Enhancement of Antibiotic Activity and Reversal of Resistance in Clinically Isolated Methicillin-Resistant Staphylococcus aureus by Trachyspermum ammi Essential Oil

Background and objectives: Methicillin-resistant Staphylococcus aureus (MRSA) has resulted in a worldwide threat due to the virulence and broad distribution in the hospital and community. Novel antibiotics are required to combat the emergence of multidrug-resistant bacteria such as MRSA. In the present study, the antibacterial activity of Trachyspermum ammi essential oil alone and in combination with fifteen antibiotics of different classes against a standard and five clinical strains of MRSAs was investigated. Methods: Chemical composition of the essential oil was investigated by using gas chromatography-mass spectrometry (GC-MS). The possible synergistic interaction of several antibiotics in combination with essential oil was screened by disc diffusion method. Interaction of the essential oil and the candidate antibiotic was investigated by checkerboard assay. Results: The essential oil was rich in thymol (74.2%), p-cymene (16%), and γ-terpinene (7.1%). Combination of sub-inhibitory concentrations of essential oil with vancomycin or gentamicin increased their inhibition zones against MRSA ATCC 33591 and clinically isolated MRSAs. All of the clinically isolated MRSAs were resistant to gentamicin, while combination of gentamicin with the essential oil caused augmentation of the antibacterial activity and 4 to 520-fold decrease in gentamicin minimum inhibitory concentrations was observed against different MRSA strains with fractional inhibitory concentration indices ranging from 0.50 to 0.75. Combination of essential oil with ciprofloxacin or imipenem increased the inhibition zones against some clinically isolated MRSAs. Conclusion: Combination of sub-inhibitory concentrations of T. ammi essential oil and gentamicin could be considered as a new choice for treatment of infectious diseases caused by MRSA strains.  </strong

Dynamic parallelization of javascript applications using an ultra-lightweight speculation mechanism

Abstrac

Sponge: Portable stream programming on graphics engines

Graphics processing units (GPUs) provide a low cost platform for accelerating high performance computations. The introduction of new programming languages, such as CUDA and OpenCL, makes GPU programming attractive to a wide variety of programmers. However, programming GPUs is still a cumbersome task for two primary reasons: tedious performance optimizations and lack of portability. First, optimizing an algorithm for a specific GPU is a time-consuming task that requires a thorough understanding of both the algorithm and the underlying hardware. Unoptimized CUDA programs typically only achieve a small fraction of the peak GPU performance. Second, GPU code lacks efficient portability as code written for one GPU can be inefficient when executed on another. Moving code from one GPU to another while maintaining the desired performance is a non-trivial task often requiring significant modifications to account for the hardware differences. In this work, we propose Sponge, a compilation framework for GPUs using synchronous data flow streaming languages. Sponge is capable of performing a wide variety of optimizations to generate efficient code for graphics engines. Sponge alleviates the problems associated with current GPU programming methods by providing portability across different generations of GPUs and CPUs, and a better abstraction of the hardware details, such as the memory hierarchy and threading model. Using streaming, we provide a writeonce software paradigm and rely on the compiler to automatically create optimized CUDA code for a wide variety of GPU targets. Sponge’s compiler optimizations improve the performance of the baseline CUDA implementations by an average of 3.2x

Platoon-Based Assessment of Two-Way Two-Lane Roads Performance Measure: A Classification Method

Two-way two-lane roads have a significant impact on road transportation infrastructure. Platoon formation on two-lane roads is one of the factors that affect the quality of traffic flow on two-lane roads. More specifically, the creation of a platoon increases the density of vehicles and the number of overtaking maneuvers and decreases the traffic performance of two-lane roads. The present study made an effort to investigate the effect of the platoon characteristics on the traffic flow of vehicles on two-lane roads. Moreover, it strived to develop the nonlinear regression model with a new approach to capacity calculation. Finally, a method for estimating the level of service (LOS) based on the number of followers per capacity (NFPC) and LOS classification using the KNN method was presented. Considering these aims, first, the relevant variables (which were related to platoon) including time headway (Ht), average travel speed (ATS), platoon size (PS), average platoon speed (APS), percentage of heavy vehicles (HV), percent time spent following (PTSF), number of overtaking (NO), density (ρ), and traffic flow were investigated on the examined roads. The results showed that the speed and the Ht were the most effective and the least effective platoon characteristics, respectively. Moreover, it was accompanied by the increase in PTSF which resulted in the increase in overtaking maneuver. Finally, the results regarding the developed model showed that the NFPC measure was able to predict the traffic flow of two-lane roads in a more satisfactory way compared to the two criteria, namely, PTSF and ATS in the Highway Capacity Manual (2016) since it increased ATS by 65% and decreased the capacity of two-lane roads by 21%