Resistive random-access memories, also known as memristors, whose resistance can be modulated by the electrically driven formation and disruption of conductive filaments within an insulator, are promising candidates for neuromorphic applications due to their scalability, low-power operation and diverse functional behaviours. However, understanding the dynamics of individual filaments, and the surrounding material, is challenging, owing to the typically very large cross-sectional areas of test devices relative to the nanometre scale of individual filaments. In the present work, conductive atomic force microscopy is used to study the evolution of conductivity at the nanoscale in a fully CMOS-compatible silicon suboxide thin film. Distinct filamentary plasticity and background conductivity enhancement are reported, suggesting that device behaviour might be best described by composite core (filament) and shell (background conductivity) dynamics. Furthermore, constant current measurements demonstrate an interplay between filament formation and rupture, resulting in current-controlled voltage spiking in nanoscale regions, with an estimated optimal energy consumption of 25 attojoules per spike. This is very promising for extremely low-power neuromorphic computation and suggests that the dynamic behaviour observed in larger devices should persist and improve as dimensions are scaled down.
Background: Several studies have shown the presence of onco viral DNA in colorectal tumor tissues. Viral infection by onco-viruses such as Human papillomaviruses (HPVs) and Epstein–Barr virus (EBV) are well-known to be involved in the onset and/or progression of numerous human carcinomas. Methods: We explored the co-presence of high-risk HPVs and EBV in a cohort of colorectal cancer samples from Lebanon (94) and Syria (102) by PCR, immunohistochemistry and tissue microarray. Results: The results of the study point out that 54% of colorectal cancer cases in Syria are positive for high-risk HPVs, while 30% of the cases in Lebanon are positive for these viruses; the most frequent high-risk HPV types in these populations are 16, 18, 31, 33 and 35. Analysis of LMP1 showed similar results in both populations; 36% of Syrian and 31% of Lebanese samples. Additionally, we report that EBV and high-risk HPVs are co-present in these samples. In Syrian samples, EBV and HPVs are co-present in 16% of the population, however, in the Lebanese samples, 20% of the cases are positive for both EBV and HPVs; their co-presence is associated with high/intermediate grade invasive carcinomas. Conclusion: These data suggest that EBV and high-risk HPVs are co-present in human colorectal cancers where they can cooperate in the progression of these cancers. Nevertheless, further studies are needed to elucidate the role of those oncoviruses in the development of human colorectal carcinomas.
Introduction: Infections with human oncoviruses such as high-risk human papillomaviruses (HPVs) and Epstein-Barr virus (EBV) are globally prevalent in the adult population. Both viruses are strongly associated with several types of human carcinomas such as cervical, head and neck, nasopharyngeal and gastric. In the present study, we explored the prevalence of these two oncoviruses in the healthy population of Qatar. Methods: The study included 385 healthy blood donors that reflect diverse nationalities in the Qatari community (Qatar, Egypt, Syria, Jordan, Pakistan, and India). DNA was extracted from the peripheral blood and genotyping was done using PCR and nested-PCR targeting E6 and E7 as well as LMP1 genes of HPVs and EBV, respectively. Results: The age of participants (378 males and 7 females) ranged between 19 and 68 years (mean 37.12 ± 9.3 years). Our data indicate that 55% and 61% of the tested samples were HPVs and EBV positive, respectively. Moreover, we found that there was (40%) co-presence of both HPVs and EBV in our samples. The most common high-risk HPV types in Qatar included HPV 59 (55%), 31 (54%), 52 (49%), 51 (49%), 58 (47%) and 35 (46%). While, HPV 16 and 18 were detected in 38% and 36% of the samples, respectively. Notably, all samples showed multiple HPVs infections. Conclusion: Our study reveals for the first time a high prevalence of both EBV and HPVs among healthy individuals in Qatar. More significantly, most cases had multiple HPV types infection in addition to the co-presence of both viruses in a substantial proportion of the samples. Given the important possible cooperative role of these viruses in human carcinogenesis, preventive measures using available and upcoming vaccines are of paramount importance.
Symptom‐focused management is one of the cornerstones of optimal atrial fibrillation (AF) therapy.
Nacre’s structure-property relationships have been a source of inspiration for designing advanced functional materials with both high strength and toughness. These outstanding mechanical properties have been mostly attributed to the interplay between aragonite platelets and organic matrices in the typical brick-and-mortar structure. Here, we show that crystallographically co-oriented stacks of aragonite platelets, in both columnar and sheet nacre, define another hierarchical level that contributes to the toughening of nacre. By correlating piezo-Raman and micro-indentation results, we quantify the residual strain energy associated with strain hardening capacity. Our findings suggest that the aragonite stacks, with characteristic dimensions of around 20 µm, effectively store energy through cooperative plastic deformation. The existence of a larger length scale beyond the brick-and-mortar structure offers an opportunity for a more efficient implementation of biomimetic design. The hierarchical structure of nacre is known to contribute to its high strength and toughness, providing inspiration for many biomimetic materials. Here, co-oriented 20 µm stacks of aragonite platelets are shown to contribute to the toughness of nacre, defining a new characteristic length scale.
Global Navigation Satellite Systems (GNSS) are nowadays the most common solutions used to cope with Positioning-Navigation-Timing (PNT) applications demands. GNSS are relied on in very diverse contexts and domains, yet the interest in systems such as GPS, GALILEO and Beidou is continuously increasing. However
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