1,609 research outputs found
Risk adjusted asset valuation using a probabilistic approach with optimized asking rents and resale timing options
Thesis (S.M. in Real Estate Development)--Massachusetts Institute of Technology, Program in Real Estate Development in Conjunction with the Center for Real Estate, 2013.Cataloged from PDF version of thesis.The model developed here provides an enhancement of the traditional DCF asset acquisition valuation template, in Excel. It provides a relatively transparent and user-friendly yet flexible risk-adjusted valuation of a subject individual acquisition, structured to consider the asset either as a core asset or a value-add asset. This study applies a basic stock flow model of space market dynamics to address the question of covariance among input variables. The model is designed with optional probabilistic inputs and historical data for the local space market (employment, rents, net rentable area, occupied space, new completions, vacancy and absorption) and the asset market (cap rates history) to produce a 15-year forecast for the relevant space and asset market for the subject property. An optional optimal rent module in the model uses the forecasted cap rates and consequent opportunity cost of capital to arrive at optimal asking rents for the subject property. The existing rent roll is combined with the future rents and vacancies along with asset level projections of operating costs and capital expenditures to arrive at the cash flow projections. Renewal probability and probability to lease up are major differentiating factors between the core and value add asset. The model also enables the user to optionally consider how flexibility in resale timing can improve the overall return performance from a probabilistic perspective. The output of the model includes an apprehension of the entire going-in risk return relationship, depicted relative to a relevant security market line generated by the input risk free interest rate and the opportunity cost of capital in the relevant asset market. Key words: Probabilistic, risk adjusted valuation, forecast, optimal rent, flexibility, renewal probability, probability to lease up.by Sarwesh Paradkar.S.M.in Real Estate Developmen
Controlled release floating multiparticulates of metoprolol succinate by hot melt extrusion
YesWe present hot melt extrusion (HME) for the design of floating multiparticulates. Metoprolol succinate was selected as the model drug. Our foremost objective was to optimize the components Eudragit® RS PO, polyethylene oxide (PEO) and hydroxypropyl methylcellulose (HPMC) to balance both buoyancy and controlled release. Gas generated by sodium bicarbonate in acidic medium was trapped in the polymer matrix to enable floating. Eudragit® RS PO and PEO with sodium bicarbonate resulted in multiparticulates which exhibited rapid flotation within 3 minutes but inadequate total floating time (TFT) of 3 hours. Addition of HPMC to the matrix did not affect floating lag time (FLT), moreover TFT increased to more than 12 hours with controlled release of metoprolol succinate. Floating multiparticulates exhibited t50% of 5.24 hours and t90% of 10.12 hours. XRD and DSC analysis revealed crystalline state of drug while FTIR suggested nonexistence of chemical interaction between the drug and the other excipients. The assay, FLT, TFT and the drug release of the multiparticulates were unchanged when stored at 40 °C/75%RH for 3 months confirming stability. We present floating multiparticulates by HME which could be extrapolated to a range of other drugs. Our approach hence presents platform technology for floating multiparticulates
Finding Bugs in Web Applications Using Dynamic Test Generation and Explicit State Model Checking
Web script crashes and malformed dynamically-generated web pages are common errors, and they seriously impact the usability of web applications. Current tools for web-page validation cannot handle the dynamically generated pages that are ubiquitous on today's Internet. We present a dynamic test generation technique for the domain of dynamic web applications. The technique utilizes both combined concrete and symbolic execution and explicit-state model checking. The technique generates tests automatically, runs the tests capturing logical constraints on inputs, and minimizes the conditions on the inputs to failing tests, so that the resulting bug reports are small and useful in finding and fixing the underlying faults. Our tool Apollo implements the technique for the PHP programming language. Apollo generates test inputs for a web application, monitors the application for crashes, and validates that the output conforms to the HTML specification. This paper presents Apollo's algorithms and implementation, and an experimental evaluation that revealed 302 faults in 6 PHP web applications
Finding Bugs In Dynamic Web Applications
Web script crashes and malformed dynamically-generated web pages are common errors, and they seriously impact usability of web applications. Currenttools for web-page validation cannot handle the dynamically-generatedpages that are ubiquitous on today's Internet.In this work, we apply a dynamic test generation technique, based oncombined concrete and symbolic execution, to the domain of dynamic webapplications. The technique generates tests automatically andminimizes the bug-inducing inputs to reduce duplication and to makethe bug reports small and easy to understand and fix.We implemented the technique in Apollo, an automated tool thatfound dozens of bugs in real PHP applications. Apollo generatestest inputs for the web application, monitors the application forcrashes, and validates that the output conforms to the HTMLspecification. This paper presents Apollo's algorithms andimplementation, and an experimental evaluation that revealed a totalof 214 bugs in 4 open-source PHP web applications
Ispitivanje vosku sličnih svojstava ibuprofena kao veziva
The study investigates ibuprofen with wax-like properties as a multifunctional agent (as an active component and as a melt binder). Binding efficiency was compared with granules prepared by wet granulation using polyvinylpyrollidone (PVP K-30) as a binder for micromeritic, physical and mechanical properties such as angle of repose, particle size distribution Carr’s index, Hausner’s ratio, crushing strength, percentage fines, Heckel plot study and tensile strength. To check the binder distribution during melt granulation, content uniformity was determined. To check changes in the physical state of ibuprofen, XRPD, DSC and FTIR studies were carried out. The present study underlines the fact that ibuprofen may be adopted as a binder in ibuprofen formulations using the melt granulation techniqueSvrha rada je ispitivanje vosku sličnih svojstava ibuprofena, tvari s višeznačnom funkcijom (ljekovita tvar i vezivo pri granulaciji). Vezivna svojstva uspoređivana su s granulama pripravljenim vlažnom granulacijom s polivinilpirolidonom (PVP K-30) kao vezivom, ispitivanjem mikrometričkih, fizikalnih i mehaničkih svojstava kao što su sipkost materijala, Carrov indeks distribucije veličine čestica, Hausnerov parameter, otpornost na vlak. Da bi se ispitala distribucija veziva tijekom granulacije taljenjem određivana je ujednačenost sadržaja. Za praćenje promjena fizikalnih svojstava ibuprofena snimljeni su XRPD, DSC, FTIR spektri. Istraživanja ukazuju da se ibuprofen može koristiti kao vezivo u ljekovitim pripravcima ibuprofena u kojima se primjenjuje granulacija taljenjem
Investigation of Plasma Treatment on Micro-Injection Moulded Microneedle for Drug Delivery
YesPlasma technology has been widely used to increase the surface energy of the polymer surfaces for many industrial applications; in particular to increase in wettability. The present work was carried out to investigate how surface modification using plasma treatment modifies the surface energy of micro-injection moulded microneedles and its influence on drug delivery. Microneedles of polyether ether ketone and polycarbonate and have been manufactured using micro-injection moulding and samples from each production batch have been subsequently subjected to a range of plasma treatment. These samples were coated with bovine serum albumin to study the protein adsorption on these treated polymer surfaces. Sample surfaces structures, before and after treatment, were studied using atomic force microscope and surface energies have been obtained using contact angle measurement and calculated using the Owens-Wendt theory. Adsorption performance of bovine serum albumin and release kinetics for each sample set was assessed using a Franz diffusion cell. Results indicate that plasma treatment significantly increases the surface energy and roughness of the microneedles resulting in better adsorption and release of BSA
Coformer Replacement as an Indicator for Thermodynamic Instability of Cocrystals: Competitive Transformation of Caffeine:Dicarboxylic Acid
yesThe thermodynamic stability of caffeine (CA) cocrystals with dicarboxylic acids (DAs) as coformers was investigated in the presence of a range of structurally related dicarboxylic acids (SRDs). Two experimental conditions (slurry and dry-grinding) were studied for mixing the cocrystal and the SRD additive. The additives oxalic, malonic and glutaric acid led to the replacement of the acid coformer for certain cocrystals. Interestingly, a change in stoichiometry was observed for the CA:maleic acid system. A stability order among the cocrystals was established depending on their tendency to replace the coformer. To understand the factors controlling the relative stabilities, lattice energies were calculated using dispersion corrected Density Functional Theory (DFT). Gibbs free energy changes were calculated from experimental solubilities. The observed stability order corroborated well with lattice energy and Gibbs free energy computations
Application of hot melt extrusion for improving bioavailability of artemisinin a thermolabile drug
Hot melt extrusion has been used to produce a solid dispersion of the thermolabile drug artemisinin. Formulation and process conditions were optimized prior to evaluation of dissolution and biopharmaceutical performance. Soluplus®, a low Tg amphiphilic polymer especially designed for solid dispersions enabled melt extrusion at 110 °C although some drug-polymer incompatibility was observed. Addition of 5% citric acid as a pH modifier was found to suppress the degradation. The area under plasma concentration time curve (AUC0–24h) and peak plasma concentration (Cmax) were four times higher for the modified solid dispersion compared to that of pure artemisinin
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