Activation of cannabinoid system in anterior cingulate cortex and orbitofrontal cortex modulates cost-benefit decision making

Despite the evidence for altered decision making in cannabis abusers, the role of the cannabinoid system in decision-making circuits has not been studied. Here, we examined the effects of cannabinoid modulation during cost-benefit decision making in the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC), key brain areas involved in decision making. We trained different groups of rats in a delay-based and an effort-based form of cost-benefit T-maze decision-making task. During test days, the rats received local injections of either vehicle or ACEA, a cannabinoid type-1 receptor (CB1R) agonist in the ACC or OFC. We measured spontaneous locomotor activity following the same treatments and characterized CB1Rs localization on different neuronal populations within these regions using immunohistochemistry. We showed that CB1R activation in the ACC impaired decision making such that rats were less willing to invest physical effort to gain high reward. Similarly, CB1R activation in the OFC induced impulsive pattern of choice such that rats preferred small immediate rewards to large delayed rewards. Control tasks ensured that the effects were specific for differential cost-benefit tasks. Furthermore, we characterized widespread colocalizations of CB1Rs on GABAergic axonal ends but few colocalizations on glutamatergic, dopaminergic, and serotonergic neuronal ends. These results provide first direct evidence that the cannabinoid system plays a critical role in regulating cost-benefit decision making in the ACC and OFC and implicate cannabinoid modulation of synaptic ends of predominantly interneurons and to a lesser degree other neuronal populations in these two frontal regions

Optimized Architectures for Elliptic Curve Cryptography over Curve448

Abstract. In this paper, we present different implementations of point multiplication over Curve448. Curve448 has recently been recommended by NIST to provide 224-bit security over elliptic curve cryptography. Although implementing high-security cryptosystems should be considered due to recent improvements in cryptanalysis, hardware implementation of Curve488 has been investigated in a few studies. Hence, in this study, we propose three variable-base-point FPGA-based Curve448 implementations, i.e., lightweight, area-time efficient, and high-performance architectures, which aim to be used for different applications. Synthesized on a Xilinx Zynq 7020 FPGA, our proposed high-performance design increases 12% throughput with executing 1,219 point multiplication per second and increases 40% efficiency in terms of required clock cycles\timesutilized area compared to the best previous work. Furthermore, the proposed lightweight architecture works in 250 MHz and saves 96% of resources with the same performance. Additionally, our area-time efficient design considers a trade-off between time and required resources, which shows a 48% efficiency improvement with 52% fewer resources. Finally, effective side-channel countermeasures are added to our proposed designs, which also outperform previous works

High-Speed NTT-based Polynomial Multiplication Accelerator for CRYSTALS-Kyber Post-Quantum Cryptography

This paper demonstrates an architecture for accelerating the polynomial multiplication using number theoretic transform (NTT). Kyber is one of the finalists in the third round of the NIST post-quantum cryptography standardization process. Simultaneously, the performance of NTT execution is its main challenge, requiring large memory and complex memory access pattern. In this paper, an efficient NTT architecture is presented to improve the respective computation time. We propose several optimization strategies for efficiency improvement targeting different performance requirements for various applications. Our NTT architecture, including four butterfly cores, occupies only 798 LUTs and 715 FFs on a small Artix-7 FPGA, showing more than 44% improvement compared to the best previous work. We also implement a coprocessor architecture for Kyber KEM benefiting from our high-speed NTT core to accomplish three phases of the key exchange in 9, 12, and 19 \mus, respectively, operating at 200 MHz

Compressed SIKE Round 3 on ARM Cortex-M4

In 2016, the National Institute of Standards and Technology (NIST) initiated a standardization process among the post-quantum secure algorithms. Forming part of the alternate group of candidates after Round 2 of the process is the Supersingular Isogeny Key Encapsulation (SIKE) mechanism which attracts with the smallest key sizes offering post-quantum security in scenarios of limited bandwidth and memory resources. Even further reduction of the exchanged information is offered by the compression mechanism, proposed by Azarderakhsh et al., which, however, introduces a significant time overhead and increases the memory requirements of the protocol, making it challenging to integrate it into an embedded system. In this paper, we propose the first compressed SIKE implementation for a resource-constrained device, where we targeted the NIST recommended platform STM32F407VG featuring ARM Cortex-M4 processor. We integrate the isogeny-based implementation strategies described previously in the literature into the compressed version of SIKE. Additionally, we propose a new assembly design for the finite field operations particular for the compressed SIKE, and observe a speedup of up to 16% and up to 25% compared to the last best-reported assembly implementations for p434, p503, and p610

Fast, Small, and Area-Time Efficient Architectures for Key-Exchange on Curve25519

Abstract--- This paper demonstrates fast and compact implementations of Elliptic Curve Cryptography (ECC) for efficient key agreement over Curve25519. Curve25519 has been recently adopted as a key exchange method for several applications such as connected small devices as well as cloud, and included in the National Institute of Standards and Technology (NIST) recommendations for public key cryptography. This paper presents three different performance level designs including lightweight, area-time efficient, and high-performance architectures. Lightweight hardware implementations are used for several Internet of Things (IoT) applications due to their resources being at premium. Our lightweight architecture utilizes 90% less resources compared to the best previous work while it is still more optimized in term of A\cdot T (area\timestime). For efficient implementation from either time or utilized resources, our area-time efficient architecture can establish almost 7,000 key sessions per second which is 64% faster than the previous works. The area-time efficient architecture uses well scheduled interleaved multiplication combined with a reduction algorithm. Additionally, we offer a fast architecture for high performance applications based on the 4-level Karatsuba method and Carry-Compact Addition (CCA). Our high-performance architecture also outperforms previous work in terms of A\cdot T. The results show 9% and 29% improvement in A\cdot T and A_{d}\cdot T (DSP_count\timestime), respectively. All architectures are variable-base-point implemented on the Xilinx Zynq-7020 FPGA family where performance and implementation metrics are reported and compared. Finally, various side-channel attack countermeasures are embedded in the proposed architectures

Enhancement Of Water-oil Separation By Electroclescence

Dispersed water droplets in organic liquids are commonly encountered in the oil, chemical and biochemical industries. A typical example is the separation of dispersed water drops in crude oil, in order to prevent catalyst fouling, viscosity and volume increase, and to meet quality specifications of the crude oil. Water drops can be removed from a continuous oil phase by various techniques, such as chemical demulsification, gravity or centrifugal separation, pH adjustment, filtration, heat treatment, membrane separation and electrostatic-enhanced coalescence. Compared to other methods, electrical demulsification is considered to be superior in terms of energy efficiency. The electrostatic effects arise from the much higher values of dielectric permittivity and conductivity of water in comparison to oil. However, the mechanism of electrocoalescence is still not fully understood and most of the conventional electro-separators are rather bulky. There is, therefore, a compelling need to optimize the design and operation of these separators by means of a better fundamental understanding of the underlying physics. This study aims at investigating the coalescence behaviour of water droplets in sunflower oil when the aqueous phase is present in the form of a chain of droplets. Chains easily form in an emulsion, since droplets tend to align themselves with the direction of the electric field. A pair of ladder-wise electrodes was implemented to set up an electric field almost parallel to the flow direction of the droplets. This design ensures that adjacent droplets in a chain experience the maximum attractive force and does not significantly disturb the hydrodynamics of the continuous phase. The effect of the electric field strength, frequency and waveform on the process performance has been investigated. Both constant and pulsed dc fields have been applied to the dispersion. Sinusoidal, sawtooth and square waves have been employed as pulsed dc waveforms. Droplet size distributions at the outlet of the device were measured by image analysis. The outcomes of the research suggest that it is possible to find a combination of electrical field intensity, frequency and waveform to maximize the separation efficiency.qscienc

Analysis of Partial Electrocoalescence by Level-Set and Finite Element Methods

The coalescence of a water drop in a dieletric oil phase at a water layer interface in the presence of an electric field is simulated by solving the Navier-Stokes and charge conservation equations with the finite element method. The proprietary software Comsol Multiphysics is used for this purpose. The interface between the oil and water phases is tracked by implementing a level-set approach. Preliminary simulations to assess the sensitivity of the model with respect to some input parameters are reported. In particular, the calculations are very sensitive to the size of the computational grid elements and the interface thickness parameter. Nevertheless, the model is able to reproduce the occurrence of partial coalescence for the experimental case examined. Good quantitative agreement can be obtained if the parameters are suitably tuned.qscienc

Indoor environment assessment of special wards of educational hospitals for the detection of fungal contamination sources: A multi-center study (2019-2021)

Background and Purpose: The hospital environment was reported as a real habitat for different microorganisms, especially mold fungi. On the other hand, these opportunistic fungi were considered hospital-acquired mold infections in patients with weak immune status. Therefore, this multi-center study aimed to evaluate 23 hospitals in 18 provinces of Iran for fungal contamination sources.Materials and Methods: In total, 43 opened Petri plates and 213 surface samples were collected throughout different wards of 23 hospitals. All collected samples were inoculated into Sabouraud Dextrose Agar containing Chloramphenicol (SC), and the plates were then incubated at 27-30ºC for 7-14 days.Results: A total of 210 fungal colonies from equipment (162, 77.1%) and air (48,22.9%) were identified. The most predominant isolated genus was Aspergillus (47.5%),followed by Rhizopus (14.2%), Mucor (11.7%), and Cladosporium (9.2%). Aspergillus(39.5%), Cladosporium (16.6%), as well as Penicillium and Sterile hyphae (10.4% each), were the most isolates from the air samples. Moreover, intensive care units (38.5%) and operating rooms (21.9%) had the highest number of isolated fungal colonies. Out of 256 collected samples from equipment and air, 163 (63.7%) were positive for fungal growth.The rate of fungal contamination in instrument and air samples was 128/213 (60.1%) and 35/43 (81.2%), respectively. Among the isolated species of Aspergillus, A. flavus complex (38/96, 39.6%), A. niger complex (31/96, 32.3%), and A. fumigatus complex (15/96, 15.6%) were the commonest species.Conclusion: According to our findings, in addition to air, equipment and instrument should be considered among the significant sources of fungal contamination in the indoor environment of hospitals. Airborne fungi, Hospital, Indoor air, Equipment, Sources of fungal contamination in the indoor environment of hospitals

Electrophysiological and behavioural studies of top-down mechanisms of attention

© 2018 Dr Mojtaba Kermani Ahangarani FarahaniMost modern skills, like driving a car, playing video games or reading a book, are relatively recent occurrences in human history and have presumably no specific hard-wired neural pathways. Instead, they piggyback on neural mechanisms that the brain evolved for other purposes, such as object recognition or visual attention. To take one specific example, reading is fundamental to function in modern daily life. It has been claimed that visuo-spatial attention is essential for selecting and binding strings of letters to identify words. In spite of half a century of extensive research on the mechanisms underlying visual processing, it is not well understood how cognitive abilities such as visual attention are related to reading. This thesis aimed to study not only the mutual interaction between reading and attention, but also first shed more light on the underlying neural mechanisms of visuospatial attention by investigating attention in one of our closest primate relatives. Study of electrical properties of several neurons surrounding an implanted microelectrode – known as extracellular recording – has been a robust method for basic understanding of how the nervous system works. However, performing this method in humans is unethical and as a result, electrophysiologists rely on recordings from animal brains, especially from the monkey as a species closely related to humans. Therefore, to understand further the neural mechanisms of top-down attention, I analysed electrophysiological neural signals which were recorded from macaques whilst they performed an attention-demanding task. I found two different parallel synchronized activities between posterior parietal and middle temporal cortices, one in the high- frequency range (high gamma) for feature discrimination and one in the low-frequency range (beta, low gamma) for attentional modulation. These results suggest that one process extracts and retains feature information, which is then used by a second process for top- down modulation of spatial attention. Although several theories have been suggested to explain how such oscillations in the neural activities reflect our performances in a particular cognitive function such as visual attention, the link between electrophysiology and psychophysics has not been fully studied. For the third experimental chapter, a slightly different version of the attention task was used from the one that earlier monkeys were trained on whilst collecting the data used for the first and second experiments. I found that reported oscillations in the neural activities in experiments one and two appear in the animal’s behaviour in a much lower frequency range: between 6 to 15 Hz. This rhythmicity in attention resembles fluctuations in the sampling of the external world by the visual system. It has been proposed that rhythmic allocation of attention is involved in the mechanisms of reading scripts. As such, languages with different scripts may therefore modulate attention differently. Using psychophysical tests, I found that visual attention is allocated asymmetrically depending on an individual’s habitual direction of reading. The results showed that efficiency of visuo-spatial attention mechanisms of left-to-right readers (such as English readers) and right-to-left readers (such as Farsi readers) were biased towards the right and left visual fields, respectively. On the other hand, bidirectional readers (fluent in both English and Farsi) were equally sensitive in the two hemifields. Search ability was not only found to be influenced by the habitual direction of reading, but such an influence could be modulated by even relatively short periods of reading. The improved visual attention was not accompanied by changes is oculomotor parameters i.e., fixation duration or saccade length. These findings provide evidence that the allocation of top-down attention in the visual field as measured by visual search ability can be influenced by the reading habit. The principle of rhythmic modulation of brain processes appears to underpin both visual attention as seen in common visual tasks as well as high level cognitive functions such as reading. The basic understanding of how complex, relatively modern, human functions are built upon processes inherited from evolution is likely to yield insights into the cause of many common ailments that affect human behaviour and indicate ways of managing them

Evaluation of the performance of a multi-layer Landfill side slope insulation system under external hydrostatic loading

Unscientific waste control and using inflamed masks and gloves in municipal garbage represent a risk of an outbreak. Furthermore, in growing nations, pollutants of the surroundings and groundwater have raised the call for landfills to decrease pandemic risk. Alternatively, municipal strong waste landfill barrier structures regularly contain an aggregate of geosynthetics and mineral layers. Throughout the last 20 years, there were full-size studies on the interactions among the substances and on the overall performance of the geosynthetics consisting of components of durability. This study has led to giant advances in the layout and specification of landfill lining structures. Although many numerical modeling applications are implemented to assess lining system stability and integrity, records to validate those models are presently limited. This paper highlights the records required to validate numerical models and instrumentation strategies that can be used to accumulate this information imposed at the liner (stress cells). The use of numerical analysis to analyze the stability and integrity of landfill liner systems has increased popularity over the last three decades. Internal landfill pressures, on the other hand, are emphasized by the majority of them. The presence of water flows behind the landfill side slope was investigated in four height level codes. The results are compared to on-site landfill data in order to validate the numerical model. This case study is the Miligate dump in the United Kingdom. The Finite Element (FE) model in three dimensions is used. To improve the accuracy of the study, the interfaces and properties of the materials were chosen from the experimental results. The findings revealed that a lining system with a water level up to 3/4 of the side slope was immune to failure, but that when the side slope was filled with respect to the full height, the geomembrane would be ripped