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Complex and tedious sample preparation processes have greatly limited rapid analyses of biological samples. In this work, an all-in-one sample preparation strategy based on a miniaturized gas membrane separation/oven ring enrichment (GMS/ORE) device was developed for efficient surface enhanced Raman scattering (SERS) analyses of trace biomarkers in biofluid samples. This strategy integrating gasification separation, liquid trapping, derivatization SERS activation, and coffee-ring enrichment could highly promote the efficiency of sample preparation. Meanwhile, the edges of membranes modified by the hydrophobic-infusing slippery liquid-induced uniform "coffee-ring" effect could significantly improve the sensitivity and stability for SERS quantification. By adapting proper derivatization approaches to the miniaturized GMS/ORE pretreatment, the matrix effects in samples could be prominently eliminated, and clear SERS responses could be obtained for the selective analyses of target biomarkers. The miniaturized GMS/ORE device was practically applied for SERS analyses of trace biomarkers in biofluids, including hydrogen sulfide in saliva samples, creatinine in serum samples, and sarcosine, creatinine, and dimethyl disulfide in urine samples. Accurate quantification of all biomarkers was achieved with recoveries of 89.5%-120.0%, and the contents found by GMS/ORE-SERS matched well with those found by corresponding chromatographic methods with relative errors from -8.6% to 9.3%. The miniaturized GMS/ORE device with multiple parallel processing units could simultaneously treat eight samples in one run with a total analysis time of 40 min. Such an efficient all-in-one strategy integrated on a miniaturized device possesses great potential for fast on-site/point-of-care detection in analytical science and clinical medicine.

The discovery of metal–organic frameworks (MOFs) has opened a new era in materials science investigations and applications in traditional fields due to their unique structures and properties. Recently, MOF-based surface-enhanced Raman scattering (SERS) has attracted much attention because MOFs can endow substrates with excellent properties to improve the sensing performance of traditional SERS substrates, such as molecular enrichment ability, selectivity, gas sensing capability, and additional chemical enhancement ability. Meanwhile, SERS can provide ultrasensitive fingerprint spectra for the rapid, non-invasive detection of trace analytes via effective SERS substrates. These advantages of the combination of MOFs and the SERS technique greatly advance the development of SERS and widen its application. To better understand this new application scenario, herein, we briefly introduce the recent progress of MOF substrates in SERS, mainly including the unique advantages of MOFs in the sensing performance improvement in SERS. Then, we present representative MOF-based SERS substrates. Furthermore, the SERS application of effective MOF-based substrates is also reviewed, including in food safety, environmental analysis, bio-medicine, real-time monitoring and other SERS applications. Finally, we present our conclusions and perspectives.

BackgroundSubarachnoid hemorrhage (SAH) is a severe stroke and the advanced treatment for SAH is still limited. Recent studies have shown that microglia-mediated neuroinflammation plays a critical role in the pathogenesis of SAH. Microglia can transform their states in response to central nervous system injury. However, the transcriptomic features of microglia remained unknown in SAH. Recent developed single-cell RNA sequencing (scRNA-seq) provides a possible way to solve this problem.MethodsEndovascular perforation (EVP) murine SAH model was established to reproduce experimental SAH. Microglia states are examined with immune staining and quantitate analysis. Post-SAH microglial single-cell suspension were harvest and sequenced using 10X scRNA-seq platform. Then, the detailed single-cell transcriptomic characterization of post-SAH microglia were analyzed with bioinformatics.ResultsTranscriptional analysis revealed at least ten diverse microglial subgroups, including SAH-associated microglia (SAM), inflammatory-associated microglia (IAM) and proliferation-associated microglia (PAM), which all exhibit distinct marker gene expression patterns. Microglia subsets interaction reveals the functional relationship between elevated signaling pathways and microglial sub-populations in SAH. Receptor-ligand pair analysis revealed that complex inter-cellular interactions exist between the microglia subsets and other cell types, and indicated that microglia are important mediators of neuroinflammation after SAH. Integrated analysis with normal microglia further proved the existence of these microglia subpopulations and different gene markers associated with SAH were clarified.ConclusionsCollectively, we first report the single-cell transcriptome of post-SAH microglia and found specific biomarkers related to the neuroinflammation in SAH. These results enhanced our understanding of the pathological mechanisms of microglial response to SAH, and may guide future development of SAH monitoring methods and therapeutics.

Aim To compare feasibility and safety after gastrointestinal checkup by standing-type magnetically controlled capsule endoscopy (SMCE) and conventional gastroscopy. Methods This was a prospective multicenter, blinded study that compared SMCE with gastroscopy in patients from April 2018 to July 2018. All patients first underwent SMCE and then subsequently had gastroscopy with i.v. anesthesia. We calculated the compliance rates of gastric lesion detection by SMCE using gastroscopy as the standard. Capsule retention rate, incidence of adverse events, and patient satisfaction were documented throughout the study. Results One hundred and sixty-one patients who completed SMCE and gastroscopy were included in the analysis. Positive compliance rate among SMCE and gastroscopy was 92.0% (95% CI: 80.77%-97.78%). Negative compliance rate was 95.5% (89.80%, 98.52%). Moreover, overall compliance rate was 94.41% (89.65%, 97.41%). Sixty-four pathological outcomes were identified. Of these 64 outcomes, 50 were detected by both procedures. The gastroscopy method neglected seven findings (such as five erosions, one polyp, and one ulcer). Furthermore, SMCE also overlooked seven lesions (i.e. one erosion, two polyps, one atrophy, and three submucosal tumors). Capsule retention or related adverse events were not reported. Conclusion Standing-type magnetically controlled capsule endoscopy provides equivalent agreement with gastroscopy and may be useful for screening of gastric illnesses without any anesthesia.

A ternary hybrid, MNPs-MoS2@Au, composed of gold nanoparticles (AuNPs) grown on a magnetic sphere (MNPs)-MoS2 microflower composite (MNPs-MoS2) was proposed for surface-enhanced Raman scattering (SERS) detection and visible-light photo-Fenton degradation of aromatic dyes. The hybrid was prepared by sequential solvothermal growth of MNPs and MoS2, and electroless deposition of AuNPs. A comparison of results revealed that the synergy among these components endowed the hybrid with a much higher SERS enhancement ability than MNPs, or MNPs@MoS2. The dosage of HAuCl4 and MNPs-MoS2 to prepare the hybrid greatly influenced the SERS activity of the hybrid. Under optimized conditions, quantitative SERS analysis of dyes including CV, MG, and MB was performed with a low detection limit (1 pM, 0.15 nM and 1 nM for CV, MG, and MB, respectively) and adequate reproducibility (RSDs were less than 6% and 11% for CV and MG, respectively). The hybrid could also serve as a visible light-active photo-Fenton catalyst for efficient degradation of aromatic dyes, and the decolorization of 20 mg/L RhB was 90% in 40 min in the presence of H2O2 because of a synergy mechanism among components confirmed by comparison experiment and first-order kinetics study. The multifunctional material prepared here possesses great values in SERS analysis, environmental monitoring, and restoration.

Surface-enhanced Raman spectroscopy (SERS) is a powerful and promising analytical technique for fast, non-destructive, and sensitive analysis of trace analytes. However, the serious matrix interference effect of complex sample is a bottleneck that limited rapid SERS analysis. Therefore, it is essential to introduce proper sample preparation techniques to address the limitation for advancing SERS analysis. With adaptable sample preparation techniques, target substances could be separated and purified from complex matrices, matrix interference effect could be eliminated/reduced, and finally pure SERS spectra could be obtained. However, the process of traditional sample preparation usually requires the tedious and time-consuming operation, large solvent consumption, high labor intensity, as well as low efficiency. Given that SERS is an ultrafast analytical technique, there is a great desire to develop advanced/modern sample preparation techniques for fast and efficient analysis of complex samples. To attract much attention and raise research enthusiasm on the beginning, recent development on advanced sample preparation techniques for rapid SERS analysis of complex sample was reviewed. (1) 'All-in-one' strategy for simultaneous separation, enrichment, and in-situ SERS detection. (2) Integrated strategy for high-speed pretreatment and high throughput analysis. (3) Derivatization strategy switches on the SERS activity of molecules with weak responses. (4) Field-assisted strategy for preconcentration acceleration. (5) Instrument combination strategy for online processing and real-time SERS analysis. Finally, conclusions and perspectives on future development were briefly discussed.

A bimetallic nanoparticles modified halloysite nanotubes (HNTs) hybrid was prepared by embedding AgNPs and modifying AuNPs on the inner or outer wall of dopamine-modified HNTs (DHNTs) in sequence. The resulting bimetallic AgNPs@DHNTs-AuNPs hybrid as surface-enhanced Raman scattering (SERS) substrate exhibited improved enhancement ability over monometallic AgNPs@DHNTs, and DHNTs-AuNPs substrates, with intensity ratios of about 48:1:9 (crystal violet) and 11:1:2 (p-phenylenediamine). The giant SERS effect of AgNPs@DHNTs-AuNPs substrate is probably attributed to the synergetic enhancement of the electromagnetic field (Au/Ag), optical plasmon force, molecular enrichment (HNTs), and charge transfer (NPs-dopamine-molecules). The sensitive and reproductive AgNPs@DHNTs-AuNPs substrate was applied for SERS determination of adenine with a linear range of 0.010–0.50 mg·L−1 and a detection limit of 2.2 μg·L−1. The SERS method enables the rapid determination of adenine in fish, chicken kidney and heart, and serum samples, with recoveries of 83.5–121.6% and relative standard deviations of 2.5–7.9%. The SERS substrate has high value for rapid analysis of food and biomarker determinations.

Since the intriguing and inspiring discovery of graphene-enhanced Raman scattering (GERS) in 2010, graphene and graphene-based substrates have attracted significant attention in both theoretical research and application exploration of surface-enhanced Raman scattering (SERS); this makes graphene-involved SERS a burgeoning area in many scientific branches. The introduction of graphene not only overcomes some intrinsic drawbacks of SERS, but also has a great synergistic effect with traditional noble metal nanoparticle enhancement substrates and thus greatly improves the sensing performance of SERS and largely expands its application area. To better learn about the recent progress in graphene-based SERS substrates and shed light on future research, an overview of graphene and graphene-based SERS substrates is presented herein. In this review, the role played by graphene in graphene-based SERS substrates is first summarized, and then, the classification and preparation methods of graphene-based substrates are presented, which are helpful for understanding the structure–property relationship. Furthermore, the SERS applications of graphene-based substrates in biomedical areas, including biomolecule detection, bio-imaging, cancer diagnosis and therapy and drug delivery, are highlighted. Other applications in hot-topic areas such as food safety and environmental monitoring are also briefly discussed. Finally, challenges and perspectives on the deficiencies, future development and achievements are presented.

Halloysite nanotubes loaded with 4-aminothiophenol capped silver nanoparticles (mHNTs-AgNPs4−ATP) composite was synthesized as a sensitive surface-enhanced Raman scattering (SERS) probe for the determination of nitrite ions in sausage and pork luncheon meat. The as-prepared composite was characterized by transmission electron microscope, X-ray diffraction spectroscopy and Fourier transform infrared spectroscopy. The as-synthesized mHNTs-AgNPs4−ATP composite with evenly distribution of AgNPs can provide in-situ derivatization site for sensitive and selective SERS detection of nitrite ions. Under acid condition, the 4-ATP capped on the AgNPs can be transformed into p,p’-dimercaptoazobenzene (DMAB) through nitrite-triggered diazo reaction. This efficient nitrite-triggered reaction can be used to detect nitrite via the characteristic peaks of DMAB at 1143 cm−1, 1392 cm−1, and 1434 cm−1. This SERS method has a wide logarithmic range of 0.0069–6.9 mg L−1, with detection limit of 0.78, 3.4, 0.51 μg L−1 at the peak of 1143 cm−1, 1392 cm−1, and 1434 cm−1, respectively. Besides, this method can be applied to detect nitrite ions in sausage and pork luncheon meat with relative standard deviation less than 10.3%, and the results were consistent with that analyzed by UV–Vis method. This method has good potential in efficient detection of meat product in food safety.

Fast and accurate practical sample detection is a great challenge in on-site detection. Herein, we developed a CoFe

In recent years, the unique properties of magnetic functional nanomaterials have received considerable attentions and show promising applications in separation, detection, diagnosis, catalysis, environment remediation and so on. Specifically, introducing magnetic nanomaterials (MNPs) into traditional sensing techniques greatly simplifies detection operation and improves sensing performances, which makes magnetic nanomaterial-based sensing techniques become a hot research topic. Compared with other sensing techniques such as chromatography, fluorescence, mass spectrum and electrochemistry, surface-enhanced Raman scattering (SERS) displays unique properties of high-sensitivity, fingerprint specificity and nondestructive detection. The introduction of MNPs in SERS has proven to be an efficient way to resolve several critical challenges in practical SERS analysis leading to highly efficient target separation and enrichment, high-sensitive detection and precise outcomes analysis. This makes the MNPs involved SERS analysis a powerful technique with very appealing and promising application in various branches of analytical science. In this review, we first briefly introduced the preparation, encapsulation and surface modification of magnetic nanoparticles, assembly of magnetic nanoparticle–plasmonic substrates and then discussed their applications in SERS analysis, including biomedical application, environmental analysis, food safety and chemical reaction monitoring. Finally, we presented some outlooks on further developments of magnetic nanoparticles in SERS applications.

An efficient SERS substrate composed of gold nanocone arrays with abundant sharp tips directly grown on 3D porous Ni foam (AuNCA@Ni foam) was developed for sensitive detection of aromatic dyes. The AuNCA@Ni foam was prepared by a facile galvanic replacement reaction between Ni foam and HAuCl4 in the presence of cetyltrimethylammonium bromide (CTAB). The concentration of CTAB played an important role in determining the morphology of the product. Without CTAB or replacing CTAB with other surfactants, no AuNCA could be obtained. Thanks to the abundant uniform sharp tips and 3D porous structure, the AuNCA@Ni foam displayed much stronger SERS enhancement ability and higher reproducibility for aromatic dye detection compared with substrates prepared in the absence of CTAB or in the presence of other surfactants. Moreover, the AuNCA@Ni foam with the robust integrated structure also avoided the tedious operation of assembly and centrifugation. The SERS application of the AuNCA@Ni foam was tested by the detection of aromatic dyes crystal violet (CV) and Nile blue (NB), which achieved a detection limit (LOD) of 0.03 nM and 0.5 nM in standard solution, respectively, and an LOD of 3 nM for determining CV in real water samples.

Background/Aim: Magnetically-controlled capsule endoscopy (MCE) is a potential option for the evaluation of gastric diseases in cases that are unsuited for conventional endoscopy, avoiding discomfort, sedation, and related complications. This retrospective study investigated associations between MCE findings and patient gender, age, and inpatient/outpatient status. Patients and Methods: The data of 580 consecutive patients who underwent MCE from 2015 to 2016 were analyzed. Data included age, gender, indication for MCE, inpatient/outpatient status, overall coverage of gastric anatomical landmarks, and comorbid conditions. Results: Compared with outpatients, inpatients had a higher rate of overall significant MCE findings (P = 0.014), polyp (P = 0.03), and ulceration (P = 0.003). MCE findings of the inpatient men and women were similar. Considering all patients, the percentage with ulceration was significantly higher in men than in women (P = 0.004), and men were younger (P < 0.001). Compared with younger patients, those aged ≥60 years had significantly higher rates of overall significant findings, mainly polyp and angiodysplasia. Conclusions: Compared with outpatients, the inpatients showed higher overall significant findings. Men undergoing MCE were younger than the women, and more likely to have ulcerations. Older patients, whether outpatient or inpatient, had higher rates of significant findings, mainly polyp and angiodysplasia.

Since the commercial applications of rare earth magnesium alloys are increasing gradually, there are considerable advantages to developing lower cost and higher performance magnesium alloys with high abundance rare earth (RE) elements. However, the alloying order of a matrix magnesium alloy is completely changed with the addition of RE elements. Therefore, further study of the strengthening mechanism of Ce element in magnesium alloys is required. In this work, the thermodynamic stability of the possible second phases in a Mg-Al-Mn-Ce multicomponent magnesium alloy were analyzed, based on first-principle calculations, and the precipitation sequence of the key RE phases was deduced as a consequence. Combined with Scanning Electron Microscope (SEM), X-ray Diffractometer (XRD), Energy Dispersive Spectrometer (EDS), and other experimental methods, it was investigated whether the preferentially precipitated second phases were the nucleation core of primary α-Mg. The complex alloying problem and strengthening mechanism in a multi-elemental magnesium alloy system were simplified with the aid of electronegativity theory. The results showed that the preferentially precipitated Al11Ce3 and Al10Ce2Mn7 phases could not be the nucleation core of primary α-Mg, and the grain refinement mechanism was such that the second phases at the grain boundary prevented the growth of magnesium grains. Moreover, the tensile test results showed that the reinforced structure, in which the Al-Ce phase was mixed with Mg-Al phase, was beneficial for improving the mechanical properties of magnesium alloys, at both ambient temperature and high temperature.

In this work, a native beta-cyclodextrin capped silver nanoparticles decorated Ti3C2Tx nanosheets (Ti3C2Tx-AgNPs@β-CD) surface-enhanced Raman scattering (SERS) substrate was developed by a facile one-pot method. The two-dimensional Ti3C2Tx nanosheets not only acted as the supporter to load AgNPs, but also served as chemical enhancement material. Meanwhile, β-CD played a critical role in the control of morphology and size of AgNPs, and its supramolecular structure also endowed the Ti3C2Tx-AgNPs@β-CD substrate with selectivity. The Ti3C2Tx-AgNPs@β-CD substrate exhibited excellent sensitivity, good intra-batch and inter-batch reproducibility, and long-term stability by detecting methylene blue model molecule. Then, the substrate was applied for selective determination of erythrosin B among pigment additives via the host-guest size-matching effect. The proposed SERS method with linear range of 1−100 mg/L and detection limit of 30 μg/L could realize rapid SERS analysis of erythrosin B in dyed food samples within 15 min with recoveries of 78.1 %–113.2 %. Erythrosin B was actually found in dyed cherry with 49 mg/kg and marshmallow with 16 mg/kg, and the result matched well with that of UV–vis method. Such a robust substrate possessed great values for efficient and rapid on-site SERS analysis in food safety issues.

Background Chemotherapy resistance is one of the main causes of recurrence in colorectal cancer (CRC) patients and leads to poor prognosis. Long noncoding RNAs (lncRNAs) have been reported to regulate chemoresistance. We aimed to determine the role of the lncRNA small nucleolar RNA host gene 6 (SNHG6) in CRC cell chemoresistance. Methods Cell drug sensitivity tests and flow cytometry were performed to analyze CRC cell chemoresistance. Animal models were used to determine chemoresistance in vivo, and micro RNA (miRNA) binding sites were detected by dual-luciferase reporter assays. Bioinformatics analysis was performed to predict miRNAs binding to SNHG6 and target genes of miR-26a-5p. SNHG6/miR-26a-5p/ULK1 axis and autophagy-related proteins were detected by qRT-PCR and western blotting. Furthermore, immunofluorescence was employed to confirm the presence of autophagosomes. Results SNHG6 enhanced CRC cell resistance to 5-fluorouracil (5-FU), promoted autophagy, inhibited 5-FU-induced apoptosis, and increased 5-FU resistance in vivo. Bioinformatics analysis showed that miR-26a-5p might bind to SNHG6 and target ULK1, and dual-luciferase reporter assays confirmed this activity. qRT-PCR and western blotting showed that SNHG6 was able to negatively regulate miR-26a-5p but correlated positively with ULK1. Conclusion SNHG6 may promote chemoresistance through ULK1-induced autophagy by sponging miR-26a-5p in CRC cells.

Magnetite (Fe3O4) spheres acting as a core were evenly decorated with gold nanoparticles (AuNPs) and coated with a shell of a metal organic framework (MOF) of type MIL-100(Fe). The resulting hybrid nanomaterial of type Fe3O4-Au@MIL-100(Fe) hybrid is shown to be a viable new SERS substrate. The integration of magnetic core, build-in plasmonic gold nanoparticles and a MOF shell endows the Fe3O4-Au@MIL-100(Fe) with highly efficient magnetic separation and enrichment ability, abundant interparticle hotspots, and significant chemical enhancement effect. This leads to a large enhancement, and greatly improved reproducibility of the SERS signals as shown for Malachite Green (MG) and the fungicide thiram. MG in solution can be quantified with a 50-fold lower detection limit (0.14 nM for peak at 1398 cm−1) and largely improved reproducibility (RSD = 9%, 1398 cm−1) when compared to the use of (a) AuNPs anchored on MIL-100(Fe) (RSD = 27%, 1186 cm−1), or (b) AuNPs embedded in MIL-100(Fe) (RSD = 36%, 1398 cm−1). The method was applied to the quantitation of MG and thiram in spiked water samples. The lower limits of detection are 4.4 nM for MG (1398 cm−1) and 15 nM for thiram (1380 cm−1), respectively, and signals’ RSDs are 13% (1398 cm−1) and 5% (1380 cm−1) for MG and thiram, respectively. The substrate is recyclable.

Recently, metal-organic frameworks (MOFs) based substrates have shown great potential for the quantitative analysis of food samples by surface-enhanced Raman scattering (SERS) due to their unique properties. Herein, we developed two UiO-66 MOFs/gold nanoparticles (AuNPs) based substrates by self-assembly, including UiO-66/AuNPs suspension substrate and UiO-66(NH2)/AuNPs/Nylon-66 flexible membrane substrate, for quantitative analysis of complex food samples by SERS. UiO-66/AuNPs suspension substrate was prepared for SERS-based determination of a carcinogenic heterocyclic amine in barbecue meat. UiO-66(NH2)/AuNPs/Nylon-66 membrane substrate was fabricated for the simultaneous separation, enrichment, and in situ analysis of Sudan Red 7B in chilli products. The heterocyclic amine and Sudan dye in real samples could be detected and quantified with the recoveries of 82.3–110% and 84.5–114% and relative standard deviations (RSDs) of 3.1–11.0% and 1.9–5.6% (n = 3) by use of these two substrates, respectively. These two UiO-66/AuNPs based substrates combined molecular enrichment and SERS activity, achieving excellent analytical accuracy and widening SERS application in practical food safety analysis.

A ternary hybrid, MNPs-MoS

Aims/Introduction Adiponectin has been proposed to have an essential role in the regulation of insulin sensitivity and metabolism, but previous studies on levels of adiponectin in prediabetes remain inconsistent. The present study aimed to assess the differences of adiponectin levels between prediabetes patients and healthy controls by carrying out a meta-analysis. Materials and Methods We carried out a systematic literature search of PubMed, EMBASE, and other databases for case–control studies and cohort studies measuring adiponectin levels in serum or plasma from prediabetes patients and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between adiponectin levels and prediabetes. Results Three cohort studies and 15 case–control studies with a total of 41,841 participants were included in the meta-analysis. The results showed that circulating adiponectin levels in prediabetes patients were significantly lower than that of healthy controls (WMD –1.694 μg/mL; 95% CI –2.151, –1.237; P 2.12 (WMD −2.95 μg/mL; 95% CI –4.103, –1.806; P 60 years (WMD −2.20 μg/mL; 95% CI –3.207, –1.201; P

Tb 3+ :NaGd(WO 4 ) 2 (Tb:NGW) phosphors with different Tb 3+ concentrations have been synthesized by a mild hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation and emission spectra and decay curve were used to characterize the Tb:NGW phosphors. XRD analysis confirmed the formation of NGW with scheelite structure. SEM study showed that the obtained Tb:NGW phosphors appeared to be nearly spherical and their sizes ranged from 1 to 1.5 μm. The excitation spectra of these systems showed an intense broad band with maximum at 270 nm related to the O→W ligand-to-metal charge-transfer state. Photoluminescence spectra indicated the phosphors emitted strong green light centered at 545 nm under UV light excitation. Analysis of the photoluminescence spectra with different Tb 3+ concentrations revealed that the optimum dopant concentration for Tb 3+ is about 15 at% of Tb 3+ ions in Tb:NGW phosphors.

A novel blue-emitting material, fine-particle phosphor (Y,Gd)P 0.5 V 0.5 O 4 :Tm 3+ , has been prepared via co-precipitation reaction. The phosphor particles were characterized by XRD, SEM, and photoluminescence under vacuum ultraviolet (VUV, 147 nm) or ultraviolet (UV, 254 nm) excitation. The XRD patterns disclosed that (Y,Gd)P 0.5 V 0.5 O 4 :Tm 3+ particles calcined at 1200 °C have the highest intensity. The SEM image showed that the size of the phosphor particles is uniform and submicron, and their morphology is regular and no agglomeration found. The fine particles blue-emitting material exhibits a narrow emission peak at 475 nm and a weak broad-band around 430 nm, whose intensity is dependent on the contents of Tm 3+ and VO 4 3− .

Green-emitting phosphor YPO 4 :Tb used in a PDP was prepared by two different methods, i.e., conventional solid-state reaction route and solution-based co-precipitation route. Results indicated that in solution-based co-precipitation route, a lower temperature was required, no grinding and milling processes were introduced, and the starting materials were mixed at molecular level, compared with conventional solid-state reaction route. Therefore, the phosphor particles obtained from solution-based co-precipitation route had several advantages in the morphology, such as excellent surface quality, almost spherical shape, narrow size distribution, and homogeneous composition. The excitation spectrum measurement showed that YPO 4 hosts had high energy absorption in VUV range, which makes it possible that YPO 4 :Tb phosphors are used in a PDP. The emission spectrum of YPO 4 :Tb under 147 nm excitation indicated that the phosphor powders obtained from solution-based co-precipitation route had high luminance since they have excellent morphologies and homogeneous composition, compared with those obtained from conventional solid-state reaction route.

Coprecipitation reaction soft chemistry method was employed to prepare fine (Y,Gd)P x V 1 −x O 4 :Eu 3+ phosphor particles. SEM image showed the size of (Y,Gd)P x V 1 −x O 4 :Eu 3+ particles is uniform, homogeneous and smaller than 1 μm. XRD indicated that the prepared resultant has a tetragonal crystal structure. The red emission color purity and intensity of (Y,Gd)P x V 1 −x O 4 :Eu 3+ phosphor is much better than and almost close to that of recent widely used commercial PDP phosphor (Y,Gd)BO 3 :Eu 3+ , respectively. It is expected that (Y,Gd)P 0.2 V 0.8 O 4 :Eu 3+ phosphor would be a promising candidate for plasma display panels application.

In this article, we have investigated energy upconversion process in erbium doped oxyfuoride tellurite glasses exciated with 980 nm diode laser. The glasses used in measurements are with a mol% composition of 70TeO2-9PbF2-190AlF3-10BaF2-1Er2O3. The Ωs intensity parameters, the radiative rates, the branching ratios and the fluorescence lifetimes were calculated based upon the Judd-Ofelt theory and the experimental absorption spectrum. Under 980 nm excitation, efficient 530, 544, and 665 nm upconversion emission are due to two-photon absorption processes.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The solution precipitation is used to synthesize the Tb doped yttrium phosphates. The as-synthesized is the monoclinic phased YPO4×2H2O with churchite-type structure, which is transformed to the tetragonal phased YPO4 with xenotime-type structure as the temperature approaches 200°C during the thermal treatment process. This phase transformation process can not be observed in some routes that need a higher synthetic temperature, in which, only a high-temperature phase is obtained. The luminescent efficiency dependence on the heat-treatment temperature is investigated. The luminescent efficiency presents a two-step increase respectively around 300 and 700°C. Results indicate that the significant increase of luminescent efficiency at 300°C is not related to the phase structure transformation, but to the decrease of OH- ions content, and that the significant increase of luminescent efficiency at 700°C is related to the increase of crystallinity, which may increase the absorption to VUV light.

Bulk Y 2 O 3 : Eu (1% in molar ratio) powders and nanocrystals with different particle size were prepared by chemical self-combustion, all of them exhibits cubic structure. Fluorescent decay curves at room temperature and 10k, excitation and emission spectra were measured. The dependence of fluorescence lifetime on the particle size and temperature were discussed. Meanwhile, the quantum efficiency of 5 D 0 level of europium ion occupying C 2 site was estimated.