Identification of the transition rule in a modified cellular automata model: the case of dendritic NH4Br crystal growth

A method of identifying the transition rule, encapsulated in a modified cellular automata (CA) model, is demonstrated using experimentally observed evolution of dendritic crystal growth patterns in NH4Br crystals. The influence of the factors, such as experimental set-up and image pre-processing, colour and size calibrations, on the method of identification are discussed in detail. A noise reduction parameter and the diffusion velocity of the crystal boundary are also considered. The results show that the proposed method can in principle provide a good representation of the dendritic growth anisotropy of any system

Spatio-temporal modelling of wave formation in an excitable chemical medium based on a revised FitzHugh-Nagumo model

The wavefront profile and the propagation velocity of waves in an experimentally observed Belousov-Zhabotinskii reaction are analyzed and a revised FitzHumgh-Nagumo(FHN) model of these systems is identified. The ratio between the excitation period and the recovery period, for a solitary wave are studied, and included within the model. Averaged travelling velocities at different spatial positions are shown to be consistent under the same experimental conditions. The relationship between the propagation velocity and the curvature of the wavefront are also studied to deduce the diffusion coefficient in the model, which is a function of the curvature of the wavefront and not a constant. The application of the identified model is demonstrated on real experimental data and validated using multi-step ahead predictions

Intratumoral Injection of Propionibacterium acnes Suppresses Malignant Melanoma by Enhancing Th1 Immune Responses

Malignant melanoma (MM) is an aggressive cutaneous malignancy associated with poor prognosis; many putatively therapeutic agents have been administered, but with mostly unsuccessful results. Propionibacterium acnes (P. acnes) is an aerotolerant anaerobic gram-positive bacteria that causes acne and inflammation. After being engulfed and processed by phagocytes, P. acnes induces a strong Th1-type cytokine immune response by producing cytokines such as IL-12, IFN-γ and TNF-α. The characteristic Th2-mediated allergic response can be counteracted by Th1 cytokines induced by P. acnes injection. This inflammatory response induced by P. acnes has been suggested to have antitumor activity, but its effect on MM has not been fully evaluated

Safety and feasibility of a cloud-based architecture for multi-vehicle system

Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 97-101).Cloud computing is widely adopted in industry sectors of finance, energy and transportation. Public cloud service providers are able to consistently deliver solutions that meet demanding needs of security, availability, scalability of mission-critical applications. The low cost of compute and storage, combined with expanding coverage of high speed cellular networks, have enabled a wide expansion of telemetry services and consumer applications in automobiles, but safety applications are not leveraging these benefits. The majority of traffic fatalities happens in high-speed multi-vehicle crashes. Causal analysis of multi-vehicle crashes reveal process model inconsistencies that lead the drivers to make wrong assumptions about vehicle capabilities and lead-vehicle separation distances during adverse road conditions. The Spot Weather Impact Warning (SWIW) is a connected vehicle application concept proposed by the US Department of Transportation (DOT) that alerts drivers to unsafe conditions at specific points on the downstream roadway as a result of weather-related impacts. The application is designed to warn drivers about inclement weather conditions that may impact travel conditions using real-time weather information that is collected from roadway infrastructure and vehicle based probe data. The information is processed to determine the nature of the alert or warning to be delivered and then communicated to connected vehicles. The effectiveness of SWIW connected vehicle application depends on the probe coverage and the speed that probe data can be collected, analyzed, and broadcasted to relevant vehicles and roadway signage. To reach a sufficient coverage without high investment in new infrastructure, SWIW applications can be architected to use existing mobile operators and cloud service providers. A deeper Systems Theoretic Process Analysis of the application reveals that varying levels of vehicle-to-cloud communication performance may lead to process model inconsistencies for drivers, resulting in unsafe control actions from driver that ignore warnings and lead to accidents. To validate the vehicle to cloud communication performance, the SWIW application prototype is built using existing cloud service and vehicle platform. The performance of the application is validated across all tier-one cloud and mobile service providers in 10,000 miles of US roadways. The test results reveal the presence of low latency corridors in the US that may support the initial deployment of low latency solution. String stability model showed that significant reduction in probability of accidents is possible even at low penetration rates of the solution. The solution's operational cost analysis also concludes that a limited deployment on commercial vehicles has the potential of saving high value corridors such as the 402-mile Wyoming I-80 corridor as much as $1.5 million per day of socio-economic losses in accidents with an operational cost of$763 per day. This thesis concludes that connected vehicle programs that are addressing multi-vehicle accidents in low latency corridors should consider commercial fleet deployments that use mobile and public cloud service providers to quickly reach minimal penetration rate and socio-economic benefits.by Ricardo DeMatos.S.M. in Engineering and Managemen

Solvent influences on metastable polymorph lifetimes: real-time interconversions using energy dispersive X-ray diffractometry

Solvent influences on the crystallization of polymorph and hydrate forms of the nootropic drug piracetam (2-oxo-pyrrolidineacetamide) were investigated from water, methanol, 2-propanol, isobutanol, and nitromethane. Crystal growth profiles of piracetam polymorphs were constructed using time-resolved diffraction snapshots collected for each solvent system. Measurements were performed by in situ energy dispersive X-ray diffraction recorded in Station 16.4 at the synchrotron radiation source (SRS) at Daresbury Laboratory, CCLRC UK. Crystallizations from methanol, 2-propanol, isobutanol, and nitromethane progressed in a similar fashion with the initial formation of form I which then converted relatively quickly to form II with form III being generated upon further cooling. However, considerable differences were observed for the polymorphs lifetime and both the rate and temperature of conversion using the different solvents. The thermodynamically unstable form I was kinetically favored in isobutanol and nitromethane where traces of this polymorph were observed below 10°C. In contrast, the transformation of form II and subsequent growth of form III were inhibited in 2-propanol and nitromethane solutions. Aqueous solutions produced hydrate forms of piracetam which are different from the reported monohydrate; this crystallization evolved through successive generation of transient structures which transformed upon exchange of intramolecular water between the liquid and crystalline phases. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association

Solution-Mediated Polymorphic Transformation: Form II to Form III Piracetam in Organic Solvents

NoThe solution-mediated polymorphic transformation from Form II to Form III 2-oxo-1-pyrrolidine acetamide (piracetam) was investigated in seven organic solvents over the temperature range of 5–50 °C. The transformation rate increased as a function of temperature, agitation, and the solubility of piracetam in the host solvent. However, this trend was reversed in 2-propanol. Molecular modeling demonstrated that 2-propanol forms interactions with piracetam molecules in solution stronger than those formed by other solvents, thereby retarding the nucleation and growth of FIII(6.525) during the transformation in this solvent.SF

Polymorphism and hydrated states in 5-nitrouracil crystallized from aqueous solution

The crystallization of 5-nitrouracil (5NU) from pure aqueous solution yields two anhydrous polymorphs and a monohydrate depending on the temperature at which the process is carried out. 5NU mimics true polymorphism in that, when retained in aqueous solution, both metastable (anhydrous) forms undergo solvent mediated phase transformations (SMPTs) into the more thermodynamically stable hydrated form as would be predicted by Ostwald’s rule of stages. The phase transformations can occur either in the classical manner of dissolution and recrystallization or, in one case, may in some circumstances be nucleated and morphologically templated by the original crystalline form. There is no appearance from aqueous solution of a known third acentric anhydrous form, previously prepared from acetonitrile solutions. Preliminary experiments suggest this nonappearance may result from the relatively high solubility of this form in aqueous solution