Structural, UV-VIS-NIR luminescence and decay associated spectral profiles of Sm3+ doped calcium phosphate glass

Rare-Earths or Lanthanide ions (Ln3+) are a group of elements from lanthanum to lutetium (Z=57 to 71), plus scandium (Z=21) and Yttrium (Z=39). Ln3+ doped glasses have been included within the Hydroxyapatite (HA) matrix, inducing promising changes in their physicochemical and biological properties. Because of the lanthanides' ability to modulate bone metabolism, inclusion of Ln3+ in the composition of calcium phosphate biomaterials for bone tissue regeneration has been considered. Earlier, the authors studied Samarium (Sm3+) doped glass-reinforced hydroxyapatite with enhanced osteoblastic performance and antibacterial properties for bone tissue regeneration. Moreover, Sm3+ substituted calcium phosphate is a non-hazardous material that luminesces under UV-visible light. In this work, we study a calcium phosphate host glass doped with samarium oxide, which has been prepared and characterized by FTIR, SEM, EDS analysis, and X-ray mapping. Pumping with two visible excitation sources at 405nm and 423nm, we observed intense, sharp Green, yellow, orange emission peaks (4G5/2â 6H5/2,7/2, 9/2) at 560nm, 596nm and 643nm respectively. A weak red emission was also observed at 704nm. Two NIR peaks at 1134nm (4G5/2â 6F11/2) and 1310 nm (4G5/2â 6F9/2) are monitored by using an excitation at 1060nm. Furthermore, by making use of time-resolved emission spectroscopy (TRES) measurements, the decay associated spectra were obtained allowing the kinetic parameters for the different emission bands to be elucidated and compared with steady state emission spectra.European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement nº REGPOT-CT2012-316331-POLARIS. Also, SHN would like to thank to Cost Action, ref. # MP 1205 under materials (soft, bio & nano) and technologies for optofluidic devices, and further acknowledge to the FCT -Fundação para a Ciência e a Tecnologia, Portugal, through the project PTDC/SAU-BEB/103034/2008

Time resolved emission spectra and electron paramagnetic resonance studies of Gd3+ doped calcium phosphate glasses

Gadolinium, Gd3+ (4f7 ), containing glasses are particularly interesting owing to their magnetic and optical properties. Gd3+ has an electron paramagnetic resonance (EPR) centre, which is often used as the EPR probe in different matrices. Another important feature of Gd3+ is that emits ultraviolet radiation (UVR) at around 310 â 313 nm from the 6 P7/2 ï  8 S7/2 transition and is suitable for the treatment of skin disease. Here, we report on Gd3+ doped calcium phosphate host glasses with four different concentrations; 0.5 - 4 mol % and labelled as 0.5Gd, 1Gd, 2Gd and 4Gd. A strong emission peak at 310 nm was observed in the reported glasses with excitation at 274 nm. The emission spectra can also be obtained at specific times during the decay. The time resolved emission data was analyzed with three different approaches namely, simple exponential, NED distribution and stretched exponential. The other approaches confirm the single exponential behaviour for all samples with deviation for the 0.5 Gd. The decay associated spectra (DAS) for the 0.5 Gd indicate that both decays have the same origin. The EPR spectrum exhibits several resonance signals characteristic of Gd3+ ions. The stimulated emission cross sections (Ï P EÃ 10â 21 cm2 ) of the UV emission transition 6 P7/2 ï  8 S7/2 were also reported in the above three approaches.The authors would like to acknowledge the financial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement nº REGPOT-CT2012-316331-POLARIS. Also, SHN would like to thank to Cost Action, ref. # MP 1205 under materials (soft, bio & nano) and technologies for ptofluidic devices, and further acknowledge to the FCT-Fundação para a Ciência e a Tecnologia, Portugal, hrough the project PTDC/SAU-BEB/103034/2008.info:eu-repo/semantics/publishedVersio

Delay Distributions in Discrete Time Multiclass Tandem Communication Network Models

An exact computational algorithm for the solution of a discrete time multiclass tandem network with a primary class and cross-traffic at each queue is developed. A sequence of truncated Lindley recursions is defined at each queue relating the delays experienced by the first packet from consecutive batches of a class at that queue. Using this sequence of recursions, a convolve-and-sweep algorithm is developed to compute the stationary distributions of the delay and inter-departure processes of each class at a queue, delays experienced by a typical packet from the primary class along its path as well as the mean end-to-end delay of such a packet. The proposed approach is designed to handle the non-renewal arrival processes arising in the network. The algorithmic solution is implemented as an abstract class which permits its easy adaptation to analyze different network configurations and sizes. The delays of a packet at different queues are shown to be associated random variables from which it follows that the variance of total delay is lower bounded by the sum of variances of delays at the queues along the path. The developed algorithm and the proposed lower bound on the variance of total delay are validated against simulation for a tandem network of two queues with three classes under different batch size distributions

IoT Enabled Smart Fertilization and Irrigation Aid for Agricultural Purposes

Soil is of great importance to agriculture, especially the moisture and nutrients in the soil are the essential ingredients for growing plants and crops. Therefore, benefits and importance of a soil moisture and nutrient monitoring system in modern agriculture and gardening is undeniable. It can also be an interesting feature of an intelligent home or smart agriculture system using the internet of things (IoT) technology. This paper presents an IoT application in Arduino platform aiming to monitor the change in soil moisture and Nitrogen (N), Phosphorus (P), Potassium (K) (NPK) value for an indoor plant using moisture sensors and optical transducers. Other functionalities and important features of this prototype include online data display infographic as user feedback, level-based nutrient classification for enabling proper type of fertilizer selection, hardware and e-mail notification of moisture and nutrients' easily accessible and user-friendly smartphone app

Exposure to Cerium Oxide Nanoparticles Is Associated With Activation of Mitogen-activated Protein Kinases Signaling and Apoptosis in Rat Lungs

Objectives: With recent advances in nanoparticle manufacturing and applications, potential exposure to nanoparticles in various settings is becoming increasing likely. No investigation has yet been performed to assess whether respiratory tract exposure to cerium oxide (CeO2) nanoparticles is associated with alterations in protein signaling, inflammation, and apoptosis in rat lungs. Methods: Specific-pathogen-free male Sprague-Dawley rats were instilled with either vehicle (saline) or CeO2 nanoparticles at a dosage of 7.0 mg/kg and euthanized 1, 3, 14, 28, 56, or 90 days after exposure. Lung tissues were collected and evaluated for the expression of proteins associated with inflammation and cellular apoptosis. Results: No change in lung weight was detected over the course of the study; however, cerium accumulation in the lungs, gross histological changes, an increased Bax to Bcl-2 ratio, elevated cleaved caspase-3 protein levels, increased phosphorylation of p38 MAPK, and diminished phosphorylation of ERK-1/2-MAPK were detected after CeO2 instillation (p\u3c0.05). Conclusions: Taken together, these data suggest that high-dose respiratory exposure to CeO2 nanoparticles is associated with lung inflammation, the activation of signaling protein kinases, and cellular apoptosis, which may be indicative of a long-term localized inflammatory response

Damage severity assessment in composite structures using multi-frequency lamb waves

When a narrowband tone burst excitation signal is used to generate Lamb waves in the thin composite plates, a suitable frequency of the excitation signal is typically chosen to excite a solitary mode of Lamb wave in the structure. However, if and as the damage severity changes in the structure, it may be possible that the frequency of the excitation signal may influence the response metric. In the present work, the use of a chirp signal as an excitation signal for damage severity assessment is proposed. The use of a chirp signal as an excitation signal may prove suitable for damage severity assessment because the chirp response contains a large frequency bandwidth, and the cumulative effect of all the frequencies with the delamination is reflected in the damage index. The sensitivity of the chirp response to varying delamination sizes is investigated through numerical simulations and experiments. The damage index calculated using the chirp response showed a monotonic trend with an increase in damage severity, in contrast to a bidirectional trend of the damage index when conventional narrow excitation signals are used. </jats:p

Ionic tags for synthesis of oligoribonucleotides

US9920084; US9920084 B2; US9920084B2; US9,920,084B2; US9,920,084 B2; 9920084; Appl. No. 14/240067US202212 bcchVersion of Recor