Evolution of structural and magnetic properties in Ta/Ni_81Fe_(19) multilayer thin films

The interdiffusion kinetics in short period (12.8 nm) Ta/Ni81Fe19 polycrystalline multilayer films has been investigated and related to the evolution of soft magnetic properties upon thermal annealing in the temperature range 300-600-degrees-C. Small angle x-ray diffraction and transmission electron microscopy were used to estimate the multilayer period. Interdiffusion in the multilayers was directly computed from the decay of the satellites near (000) in a small angle x-ray diffraction spectrum. A kinetic analysis of interdiffusion suggests that grain growth is concurrent with grain boundary diffusion of Ta in Ni81Fe19. The evolution of soft magnetic properties of Ni81Fe19, i.e., lowering of 4piM(s) and increase in coercivity H(c), also lend support to the above analysis

Ridge-Adjusted Slack Variable Optimization for Supervised Classification

This paper presents an iterative classification algorithm called Ridge-adjusted Slack Variable Optimization (RiSVO). RiSVO is an iterative procedure with two steps: (1) A working subset of the training data is selected so as to reject "extreme" patterns. (2) the decision vector and threshold value are obtained by minimizing the energy function associated with the slack variables. From a computational perspective, we have established a sufficient condition for the "inclusion property" among successive working sets, which allows us to save computation time. Most importantly, under the inclusion property, the monotonic reduction of the energy function can be assured in both substeps at each iteration, thus assuring the convergence of the algorithm. Moreover, ridge regularization is incorporated to improve the robustness and better cope with over-fitting and ill-conditioned problems. To verify the proposed algorithm, we conducted simulations on three data sets from the UCI database: adult, shuttle and bank. Our simulation shows stability and convergence of the RiSVO method. The results also show improvement of performance over the SVM classifier

Clinical development of liposome-based drugs: formulation, characterization, and therapeutic efficacy

Research on liposome formulations has progressed from that on conventional vesicles to new generation liposomes, such as cationic liposomes, temperature sensitive liposomes, and virosomes, by modulating the formulation techniques and lipid composition. Many research papers focus on the correlation of blood circulation time and drug accumulation in target tissues with physicochemical properties of liposomal formulations, including particle size, membrane lamellarity, surface charge, permeability, encapsulation volume, shelf time, and release rate. This review is mainly to compare the therapeutic effect of current clinically approved liposome-based drugs with free drugs, and to also determine the clinical effect via liposomal variations in lipid composition. Furthermore, the major preclinical and clinical data related to the principal liposomal formulations are also summarized

Approximations from Anywhere and General Rough Sets

Not all approximations arise from information systems. The problem of fitting approximations, subjected to some rules (and related data), to information systems in a rough scheme of things is known as the \emph{inverse problem}. The inverse problem is more general than the duality (or abstract representation) problems and was introduced by the present author in her earlier papers. From the practical perspective, a few (as opposed to one) theoretical frameworks may be suitable for formulating the problem itself. \emph{Granular operator spaces} have been recently introduced and investigated by the present author in her recent work in the context of antichain based and dialectical semantics for general rough sets. The nature of the inverse problem is examined from number-theoretic and combinatorial perspectives in a higher order variant of granular operator spaces and some necessary conditions are proved. The results and the novel approach would be useful in a number of unsupervised and semi supervised learning contexts and algorithms.Comment: 20 Pages. Scheduled to appear in IJCRS'2017 LNCS Proceedings, Springe

Mechanical loading impacts intramuscular drug transport : impact on local drug delivery

Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2008.Includes bibliographical references (leaves 152-166).Controlled-release drug-delivery systems enable efficient and defined administration of therapeutic agents to target tissues. However, ultimate drug distribution and pharmacologic effect are determined by target tissue pharmacokinetics. In muscular tissues, complex architecture that is further augmented by dynamic motion and contraction can alter the pharmacokinetics and deposition of locally delivered macromolecules. We developed a system and applied a quantitative schema to investigate the impact of controlled mechanical loads applied to skeletal and cardiac muscle tissue on intramuscular transport of locally delivered drug. In a series of studies, we examined how the interaction between architectural configuration and functional mechanics alters the transport of drugs across both physicochemical and binding properties. We correlated these pharmacokinetic effects with characteristic parameters in the physiologic range of the tissue to derive mechanistic insight into the fundamental structural and dynamic elements that underlie these effects. While previous studies have revealed the unilateral scaling of substrate uptake with mechanical influences, we elucidated an architecturally defined pharmacokinetic setpoint whereby maximal drug penetration corresponds with optimal muscle function. Our findings elucidate basic biologic design in muscle that optimizes the interface between tissue and its physical environment. The unique insights from our investigations have broad impact on current understanding of the pharmacokinetic influences of biologic form and function, and elucidate new clinical strategies for controlled release and local delivery of a wide range of therapeutic compounds to mechanically active tissues.by Peter I-Kung Wu.Ph.D

Skeletal muscle biomechanics drives intramuscular transport of locally delivered drugs

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaves 70-74).Introduction: Effective local drug delivery to contractile tissues such as skeletal muscle requires a thorough understanding of the impact of mechanical loads on intramuscular pharmacokinetics. Current preparations for studying skeletal muscle biomechanics typically use: mounting techniques that lead to mechanical disruption of the tissue, which can create drug transport artifacts. In order to accurately study mechanical influences on drug transport, experimental techniques and setups need to meet the particular design requirements of both biomechanical testing setups and local drug delivery preparations. Studies of intramuscular pharmacokinetics require anatomically physiologic and functionally viable conditions for accurate drug transport. In this study, we invent a method for the surgical isolation and mounting of whole skeletal muscles of small rodents that maintains the physiologic configuration of the tissue. We also invent a mounting assembly and dynamic loading system designed appropriately for in vitro drug transport studies. We present an effective protocol for tissue processing and visually quantifying intramuscular distribution of drug. With the primary objective of investigating muscle pharmacokinetics, we use these techniques in a study to elucidate the influence of mechanical loading on the intramuscular transport and distribution of locally delivered drug. Methods and Results: The dynamic loading system was characterized and used to investigate intramuscular transport of aqueous macromolecular drug. The loading system was designed to achieve a maximal force, velocity, and acceleration of up to 72N, 0.45m/s, and 8.5m/s2, respectively, for imposing cyclic strain on soleus muscle samples. Total compliance of the series assembly from the motor to muscle mounting blocks was less then 0.0057 ± 0.002mm/N.(cont.) Under proportional-integral-derivative (PID) control with a positional resolution of 20gpm, the loading system achieved a positional precision of +60gm or better for sinusoidal reference curves required in our studies. Tissue architectural and functional integrity as well as a technique for quantifying intramuscular fluorescent dextran were validated using the loading system. Histologic studies of rat soleus showed that interstitial porosity was consistent in tissues subjected to mechanical loading for 70 minutes, and changes in porosity were independent of the nature of imposed static (0-15% fixed strain) and cyclic (3Hz sinusoidal strain with amplitude of 2.5% oscillating about mean strains of 5-15%) loads. Permanent changes in architectural integrity depended only on the duration of time spent in vitro after isolation, in which porosity increased at the tissue edge from 11.1 + 3.3% to 21.0 + 6.1% over the course of a 70-minute incubation. The source solution used for local delivery of drug (dextran) preserved tissue functional viability, allowing muscle samples to maintain isometric twitch contractile activity at a rate of 3Hz for at least 1 hour. The active twitch force- length characteristic of soleus samples showed 0.24 + 0.06N at 0% strain, a maximum of 0.35 + 0.06N at 10% strain, and a decrease to 0.19 + 0.06N at 20% strain. Isometric twitch contractile force was at least 0.19N when measured every 15 minutes over a 2 hour period. Fractional volume of distribution for dextran was 84% of the bulk source concentration over the range of 0.1 M-lmM bulk concentrations, and demonstrated the non-binding properties of dextran. Fluorescence intensity of FITC-dextran equilibrated in soleus tissue exhibited a linear dependence on dextran concentration.(cont.) Dextran penetration and distribution in soleus muscles under either cyclic (3Hz, 0-20% peak-to- peak) or static (fixed at 0%) tensile strain for 80 minutes was quantified by fluorescent imaging. Penetration depth of 1mM 20kDa FITC-dextran at the planar surfaces of the soleus increased significantly from 0.52 + 0.09mm under static strain to 0.81 + 0.09mm under cyclic strain. Penetration at the curved margins of the soleus was significantly greater than at planar surfaces by a factor of 1.57 and 2.52 under static and cyclic strain, respectively. Penetration at curved surfaces increased to a greater extent, by a factor of 1.6, than at planar surfaces under cyclic strain. Discussion: This investigation demonstrated that dynamic, or cyclic, tensile strain impacts the penetration and distribution of aqueous drug in skeletal muscle. In the course of this study, we established an effective and robust experimental system and protocol for studying mechanical influences on intramuscular pharmacokinetics. The innovation of our surgical isolation and mounting technique allowed for the investigation of an isolated soleus muscle without disrupting the muscle, tendons, or physiologic bone attachments. The mounting device enabled muscles to be secured in a physiologic in situ configuration, to undergo more physiologically distributed tensile stresses and strains, and to be mechanically loaded while incubated in vitro in drug. Thus, the method and device eliminated the artificial tissue stresses typically introduced by current tissue handling techniques that could result in drug transport artifacts.(cont.) While effective as a standalone biomechanical testing preparation, characterization and validation of the dynamic loading system with a protocol for tissue processing and quantitative assessment of intramuscular fluorescent drug distribution demonstrated that it is a novel and robust preparation for investigating both tissue biomechanics and pharmacokinetics. With the finding from the present study that dynamic loading influences intramuscular drug transport in an architecturally dependent manner, we intend to investigate the isolated effects of different mechanical loading regimens on drug transport to establish a broader understanding of muscle pharmacokinetics. It is hoped that the insights from this work will guide the design and application of future local drug delivery strategies to mechanically active tissues.by Peter I-Kung Wu.S.M

Simulation Modeling of Dual Warehouse System

Warehouse space allocation is a critical issue to be addressed in many firms, especially firms that have various types of products. Further, most of the owned warehouse has a limited capacity which leads to the usage of outsourcing policy for warehouse storage. In this case, a rented warehouse that has more flexibility in terms of capacity is used to store the products. Therefore, an optimal decision of warehouse configuration is required. The previous study proposed a two-stage stochastic optimization model for warehouse configuration and inventory policy for deteriorating items. Unfortunately, direct implementation of their proposed method in real case problems will incur high cost and takes up a lot of time. In this research, a simulation model is developed to monitor the real condition in the company as well as to ensure that the warehouse configuration is suitable to be implemented. A textile and apparel company is used as the study case. The result shows that simulation model can be used to monitor the real condition as well as to obtain the net profit when facing different demand possibility. Keywords: inventory control; real-time monitoring; system simulation; warehouse configuration; warehouse space allocatio

Hydrodynamics of polar liquid crystals

Starting from a microscopic definition of an alignment vector proportional to the polarization, we discuss the hydrodynamics of polar liquid crystals with local $C_{\infty v}$-symmetry. The free energy for polar liquid crystals differs from that of nematic liquid crystals ($D_{\infty h}$) in that it contains terms violating the ${\bf{n}}\to -{\bf{n}}$ symmetry. First we show that these $\mathcal{Z}_2$-odd terms induce a general splay instability of a uniform polarized state in a range of parameters. Next we use the general Poisson-bracket formalism to derive the hydrodynamic equations of the system in the polarized state. The structure of the linear hydrodynamic modes confirms the existence of the splay instability.Comment: 9 pages, corrected typos, added references, revised content, to appear in PR