Managing lane-changing of algorithm-assisted drivers

Theoretical models of vehicular traffic ascribe the fundamental cause of velocity oscillations and stop-and-go waves to suboptimal or unpredictable human driving behavior. In this paper we ask: if vehicles were controlled or assisted by algorithms, and hence driven “optimally,” would these phenomena simply go away? If they do not, how should a regulator manage algorithm-assisted vehicular traffic for a smooth flow? We study these questions in the context of a mandatory lane-changing scenario from the perspective of an algorithm-assisted driver on a curtailed lane that has to merge to an adjacent free lane with a relatively dense platoon. In a stylized model of algorithm-assisted driving, we liken the blocked-lane driver to a rational self-interested agent, whose objective is to minimize her expected travel time through the blockage, deciding (a) at what velocity to move, and (b) whether to merge to the free lane if an adequate gap arises. Moving at higher velocities reduces travel time, but also reduces the probability of finding a large enough gap to merge. We analyze the problem via dynamic programming, and we show that the optimal policy has a surprising structure: in the presence of uncertainty on adequate-sized gaps in the target lane, it may be optimal for the blocked-lane driver, in certain parameter regimes, to oscillate between high and low velocities while attempting to merge. Hence, traffic oscillations can arise not just due to suboptimal or unpredictable human driving behavior, but also endogenously, as the outcome of a driver’s rational, optimizing behavior. We provide theoretical support for this finding by drawing similarities to bang–bang control. As velocity oscillations are known to be detrimental to a smooth traffic flow, we provide sufficient conditions such that traffic oscillations, due to such optimizing behavior, do not arise. Finally, we investigate the fundamental flow-density and travel time-density diagrams through traffic micro-simulations performed in SUMO. We establish that the proposed approach exhibits consistently near-optimal performance, in a broad variety of traffic conditions

Novel microfilaricidal activity of nanosilver

Sunil K Singh1, Kalyan Goswami2, Richa D Sharma2, Maryada VR Reddy2, Debabrata Dash11Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 2Department of Biochemistry, Mahatma Gandhi Institute of Medical Sciences, Sevagram, IndiaPurpose: The currently available drug repertoire against lymphatic filariasis, a major health hazard in the developing world, is inadequate and is fraught with serious limitations. Thus, the development of an effective antifilarial strategy has become a global research thrust mandated by the World Health Organization. Nanoparticles of silver endowed with antibacterial potency are known to induce apoptosis in eukaryotic cells. The present study was designed to investigate the possible microfilaricidal efficacy of silver nanoparticles and to establish the validity of apoptotic rationale in antifilarial drug designing.Methods: This report analyzed the effect of nanoparticles of silver as well as gold (size range: 10–15 nm) on the microfilariae of Brugia malayi obtained from the lavage of peritoneal cavities of infected jirds (Meriones unguiculatus). The study included a microfilarial motility assay, a trypan blue exclusion test, a poly(adenosine diphosphate-ribose) polymerase activity study, ethidium bromide/acridine orange differential staining, and transmission, as well as scanning electron microscopic evaluation of ultrastructural changes in microfilariae.Results: The study demonstrates that nanoparticles of silver, but not of gold, elicited significant loss in microfilarial motility. Differential staining of parasites with ethidium bromide and acridine orange, poly(adenosine diphosphate-ribose) polymerase activity in microfilarial lysate, and electron microscopic findings underscored apoptotic death of parasites attributable to nanosilver. In a trypan blue exclusion test, the 50% lethal dose of nanosilver was measured to be 101.2 µM, which was higher than the recorded complete inhibitory concentration value (50.6 µM), thus supporting nanosilver as a potential drug candidate against lymphatic filariasis.Conclusion: The present report provides the first ever conclusive proof in support of apoptosis as a novel stratagem in antifilarial drug designing and nanoscale silver as a valid lead in research on antifilarial therapeutics. The main embargo about the current drug diethylcarbamazine citrate is its empirical use without rationale. Effective microfilaricidal activity of nanosilver at relatively low concentrations as reported in this study, with evidence of the induction of apoptosis in microfilariae, projects nanosilver as a potential drug adjuvant against lymphatic filariasis. The much higher 50% lethal dose value of nanosilver compared to the complete inhibitory concentration value reported in this study argues in favor of a safe therapeutic window of this agent in its antifilarial efficacy.Keywords: silver nanoparticles, apoptosis, lymphatic filariasis, microfilaricidal agent, parasitic disease

Comparative evaluation of sealer penetration depth into radicular dentinal tubules using confocal scanning microscope: an in vitro study

Background: Endodontic treatment involves the removal of the vital and necrotic contents of the root canal through chemo-mechanical means followed by obturation of the prepared root canal to prevent the ingress of fluids and avoid bacterial infection or regrowth. Root canal sealers and core filling materials are used together to fill the irregularities in the root. Penetration into the dentinal tubules also results in the inhibition of bacterial regrowth and increases the success of root canal therapy. Aim: This study aimed to evaluate the penetration depth of various sealers into the dentinal tubules using a confocal microscope. Materials and methods: A total of 65 specimens were decoronated to standardize the root length of 13mm. Working length was determined, and Biomechanical preparation for all the samples was done with a rotary ProTaper file till F4. Samples were randomly divided into five groups containing 13 teeth in each group based on the sealer used, namely Group 1: Endomethasone (n=13), Group 2: AH-Plus (n=13), Group 3: Roekoseal (n=13), Group 4: MTA Fillapex (n=13), Group 5: Endosequence BC (n=13). All the sealers were labelled with Rhodamine-B dye, and samples were obturated using cold lateral compaction technique. The specimens were sectioned orthogonally at coronal, middle, and apical thirds. All the samples were examined with a Zeiss Pascal Laser Scanning Microscope to examine the sealer penetration depth into the dentinal tubules. The data were subjected to statistical analysis using one- way Analysis of Variance (ANOVA) and Tukey\u27s Honest Significant Difference (HSD) tests. Results: Endosequence BC showed the highest penetration into dentinal tubules, followed by MTA Fillapex and Roekoseal, AH-Plus, and Endomethasone exhibited the least penetration. Conclusion: Endosequence BC sealer exhibited maximum penetration. All the groups showed maximum penetration at coronal third, followed by the middle and apical third

A comprehensive review on electrospinning design, parameters and potential use of electrospun nanofibers in regenerative endodontics

Electrospinning is a versatile technique that has gathered interest due to its ability to fabricate nano and microscale fibres with unique properties of high surface area and fibrous porosity. This technique has been widely used in the late 20th (1990) and early 21st (2000) centuries. Since the beginning of its use, significant improvements have been made in the design, materials used, and fibres produced. The electrospinning technique is used to fabricate a material with therapeutic properties as it allows the researchers to incorporate various anti-microbial agents to different polymers without altering the chemical characteristicsof polymers.The production of nanofibres through electrospinning is affected by many operating parameters. It is, therefore, essential to know various parameters and processes that aid in fabricating the desired fibre assemblies. The nanofibres remain an essential division of biomaterials due to a wide range of biomedicalapplications. Nanofibres have unique properties such as protein absorption, binding sites to cell receptors, can provide maximum volume fraction by controlling fibres\u27 alignment and orientation hence improving the material properties like surface morphology, porosity, and geometry.Recent trends in endodontics, encourage regenerative therapy for the treatment of necrotic immature permanent teeth for root development and maturation. In this context, efficient disinfection of the root canal system is a crucial step. Existing chemical irrigating solutions (for eg., NaOCl) and antibiotic pastes (for eg., Triple antibiotic paste) usage at higher doses showed toxic results on the pulpal stem cells. Therefore, it was found to be beneficial to use a nanofibre-based intracanal drug delivery construct to release antibiotics at lower, yet anti-microbially effective concentrations.This review aims to discuss the basic concepts of electrospinning and its potential application in regenerative endodontics along with various parameters, which affect the fibre morphology and properties of produced nanofibres

Video face replacement

We present a method for replacing facial performances in video. Our approach accounts for differences in identity, visual appearance, speech, and timing between source and target videos. Unlike prior work, it does not require substantial manual operation or complex acquisition hardware, only single-camera video. We use a 3D multilinear model to track the facial performance in both videos. Using the corresponding 3D geometry, we warp the source to the target face and retime the source to match the target performance. We then compute an optimal seam through the video volume that maintains temporal consistency in the final composite. We showcase the use of our method on a variety of examples and present the result of a user study that suggests our results are difficult to distinguish from real video footage.National Science Foundation (U.S.) (Grant PHY-0835713)National Science Foundation (U.S.) (Grant DMS-0739255

Network Modeling of Liver Metabolism to Predict Plasma Metabolite Changes During Short-Term Fasting in the Laboratory Rat

The liver—a central metabolic organ that integrates whole-body metabolism to maintain glucose and fatty-acid regulation, and detoxify ammonia—is susceptible to injuries induced by drugs and toxic substances. Although plasma metabolite profiles are increasingly investigated for their potential to detect liver injury earlier than current clinical markers, their utility may be compromised because such profiles are affected by the nutritional state and the physiological state of the animal, and by contributions from extrahepatic sources. To tease apart the contributions of liver and non-liver sources to alterations in plasma metabolite profiles, here we sought to computationally isolate the plasma metabolite changes originating in the liver during short-term fasting. We used a constraint-based metabolic modeling approach to integrate central carbon fluxes measured in our study, and physiological flux boundary conditions gathered from the literature, into a genome-scale model of rat liver metabolism. We then measured plasma metabolite profiles in rats fasted for 5–7 or 10–13 h to test our model predictions. Our computational model accounted for two-thirds of the observed directions of change (an increase or decrease) in plasma metabolites, indicating their origin in the liver. Specifically, our work suggests that changes in plasma lipid metabolites, which are reliably predicted by our liver metabolism model, are key features of short-term fasting. Our approach provides a mechanistic model for identifying plasma metabolite changes originating in the liver

Detailed Enzyme Kinetics in Terms of Biochemical Species: Study of Citrate Synthase

The compulsory-ordered ternary catalytic mechanism for two-substrate two-product enzymes is analyzed to account for binding of inhibitors to each of the four enzyme states and to maintain the relationship between the kinetic constants and the reaction equilibrium constant. The developed quasi-steady flux expression is applied to the analysis of data from citrate synthase to determine and parameterize a kinetic scheme in terms of biochemical species, in which the effects of pH, ionic strength, and cation binding to biochemical species are explicitly accounted for in the analysis of the data. This analysis provides a mechanistic model that is consistent with the data that have been used support competing hypotheses regarding the catalytic mechanism of this enzyme

T-Cell Assays for Tuberculosis Infection: Deriving Cut-Offs for Conversions Using Reproducibility Data

Although interferon-gamma release assays (IGRA) are promising alternatives to the tuberculin skin test, interpretation of repeated testing results is hampered by lack of evidence on optimal cut-offs for conversions and reversions. A logical start is to determine the within-person variability of T-cell responses during serial testing.We performed a pilot study in India, to evaluate the short-term reproducibility of QuantiFERON-TB Gold In Tube assay (QFT) among 14 healthcare workers (HCWs) who underwent 4 serial QFT tests on day 0, 3, 9 and 12. QFT ELISA was repeated twice on the same sets of specimens. We assessed two types of reproducibility: 1) test-retest reproducibility (between-test variability), and 2) within-person reproducibility over time. Test-retest reproducibility: with dichotomous test results, extremely high concordance was noticed between two tests performed on the same sets of specimens: of the 56 samples, the test and re-test results agreed for all but 2 individuals (kappa = 0.94). Discordance was noted in subjects who had IFN-gamma values around the cut-off point, with both increases and decreases noted. With continuous IFN-gamma results, re-test results tended to produce higher estimates of IFN-gamma than the original test. Within-person reproducibility: when continuous IFN-gamma data were analyzed, the within-person reproducibility was moderate to high. While persons with negative QFT results generally stayed negative, positive results tended to vary over time. Our data showed that increases of more than 16% in the IFN-gamma levels are statistically improbable in the short-term.Conservatively assuming that long-term variability might be at least twice higher than short-term, we hypothesize that a QFT conversion requires two conditions to be met: 1) change from negative to positive result, and 2) at least 30% increase in the baseline IFN-gamma response. Larger studies are needed to confirm our preliminary findings, and determine the conversion thresholds for IGRAs