Toroidal Dipolar Response in a Metamaterial Kaelberer, T; Fedotov, V.A; Papasimakis, N ...
Science (American Association for the Advancement of Science),
12/2010, Letnik:
330, Številka:
6010
Journal Article
Recenzirano
Odprti dostop
Toroidal multipoles are fundamental electromagnetic excitations different from those associated with the familiar charge and magnetic multipoles. They have been held responsible for parity violation ...in nuclear and particle physics, but direct evidence of their existence in classical electrodynamics has remained elusive. We report on the observation of a resonant electromagnetic response in an artificially engineered medium, or metamaterial, that cannot be attributed to magnetic or charge multipoles and can only be explained by the existence of a toroidal dipole. Our direct experimental evidence of the toroidal response brings attention to the often ignored electromagnetic interactions involving toroidal multipoles, which could be present in naturally occurring systems, especially at the macromolecule level, where toroidal symmetry is ubiquitous.
HLA-A*31:01 was reported to be associated with carbamazepine (CBZ)-induced severe cutaneous adverse reactions (SCAR), including drug reaction with eosinophilia and systemic symptoms (DRESS), ...Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). We conducted an international study using consensus diagnosis criteria to enroll a total of 93 patients with CBZ-SCAR from Europe or Asia. We found that HLA-A*31:01 showed a significant association with CBZ-DRESS in Europeans (P<0.001; odds ratio (OR) (95% confidence interval (CI))=57.6 (11.0-340)), and the strong association was also found in Chinese (P<0.001; OR (95% CI)=23.0 (4.2-125)). However, HLA-A*31:01 had no association with CBZ-SJS/TEN in neither Chinese nor Europeans. By comparison, HLA-B*15:02 showed a strong association with CBZ-SJS/TEN in Chinese (P<0.001, OR (95% CI)=58.1 (17.6-192)). A meta-analysis of this and other published studies confirmed that in all populations, HLA-A*31:01 had an extremely strong association with CBZ-DRESS (P<0.001, a pooled OR (95% CI)=13.2 (8.4-20.8)), but a much weaker association with CBZ-SJS/TEN (P=0.01, OR (95% CI)=3.94 (1.4-11.5)). Our data revealed that HLA-A*31:01 is a specific predictor for CBZ-DRESS but not for CBZ-SJS/TEN. More studies are needed to investigate the genetic determinant of CBZ-SJS/TEN in Europeans. Considering the potential clinical utility, the cost-effectiveness of the combined HLA-A*31:01 and HLA-B*15:02 genetic test to prevent CBZ-SCAR in Chinese needs further investigation.
Engaging strongly resonant interactions allows dramatic enhancement of functionalities of many electromagnetic devices. However, resonances can be dampened by Joule and radiation losses. While in ...many cases Joule losses may be minimized by the choice of constituting materials, controlling radiation losses is often a bigger problem. Recent solutions include the use of coupled radiant and sub-radiant modes yielding narrow asymmetric Fano resonances in a wide range of systems, from defect states in photonic crystals and optical waveguides with mesoscopic ring resonators to nanoscale plasmonic and metamaterial systems exhibiting interference effects akin to electromagnetically-induced transparency. Here we demonstrate theoretically and confirm experimentally a new mechanism of resonant electromagnetic transparency, which yields very narrow isolated symmetric Lorentzian transmission lines in toroidal metamaterials. It exploits the long sought non-trivial non-radiating charge-current excitation based on interfering electric and toroidal dipoles that was first proposed by Afanasiev and Stepanovsky in J. Phys. A Math. Gen. 28, 4565 (1995).
Particle trapping and binding in optical potential wells provide a versatile platform for various biomedical applications. However, implementation systems to study multi-particle contact interactions ...in an optical lattice remain rare. By configuring an optofluidic lattice, we demonstrate the precise control of particle interactions and functions such as controlling aggregation and multi-hopping. The mean residence time of a single particle is found considerably reduced from 7 s, as predicted by Kramer's theory, to 0.6 s, owing to the mechanical interactions among aggregated particles. The optofluidic lattice also enables single-bacteria-level screening of biological binding agents such as antibodies through particle-enabled bacteria hopping. The binding efficiency of antibodies could be determined directly, selectively, quantitatively and efficiently. This work enriches the fundamental mechanisms of particle kinetics and offers new possibilities for probing and utilising unprecedented biomolecule interactions at single-bacteria level.
We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in ...artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media.
Using a large sample of residential retail electricity plans advertised on the Public Utility Commission of Texas's Power-to-Choose website between January 2014 to December 2018, we analyse how a ...retail price quote varies with its per MWh procurement cost forecast based on wholesale prices and other product attributes. Our panel regression analysis finds that a retail price quote partially passes through 43% to 47% of a wholesale price forecast changes and embodies a risk premium that increases with wholesale price forecast volatility. Prepayment and time-of-use plans contain price premia. The price premia associated with higher-than-average renewable energy contents in the early years of our sample have largely vanished by 2018. Longer contract terms come at a higher price. Finally, increased one-month lagged customer switching tends to be associated with reduced retail price quotes.
•We explain variations in retail electric energy prices in Texas' competitive retail market.•Changes in the projected wholesale price are not fully reflected as changes in retail plans' price quotes.•Rates of wholesale price pass-through rates range from 43% to 47%.•The price premia associated with higher-than-average renewable energy contents have largely vanished by 2018.•Increased customer switching tends to reduce retail price quotes
Introduction
Osteoporosis is a metabolic bone disease with low bone mineral density (BMD) and high incidence of vertebral fractures (VFs). Postmenopausal women with osteoporosis have decreased total ...fat and lean mass. This study aimed to investigate the associations between body composition and VF risk and explore the potential predictor of VF risk in postmenopausal women.
Methods
Enrolled 731 postmenopausal women were referred by various departments and outpatient clinics to assess vertebral status between October 2016 and November 2017. The main measures were total body lean mass, fat mass, and BMD. Patients were divided into osteopenia, osteoporosis, and normal groups based on T-scores. Logistic regression analyses were performed to evaluate associations between body composition parameters and VF.
Results
VF was significantly associated with increased age, lower height, and lighter weight in all participants, and higher BMI was observed in VF participants. Participants in the osteoporosis group were older and had lower height, weight, and BMD than those in normal and osteopenia groups. Femoral and total hip T-scores as well as T-scores for lumbar spine were significantly lower in participants with VF than in non-VF participants. Percentage of bone mass was also significantly lower in VF participants compared to that of non-VF participants. Women with increased BMD and lower bone mass had reduced odds for VF occurrence. Bone mass was significantly able to identify VF occurrence.
Conclusions
Body composition analysis discerns differences in the bone status of postmenopausal women with and without VF. The cutoff value of the bone mass might be used effectively as an indicator of risk for VF occurrence.
Dichroic polarizers and waveplates exploiting anisotropic materials have vast applications in displays and numerous optical components, such as filters, beamsplitters and isolators. Artificial ...anisotropic media were recently suggested for the realization of negative refraction, cloaking, hyperlenses, and controlling luminescence. However, extending these applications into the terahertz domain is hampered by a lack of natural anisotropic media, while artificial metamaterials offer a strong engineered anisotropic response. Here we demonstrate a terahertz metamaterial with anisotropy tunable from positive to negative values. It is based on the Maltese-cross pattern, where anisotropy is induced by breaking the four-fold symmetry of the cross by displacing one of its beams. The symmetry breaking permits the excitation of a Fano mode active for one of the polarization eigenstates controlled by actuators using microelectromechanical systems. The metamaterial offers new opportunities for the development of terahertz variable waveplates, tunable filters and polarimetry.
Transformation optics represents a new paradigm for designing light-manipulating devices, such as cloaks and field concentrators, through the engineering of electromagnetic space using materials with ...spatially variable parameters. Here we analyse liquid flowing in an optofluidic waveguide as a new type of controllable transformation optics medium. We show that a laminar liquid flow in an optofluidic channel exhibits spatially variable dielectric properties that support novel wave-focussing and interference phenomena, which are distinctively different from the discrete diffraction observed in solid waveguide arrays. Our work provides new insight into the unique optical properties of optofluidic waveguides and their potential applications.
Background
The soil quality and health of the tea plantations are dependent on agriculture management practices, and long-term chemical fertilizer use is implicated in soil decline. Hence, several ...sustainable practices are used to improve and maintain the soil quality. Here, in this study, changes in soil properties, enzymatic activity, and dysbiosis in bacterial community composition were compared using three agricultural management practices, namely conventional (CA), sustainable (SA), and transformational agriculture (TA) in the tea plantation during 2016 and 2017 period. Soil samples at two-months intervals were collected and analyzed.
Results
The results of the enzyme activities revealed that acid phosphatase, arylsulfatase, β-glucosidase, and urease activities differed considerably among the soils representing the three management practices. Combining the redundancy and multiple regression analysis, the change in the arylsulfatase activity was explained by soil pH as a significant predictor in the SA soils. The soil bacterial community was predominated by the phyla Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Bacteroidetes in the soil throughout the sampling period. Higher Alpha diversity scores indicated increased bacterial abundance and diversity in the SA soils. A significant relationship between bacterial richness indices (SOBS, Chao and ACE) and soil pH, K and, P was observed in the SA soils. The diversity indices namely Shannon and Simpson also showed variations, suggesting the shift in the diversity of less abundant and more common species. Furthermore, the agricultural management practices, soil pH fluctuation, and the extractable elements had a greater influence on bacterial structure than that of temporal change.
Conclusions
Based on the cross-over analysis of the bacterial composition, enzymatic activity, and soil properties, the relationship between bacterial composition and biologically-driven ecological processes can be identified as indicators of sustainability for the tea plantation.
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