470 research outputs found

    Enhanced self-collimation effect by low rotational symmetry in hexagonal lattice photonic crystals

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    In this study, we present the design of a photonic crystal (PC) structure with a hexagonal lattice, where adjustments to the PC unit cell symmetry reveal an all-angle self-collimation (SC) effect. By optimizing opto-geometric parameters, such as the rotational angle of auxiliary rods and adjacent distances, we analyze the SC property in detail, leveraging group velocity dispersion (GVD) and third-order dispersion (TOD) characteristics. We also investigate the relationship between symmetry properties and their influence on dispersion characteristics. Through symmetry manipulation, we gain a comprehensive understanding of the underlying mechanisms governing light collimation and confinement in the proposed configurations. The PC structure with a C1C_1 symmetry group exhibits all-angle SC effect within the range of a/λ=0.652a/\lambda=0.652 and a/λ=0.668a/\lambda=0.668 normalized frequencies, with a bandwidth of Δω/ωc=2.4%\Delta \omega/\omega_c = 2.4\%. Further breaking the symmetry, transforming from C1C_1 to C2C_2 group symmetry, enhances the SC bandwidth to Δω/ωc=6.5%\Delta \omega/\omega_c =6.5\% and reveals the perfect linear equi-frequency contours (EFC) at two different frequency bands: all angle SC between a/λ=0.616a/\lambda = 0.616 and a/λ=0.656a/\lambda = 0.656 normalized frequencies in the 4th transverse magnetic (TM) band and between a/λ=0.712a/\lambda=0.712 and a/λ=0.760a/\lambda=0.760 in the 5th TM band. Additionally, we propose a composite/hybrid PC structure resembling C2C_2 group symmetry, where two auxiliary rods are replaced by rectangular photonic wires with the same refractive index and width equal to the diameter of auxiliary rods. This hybrid structure exhibits an all-angle SC effect with an operating bandwidth of Δω/ωc=11.7%\Delta \omega/\omega_c =11.7\%, displays near-zero GVD and TOD performance and offers enhanced robustness against potential fabrication precision issues

    The first clinical case due to AP92 like strain of Crimean-Congo Hemorrhagic Fever virus and a field survey

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    <p>Abstract</p> <p>Background</p> <p>Crimean-Congo Hemorrhagic Fever (CCHF) is a fatal infection, but no clinical case due to AP92 strain was reported. We described the first clinical case due to AP92 like CCHFV.</p> <p>Methods</p> <p>A case infected by a AP92 like CCHFV was detected in Balkanian part of Turkey. Diagnosis was confirmed by RT-PCR and sequencing. A human serologic and tick survey studies were performed in the region, where the case detected.</p> <p>Results</p> <p>Thirty eight individuals out of 741 were found to be anti CCHFV IgM positive. The attack rate for overall CCHFV was calculated as 5.2%. In univariate analyses, CCHFV IgM positivity was found to be associated with the age (p < 0.001), male gender (p = 0.001), agricultural activity (p = 0.036), and history of tick bite (p = 0.014). In multivariate analysis, older age (OR: 1.03, CI:1.01–1.05, p < 0.001), male gender were found to be the risk factors (OR: 2.5, CI:1.15–5.63, p = 0.020) for CCHFV infection.</p> <p>Conclusion</p> <p>This is the first human case with AP92 like CCHFV infection. Furthermore, this is the first report of AP92 like strain in Turkey. In the region, elderly males carry the highest risk for CCHFV infection.</p

    Quantum Cosmology of Generalized Two--Dimensional Dilaton Gravity Models

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    The quantum cosmology of two-dimensional dilaton-gravity models is investigated. A class of models is mapped onto the constrained oscillator-ghost-oscillator model. A number of exact and approximate solutions to the corresponding Wheeler-DeWitt equation are presented. A wider class of minisuperspace models that can be solved in this fashion is identified. Supersymmetric extensions to the induced gravity theory and the bosonic string theory are then considered and closed-form solutions to the associated quantum constraints are derived. The possibility of applying the third-quantization procedure to two-dimensional dilaton-gravity is briefly discussed.Comment: 28 pages, late

    Trend in potassium intake and Na/K ratio in the Italian adult population between the 2008 and 2018 CUORE project surveys

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    Background and aims: Low potassium intake, in addition to high sodium, has been associated with higher risk of hypertension and CVD. The Study assessed habitual potassium intake and sodium/potassium ratio of the Italian adult population from 2008 to 2012 to 2018–2019 based on 24-h urine collection, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU’ SALUTE national surveys. Methods and results: Data were from cross-sectional surveys of randomly selected age-and-sex stratified samples of resident persons aged 35–74 years in 10 (out of 20) Italian regions. Urinary electrolyte and creatinine measurements were performed in a central laboratory. Analyses considered 942 men and 916 women, examined in 2008–2012, and 967 men and 1010 women, examined in 2018–2019. In 2008–2012, the age-standardized mean of potassium intake (urinary potassium accounts for 70% of potassium intake) was 3147 mg (95% CI 3086–3208) in men and 2784 mg (2727–2841) in women, whereas in 2018–2019, it was 3043 mg (2968–3118) and 2561 mg (2508–2614) respectively. In 2008–2012, age-adjusted prevalence of persons with an adequate potassium intake (i.e. ≥ 3510 mg/day) was 31% (95% CI 28–34%) for men and 18% (16–21%) for women; in 2018–2019, it was 26% (23–29%) and 12% (10–14%) respectively. The sodium/potassium ratio significantly decreased both in men and women. Conclusions: The average daily potassium intake of the Italian general adult population remains lower than the WHO and EFSA recommended level. These results suggest the need of a revision to strengthen initiatives for the promotion of an adequate potassium intake at the population level

    Trend of salt intake measured by 24-h urine collection in the Italian adult population between the 2008 and 2018 CUORE project surveys

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    Background and aims: The WHO Global Action Plan for the Prevention of non-communicable diseases (NCDs) recommends a 30% relative reduction in mean population salt/sodium intake. The study assessed the trend in the habitual salt intake of the Italian adult population from 2008 to 2012 to 2018–2019 based on 24-h urinary sodium excretion, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU’ SALUTE national surveys. Methods and results: Data were from cross-sectional surveys of randomly selected age and sex–stratified samples of resident persons aged 35–74 years in 10 (out of 20) Italian Regions distributed in North, Centre and South of the Country. Urinary sodium and creatinine measurements were carried out in a central laboratory. The analyses included 942 men and 916 women examined in 2008–2012, and 967 men and 1010 women examined in 2018–2019. The age-standardized mean daily population salt (sodium chloride) intake was 10.8 g (95% CI 10.5–11.1) in men and 8.3 g (8.1–8.5) in women in 2008–2012 and respectively 9.5 g (9.3–9.8) and 7.2 g (7.0–7.4) in 2018–2019. A statistically significant (p<0.0001) salt intake reduction was thus observed over 10 years for both genders, and all age, body mass index (BMI) and educational classes. Conclusions: The average daily salt intake of the Italian general adult population remains higher than the WHO recommended level, but a significant reduction of 12% in men and 13% in women has occurred in the past ten years. These results encourage the initiatives undertaken by the Italian Ministry of Health aimed at the reduction of salt intake at the population level

    Imported Crimean-Congo hemorrhagic fever cases in Istanbul

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    We described a series of imported cases of Crimean-Congo Hemorrhagic Fever (CCHF) in Istanbul and investigated the genetic diversity of the virus. All the suspected cases of CCHF, who were applied to the health centers in Istanbul, were screened for CCHF virus (CCHFv) infection by using semi-nested Polymerase Chain Reaction (PCR) following RT-PCR. Simultaneous blood samples were also sent to the national reference laboratory in Ankara for serologic investigation. In 10 out of 91 patients, CCHFv was detected by PCR, and among 9 out of 10, anti-CCHFv IgM antibodies were also positive. Clinical features were characterized by fever, myalgia, and hemorrhage. The levels of liver enzymes, creatinine phosphokinase, and lactate dehydrogenase were elevated, and bleeding markers were prolonged. All the cases were treated with ribavirin. There was no fatal case. All the strains clustered within the same group as other Europe/Turkey isolates

    Cis P-tau is induced in clinical and preclinical brain injury and contributes to post-injury sequelae

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    Traumatic brain injury (TBI) is characterized by acute neurological dysfunction and asso- ciated with the development of chronic traumatic encephalopathy (CTE) and Alzheimer’s disease. We previously showed that cis phosphorylated tau (cis P-tau), but not the trans form, contributes to tau pathology and functional impairment in an animal model of severe TBI. Here we found that in human samples obtained post TBI due to a variety of causes, cis P-tau is induced in cortical axons and cerebrospinal fluid and positively correlates with axonal injury and clinical outcome. Using mouse models of severe or repetitive TBI, we showed that cis P-tau elimination with a specific neutralizing antibody administered immediately or at delayed time points after injury, attenuates the development of neuropathology and brain dysfunction during acute and chronic phases including CTE-like pathology and dysfunction after repetitive TBI. Thus, cis P-tau contributes to short-term and long-term sequelae after TBI, but is effectively neutralized by cis antibody treatment
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