Full-Service MAC Protocol for Metro-Reach GPONs

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”An advanced medium access control protocol is presented demonstrating dynamic bandwidth allocation for long-reach gigabit-capable passive optical networks (GPONs). The protocol enables the optical line terminal to overlap the idle time slots in each packet transmission cycle with a virtual polling cycle to increase the effective transmission bandwidth. Contrasting the new scheme with developed algorithms, network modeling has exhibited significant improvement in channel throughput, mean packet delay, and packet loss rate in the presence of class-of-service and service-level differentiation. In particular, the displayed 34% increase in the overall channel throughput and 30 times reduction in mean packet delay for service-level 1 and service-level 2 optical network units (ONUs) at accustomed 50% ONU load constitutes the highest extended-reach GPON performance reported up to date.Peer reviewe

Systematic review and meta-analysis of ocean acidification effects in Halimeda: Implications for algal carbonate production

Ocean acidification (OA) has been identified as one of the major climate-change related threats, mainly due to its significant impacts on marine calcifiers. Among those are the calcareous green algae of the genus Halimeda that are known to be major carbonate producers in shallow tropical and subtropical seas. Hence, any negative OA impacts on these organisms may translate into significant declines in regional and global carbonate production. In this study, we compiled the available information regarding Halimeda spp. responses to OA (experimental, in situ), with special focus on the calcification responses, one of the most studied response parameters in this group. Furthermore, among the compiled studies (n = 31), we selected those reporting quantitative data of OA effects on algal net calcification in an attempt to identify potential general patterns of species- and/or regional-specific OA responses and hence, impacts on carbonate production. While obtaining general patterns was largely hampered by the often scarce number of studies on individual species and/or regions, the currently available information indicates species-specific susceptibility to OA, seemingly unrelated to evolutionary lineages (and associated differences in morphology), that is often accompanied by differences in a species� response across different regions. Thus, for projections of future declines in Halimeda-associated carbonate production, we used available regional reports of species-specific carbonate production in conjunction with experimental OA responses for the respective species and regions. Based on the available information, declines can be expected worldwide, though some regions harbouring more sensitive species might be more impacted than others

Semi-solid extrusion 3D printing in drug delivery and biomedicine: Personalised solutions for healthcare challenges

Three-dimensional (3D) printing is an innovative additive manufacturing technology, capable of fabricating unique objects in a layer-by-layer manner. Semi-solid extrusion (SSE) is a subset of material extrusion 3D printing, based on the sequential deposition of layers of gel or paste to create an object of a desired size and shape. In comparison to other extrusion-based technologies, SSE 3D printing employs low printing temperatures making it suitable for drug delivery and biomedical applications, and the use of disposable syringes provides benefits in meeting critical quality requirements for pharmaceutical use. Besides pharmaceutical manufacture, SSE 3D printing has attracted increasing attention in the field of bioelectronics, particularly in the manufacture of biosensors capable of measuring physiological parameters or as a means to trigger drug release from medical devices. This review begins by highlighting the major printing process parameters and material properties that influence the feasibility of transforming a 3D design into a 3D object, followed by a discussion of the current SSE 3D printing developments and applications in the fields of pharmaceutics, bioprinting and bioelectronics. Finally, the advantages and limitations offered by this technology are explored, focusing on its potential clinical applications and suitability for preparing personalised medicines

Synthesis of temperature-responsive Dextran-MA/PNIPAAm particles for controlled drug delivery using superhydrophobic surfaces

Purpose: To implement a bioinspired methodology using superhydrophobic surfaces suitable for producing smart hydro- gel beads in which the bioactive substance is introduced in the particles during their formation. Methods: Several superhydrophobic surfaces, including polystyrene, aluminum and copper, were prepared. Polymeric solutions composed by photo-crosslinked dextran-methacrylated and thermal responsive poly(N-isopropylacrylamide) mixed with a protein (insulin or albumin) were dropped on the superhydrophobic surfaces, and the obtained millimetric spheres were hardened in a dry environment under UV light. Results: Spherical and non-sticky hydrogels particles were formed in few minutes on the superhydrophobic surfaces. The proteins included in the liquid formulation were homogeneously distributed in the particle network. The particles exhibited temperature-sensitive swelling, porosity and protein release rate, with the responsiveness tunable by the dextran-MA/PNIPAAm weight ratio.Conclusions: The proposed method permitted the preparation of smart hydrogel particles in one step with almost 100% encapsulation yield. The temperature-sensitive release profiles suggest that the obtained spherical-shaped biomaterials are suitable as protein carriers. These stimuli-responsive beads could have potential to be used in pharmaceutical or other biomedical applications, including tissue engineering and regenerative medicine.The authors acknowledge funding from the project: PTDC/QUI/68804/2006 (FCT), IBEROMARE-Procept, FEDER and MICINN (SAF2008-01679). The research leading to these results has also received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement #NMP4-SL-2009-229292. The authors are grateful to project DISC REGENERATION, Collaborative Project-Large-scale integrating project, NMP3-LA-2008-213904 for the use of the UV lamp

Dually sensitive dextran-based micelles for methotrexate delivery

Temperature-sensitive polymeric micelles were prepared from dextran grafted with poly(N-isopropylacrylamide) (PNIPAAm) or polyethylene glycol methyl ether (PEGMA) via controlled radical polymerization and evaluated as delivery systems of the anticancer drug methotrexate (MTX). Polymer-grafting was carried out after introduction of initiating groups onto the polysaccharide backbone, without the need for protection of hydroxyl groups and avoiding the use of toxic solvents. Temperature-responsive dextran-based copolymers were designed to exhibit self-aggregation behaviour, affinity for MTX and high cellular internalization. In addition, some grafted polymers incorporated 2-aminoethyl methacrylate to reinforce MTX encapsulation in the micelles by means of ionic interactions. Dextran-based micelles were cytocompatible and had an appropriate size to be used as drug carriers. MTX release was dependent on the pH and temperature. The combination of poly(2-aminoethylmethacrylate) and PNIPAAm with the dextran backbone permitted the complete release of MTX at normal physiological temperature. Co-polymer micelles were highly internalized by tumour cells (CHO-K1) and, when loaded with MTX, led to enhanced cytotoxicity compared to the free drug

Stereolithography (SLA) 3D printing of a bladder device for intravesical drug delivery

Intravesical instillation therapy is an alternative approach to oral medications for the treatment of severe bladder diseases, offering high drug concentrations at the site of action while minimising systemic side effects. However, therapeutic efficacy is often limited because of the short residence time of the drug in the bladder and the need for repeated instillations. This study reports, for the first time, the use of stereolithography (SLA) 3D printing to manufacture novel indwelling bladder devices using an elastic polymer to achieve extended and localised delivery of lidocaine hydrochloride. The devices were designed to be inserted into and retrieved from the bladder using a urethral catheter. Two types of bladder devices (hollow and solid) were prepared with a resilient material (Elastic Resin) incorporating three drug loads of lidocaine hydrochloride (10% w/w, 30% w/w and 50% w/w); a drug frequently used to treat interstitial cystitis and bladder pain. All of the devices showed acceptable blood compatibility, good resistance to compressive and stretching forces and were able to recover their original shape immediately once external forces were removed. In vitro drug release studies showed that a complete release of lidocaine was achieved within 4 days from the hollow devices, whereas the solid devices enabled sustained drug release for up to 14 days. SLA 3D printing therefore provides a new manufacturing route to produce bladder-retentive drug delivery devices using elastic polymers, and offers a revolutionary and personalised approach for clinical intravesical drug delivery

Layer-by-layer coated silicone-based soft contact lens hydrogel for diclofenac sustained release

Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

A Pathway From Porous Particle Technology Toward Tailoring Aerogels for Pulmonary Drug Administration

Pulmonary drug delivery has recognized benefits for both local and systemic treatments. Dry powder inhalers (DPIs) are convenient, portable and environmentally friendly devices, becoming an optimal choice for patients. The tailoring of novel formulations for DPIs, namely in the form of porous particles, is stimulating in the pharmaceutical research area to improve delivery efficiency. Suitable powder technological approaches are being sought to design such formulations. Namely, aerogel powders are nanostructured porous particles with particularly attractive properties (large surface area, excellent aerodynamic properties and high fluid uptake capacity) for these purposes. In this review, the most recent development on powder technologies used for the processing of particulate porous carriers are described via updated examples and critically discussed. A special focus will be devoted to the most recent advances and uses of aerogel technology to obtain porous particles with advanced performance in pulmonary delivery.Work carried out in the framework of COST Action CA18125 “Advanced Engineering and Research of aeroGels for Environment and Life Sciences” (AERoGELS), funded by the European Commission. This work was also supported by Xunta de Galicia [ED431C 2020/17], MCIUN [RTI2018-094131-AI00], Agencia Estatal de Investigación [AEI], and FEDER funds. CG-G acknowledges to MINECO for a Ramón y Cajal Fellowship [RYC2014-15239]

Acute fasting before conception affects metabolic and endocrine status without impacting follicle and oocyte development and embryo gene expression in the rabbit.

Food deprivation affects female reproduction. The goal of the present study was to elucidate in the rabbit model the effects of acute energy restriction on ovarian function (follicle development, atresia rate and in vitro oocyte maturation) and embryonic development and gene expression of some candidate genes. Serum metabolic parameters (non-esterified fatty acids (NEFA), triglycerides, glucose, insulin and leptin concentrations) and endocrine markers (oestradiol-17β and progesterone concentrations) were also studied. A control group of nulliparous does fed ad libitum and a 72-h fasted group were used. At the end of the nutritional treatment, the ovaries of half of the animals were retrieved while the other animals were re-fed and artificially inseminated to recover embryos at 84 h after insemination, during the luteal phase. At the end of fasting, increased serum NEFA and decreased leptin concentrations were observed in the fasted group, but no differences appeared in serum steroid concentrations, follicle population and atresia rate or nuclear and cytoplasmic oocyte maturation. In the luteal phase, insulin concentrations increased notably in the fasted group. The number of recovered embryos per female and the speed of embryo development were reduced in the food-deprived group. Acute fasting altered both metabolic and endocrine markers and embryo development, but follicle and oocyte development and embryo gene expression were not affected

3D Printed Punctal Plugs for Controlled Ocular Drug Delivery

Dry eye disease is a common ocular disorder that is characterised by tear deficiency or excessive tear evaporation. Current treatment involves the use of eye drops; however, therapeutic efficacy is limited because of poor ocular bioavailability of topically applied formulations. In this study, digital light processing (DLP) 3D printing was employed to develop dexamethasone-loaded punctal plugs. Punctal plugs with different drug loadings were fabricated using polyethylene glycol diacrylate (PEGDA) and polyethylene glycol 400 (PEG 400) to create a semi-interpenetrating network (semi-IPN). Drug-loaded punctal plugs were characterised in terms of physical characteristics (XRD and DSC), potential drug-photopolymer interactions (FTIR), drug release profile, and cytocompatibility. In vitro release kinetics of the punctal plugs were evaluated using an in-house flow rig model that mimics the subconjunctival space. The results showed sustained release of dexamethasone for up to 7 days from punctal plugs made with 20% w/w PEG 400 and 80% w/w PEGDA, while punctal plugs made with 100% PEGDA exhibited prolonged releases for more than 21 days. Herein, our study demonstrates that DLP 3D printing represents a potential manufacturing platform for fabricating personalised drug-loaded punctal plugs with extended release characteristics for ocular administration