Unique ghost surface phonon polaritons in biaxially hyperbolic materials.

We predicted peculiar ghost surface phonon polaritons in biaxially hyperbolic materials, where the two hyperbolic principal axes lie in the plane of propagation. We took the biaxially-hyperbolic α-MoO3 as one example of the materials to numerically simulate the ghost surface phonon polaritons. We found three unique ghost surface polaritons to appear in three enclosed wavenumber-frequency regions, respectively. These ghost surface phonon polaritons have different features from the surface phonon polaritons found previously, i.e., they are some hybrid-polarization surface waves composed of two coherent evanescent branch-waves in the α-MoO3 crystal. The interference of branch-waves leads to that their Poynting vector and electromagnetic fields both exhibit the oscillation-attenuation behavior along the surface normal, or a series of rapidly attenuated fringes. We found that the in-plane hyperbolic anisotropy and low-symmetric geometry of surface are the two necessary conditions for the existence of these ghost surface polaritons.

Spin-splitting in a reflective beam off an antiferromagnetic surface.

A linearly-polarized radiation can be considered as the superposition of two circularly-polarized components with the same propagating direction and opposite spins. We investigated the splitting between the two spin-components in the reflective beam off the antiferromagnetic surface. The gyromagnetism and surface impedance mismatch cause the difference between the spatial shifts of the two spin-components, i.e., the spin-splitting. We analytically achieved the in- and out-plane shift-expressions of either spin-component for two typical linearly-polarized incident beams (i.e., the p- and s-incidences). In the case of no gyromagnetism, we obtained very simple shift-expressions, which indicate a key role played by the gyromagnetism or the surface impedance-mismatch in spin-splitting. Based on a FeF2 crystal, the spin-splitting distance was calculated. The spin-splitting distance is much longer for the p-incidence than the s-incidence, and meanwhile the in-plane splitting distance is much larger than the out-plane one. The gyromagnetism plays a key role for the in-plane spin-splitting and the surface impedance-mismatch is a crucial factor for the out-plane spin-splitting distance. The results are useful for the manipulation of infrared radiations and infrared optical detection.

Large spatial shifts of reflective beam at the surface of graphene/hBN metamaterials.

We theoretically studied the Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts of reflective beam at the surface of graphene/hBN metamaterials. The results show that the GH-shift is significantly enhanced and also possesses the large reflectivity when the light beam is incident at the critical angle near the Brewster angle. We found that the IF-shift is the largest when the reflective beam is a special polarized-beam or the reflective coefficients satisfy the conditions |rs | = |rp | and φs - φp = 2jπ (j is an integer). By changing the chemical potential, filling ratio and tilted angle, the position and width of frequency windows obtaining the maximum values of shifts can be effectively adjusted. The large and tunable GH- and IF-shifts with the higher reflectivity provide an alternative scheme to develop new nano-optical devices.

Goos-Hänchen and Imbert-Fedorov shifts on hyperbolic crystals.

We investigated Goos-Hänchen (GH) and Imbert-Fedorov (IF) shifts on a uniaxial hyperbolic crystal, where a circularly-polarized beam was incident on the crystal from the free space. The GH- and IF-shifts were analytically obtained and numerically calculated for the hexagonal boron nitride. Our results demonstrate that the GH- and IF-shift spectra are complicated and completely different in and out the hyperbolic frequency-bands (the reststrahlen bands in the infrared region). At the critical or Brewster angle, concisely analytical expressions of GH-shift was found, which explicitly state the optical-loss dependence of GH-shift at these special angles. We found the GH-shifts are very large at the critical and Brewster angles. It is very necessary to know these effects since hyperbolic materials are usually applied in the nano- and micro-optics or technology fields.

Extraordinary reflection and refraction from natural hyperbolic materials.

The reflection and refraction were theoretically investigated for a linearly-polarized wave incident upon the surface of a naturally hyperbolic material. We proposed that this material is uniaxial and possesses two hyperbolic-frequency bands (HB-I and HB-II), whose optical axis is arbitrarily pointed. We paid our attention to reflective and refractive features in the HBs and predicted some extraordinary phenomena. The double reflection was found, where the reflective wave contains a transverse electric branch and a transverse magnetic branch with different amplitudes and phases. The asymmetry of reflection exists and the reflective coefficient abnormally decreases as the incident angle is enlarged. The double refraction inside the material means two refractive branches (the o-wave and e-wave). For the e-wave, there is a special frequency point (SP) in either HB, depending on the orientation of the optical axis. The e-wave and reflective wave exhibit completely different behaviors on the two sides of the SP. The e-wave is a normal refractive wave on the left side of the SP, but it is an evanescent wave on the right side. Its energy-flux seriously deviates from the incident plane and is highly condensed at the inner surface near the SP. It is more interesting that the energy-flux density of the e-wave in the HB-II can even be much larger than that of the incident wave and is opposite in direction on the two sides of the SP, which means an evident radiation-switching effect. The o-wave is a normal refractive wave in the HB-I, but it is an evanescent wave in the HB-II. The above results and conclusions were obtained from the hexagonal boron nitride (hBN). These unique properties may be very useful in optical or optoelectronic technology.

The Clinicopathological and Prognostic Significance of IDO1 Expression in Human Solid Tumors: Evidence from a Systematic Review and Meta-Analysis.

BACKGROUND/AIMS: Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing enzyme catalyzing the initial and rate-limiting steps in the kynurenine pathway, which converts tryptophan into kynurenine. Upregulation of IDO1 decreases tryptophan levels and increases the accumulation of kynurenine and its metabolites. These metabolites can affect the proliferation of T cells. Increasing evidence has shown that IDO1 is highly expressed in various cancer types and associated with poor prognosis of cancer patients. However, the results were inconsistent. METHODS: We searched the Web of Science, PubMed, Embase and Cochrane library databases to identify studies evaluating the prognostic value of IDO1 in cancer patients. Pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by using fixed-effects/random-effects models. RESULTS: This systematic review and meta-analysis included 2706 patients from 24 articles. The results indicated a shorter overall survival in patients with high expression of IDO1 (hazard ratio [HR] = 2.03, 95% confidence interval [CI]: 1.56-2.63). Furthermore, disease-free survival was worse in patients with high expression of IDO1 (HR = 2.47, 95% CI: 1.46-4.20). Additionally, the pooled odds ratios (ORs) showed that increased IDO1 was significantly associated with tumor differentiation (OR = 1.81, 95% CI: 1.05-3.12), distant metastasis (OR = 1.45, 95% CI: 1.02-2.06), and poor clinical stage (OR = 1.89, 95% CI: 1.13-3.17). However, no significant correlation was observed of increased IDO1 expression with age, sex, lymph node metastasis, and tumor size. CONCLUSION: High expression of IDO1 is associated with poor clinical outcomes. IDO1 could serve as a biomarker of prognosis and a potential predictive factor of clinicopathology in various cancers. Further studies should be performed to verify the clinical utility of IDO1 in human solid tumors.

Generation of Elliptically Polarized Terahertz Waves from Antiferromagnetic Sandwiched Structure.

The generation of elliptically polarized electromagnetic wave of an antiferromagnetic (AF)/dielectric sandwiched structure in the terahertz range is studied. The frequency and external magnetic field can change the AF optical response, resulting in the generation of elliptical polarization. An especially useful geometry with high levels of the generation of elliptical polarization is found in the case where an incident electromagnetic wave perpendicularly illuminates the sandwiched structure, the AF anisotropy axis is vertical to the wave-vector and the external magnetic field is pointed along the wave-vector. In numerical calculations, the AF layer is FeF2 and the dielectric layers are ZnF2. Although the effect originates from the AF layer, it can be also influenced by the sandwiched structure. We found that the ZnF2/FeF2/ZnF2 structure possesses optimal rotation of the principal axis and ellipticity, which can reach up to about thrice that of a single FeF2 layer.

[Changes in serum levels of resistin and visfatin in pediatric patients with acute Kawasaki disease following intravenous immune globulin treatment].

OBJECTIVE: To determine serum levels of resistin and visfatin in the patients with acute Kawasaki disease before and after intravenous immune globulin (IVIG) treatment. METHODS: A total of 50 children with acute Kawasaki disease were treated with IVIG for 48 hours between January 2011 and January 2013. As controls, 30 healthy children and 30 children with acute infectious diseases were included. Serum levels of resistin and visfatin were measured by ELISA both before and after the treatment. RESULTS: The baseline serum levels of resistin and visfatin were significantly higher in patients with acute Kawasaki disease than in the two control groups of subjects (i.e., healthy children and patients with acute infectious diseases; P<0.05). In the 50 patients with Kawasaki disease, 38 were not responding and 12 were responding. Serum resistin levels before treatment were significantly higher in non-responders than those in responders (P<0.05). A significant decrease in serum levels of resistin after treatment was observed in IVIG responders (P<0.05). Serum visfatin levels were not significantly different between IVIG responders and non-responders (P>0.05). Additionally, serum resistin and visfatin levels were not significantly different between acute Kawasaki disease patients with and without coronary artery lesions. CONCLUSIONS: Resistin and visfatin may play important roles in the development of Kawasaki disease and serum resistin may be used as a novel outcome indicator of the IVIG treatment.

[Epidemiological analysis of childhood asthma in Yichang City, China].

OBJECTIVE: To study the prevalence, epidemiological characteristics, and risk factors for childhood asthma in Yichang City, China and to collect evidence for the early diagnosis and preventive treatment of asthma. METHODS: Preliminary screening questionnaires were distributed to more than 90% of children in 5 kindergartens, 10 primary and secondary schools, and 5 communities in Yichang City to detect children with suspected asthma. These surveyed children were selected by cluster random sampling. A further questionnaire survey was conducted for suspected cases. Meanwhile, a similar number of sex- and age-matched non-asthmatic children were selected for the case-control study. Information from returned questionnaires was entered into a database for statistical analysis. RESULTS: A total of 11 000 questionnaires were distributed, and 10 456 (95.1%) questionnaires were returned. The prevalence rate of asthma among children in Yichang was 3.47%, significantly higher in boys than in girls (P<0.05). A total of 107 out of 363 children with asthma had a history of drug allergy, and 152 cases had a family history of allergy. The majority of asthmatic children had irregular onset-prone seasons and hours. Respiratory tract infections were the most common trigger of asthma attacks, accounting for 93.1% of all onsets; family history of allergy, history of early use of antibiotics, history of housing renovation, and history of passive smoking were the major risk factors for asthma. CONCLUSIONS: Prevention of respiratory tract infections may reduce the frequency of asthma attacks; reducing the use of antibiotics during early childhood, decreasing the frequency of housing renovation, and advocating for smoking cessation among parents have preventive effects on asthma.

Physico-chemical and antioxidant properties of four mango (Mangifera indica L.) cultivars in China.

Four principal mango cultivars (Tainong No.1, Irwin, JinHwang and Keitt) grown in southern China were selected, and their physico-chemical and antioxidant properties were characterized and compared. Of all the four cultivars, Tainong No.1 had highest content of total phenols, ρ-coumaric acid, sinapic acid, quercetin, titratable acidity, citric acid, malic acid, fructose, higher antioxidant activities (DPPH, FRAP) and L(*), lower pH, PPO activity and individual weight. Keitt mangoes showed significantly (p<0.05) higher contents of ß-carotene, ρ-hydroxybenzoic acid, sucrose, total sugar, total soluble solid, catechin, succinic acid and higher PPO activity. JinHwang mangoes exhibited significantly (p<0.05) higher individual weight and PPO activity, but had lower content of total phenols, ß-carotene and lower antioxidant activity. Principal component analysis (PCA) allowed the four mango cultivars to be differentiated clearly based on all these physico-chemical and antioxidant properties determined in the study.