High‐Throughput Miniaturized Screening of Nanoparticle Formation via Inkjet Printing

The self‐assembly of specific polymers into well‐defined nanoparticles (NPs) is of great interest to the pharmaceutical industry as the resultant materials can act as drug delivery vehicles. In this work, a high‐throughput method to screen the ability of polymers to self‐assemble into NPs using a picoliter inkjet printer is presented. By dispensing polymer solutions in dimethyl sulfoxide (DMSO) from the printer into the wells of a 96‐well plate, containing water as an antisolvent, 50 suspensions are screened for nanoparticle formation rapidly using only nanoliters to microliters. A variety of polymer classes are used and in situ characterization of the submicroliter nanosuspensions shows that the particle size distributions match those of nanoparticles made from bulk suspensions. Dispensing organic polymer solutions into well plates via the printer is thus shown to be a reproducible and fast method for screening nanoparticle formation which uses two to three orders of magnitude less material than conventional techniques. Finally, a pilot study for a high‐throughput pipeline of nanoparticle production, physical property characterization, and cytocompatibility demonstrates the feasibility of the printing approach for screening of nanodrug delivery formulations. Nanoparticles are produced in the well plates, characterized for size and evaluated for effects on metabolic activity of lung cancer cells.     

Acrylic acid–methyl methacrylate copolymer for oral prolonged drug release

Acrylic acid (AA)–methyl methacrylate (MMA) based copolymers, in different molar ratios (3:7, 4:6, 5:5, 6:4, and 7:3) were synthesized using tetrahydrofuran as solvent and AIBN as free radical initiator. Increase in acrylic acid concentration promoted pH-dependent swelling of copolymer and copolymer AA:MMA (3:7) was selected due to minimum swelling. ATR/FTIR and ¹H NMR spectra of the copolymer showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. The copolymer was hemocompatible. Flurbiprofen sodium microspheres made with the copolymer, by oil/oil solvent evaporation, were spherical, anionic (zeta potential −59.0 mV) and contained 4.53% drug. ATR spectrum of microspheres showed peaks for aromatic C=C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. XRD analysis revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymer and microspheres having peaks at 82.24 and 86.59°C, respectively. The thermogram of microspheres did not show the melting peak of flurbiprofen. The microspheres exhibited no drug release at pH <6.8 and released 83.4 and 99% drug at pH 6.8 and 7.4 in 3 h. The microspheres did not adhere on gastric mucosa at pH 1.2 but showed mucoadhesion time of 28 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in distal ileum, suggesting the potential of the hemocompatible copolymer for enteric coating for prolonged drug release.     

Local jet pattern: a robust descriptor for texture classification

Multimedia Tools and Applications - Methods based on locally encoded image features have recently become popular for texture classification tasks, particularly in the existence of large intra-class...     

Bending and free vibration analysis of shear deformable laminated composite beams by finite element method

In the present investigation a higher-order shear deformation theory and the conventional first-order theory are used to develop a finite element method to analyse accurately the bending and free vibration behaviour of laminated composite beams, using nine-noded isoparametric elements. The higher-order theory assumes all the displacement components, u, v and w, which contain variation up to a cubic power of z. The effects of various parameters such as fibre orientation, stacking sequence, span-to-thickness ratio and support condition on the non-dimensionalised deflections, stresses and fundamental frequencies are investigated. Cases where only the higher-order theory is likely to yield accurate results are highlighted.     

A Call-Admission Control (CAC) Algorithm for Providing Guaranteed QoS in Cellular Networks

Future broadband wireless access systems are expected to integrate various classes of mobile terminals (MTs), each class with a different type of quality of service (QoS) requirement. When the load on a wireless network is high, the guarantee of QoS for each class of MTs is a challenging task. This study considers two classes of MTs—profiled MTs and nonprofiled or regular MTs. It is assumed that profiled users require a guaranteed QoS. The measure of QoS is the probability of forced termination of a call that was allowed to access the network. Two previous handoff prioritization schemes—(i) prerequest scheme and (ii) guard channel scheme—decrease handoff failure (and hence forced termination). In this work, we compare and contrast both the schemes through extensive simulation and we find that neither guard channel nor channel prerequest scheme can guarantee a desired level of QoS for the profiled MTs. We then propose a novel call-admission control (CAC) algorithm that can maintain any desired level of QoS, while the successful call completion rate is very high. In the proposed algorithm, the new call arrival rate is estimated continuously, and when the estimated arrival rate is higher than a predetermined level, some new calls are blocked irrespective of the availability of channels. The objective of this new call preblocking is to maintain a cell's observed new call arrival rate at no more than the predetermined rate. We show that the proposed method can guarantee any desired level of QoS for profiled users.     

Similarity considerations in the physical modelling of steel making tundish systems

To assess and quantify the relative importance of Reynolds and Froude numbers in reduced scale model studies (these cannot be simultaneously respected when the scale factor is less than unity), aqueous model investigations were carried out on three different laboratory scale tundish models. The experimental tundish systems included two strand, five strand skewed delta shaped and six strand rectangular shaped vessels. Experimental observations show that the depth of liquid in the model would only correspond to that in the full scale system, provided the model flow rate is scaled in accordance with the relationship: Q_m = λ^5/2 Q_f.S, in which, A is the geometrical scaling factor. Furthermore, on the basis of residence time distribution measurements in two different configurations of the five strand tundish, it was demonstrated explicitly that flow phenomena in tundish systems are largely dominated by inertial forces and are therefore, essentially Froude dominated.     

A higher-order triangular plate bending element revisited

A new formulation of an eighteen-degrees-of-freedom higher-order triangular plate bending element using triangular area co-ordinates is presented. The displacement function w is taken as the complete fifth-order polynomial in area co-ordinates. The normal slope along an edge of the triangle is constrained to vary cubically. The twenty-one constants are expressed explicity in terms of eighteen degrees of freedom. The element stiffness matrix is expressed as a product of component matrices for which explicit expressions are developed and presented. No numerical inversion or integration is necessary. The formulation is expected to be useful specially for microcomputers.     

Acrylic acid–methyl methacrylate (2.5:7.5/2:8) enteric copolymer for colon targeted drug delivery

Enteric copolymers of acrylic acid and methyl methacrylate (2.5:7.5 and 2:8) were prepared using tetrahydrofuran as solvent and AIBN as free radical initiator for colon targeting. FTIR and ¹H NMR spectra of the copolymers showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. Flurbiprofen sodium microspheres (M1 and M2) made with the copolymers, by oil/oil solvent evaporation, were spherical, anionic (zeta potential –57.8 and –53.7 mV) and contained 5.47 and 5.89% drug. FTIR spectrum of microspheres showed peaks for aromatic C = C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. PXRD revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymers and microspheres. The microspheres released 43 and 36% drug at pH 6.8 in 2 h and 99 and 96% at pH 7.4 in next 3–4 h.The microspheres did not adhere on gastric-mucosa at pH 1.2 but showed mucoadhesion time of 18 min and 9 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in colon, suggesting the potential of the hemocompatible copolymers for pH dependent colon targeted drug delivery system.