Eudragit S100 coated microsponges for Colon targeting of prednisolone

Context: Microsponge is a novel approach for targeting the drug to the colon for the management of colon ailments such as inflammatory bowel disease.

Objective: Prednisolone loaded microsponges (PLMs) were prepared and coated with Eudragit S 100 (ES) and evaluated for colon-specific drug delivery.

Materials and methods: PLMs were prepared using quasi emulsion solvent diffusion technique using ethyl cellulose, triethylcitrate (1% v/v, plasticizer) and polyvinyl alcohol (Mol. Wt. 72?kDa, emulsifying agent). The developed microsponges were compressed into tablets via direct compression technique using sodium carboxymethyl cellulose (Na CMC) and magnesium stearate as super-disintegrant and lubricant, respectively. The tablets were then coated with ES to provide protection against harsh gastric environment and manifest colon-specific drug release.

Results: PLMs were found to be nano-porous spherical microstructures with size around 35?µm and 86% drug encapsulation efficiency. Finally, they were compressed into tablets which were coated with Eudragit S 100 In vitro drug release from ES coated tablets was carried out at various simulated gastrointestinal fluids i.e. 1?hr in SGF (pH 1.2), 2 to 3?h in SIF (pH 4.6), 4–5?h in SIF (pH 6.8), and 6–24?h in SCF (pH 7.4) and the results showed the biphasic release pattern indicating prolonged release for about 24?h.

Discussion and conclusion: In vitro drug release studies revealed that drug starts releasing after 5?h by the time PLMs may enter into the proximal colon. Hence maximum amount of drug could be released in the colon that may result in reduction in dose and dose frequency as well as side effects of drug as observed with the conventional dosage form of prednisolone.     

A fast algorithm for the elastic fields due to interacting fibre breaks in a periodic fibre composite

Monte Carlo simulations of the failure of unidirectional fibre composites typically require numerous evaluations of the stress-state in partially damaged composite patches. In a simulated composite patch comprised of N fibres, of which \(N_b\) fibres are broken in a common cross-sectional plane transverse to the fibre direction, the stress overloads in the intact fibres are given by the weighted superposition of the unit break solutions associated with each of the breaks. Determining the weights involves solving \(N_b\) linear equations, and determining overloads in the intact fibres requires matrix-vector multiplication. These operations require \(O(N_b^3)\), and \(O(N N_b)\) floating point operations, respectively. These costs become prohibitive for large N, and \(N_b\); they limit Monte Carlo failure simulations to composite patches of only a few thousand fibres. In the present work, a fast algorithm to determine the overloads in a partially damaged composite, requiring \(O( N_b^{1/3} N \log N)\) floating point operations, is proposed. This algorithm is based on the discrete Fourier transform. The efficiency of the proposed method derives from the computational simplicity of weighted superposition in Fourier space. Computations of the stress state ahead of large circular clusters of breaks in composite patches comprised of about one million fibres are used to demonstrate the efficiency of the proposed algorithm.     

Simplistic approach in extracellular synthesis of silver nanoparticles via bioreducing potential of Planococcus plakortidis strain BGCC‐51 isolated from dye industry effluent soil

Here, extracellular synthesis of silver nanoparticles (AgNPs) was carried out by Planococcus plakortidis strain BGCC‐51 isolated from dye industry effluent soil. The microbes were isolated, screened, and characterised by molecular analysis (accession number {"type":"entrez-nucleotide","attrs":{"text":"KX776160","term_id":"1059906406"}}KX776160). The optimisation of synthesis of AgNPs to determine the optimum substrate level (1–5 mM), pH (5–9), and temperature (25–55°C) were further carried out. P. plakortidis strain BGCC‐51 gave best yield of AgNPs at substrate concentration 5 mM, pH 8, and at 35°C. Synthesised AgNPs were characterised by scanning electron microscope and high‐resolution transmission electron microscope. The size of synthesised AgNPs was in the range of 20–40 nm having spherical morphology. The AgNPs were found to show antimicrobial activity against bacteria such as Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Staphylococcus aureus (ATCC 29213).Inspec keywords: cellular biophysics, silver, nanoparticles, nanofabrication, microorganisms, particle size, effluents, soil, pH, scanning electron microscopy, transmission electron microscopy, antibacterial activity, nanomedicineOther keywords: extracellular synthesis, silver nanoparticles, bioreducing potential, Planococcus plakortidis strain BGCC‐51, dye industry effluent soil, microbes, molecular analysis, accession number {"type":"entrez-nucleotide","attrs":{"text":"KX776160","term_id":"1059906406"}}KX776160, pH, substrate concentration, scanning electron microscopy, high‐resolution transmission electron microscopy, spherical morphology, antimicrobial activity, bacteria, Escherichia coli, ATCC 25922, Pseudomonas aeruginosa, ATCC 27853, Staphylococcus aureus, ATCC 29213, temperature 25 degC to 55 degC, Ag     

EMPSO-based optimization for inter-temporal multi-product revenue management under salvage consideration

The retail market is governed by customer behavior, demand pattern and inventory replenishment policies. It is also observed that any decision would prove to be full of errors, and objective of enhancing the market share could not be achieved, without inclusion of these factors and policies. While an extensive set of literature exists on single and multi-product dynamic pricing, the issue of liquidation of leftover inventory has so far received scant attention from the researchers of Operations Management community. The current work primarily tries to bridge this research gap by addressing dual objectives of revenue maximization and reduction of salvaging losses. In this paper an inter-temporal dynamic pricing model for multiple products is developed under a market setup with price-sensitive demand. Ideas proposed by [1] and [2] have been taken into account for constructing a revenue structure. The formulated objective function is found to be tractable for deriving prices and procurement quantities of large product portfolios. A multi-objective problem has been devised to handle the optimization of normal and clearance revenue by satisfying several pragmatic constraints. Subsequently, an effective algorithm deriving its traits from Particle Swarm Optimization has been proposed to address this problem. An illustrative example from retail apparel industry has been simulated and solved by the afore-mentioned approach. To validate the model statistical analysis has been carried out and the managerial insights portrayed to reveal the practical complexities involved.     

IP Mobility Issues for a Mobile Tele-Robotic System-NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force's (IETF) network layer mobility protocol-Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.     

IP mobility issues for a mobile tele-robotic system—NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet–the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force’s(IETF) network layer mobility protocol—Mobile IP[1] suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a suffcient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol[2] described in Section 4.4 with simulation results in Section 6.2.     

Predicting Spam Messages Using Back Propagation Neural Network

Wireless Personal Communications - With the increase in popularity of smartphones, text-based communication has also gained popularity. Availability of messaging services at low cost has resulted...     

Plastic collapse moment of 90° long radius elbows with internal circumferential surface crack at intrados under in-plane bending

Piping elbows under in-plane bending moment are vulnerable to cracking. The crack initiates at the surface and eventually reaches through the thickness and may lead to failure. The structural integrity assessment requires knowledge of the limit load. Limit load solutions for elbows with through-wall crack configurations are available in the open literature. But solutions for surface crack are not available. This paper presents a closed form expression for the plastic collapse moment (PCM) of 90°, long radius elbows with circumferential surface cracks at the intrados, under in-plane bending moment. The expression is derived, based on the results of non-linear (geometric and material) FE analyses covering a wide range of geometries and crack sizes. These plastic collapse moments evaluated herein will help in structural integrity assessment.     

Experimental exergy and entransy analyses on designed and fabricated crossflow heat exchanger

A crossflow heat exchanger (CFHEx) is designed and fabricated in a workshop. For designing this heat exchanger (HEx), the number of passes, frontal areas, HEx volumes, heat transfer areas, free-flow areas, ratios of minimum free-flow area to frontal area, densities, mass flow rates of flowing fluids, maximum/minimum heat capacities, heat capacity ratio, outlet temperatures of hot/cold fluids, average temperatures, mass velocities, Reynolds numbers, and convective heat transfer coefficients are evaluated by considering Colburn/friction factors. After fabrication of the HEx, effectiveness, exergy destruction, entransy dissipation, entransy dissipation-based thermal resistance, entransy dissipation number, and entransy effectiveness for hot/cold fluids sides are found at different flow rates and inlet temperatures of fluids. By experimental results, optimum operating conditions are found, which gives maximum effectiveness and entransy effectiveness but minimum rates of exergy destruction, entransy dissipation, entransy dissipation-based thermal resistance, and entransy dissipation number for the fabricated CFHEx. This study is concluded as follows: minimum exergy destruction and entransy dissipation rates (ie, 3.061 kJ/s·K and 1125.44 kJ·K/s, respectively) are found during experiment 2. Maximum entransy effectiveness of hot/cold fluids (ie, 0.689/0.21) is achieved in experiment 1. Moderate values of entransy dissipation number (ie, 4.689), entransy dissipation-based thermal resistance (ie, 0.04 s·K/J), exergy destruction (ie, 3.845 kJ/s·K), and entransy dissipation (ie, 1374.04 kJ·K/s) rates are found during experiment 1. Maximum effectiveness (ie, 0.4) for the fabricated HEx is also obtained through experiment 1. After comparative analyses, it is found that experiment 1 provides optimum results, which shows the best performance of the fabricated HEx.     

Characterization of molecular and biomolecular layers on diamond thin films by infrared reflection–absorption spectroscopy

We explore the use of single-bounce infrared reflection–absorption spectroscopy (IRRAS) to characterize molecular and biomolecular layers on doped and undoped diamond thin films on silicon substrates. Experimental measurements of thin layers of poly(methyl methacrylate) (PMMA) as a function of polarization and angle of incidence were used to characterize the intensity, frequency, and symmetry of the vibrational features. Fresnel multilayer reflectivity calculations were used to identify optimized conditions and to understand the observed trends. The measurements were then extended to characterize the nonspecific binding of fibrinogen as a model system. Finally, we present data demonstrating the ability to characterize Escherichia coli antibodies covalently linked to diamond surfaces, including changes in Amide I band due to conformational changes associated with protein denaturation. Our results show that dispersion and reflection effects under different experimental conditions lead to changes in the frequency of the PMMA CO mode and the fibrinogen Amide I band that are comparable to the changes due to different protein conformations. This has significant implications for the use of the Amide I feature to analyze the conformation of proteins on diamond thin film and highlights the utility of Fresnel modeling in the interpretation of FTIR spectra at surfaces.