an ultra-broadband UV-VIS-SWIR 640 × 512 15 µm InGaAs FPA detector by removing the n-InP contact layer in the active area and reserving the InP contact layer around the pixels for n contact, creating incident light to be directly absorbed by the In0.53Ga0.47As absorption layer. In addition, the optical absorption characteristics of InGaAs infrared detectors with and without an n-InP contact layer are studied theoretically. The test results show that the spectral response is extended to the range of 200-1700 nm. The quantum efficiency is higher than 45% over a broad wavelength range of 300-1650 nm. The operability is up to 99.98%, and the responsivity non-uniformity is 3.28%. The imaging capability of InGaAs FPAs without the n-InP contact layer has also been demonstrated, which proves the feasibility of simultaneous detection for these three bands.

GSTP1 rs4147581 C>G and NLRP3 rs3806265 T>C as Risk Factors for Chronic Obstructive Pulmonary Disease: A Case-Control Study.

Background: Chronic obstructive pulmonary disease (COPD) is a chronic respiratory ailment influenced by a blend of genetic and environmental factors. Inflammatory response and an imbalance in oxidative-antioxidant mechanisms constitute the primary pathogenesis of COPD. Glutathione S-transferase P1(GSTP1) plays a pivotal role as an antioxidant enzyme in regulating oxidative-antioxidant responses in the pulmonary system. The activation of the NOD-like receptor thermal protein domain (NLRP3) inflammatory vesicle can trigger an inflammatory response. Several investigations have implicated GSTP1 and NLRP3 in the progression of COPD; nonetheless, there remains debate regarding this mechanism. Methods: Employing a case-control study design, 312 individuals diagnosed with COPD and 314 healthy controls were recruited from Gansu Province to evaluate the correlation between GSTP1 (rs4147581C>G and rs1695A>G) and NLRP3 (rs3806265T>C and rs10754558G>C) polymorphisms and the susceptibility to COPD. Results: The presence of the GSTP1 rs4147581G allele substantially elevated the susceptibility to COPD (CGvs.CC:OR=3.11,95% CI=1.961-4.935, P<0.001;GGvs.CC:OR=2.065,95% CI=1.273-3.350, P=0.003; CG+GGvs.CC:OR=2.594,95% CI=1.718-3.916, P<0.001). Similarly, the NLRP3rs3806265T allele significantly increased the susceptibility to COPD (TC:TT:OR=0.432,95% CI=0.296-0.630; TC+CCvs.TT:OR=2.132,95% CI=1.479-3.074, P<0.001). However, no statistically significant association was discerned between the rs1695A>G and rs10754558G>C polymorphisms and COPD susceptibility (P>0.05). Conclusion: In summary, this study ascertained that the GSTP1 rs4147581C>G polymorphism is associated with increased COPD susceptibility, with the G allele elevating the risk of COPD. Similarly, the NLRP3 rs3806265T>C polymorphism is linked to elevated COPD susceptibility, with the T allele heightening the risk of COPD.

The quest for nanoparticle-powered vaccines in cancer immunotherapy.

Despite recent advancements in cancer treatment, this disease still poses a serious threat to public health. Vaccines play an important role in preventing illness by preparing the body's adaptive and innate immune responses to combat diseases. As our understanding of malignancies and their connection to the immune system improves, there has been a growing interest in priming the immune system to fight malignancies more effectively and comprehensively. One promising approach involves utilizing nanoparticle systems for antigen delivery, which has been shown to potentiate immune responses as vaccines and/or adjuvants. In this review, we comprehensively summarized the immunological mechanisms of cancer vaccines while focusing specifically on the recent applications of various types of nanoparticles in the field of cancer immunotherapy. By exploring these recent breakthroughs, we hope to identify significant challenges and obstacles in making nanoparticle-based vaccines and adjuvants feasible for clinical application. This review serves to assess recent breakthroughs in nanoparticle-based cancer vaccinations and shed light on their prospects and potential barriers. By doing so, we aim to inspire future immunotherapies for cancer that harness the potential of nanotechnology to deliver more effective and targeted treatments.

A Case-Control Study of the Associations between EGLN1 Gene Polymorphisms and COPD.

BACKGROUND: Environmental and genetic factors are jointly involved in the development of chronic obstructive pulmonary disease (COPD). The EGLN1 gene is a major factor in upstream regulation of the hypoxia-inducible pathway. EGLN1 negatively regulates the hypoxia-inducible factors HIF-lα and HIF-2α by regulating the concentration of oxygen, mainly in a hypoxic environment. Hypoxia is a common physiologic condition during the progression of COPD, and several studies have identified genetic variants in EGLN1 as a key factor in the adaptation to hypoxic environments. However, it is still unclear whether there is an association between EGLN1 variants and the risk of developing COPD. METHODS: A case-control study was conducted in the Gannan Tibetan Autonomous Prefecture, Gansu Province. A total of 292 COPD patients and 297 healthy controls were enrolled to assess the association of EGLN1 single nucleotide polymorphisms (SNPs) (rs41303095 A>G, rs480902 C>T, rs12097901 C>G, rs2153364 G>A) with COPD susceptibility. RESULTS: The EGLN1 rs41303095 A>G, rs480902 C>T, rs12097901 C>G, and rs2153364 G>A polymorphisms were not associated with COPD susceptibility (p > 0.05). CONCLUSIONS: The EGLN1 rs41303095 A>G, rs480902 C>T, rs12097901 C>G and rs2153364 G>A polymorphisms were found in this study not to be associated with susceptibility to COPD in Gannan Tibetans.

Selection and identification of a prohibitin 2-binding DNA aptamer for tumor tissue imaging and targeted chemotherapy.

Tumor cell-targeting molecules play a vital role in cancer diagnosis, targeted therapy, and biomarker discovery. Aptamers are emerging as novel targeting molecules with unique advantages in cancer research. In this work, we have developed several DNA aptamers through cell-based systematic evolution of ligands by exponential enrichment (Cell-SELEX). The selected SYL-6 aptamer can bind to a variety of cancer cells with high signal. Tumor tissue imaging demonstrated that SYL-6-Cy5 fluorescent probe was able to recognize multiple clinical tumor tissues but not the normal tissues, which indicates great potential of SYL-6 for clinical tumor diagnosis. Meanwhile, we identified prohibitin 2 (PHB2) as the molecular target of SYL-6 using mass spectrometry, pull-down and RNA interference assays. Moreover, SYL-6 can be used as a delivery vehicle to carry with doxorubicin (Dox) chemotherapeutic agents for antitumor targeted chemotherapy. The constructed SYL-6-Dox can not only selectively kill tumor cells in vitro, but also inhibit tumor growth with reduced side effects in vivo. This work may provide a general tumor cell-targeting molecule and a potential biomarker for cancer diagnosis and targeted therapy.

Diagnostic biomarkers and aortic dissection: a systematic review and meta-analysis.

BACKGROUND: Aortic dissection (AD) is a serious and fatal vascular disease. The earlier the condition of AD patients can be assessed precisely, the more scientifically controlled the patient's condition will be. Therefore, timely and accurate diagnosis is significant for AD. Blood biomarker testing as a method of liquid biopsy can improve the diagnostic efficiency of AD. This study conducted a systematic review of the current blood diagnostic biomarkers of AD. METHODS: The PubMed, Cochrane Library, Web of Science, and Embase electronic databases were systematically searched from inception to January 1, 2023, using the terms "aortic dissection", "serum", "plasma" and "diagnosis". Stata 12.0 software was used to perform Random effects meta-analysis was performed using Stata 12.0 software to determine the effect sizes and corresponding 95% confidence intervals. Then, a summary receiver operator characteristic (SROC) curve was drawn, and the area under the ROC curve (AUC) was calculated. RESULTS: D-dimer had the best sensitivity and AUC for AD, with values of 0.96 (95% CI: 0.93-0.98) and 0.95 (95% CI: 0.93-0.97), respectively. The sensitivity and AUC values for D-dimer with a cut-off value of 500 ng/mL were 0.97 (95% CI: 0.95-0.99) and 0.94 (95% CI: 0.92-0.96), respectively. In contrast, microRNA had a better specificity value for AD, at 0.79 (95% CI: 0.73-0.83). CONCLUSIONS: D-dimer and microRNA have good accuracy in the diagnosis of AD, but the specificity of D-dimer is worse, and studies of microRNA are insufficient. The combination of different biomarkers can improve the diagnostic accuracy. Other blood biomarkers are related to the pathological progression of AD and can be selected according to pathological progress.

Ultrapure single-band red upconversion luminescence in Er3+ doped sensitizer-rich ytterbium oxide transparent ceramics for solid-state lighting and temperature sensing.

Achieving single-band upconversion (UC) is a challenging but rewarding approach to attain optimal performance in diverse applications. In this paper, we successfully achieved single-band red UC luminescence in Yb2O3: Er transparent ceramics (TCs) through the utilization of a sensitizer-rich design. The Yb2O3 host, which has a maximum host lattice occupancy by Yb3+ sensitizers, facilitates the utilization of excitation light and enhances energy transfer to activators, resulting in improved UC luminescence. Specifically, by shortening the ionic spacing between sensitizer and activator, the energy back transfer and the cross-relaxation process are promoted, resulting in weakening of green energy level 4S3/2 and 2H11/2 emission and enhancement of red energy level 4F9/2 emission. The prepared Yb2O3: Er TCs exhibited superior optical properties with in-line transmittance over 80% at 600 nm. Notably, in the 980nm-excited UC spectrum, green emission does not appear, thus Yb2O3: Er TCs exhibit ultra-pure single band red emission, with CIE coordinates of (0.72, 0.28) and color purity exceeding 99.9%. To the best of our knowledge, this is the first demonstration of pure red UC luminescence in TCs. Furthermore, the luminescent intensity ratio (LIR) technique was utilized to apply this pure red-emitting TCs for temperature sensing. The absolute sensitivity of Yb2O3: Er TCs was calculated to be 0.319% K-1 at 304 K, which is the highest level of optical thermometry based on 4F9/2 levels splitting of Er3+ known so far. The integration between pure red UC luminescence and temperature sensing performance opens up new possibilities for the development of multi-functional smart windows.

Chiral Oxazaborolidinium Ion (COBI)-Catalyzed Reaction of Aldimine with Tributyltin Cyanide: Mechanism and Origin of Stereoselectivity.

By conducting density functional theory (DFT) calculations, the detailed reaction mechanisms of aldimines with tributyltin cyanide under the catalytic influence of chiral oxazaborolidinium ion (COBI) have been uncovered. Three potential reaction pathways were examined, and two stereoselective routes were determined for the most energetically favorable mechanism. In the primary route, a proton is transferred from the COBI catalyst to the aldimine substrate, which is then followed by the C-C bond formation to produce the final product. Subsequently, NBO analyses of the stereoselectivity-determining transition states were conducted to identify the crucial role of hydrogen bond interactions in controlling stereoselectivity. These computed findings should prove invaluable in comprehending the detailed mechanisms and underlying origins of stereoselectivity for COBI-mediated reactions of this type.

Novel uniplanar pedicle screw systems applied to thoracolumbar fractures: a biomechanical study.

Objective: In this study, the advantages of the internal fixation configuration composed of uniplanar pedicle screws in the treatment of thoracolumbar fractures were verified by biomechanical experimental methods, which provided the basis for subsequent clinical experiments and clinical applications. Methods: A total of 24 fresh cadaveric spine specimens (T12-L2) were utilized to conduct biomechanical experiments. Two different internal fixation configurations, namely, the 6-screw configuration and the 4-screw/2-NIS (new intermediate screws) configuration, were tested using fixed-axis pedicle screws (FAPS), uniplanar pedicle screws (UPPS), and polyaxial pedicle screws (PAPS) respectively. The spine specimens were uniformly loaded with 8NM pure force couples in the directions of anteflexion, extension, left bending, right bending, left rotation, and right rotation, and the range of motion (ROM) of the T12-L1 and L1-L2 segments of the spine was measured and recorded to access biomechanical stability. Results: No structural damage such as ligament rupture or fracture occurred during all experimental tests. In the 6-screw configuration, the ROM of the specimens in the UPPS group was significantly better than that of the PAPS group but weaker than those of the FAPS group (p < 0.01). In the 4-screw/2-NIS configuration, the results were identical to the biomechanical test results for the 6-screw configuration (p < 0.01). Conclusion: Biomechanical test results show that the internal fixation configuration with UPPS can maintain the stability of the spine well, and the results are better than that of PAPS. UPPS has both the biomechanical advantages of FAPS and the superiority of easy operation of PAPS. We believe it is an optional internal fixation device for minimally invasive treatment of thoracolumbar fractures.

Improvement Strategies for Stability and Efficiency of Perovskite Solar Cells.

Recently, perovskites have garnered great attention owing to their outstanding characteristics, such as tunable bandgap, rapid absorption reaction, low cost and solution-based processing, leading to the development of high-quality and low-cost photovoltaic devices. However, the key challenges, such as stability, large-area processing, and toxicity, hinder the commercialization of perovskite solar cells (PSCs). In recent years, several studies have been carried out to overcome these issues and realize the commercialization of PSCs. Herein, the stability and photovoltaic efficiency improvement strategies of perovskite solar cells are briefly summarized from several directions, such as precursor doping, selection of hole/electron transport layer, tandem solar cell structure, and graphene-based PSCs. According to reference and analysis, we present our perspective on the future research directions and challenges of PSCs.

Suppression of the Electrical Crosstalk of Planar-Type High-Density InGaAs Detectors with a Guard Hole.

The resolution of InGaAs FPA detectors is degraded by the electrical crosstalk, which is especially severe in high-density FPAs. We propose a guard-hole structure to suppress the electrical crosstalk in a planar-type 640 × 512 15 µm InGaAs short wavelength infrared FPA detector. For comparison, the frequently used guard ring is also prepared according to the same processing. The calculation results show that the electrical crosstalk with a guard hole is suppressed from 13.4% to 4.5%, reducing by 66%, while the electrical crosstalk with a guard ring is suppressed to 0.4%. Furthermore, we discuss the effects of the guard ring and the guard hole on the dark current, quantum efficiency, and detectivity. Experimental results show the detector with a guard-hole structure has higher performance compared with the detector with a guard-ring structure, the dark current density is reduced by 60%, the QE is increased by 64.5%, and the detectivity is increased by 1.36 times, respectively. The guard-hole structure provides a novel suppression method for the electrical crosstalk of high-density InGaAs detectors.

Buccal bone thickness of posterior mandible for microscrews implantation in molar distalization.

BACKGROUND: This study explored the inter-radicular space and buccal bone thickness of the posterior mandibular region to provide an appropriate miniscrew insertion site for lower dentition distalization. METHODS: The cone-beam computed tomographic (CBCT) records of 63 subjects were collected. Buccal bone thickness (BBT) was measured at four sections: (I) the root of the second premolar(P1); (II) the mesial root of the first molar(P2); (III) the distal root of the first molar(P3); (IV) the mesial root of the second molar(P4). The narrowest inter-radicular space of the four sections was also detected. Both BBT and inter-radicular space were measured at 4 height levels, 2, 4, 6 and 8 mm from the alveolar ridge. RESULTS: The largest BBT was observed at the mesial root of the second molar at 6 and 8 mm, demonstrating a thickness of 6.77 ± 2.50 mm and 7.46 ± 1.94 mm, respectively. It provided sufficient coverage for mini-implants inserted 10°- 30° oblique to the root. Therefore, during distalization of the mandibular dentition, roots have sufficient space to bypass the inclined mini-implants on the lingual side, avoiding miniscrew-root contact. The width between the mesiodistal roots of the first molar was the smallest, showing 1.53 ± 0.69 mm and 2.13 ± 0.65 mm at 4 and 6 mm. Miniscrews implanted in this region had an increased risk of root proximity. CONCLUSIONS: The most appropriate insertion site at the mandibular buccal shelf was the mesial point of the second molar at 6-8 mm from the alveolar ridge, and an insertion angle of 10°- 30° was recommended to avoid miniscrew-root contact. CBCT analysis is recommended before implantation due to individual differences.

Defect Regulation of Terbium-Doped Y2Zr2O7 Transparent Ceramic for Wide-Range Multimode Tunable Light-Shielding Windows.

In the most promising new window materials, the light-blocking property of the state-of-the-art transparent polycrystalline ceramics is still located in the UV range, which undoubtedly limits their applications. Herein, a transparent Y2Zr2O7:Tb (YZO:Tb) ceramic for light-shielding windows was prepared by a solid-state reaction and vacuum sintering method. Two simple and efficient routes, with doping concentrations varying and air-annealing temperatures regulating, were developed for the first time to control the content of defect clusters [TbY4+-O2--TbY4+] and [TbY4+-e•], enabling the optical cutoff waveband of these ceramics spanning from UV and BV to green light. These defect clusters generated from an air-annealing process were proposed for the relevant reaction mechanisms concerning light erasure behavior. The controllably tailoring of optical cutoff wavelength from Tb single-doped YZO ceramics, adjusted by defect clusters, may open a novel door to develop lanthanide-doped transparent ceramics for wide-range tunable light-shielding windows.

Schistosoma japonicum proteins that interact with the gynecophoral canal protein identified using a yeast two-hybrid system.

The large amount of schistosome eggs produced by mature female worms not only induce major pathological damage to the host but also lead to the transmission of schistosomiasis. Mature female schistosome worms need constant pairing contact with a male partner as male signaling is indispensable to female growth, development, and reproduction. The gynecophoral canal protein (GCP), a cell-surface glycoprotein, plays a potential role in the interaction between males and females and in stimulating female development and maturation. In this study, a yeast two-hybrid cDNA library of Schistosoma japonicum (Sj) parasites 18 days post-infection (dpi) was constructed; the Sjgcp gene was inserted into a pGBKT7-BD bait plasmid and used as a bait protein to screen for its molecular interactions using a yeast mating procedure. Twenty-four prey proteins that interacted with the SjGCP were selected after excluding false positives; the interactions between S.japonicum lethal giant larvae (SjLGL) and SjGCP, S.japonicum type V collagen (SjColV) and SjGCP, were verified by co-immunoprecipitation. The RNA interference against SjGCP, SjColV and SjGCP + SjColV led to severe underdevelopment of tegument in male worms and vitelline globules in female worms as well as reduced reproductive capacity of the females. Collectively, SjGCP and its interacting proteins may play pivotal roles in growth and development. The findings also suggested that SjGCP and its interacting protein partners might represent new candidate targets for drug development against schistosomiasis.

Dual-site recognition of Pseudomonas aeruginosa using polymyxin B and bacteriophage tail fiber protein.

As one of the top three opportunistic pathogens, Pseudomonas aeruginosa (P. aeruginosa) has long accounted for hospital-acquired infections with high risk of death. In this work, a fluorescent method based on a dual-site recognition mode was developed for rapid assay of P. aeruginosa. Employing its strong binding capability towards lipid A on the outer membrane of Gram-negative bacteria, polymyxin B acted as one recognition element for P. aeruginosa. To overcome the poor binding specificity of polymyxin B, a recombinant bacteriophage tail fiber protein was expressed and employed as a species-specific recognition element for the target pathogen. Thus a dual-site recognition mode was developed for specific assay of P. aeruginosa species by using fluorescein isothiocyanate as a fluorescent probe. The target pathogen can be assayed within a broad dynamic range from 2.0 × 103 CFU mL-1 to 2.0 × 107 CFU mL-1. Due to the ideal specificity of tail fiber protein, the method is capable of excluding the interference from other Gram-negative bacteria and all Gram-positive bacteria. It has been employed for assaying P. aeruginosa in various types of sample matrixes inclusive of lake water, physiological saline injection, human urine and milk. The acceptable assay results demonstrate its promising prospect for practical application in various areas such as environmental hygiene, medical diagnosis, as well as drug and food safety.

Evolution of DNA aptamers against esophageal squamous cell carcinoma using cell-SELEX.

Esophageal cancer is the ninth most common cancer and the sixth most common cause of cancer-related death worldwide, and the esophageal squamous cell carcinoma (ESCC) subtype accounts for about 90% of all cases of esophageal cancer globally. Currently, ESCC is usually diagnosed in late stages, and targeted therapy is lacking. Therefore, the development of ESCC-specific recognition molecules for an early detection and targeted treatment of ESCC is urgently needed. Aptamers are an excellent molecular recognition tool with unique advantages. In this manuscript, three aptamers (S2, S3, and S8) specific to ESCC cells were successfully screened via cell-SELEX. The experimental results displayed the high affinities of the three aptamers for target KYSE150 cells with dissociation constants in the nanomolar range. The specificity evaluation showed that S2 only bound target KYSE150 cells, but S3 and S8 were capable of targeting a series of ESCC cells. Moreover, several truncated aptamers were generated through sequence optimization. In particular, an ultrashort aptamer S3-2-3 with only 18 bases was successfully obtained; after labeling with Cy5 dyes, it was feasible for the specific imaging of ESCC tissues. Furthermore, the target types of the selected aptamers were preliminarily identified as membrane proteins, and target proteins could be captured by S3-2-3, which may be useful for biomarker discovery. Therefore, the selected aptamers hold great potential for clinical diagnosis, biomarker discovery, and the targeted therapy of ESCC.

Uranium-Incorporated Pyrochlore La2(UxMgxZr1-2x)2O7 Nuclear Waste Form: Structure and Phase Stability.

As efficient and stable nuclear waste forms, single-phase uranium (U6+)-incorporated La2Zr2O7 nanoparticles were designed and synthesized in an air atmosphere. To obtain a high U loading, divalent magnesium (Mg2+) was introduced to balance the extra charge from the substitution of tetravalent zirconium (Zr4+) by U6+ with a minimized impact to the lattice. There is a composition-driven phase transition from order pyrochlore to defect fluorite as the U concentration increases from 10 to 30 mol %, demonstrating both good solubility and stability of the La2Zr2O7 host for U and potentially for other actinides. La2(UxMgxZr1-2x)2O7 (x = 0-0.3) nanoparticles showed good dispersity and crystallinity with an average particle size of ∼48 nm. Furthermore, X-ray photoelectron spectroscopy, Raman spectroscopy, and emission spectroscopy revealed that U was stabilized in the hexavalent state in the form of a UO22+ ion. Spectroscopic methods also demonstrated that our samples caused a scintillating response with an orange emission (597 nm) by 230 nm excitation. In addition, density functional theory simulations were employed to investigate the atomic structures and electronic properties of the U-incorporated pyrochlores. The calculated bond lengths, atomic charges, and charge density confirm the existence of UO22+ ions. Supported by both experimental and computational results, a novel geometrical structure was proposed to explain the Mg2+-U6+ substitution. This work demonstrated the successful development of U-incorporated La2Zr2O7 nanoparticles and provided an efficient way to immobilize U in these ceramic waste matrixes.

Influence of Group Modification at the Edges of Carbon Quantum Dots on Fluorescent Emission.

We present a detailed investigation on the effect of functional group modulation at the edges of carbon quantum dots (CQDs) on the fluorescence from the CQDs. The CQDs attached by N, S, and P elements are synthesized via pyrolysis of a mixture of citric acid and NH3H2O, H2SO4, and H3PO4, respectively. Thus, part of -COOH at the edges of CQDs can be converted into -C=O and functional groups such as -NH2, -SO2, -HSO3, and -H2PO4 can connect to the carbon bonds. We find that the formation of the N/S/P-CQDs can reduce the amount of -COOH that attaches to the edges of sp2-conjugated π-domains located at centers of these CQDs. This effect can result in the reduction of the non-radiative recombination for electronic transition in these CQDs. As a result, the quantum yield (QY) for fluorescence from the CQDs can be efficiently enhanced. We demonstrate experimentally that the QYs for N/S/P-CQDs can reach up to 18.7%, 29.7%, and 10.3%, respectively, in comparison to 9% for these without functional group modulation. This work can provide a practical experimental approach in improving the optical properties of fluorescent CQDs.

Antibiotic-affinity chromatographic test strip for quantitative analysis and antibiotic resistance testing of Staphylococcus aureus.

Bacterial analysis and antibiotic resistance testing (ART) are of great significance in clinical diagnosis and therapy of bacterial infectious diseases. In this work, a portable antibiotic-affinity chromatographic test strip has been developed for rapid analysis of Staphylococcus aureus (S. aureus) and further applied for ART of this pathogen. Porcine IgG was immobilized on a nitrocellulose membrane for capturing S. aureus based on the selective binding capability of the Fc fragment of IgG toward protein A on the surface of the target bacteria. Fluorescent microspheres modified with teicoplanin (TEI) were applied as signal substances to trace S. aureus utilizing the hydrogen bond conjugation between this antibiotic and Gram-positive bacteria. S. aureus can be analyzed within the concentration range from 1.4 × 103 CFU mL-1 to 1.4 × 107 CFU mL-1. The recovery values for spiked samples were 93.3-110.0%. The obtained results of ART for penicillin, daptomycin, gentamicin, cefoxitin and clindamycin against S. aureus showed agreement with those of traditional broth dilution method. The procedures for bacterial analysis and ART can be accomplished within 20 and 110 min, respectively. The antibiotic-affinity chromatographic test strip showed great promise in point-of-care testing because of its ideal portability and rapidity.