Key Signature Research Articles

4polar-STORM polarized super-resolution imaging of actin filament organization in cells

Single-molecule localization microscopy provides insights into the nanometer-scale spatial organization of proteins in cells, however it does not provide information on their conformation and orientation, which are key functional signatures. Detecting single molecules’ orientation in addition to their localization in cells is still a challenging task, in particular in dense cell samples. Here, we present a polarization-splitting scheme which combines Stochastic Optical Reconstruction Microscopy (STORM) with single molecule 2D orientation and wobbling measurements, without requiring a strong deformation of the imaged point spread function. This method called 4polar-STORM allows, thanks to a control of its detection numerical aperture, to determine both single molecules’ localization and orientation in 2D and to infer their 3D orientation. 4polar-STORM is compatible with relatively high densities of diffraction-limited spots in an image, and is thus ideally placed for the investigation of dense protein assemblies in cells. We demonstrate the potential of this method in dense actin filament organizations driving cell adhesion and motility.

Identification of key tumor stroma-associated transcriptional signatures correlated with survival prognosis and tumor progression in breast cancer.

The aberrant expression of stromal gene signatures in breast cancer has been widely studied. However, the association of stromal gene signatures with tumor immunity, progression, and clinical outcomes remains lacking. Based on eight breast tumor stroma (BTS) transcriptomics datasets, we identified differentially expressed genes (DEGs) between BTS and normal breast stroma. Based on the DEGs, we identified dysregulated pathways and prognostic hub genes, hub oncogenes, hub protein kinases, and other key marker genes associated with breast cancer. Moreover, we compared the enrichment levels of stromal and immune signatures between breast cancer patients with bad and good clinical outcomes. We also investigated the association between tumor stroma-related genes and breast cancer progression. The DEGs included 782 upregulated and 276 downregulated genes in BTS versus normal breast stroma. The pathways significantly associated with the DEGs included cytokine-cytokine receptor interaction, chemokine signaling, T cell receptor signaling, cell adhesion molecules, focal adhesion, and extracellular matrix-receptor interaction. Protein-protein interaction network analysis identified the stromal hub genes with prognostic value in breast cancer, including two oncogenes (COL1A1 and IL21R), two protein kinases encoding genes (PRKACA and CSK), and a growth factor encoding gene (PLAU). Moreover, we observed that the patients with bad clinical outcomes were less enriched in stromal and antitumor immune signatures (CD8 + T cells and tumor-infiltrating lymphocytes) but more enriched in tumor cells and immunosuppressive signatures (MDSCs and CD4 + regulatory T cells) compared with the patients with good clinical outcomes. The ratios of CD8 + /CD4 + regulatory T cells were lower in the patients with bad clinical outcomes. Furthermore, we identified the tumor stroma-related genes, including MCM4, SPECC1, IMPA2, and AGO2, which were gradually upregulated through grade I, II, and III breast cancers. In contrast, COL14A1, ESR1, SLIT2, IGF1, CH25H, PRR5L, ABCA6, CEP126, IGDCC4, LHFP, MFAP3, PCSK5, RAB37, RBMS3, SETBP1, and TSPAN11 were gradually downregulated through grade I, II, and III breast cancers. It suggests that the expression of these stromal genes has an association with the progression of breast cancers. These progression-associated genes also displayed an expression association with recurrence-free survival in breast cancer patients. This study identified tumor stroma-associated biomarkers correlated with deregulated pathways, tumor immunity, tumor progression, and clinical outcomes in breast cancer. Our findings provide new insights into the pathogenesis of breast cancer.

Healthy Subcutaneous and Omental Adipose Tissue Is Associated with High Expression of Extracellular Matrix Components

Obesity is associated with extensive expansion and remodeling of the adipose tissue architecture, including its microenvironment and extracellular matrix (ECM). Although obesity has been reported to induce adipose tissue fibrosis, the composition of the ECM under healthy physiological conditions has remained underexplored and debated. Here, we used a combination of three established techniques (picrosirius red staining, a colorimetric hydroxyproline assay, and sensitive gene expression measurements) to evaluate the status of the ECM in metabolically healthy lean (MHL) and metabolically unhealthy obese (MUO) subjects. We investigated ECM deposition in the two major human adipose tissues, namely the omental and subcutaneous depots. Biopsies were obtained from the same anatomic region of respective individuals. We found robust ECM deposition in MHL subjects, which correlated with high expression of collagens and enzymes involved in ECM remodeling. In contrast, MUO individuals showed lower expression of ECM components but elevated levels of ECM cross-linking and adhesion proteins, e.g., lysyl oxidase and thrombospondin. Our data suggests that subcutaneous fat is more prone to express proteins involved in ECM remodeling than omental adipose tissues. We conclude that a more dynamic ability to deposit and remodel ECM may be a key signature of healthy adipose tissue, and that subcutaneous fat may adapt more readily to changing metabolic conditions than omental fat.

Nuclear Exportin 1 (XPO1) Binds to the Nuclear Localization/Export Signal of the Turnip Mosaic Virus NIb to Promote Viral Infection.

The nuclear localization signal (NLS) and nuclear export signal (NES) are key signatures of proteins for controlling nuclear import and export. The NIb protein of turnip mosaic virus (TuMV) is an RNA-dependent RNA polymerase (RdRP) that is absolutely required for viral genome replication. Previous studies have shown that NIb is a nucleocytoplasmic shuttling protein and contains four putative NES and four putative NLS motifs. Here, we analyzed the function of these NESs and NLSs, and identified two functional NESs and one functional NLS. Mutation of the identified functional NESs or NLS inhibited viral RNA accumulation and systemic infection. Exportin 1 (XPO1) is a nuclear export receptor that binds directly to cargo proteins harboring a leucine-rich NES and translocates them to the cytoplasm. We found that XPO1 contains two NIb-binding domains, which recognize the NLS and NES of NIb, respectively, to mediate the nucleocytoplasmic transport of NIb and promote viral infection. Taken together, these data suggest that the nucleocytoplasmic transport of NIb is modulated by XPO1 through its interactions with the functional NLS and NES of NIb to promote viral infection.

Non-Hermitian skin effect in a spin-orbit-coupled Bose-Einstein condensate

We study a Bose-Einstein condensate of ultracold atoms subject to a non-Hermitian spin-orbit coupling, where the system acquires the non-Hermitian skin effect under the interplay of spin-orbit coupling and laser-induced atom loss. The presence of the non-Hermitian skin effect is confirmed through its key signatures in terms of the spectral winding under the periodic boundary condition, the accumulation of eigen wavefunctions at boundaries under an open boundary condition, and bulk dynamics signaled by a directional flow. We show that bulk dynamics, in particular, serves as a convenient signal for experimental detection. The impact of interaction and trapping potentials is also discussed based on the non-Hermitian Gross-Pitaevskii equations. Our work demonstrates that the non-Hermitian skin effect and its rich implications in topology, dynamics, and beyond are well within the reach of current cold-atom experiments.

Attribute-Based Blind Signature Scheme Based on Elliptic Curve Cryptography

Blind signature is a special digital signature that allows the signer to sign a document without knowing its content. However, in many situations, multiple people need to blindly sign messages. At this time, the traditional blind signature can no longer satisfy the application requirements. To solve this problem, attribute-based cryptography has been combined with the blind signature. The concept of the attribute-based blind signature is generated. At present, all attribute-based blind signature schemes require the support of bilinear pairing technology, which involves several complex pairing and exponential operations in the signature and verification processes, and the computational efficiency is not high. In this paper, we present an attribute-based blind signature scheme based on elliptic curve cryptography (ECC), and the security of new scheme is proved under the intractability of elliptic curve discrete logarithm problem (ECDLP). Our scheme is a key policy attribute-based signature (KP-ABS). The new scheme uses linear secret sharing scheme (LSSS) matrix technology that does not require recursive operation to achieve more flexible and fine-grained access control. In addition, the scheme is based on Elliptic Curve Cryptography (ECC) using scalar multiplication on an elliptic curve instead of a bilinear pairing operation. Our scheme has significant advantages in terms of computational efficiency and storage compared with existing attribute-based blind signature schemes.

Noninvasive detection and interpretation of gastrointestinal diseases by collaborative serum metabolite and magnetically controlled capsule endoscopy

Gastrointestinal diseases are complex diseases that occur in the gastrointestinal tract. Common gastrointestinal diseases include chronic gastritis, peptic ulcers, inflammatory bowel disease, and gastrointestinal tumors. These diseases may manifest a long course, difficult treatment, and repeated attacks.Gastroscopy and mucosal biopsy are the gold standard methods for diagnosing gastric and duodenal diseases, but they are invasive procedures and carry risks due to the necessity of sedation and anesthesia. Recently, several new approaches have been developed, including serological examination and magnetically controlled capsule endoscopy (MGCE). However, serological markers lack lesion information, while MGCE images lack molecular information.This study proposes combining these two technologies in a collaborative noninvasive diagnostic scheme as an alternative to the standard procedures. We introduce an interpretable framework for the clinical diagnosis of gastrointestinal diseases. Based on collected blood samples and MGCE records of patients with gastrointestinal diseases and comparisons with normal individuals, we selected serum metabolite signatures by bioinformatic analysis, captured image embedding signatures by convolutional neural networks, and inferred the location-specific associations between these signatures.Our study successfully identified five key metabolite signatures with functional relevance to gastrointestinal disease. The combined signatures achieved discrimination AUC of 0.88. Meanwhile, the image embedding signatures showed different levels of validation and testing accuracy ranging from 0.7 to 0.9 according to different locations in the gastrointestinal tract as explained by their specific associations with metabolite signatures. Overall, our work provides a new collaborative noninvasive identification pipeline and candidate metabolite biomarkers for image auxiliary diagnosis. This method should be valuable for the noninvasive detection and interpretation of gastrointestinal and other complex diseases.

Secure and Light Weight Elliptic Curve Cipher Suites in SSL/TLS

In the current circumstance, e-commerce through an online banking system plays a significant role. Customers may either buy goods from E-Commerce websites or use online banking to move money to other accounts. When a user participates in these types of behaviors, their sensitive information is sent to an untrustworthy network. As a consequence, when transmitting data from an internal browser to an external E-commerce web server using the cryptographic protocol SSL/TLS, the E-commerce web server ensures the security of the user’s data. The user should be pleased with the confidentiality, authentication, and authenticity properties of the SSL/TLS on both the user’s web browser and the remote E-commerce web server. E-Commerce web servers should choose the best SSL/TLS cipher suites for negotiating the user in order to attain such optimistic scenarios, as the cipher suite used in SSL/TLS plays an important role in securing E-Commerce web servers. The paper primarily focuses on analyzing the SSL/TLS cipher and elliptic curves. The paper also recommends the best elliptic curve cipher suites for E-Commerce and online banking servers, based on their power consumption, handshake execution time, and key exchange and signature verification time.

Environmental Adaptive Privacy Preserving Contact Tracing System: A Construction From Public Key Rerandomizable BLS Signatures

The COVID-19 pandemic has made the scientific community devise means to implement “contact tracing” mechanisms to mitigate the spread of the infection. The crucial idea is to scan and record close contacts between users using mobile device, in order to notify persons when their close contact(s) is diagnosed positive. First, the ability granted to service providers of the contact tracing systems to access user data violates user privacy, and attackers can fabricate identities and contact records in their devices, which harms the integrity of the system. Moreover, current contact tracing systems’ false-positive rate is too high to be practical as they do not filter scan results outside the range of infections, since the range of transmission for droplets is far less than the scanning range for Bluetooth Low Energy used by these systems. Furthermore, current systems neglect airborne transmission, a far cry from a tool against viruses suspended in the air. In this paper, we propose a cryptographic framework for contact tracing and provide a construction based on public key rerandomizable BLS signature, being capable of providing users of contact tracing with comprehensive privacy protection. Besides, we also implement a commitment scheme to prevent fabrication of identities and contact records. To prove the concept of our framework and to solve other problems mentioned above, we proposed a new contact tracing system, using environmental factors (temperature, humidity and airflow) to filter out results outside estimated effective transmission distance, and also take airborne transmission into consideration. Finally, we evaluate the performance of our design by implementing our algorithm on mobile devices with satisfactory results.

Key Signatures of Magnetofossils Elucidated by Mutant Magnetotactic Bacteria and Micromagnetic Calculations.

Magnetotactic bacteria (MTB) produce single‐stranded or multi‐stranded chains of magnetic nanoparticles that contribute to the magnetization of sediments and rocks. Their magnetic fingerprint can be detected in ancient geological samples and serve as a unique biosignature of microbial life. However, some fossilized assemblages bear contradictory signatures pointing to magnetic components that have distinct origin(s). Here, using micromagnetic simulations and mutant MTB producing looped magnetosome chains, we demonstrate that the observed magnetofossil fingerprints are produced by a mixture of single‐stranded and multi‐stranded chains, and that diagenetically induced chain collapse, if occurring, must preserve the strong uniaxial anisotropy of native chains. This anisotropy is the key factor for distinguishing magnetofossils from other populations of natural magnetite particles, including those with similar individual crystal characteristics. Furthermore, the detailed properties of magnetofossil signatures depend on the proportion of equant and elongated magnetosomes, as well as on the relative abundances of single‐stranded and multi‐stranded chains. This work has important paleoclimatic, paleontological, and phylogenetic implications, as it provides reference data to differentiate distinct MTB lineages according to their chain and magnetosome morphologies, which will enable the tracking of the evolution of some of the most ancient biomineralizing organisms in a time‐resolved manner. It also enables a more accurate discrimination of different sources of magnetite particles, which is pivotal for gaining better environmental and relative paleointensity reconstructions from sedimentary records.

Integrative analysis of lung molecular signatures reveals key drivers of systemic sclerosis-associated interstitial lung disease

ObjectivesInterstitial lung disease is a significant comorbidity and the leading cause of mortality in patients with systemic sclerosis. Transcriptomic data of systemic sclerosis-associated interstitial lung disease (SSc-ILD) were analysed to...

Secure VANET Authentication Protocol (SVAP) Using Chebyshev Chaotic Maps for Emergency Conditions

It is crucial to support emergency applications provided by vehicular adhoc network (VANET) through enabling vehicles to quickly access to the infrastructure and consequently request rescue services. Additionally, the communication channels between vehicles and the infrastructure lack various security features due to the inferior wireless characteristics of their environment. However, most of the existing authentication schemes which are used to fix the security drawbacks lead to heavy computations and large storage burdens on the vehicle onboard unit (OBU). These schemes utilize secure channels while distributing the network parameters between the various participants. Yet, it is not efficient to establish secure channels during the interactions between entities. Furthermore, lightweight cryptography is an efficient security solution which is adequate for OBU to maintain a reasonable efficiency with low computational and communication costs. Two basic demerits for lightweight authentication protocols are highlighted as follows: Firstly, symmetric key-based authentication protocols dismiss achieving non-repudiation feature, leading to several security attacks in VANET. Secondly, public key-based authentication schemes are relied on elliptic curve cryptography (ECC) which makes the protocol implementation more difficult. Hence, this paper introduces a novel authentication protocol that utilizes Chebyshev chaotic maps to secure connectivity between the vehicles and infrastructure without using secure channels to distribute the network parameters. The new protocol combines the concept of the symmetric key cryptography with the public key signature to satisfy both the lightweight property and non-repudiation feature. Thus, this protocol introduces a novel network model which is the lowest hardware complexity, compared with others. The performance analysis is performed by Wolfram Mathematica, proving that the proposed protocol is superior in terms of security and performance aspects; its computation and storage costs of OBU are enhanced with 24.09% and 16.99%, respectively, compared to the most competing scheme. Besides, the Scyther simulation confirms the security of the protocol.

Provably Secure Lattice-Based Self-Certified Signature Scheme

Digital signatures are crucial network security technologies. However, in traditional public key signature schemes, the certificate management is complicated and the schemes are vulnerable to public key replacement attacks. In order to solve the problems, in this paper, we propose a self-certified signature scheme over lattice. Using the self-certified public key, our scheme allows a user to certify the public key without an extra certificate. It can reduce the communication overhead and computational cost of the signature scheme. Moreover, the lattice helps prevent quantum computing attacks. Then, based on the small integer solution problem, our scheme is provable secure in the random oracle model. Furthermore, compared with the previous self-certified signature schemes, our scheme is more secure.

Recombinant Fasciola hepatica Fatty Acid Binding Protein as a Novel Anti-Inflammatory Biotherapeutic Drug in an Acute Gram-Negative Nonhuman Primate Sepsis Model.

ABSTRACTDue to their phylogenetic proximity to humans, nonhuman primates (NHPs) are considered an adequate choice for a basic and preclinical model of sepsis. Gram-negative bacteria are the primary causative of sepsis. During infection, bacteria continuously release the potent toxin lipopolysaccharide (LPS) into the bloodstream, which triggers an uncontrolled systemic inflammatory response leading to death. Our previous research has demonstrated in vitro and in vivo using a mouse model of septic shock that Fh15, a recombinant variant of the Fasciola hepatica fatty acid binding protein, acts as an antagonist of Toll-like receptor 4 (TLR4) suppressing the LPS-induced proinflammatory cytokine storm. The present communication is a proof-of concept study aimed to demonstrate that a low-dose of Fh15 suppresses the cytokine storm and other inflammatory markers during the early phase of sepsis induced in rhesus macaques by intravenous (i.v.) infusion with lethal doses of live Escherichia coli. Fh15 was administered as an isotonic infusion 30 min prior to the bacterial infusion. Among the novel findings reported in this communication, Fh15 (i) significantly prevented bacteremia, suppressed LPS levels in plasma, and the production of C-reactive protein and procalcitonin, which are key signatures of inflammation and bacterial infection, respectively; (ii) reduced the production of proinflammatory cytokines; and (iii) increased innate immune cell populations in blood, which suggests a role in promoting a prolonged steady state in rhesus macaques even in the presence of inflammatory stimuli. This report is the first to demonstrate that a F. hepatica-derived molecule possesses potential as an anti-inflammatory drug against sepsis in an NHP model.IMPORTANCE Sepsis caused by Gram-negative bacteria affects 1.7 million adults annually in the United States and is one of the most important causes of death at intensive care units. Although the effective use of antibiotics has resulted in improved prognosis of sepsis, the pathological and deathly effects have been attributed to the persistent inflammatory cascade. There is a present need to develop anti-inflammatory agents that can suppress or neutralize the inflammatory responses and prevent the lethal consequences of sepsis. We demonstrated here that a small molecule of 14.5 kDa can suppress the bacteremia, endotoxemia, and many other inflammatory markers in an acute Gram-negative sepsis rhesus macaque model. These results reinforce the notion that Fh15 constitutes an excellent candidate for drug development against sepsis.

Sensitivity and reliability of key electrochemical markers for detecting lithium plating during extreme fast charging

Lithium plating is one of the key challenges for enabling extreme fast charging (XFC, ≤10 to 15 min charging at ≥6C) in graphite-based lithium-ion batteries. Significant R&D effort has been focused on how to mitigate Li plating. Parallel effort is also being devoted to developing methods to detect Li plating when and if it happens during fast charging. In that regard, electrochemical (EC) signature-based detection techniques are less resource intensive, more convenient, and more practical from an end-user application perspective. However, a comprehensive understanding of key plating related EC signatures for extreme fast charging is presently unavailable. In particular, there exist distinct issues of unreliability with key plating-related EC signatures—e.g., incremental capacity (dQ.dV−1), differential OCV (dOCV.dt−1), end of lithiation (EOL) rest voltage—at XFC conditions, and the underlying reasons have not been explored and identified methodically. Using a comprehensive test matrix and XFC conditions with Li/graphite half cells, this article highlights the unreliability issues associated with the EC Li plating diagnostics and explains the underlying root cause. This study finds distinct sensitivity and unreliability issues with plating related dQ.dV−1, dOCV.dt−1, and EOL rest voltage signatures with charging rates. The complex interaction between graphite and plated Li that happens through multiple competing mechanisms —Li stripping and chemical intercalation— at different charging rates is at the core of the sensitivity and unreliability issue.

Energy limitation or sensitive predators? Trophic and non-trophic impacts of wastewater pollution on stream food webs.

Impacts of environmental stressors on food webs are often difficult to predict because trophic levels can respond in divergent ways, and biotic interactions may dampen or amplify responses. Here we studied food-web-level impacts of urban wastewater pollution, a widespread source of degradation that can alter stream food webs via top-down and bottom-up processes. Wastewater may (1) subsidize primary producers by decreasing nutrient limitation, inducing a wide-bottomed trophic pyramid. However, (2) wastewater may also reduce the quality and diversity of resources, which could decrease energy transfer efficiency by reducing consumer fitness, leading to predator starvation. Additionally, (3) if higher trophic levels are particularly sensitive to pollution, primary consumers could be released from predation pressure. We tested these hypotheses in 10 pairs of stream sites located upstream and downstream of urban wastewater effluents with different pollutant levels. We found that wastewater pollution reduced predator richness by ∼34%. Community size spectra (CSS) slopes were steeper downstream than upstream of wastewater effluents in all except one impact site where predators became locally extinct. Further, variation in downstream CSS slopes were correlated with pollution loads: the more polluted the stream, the steeper the CSS. We estimate that wastewater pollution decreased energy transfer efficiencies to primary consumers by ∼70%, limiting energy supply to predators. Additionally, traits increasing vulnerability to chemical pollution were overrepresented among predators, which presented compressed trophic niches (δ15 N-δ13 C) downstream of effluents. Our results show that wastewater pollution can impact stream food webs via a combination of energy limitation to consumers and extirpation of pollution-sensitive top predators. Understanding the indirect (biotically mediated) vs. direct (abiotic) mechanisms controlling responses to stress may help anticipating impacts of altered water quantity and quality, key signatures of global change.

Modeling streamflow variability at the regional scale: (2) Development of a bespoke distributed conceptual model

Regional scale distributed conceptual models are typically developed with a bottom-up approach, which is process-inclusive but prone to over-parameterization. Here we demonstrate a proof of concept top-down approach for distributed conceptual model development, intended to emphasize dominant streamflow generating processes and to fulfill the principle of model parsimony. A key challenge in applying the top-down approach to distributed model development is devising a model comparison experiment that is both informative and limited to a few model alternatives. Here, we show how such model comparisons can be informed by a perceptual model of key processes that control streamflow response variability at the regional scale. We demonstrate our approach for the 27,100 km2 Moselle catchment, using the perceptual model developed in Part 1 of this two-part paper. We develop 5 distributed model structures for simulating daily streamflow at 26 subcatchments, and validate them on subcatchments that are not used during the calibration process. Our model comparisons illustrate how the spatial distribution of precipitation, lithology and topography affect the simulation of key signatures of streamflow response variability in the Moselle catchment, providing a basis to justify model decisions. Our analyses show how a minimally parameterized distributed model, with 12 calibration parameters, matches signatures of streamflow average (r = 0.96), baseflow index (r = 0.86), and hydrograph lag time (correct at 22 out of 26 subcatchments). Our proposed top-down approach contributes to improving distributed model development strategies, and can be used to develop parsimonious process based regional models elsewhere.

Mindfulness Meditation Improves Musical Aesthetic Emotion Processing in Young Adults.

This study explored the behavioral and neural correlates of mindfulness meditation improvement in musical aesthetic emotion processing (MAEP) in young adults, using the revised across-modal priming paradigm. Sixty-two participants were selected from 652 college students who assessed their mindfulness traits using the Mindful Attention Awareness Scale (MAAS). According to the 27% ratio of the high and low total scores, participants were divided into two subgroups: high trait group (n = 31) and low trait group (n = 31). Participants underwent facial recognition and emotional arousal tasks while listening to music, and simultaneously recorded event-related potentials (ERPs). The N400, P3, and late positive component (LPC) were investigated. The behavioral results showed that mindfulness meditation improved executive control abilities in emotional face processing and effectively regulated the emotional arousal of repeated listening to familiar music among young adults. These improvements were associated with positive changes in key neural signatures of facial recognition (smaller P3 and larger LPC effects) and emotional arousal (smaller N400 and larger LPC effects). Our results show that P3, N400, and LPC are important neural markers for the improvement of executive control and regulating emotional arousal in musical aesthetic emotion processing, providing new evidence for exploring attention training and emotional processing. We revised the affecting priming paradigm and E-prime 3.0 procedure to fulfill the simultaneous measurement of music listening and experimental tasks and provide a new experimental paradigm to simultaneously detect the behavioral and neural correlates of mindfulness-based musical aesthetic processing.

Torque Ripple Reduction of Switched Reluctance Motor with Non-Uniform Air-Gap and a Rotor Hole

A switched reluctance motor has a very simple structure which becomes its key signature and leads to various advantages. However, because of its double saliency and switching principle, the motor is also known to have a relatively high torque ripple, and this hinders its use as a high-performance drive. In this paper, a method to reduce torque ripple while maintaining average torque is introduced. Two elements are used to achieve this, namely, a non-uniform air-gap on the rotor-pole face and one hole in each non-uniform region, which maintains the saturation level of the air-gap. This approach preserves the mechanical simplicity of the motor and is easy to implement. Simulations and experiments were performed to verify the effectiveness of the proposed design.

SE-CPPA: A Secure and Efficient Conditional Privacy-Preserving Authentication Scheme in Vehicular Ad-Hoc Networks.

Communications between nodes in Vehicular Ad-Hoc Networks (VANETs) are inherently vulnerable to security attacks, which may mean disruption to the system. Therefore, the security and privacy issues in VANETs are entitled to be the most important. To address these issues, the existing Conditional Privacy-Preserving Authentication (CPPA) schemes based on either public key infrastructure, group signature, or identity have been proposed. However, an attacker could impersonate an authenticated node in these schemes for broadcasting fake messages. Besides, none of these schemes have satisfactorily addressed the performance efficiency related to signing and verifying safety traffic-related messages. For resisting impersonation attacks and achieving better performance efficiency, a Secure and Efficient Conditional Privacy-Preserving Authentication (SE-CPPA) scheme is proposed in this paper. The proposed SE-CPPA scheme is based on the cryptographic hash function and bilinear pair cryptography for the signing and verifying of messages. Through security analysis and comparison, the proposed SE-CPPA scheme can accomplish security goals in terms of formal and informal analysis. More precisely, to resist impersonation attacks, the true identity of the vehicle stored in the tamper-proof device (TPD) is frequently updated, having a short period of validity. Since the MapToPoint hash function and a large number of cryptography operations are not employed, simulation results show that the proposed SE-CPPA scheme outperforms the existing schemes in terms of computation and communication costs. Finally, the proposed SE-CPPA scheme reduces the computation costs of signing the message and verifying the message by 99.95% and 35.93%, respectively. Meanwhile, the proposed SE-CPPA scheme reduces the communication costs of the message size by 27.3%.