Machine vision: an aid in reverse Turing test

Information security is perceived as an important and vital aspect for the survival of any business. Preserving user identity and limiting the access of web resources only to the humans and restricting ‘bots’ is an ever challenging area of study. With the increase in computing power and development of newer approaches towards circumvention and reverse-engineering, the recognition gap present between the machines and the humans is said to be decreasing. Turing test and its modified versions are in place to deal with such problems and ways to resolve them by developing complex algorithms for bot prevention systems like CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). This paper will deal with the use of “Machine Vision” for judging the ability of the machines to compete with humans in breaking sequences of security systems like CAPTCHA. Reverse Turing test will be put to practise here. Complex image recognition technologies and novel approaches towards using Human interactive proofs (HIP) are discussed. The progress of Turing test over the past 60 years has been paid due attention at the end. After all this experimentation, it can be said that the current machine vision is quite poor and is far worse than it is expected to be.     

Segmentation of Rumex obtusifolius using Gaussian Markov random fields

Rumex obtusifolius is a common weed that is difficult to control. The most common way to control weeds—using herbicides—is being reconsidered because of its adverse environmental impact. Robotic systems are regarded as a viable non-chemical alternative for treating R. obtusifolius and also other weeds. Among the existing systems for weed control, only a few are applicable in real-time and operate in a controlled environment. In this study, we develop a new algorithm for segmentation of R. obtusifolius using texture features based on Markov random fields that works in real-time under natural lighting conditions. We show its performance by comparing it with an existing real-time algorithm that uses spectral power as texture feature. We show that the new algorithm is not only accurate with detection rate of 97.8 % and average error of 56 mm in estimating the location of the tap-root of the plant, but is also fast taking just 0.18 s to process an image of size $576 \times 432$ pixels making it feasible for real-time applications.     

Collimation testing by use of the Lau effect coupled with moiré readout

We present an easy, simple, and inexpensive technique for checking the quality of the collimation of optical beams using the Lau effect combined with moiré readout. The experimental arrangement consists of a modified Lau-based interferometer in which a white-light incoherent source illuminates a set of two gratings. A collimating lens is placed between the two gratings such that the self-images of the second grating are formed. The third grating is positioned at one of the self-imaging planes forming moiré fringes. The type of the moiré fringe demonstrates the quality of collimation of the optical beam. The necessary theoretical background is presented and the results of our experimental investigation are reported. The technique can also be used for accurate determination of the focal length of a collimating lens using low-cost components.     

Lithium Enhances the GABAergic Synaptic Activities on the Hypothalamic Preoptic Area (hPOA) Neurons

Lithium (Li⁺) salt is widely used as a therapeutic agent for treating neurological and psychiatric disorders. Despite its therapeutic effects on neurological and psychiatric disorders, it can also disturb the neuroendocrine axis in patients under lithium therapy. The hypothalamic area contains GABAergic and glutamatergic neurons and their receptors, which regulate various hypothalamic functions such as the release of neurohormones, control circadian activities. At the neuronal level, several neurotransmitter systems are modulated by lithium exposure. However, the effect of Li⁺ on hypothalamic neuron excitability and the precise action mechanism involved in such an effect have not been fully understood yet. Therefore, Li⁺ action on hypothalamic neurons was investigated using a whole-cell patch-clamp technique. In hypothalamic neurons, Li⁺ increased the GABAergic synaptic activities via action potential independent presynaptic mechanisms. Next, concentration-dependent replacement of Na⁺ by Li⁺ in artificial cerebrospinal fluid increased frequencies of GABAergic miniature inhibitory postsynaptic currents without altering their amplitudes. Li⁺ perfusion induced inward currents in the majority of hypothalamic neurons independent of amino-acids receptor activation. These results suggests that Li⁺ treatment can directly affect the hypothalamic region of the brain and regulate the release of various neurohormones involved in synchronizing the neuroendocrine axis.     

Role of energy transfer,defect, and lattice dimension in photophysical characteristics of AWO4:Nd3+ (A=Ca,Sr and Ba)

The fact that the scheelite based compounds are of high technological importance in the area of scintillator and optoelectronics, makes their detailed photophysical study relevant not only for fundamental material science but also in tailoring their optical properties for advanced applications. With this view, we have carried out a very systematic study on near infra-red (NIR) emitting Nd³⁺ doped CaWO₄, SrWO₄, and BaWO₄ compounds. Light emitting efficiency in AWO4:Nd³⁺ is governed strongly by radiative/nonradiative properties, host-dopant energy transfer (HDET) efficiency and defect density. We have used photoluminescence, positron annihilation, and photoacoustic (PA) spectroscopy to study the factors effecting light emission. These scheelites are known to exhibit self activated luminescence in visible region due to charge transfer within the tungstate group and wavelength maxima exhibited red shift as we move from Ca→Sr→Ba. This can provide a new strategy to achieve spectral tunability in AWO₄ scheelite by changing A²⁺ ionic radius. The fractional intensity in the green region is least in the case of SrWO₄ samples suggesting that the oxygen vacancy density is minimal in case of SrWO₄ which is well-supported by the positron annihilation lifetime spectroscopy (PALS). Based on our studies, we found that the HDET was highly efficient in CaWO₄:Nd³⁺ and minimal in BaWO₄:Nd³⁺ which get's reflected in photoluminescence intensity. Emission lifetimes are shorter in CaWO₄ and highest in SrWO₄ host which are in sync with positron annihilation lifetime values. Based on our results of PALS, it was found that CaWO₄:Nd³⁺ has the highest concentration of defects i.e. cation vacancies; so larger is the probability of nonradiative signals and hence higher PA intensity from it.     

A Drug Screening Pipeline Using 2D and 3D Patient-Derived In Vitro Models for Pre-Clinical Analysis of Therapy Response in Glioblastoma

Glioblastoma is one of the most common and lethal types of primary brain tumor. Despite aggressive treatment with chemotherapy and radiotherapy, tumor recurrence within 6–9 months is common. To overcome this, more effective therapies targeting cancer cell stemness, invasion, metabolism, cell death resistance and the interactions of tumor cells with their surrounding microenvironment are required. In this study, we performed a systematic review of the molecular mechanisms that drive glioblastoma progression, which led to the identification of 65 drugs/inhibitors that we screened for their efficacy to kill patient-derived glioma stem cells in two dimensional (2D) cultures and patient-derived three dimensional (3D) glioblastoma explant organoids (GBOs). From the screening, we found a group of drugs that presented different selectivity on different patient-derived in vitro models. Moreover, we found that Costunolide, a TERT inhibitor, was effective in reducing the cell viability in vitro of both primary tumor models as well as tumor models pre-treated with chemotherapy and radiotherapy. These results present a novel workflow for screening a relatively large groups of drugs, whose results could lead to the identification of more personalized and effective treatment for recurrent glioblastoma.     

Indoor Polycyclic Aromatic Hydrocarbon Concentration in Central India

The indoor burning of different materials like fuels, incense, mosquito coil, candles etc. results in generation of polycyclic aromatic hydrocarbons (PAHs) in an uncontrolled manner. The PAH, i.e., Benzo(a)pyrene (BaP) is considered as most toxic or carcinogenic and the toxicity of other PAHs is related to this compound. Therefore, the concentration and emission fluxes of polycyclic aromatic hydrocarbons (PAHs) emitted during burning of commonly used indoor materials, i.e., 15 fuels (i.e., biomass (BM), coal (C), cow dung (CD), kerosene (K)), 4 incense (IS) and mosquito coil (MC) in Raipur district, Chhattisgarh, central India is described. The samples were taken in September 2013 in indoor environments and respective smoke emitted were collected using high volume United State of America (USA) air sampler on quartz fiber filters. The concentration of total 13 PAHs (∑PAH₁₃) (i.e., phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)-pyrene, dibenz(ah)anthracene, benzo(ghi) perylene, indeno1,2,3-(cd)pyrene, and coronene) in particulate matter (PM₁₀) in the indoor air during burning of the fuels, IS and MC materials ranged from 367–92052 ng m^?3, 4089–14047 ng m^?3, and 66–103 ng m^?3 with mean values of 7767 ± 11809 ng m^?3, 9977 ± 4137 ng m^?3, and 74 ± 20 ng m^?3, respectively. The mean concentration of the ∑PAH₁₃ present in indoor environment is much higher than the WHO limit value of 1.0 ng m^?3. The sources and toxicities of PAHs are discussed.     

Synthesis and in Vitro Evaluation of Novel 5-Nitroindole Derivatives as c-Myc G-Quadruplex Binders with Anticancer Activity

Lead-optimization strategies for compounds targeting c-Myc G-quadruplex (G4) DNA are being pursued to develop anticancer drugs. Here, we investigate the structure-activity- relationship (SAR) of a newly synthesized series of molecules based on the pyrrolidine-substituted 5-nitro indole scaffold to target G4 DNA. Our synthesized series allows modulation of flexible elements with a structurally preserved scaffold. Biological and biophysical analyses illustrate that substituted 5-nitroindole scaffolds bind to the c-Myc promoter G-quadruplex. These compounds downregulate c-Myc expression and induce cell-cycle arrest in the sub-G1/G1 phase in cancer cells. They further increase the concentration of intracellular reactive oxygen species. NMR spectra show that three of the newly synthesized compounds interact with the terminal G-quartets (5′- and 3′-ends) in a 2 : 1 stoichiometry.     

Effects of layered double hydroxides on the thermal and flame retardant properties of intumescent flame retardant high density polyethylene composites

In this study, two layered double hydroxides (LDHs), ZnAl-LDH, and MgAl-LDH, were combined with intumescent flame retardant (IFR) consisting of ammonium polyphosphate and tris (2-hydroxyethyl) isocyanurate to prepare flame retardant high density polyethylene composites. The thermal and flame retardant properties of these composites were investigated by thermogravimetric analysis, limiting oxygen index measurement, and cone calorimetry, while the morphology and chemical structure of the char residue were analyzed by scanning electron microscopy, Fourier transfer infrared spectroscopy, and laser Raman spectroscopy. The results showed that the peak heat release rate (PHRR) of both HD/IFR/Zn-LDH and HD/IFR/Mg-LDH composites was 52.0% and 12.0% lower than that of HD and HD/IFR, respectively, suggesting that there was no difference in the reduction of PHRR between the two LDHs. The use of LDHs resulted in the formation of compact char residue with a high graphitic degree, but no significant increase in tensile strength.     

Solvent‐free cyanoethylation of selected alcohols using amberlyst A‐21 polymer resin

Solvent‐free cyanoethylation of selected alcohols with acrylonitrile (AN) using a weakly basic polymer resin, Amberlyst A‐21 (AA‐21) was studied at 75°C. The conversion of primary alcohols, 1‐octadecanol, hexane‐1,6‐diol, pentaerythritol, but‐2‐yne‐1,4‐diol, N‐methyldiethanolamine, triethanolamine and diethanolamine is higher than secondary alcohols, isopropanol and glycerol in the presence of polymer resin. Of various alcohols, but‐2‐yne‐1,4‐diol gave the product in high conversion (87%) in cyanoethylation with a polymer resin/AN weight ratio of 0.04. The polymer resin showed recycling ability only in two cycles to produce cyanoethylated product from diethanolamine. In case of 1‐octadecanol, hexane‐1,6‐diol, and N‐methyldiethanolamine with AN under similar conditions, no recycling ability was observed. Thermally treated polymer resin at 75°C afforded the product in lower conversion (55%) whereas the same product was obtained in 69% when fresh polymer resin was used in cyanoethylation of 1‐octadecanol. No catalytic effect was observed for polymer resin treated at 100°C. Fourier transform infrared (FTIR) spectra showed CN stretching at 2248 cm^?1 for the polymer resin collected after the reaction which was caused by the AN binding on polymer resin during the reaction. As per thermogravimetric curves, 5% weight loss was observed at 201°C for recovered resin and at 161°C for polymer resin treated at 100°C. Scanning electron microscope images confirmed the AN binding on polymer beads after catalytic activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013