Diffraction-Free Bloch Surface Waves

In this letter, we demonstrate a novel diffraction-free Bloch surface wave (DF-BSW) sustained on all-dielectric multilayers that does not diffract after being passed through three obstacles or across a single mode fiber. It can propagate in a straight line for distances longer than 110 {\mu}m at a wavelength of 633 nm and could be applied as an in-plane optical virtual probe, both in air and in an aqueous environment. The ability to be used in water, its long diffraction-free distance, and its tolerance to multiple obstacles make this DF-BSW ideal for certain applications in areas such as the biological sciences, where many measurements are made on glass surfaces or for which an aqueous environment is required, and for high-speed interconnections between chips, where low loss is necessary. Specifically, the DF-BSW on the dielectric multilayer can be used to develop novel flow cytometry that is based on the surface wave, but not the free space beam, to detect the surface-bound targets

Stem hydraulic traits and leaf water-stress tolerance are co-ordinated with the leaf phenology of angiosperm trees in an Asian tropical dry karst forest

Background and Aims The co-occurring of evergreen and deciduous angiosperm trees in Asian tropical dry forests on karst substrates suggests the existence of different water-use strategies among species. In this study it is hypothesized that the co-occurring evergreen and deciduous trees differ in stem hydraulic traits and leaf water relationships, and there will be correlated evolution in drought tolerance between leaves and stems. † Methods A comparison was made of stem hydraulic conductivity, vulnerability curves, wood anatomy, leaf life span, leaf pressure -volume characteristics and photosynthetic capacity of six evergreen and six deciduous tree species co-occurring in a tropical dry karst forest in south-west China. The correlated evolution of leaf and stem traits was examined using both traditional and phylogenetic independent contrasts correlations. † Key Results It was found that the deciduous trees had higher stem hydraulic efficiency, greater hydraulically weighted vessel diameter (D h ) and higher mass-based photosynthetic rate (A m ); while the evergreen species had greater xylem-cavitation resistance, lower leaf turgor-loss point water potential (p 0 ) and higher bulk modulus of elasticity. There were evolutionary correlations between leaf life span and stem hydraulic efficiency, A m , and dry season p 0 . Xylem-cavitation resistance was evolutionarily correlated with stem hydraulic efficiency, D h , as well as dry season p 0 . Both wood density and leaf density were closely correlated with leaf water-stress tolerance and A m . † Conclusions The results reveal the clear distinctions in stem hydraulic traits and leaf water-stress tolerance between the co-occurring evergreen and deciduous angiosperm trees in an Asian dry karst forest. A novel pattern was demonstrated linking leaf longevity with stem hydraulic efficiency and leaf water-stress tolerance. The results show the correlated evolution in drought tolerance between stems and leaves

Higher Serum Uric Acid Is Associated with Higher Bone Mineral Density in Chinese Men with Type 2 Diabetes Mellitus

Accumulating evidence suggests that oxidative stress is associated with osteoporosis. Serum uric acid (UA) is a strong endogenous antioxidant. Therefore, we investigated the relationship between the serum UA and BMD in Chinese men with T2DM. In this cross-sectional study of 621 men with T2DM, BMDs at lumbar spine (L2–4), femoral neck (FN), and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). Serum levels of UA, calcium (Ca), 25-OH vitamin D3 (vitD3), parathyroid hormone (PTH), and creatinine (Cr) were also tested. Data analyses revealed that serum UA levels were positively associated with BMD at all sites (p<0.05) in men with T2DM after adjusting for multiple confounders. The serum UA levels were positively correlated with body weight (r=0.322), body mass index (BMI) (r=0.331), Ca (r=0.179), and Cr (r=0.239) (p<0.001) and were also positively associated with the concentrations of PTH (r=0.10, p<0.05). When compared with those in the lowest tertile of UA levels, men with T2DM in the highest tertile had a lower prevalence of osteoporosis or osteopenia (adjusted odds ratio 0.54, 95% confidence interval [CI] 0.31–0.95). These data suggest that higher serum levels of UA are associated with higher BMDs and lower risks of osteoporosis in Chinese men with T2DM

Molecular Design Principle of All‐organic Dyes for Dye‐Sensitized Solar Cells

All‐organic dyes have shown promising potential as an effective sensitizer in dye‐sensitized solar cells (DSSCs). The design concept of all‐organic dyes to improve light‐to‐electric‐energy conversion is discussed based on the absorption, electron injection, dye regeneration, and recombination. How the electron‐donor–acceptor‐type framework can provide better light harvesting through bandgap‐tuning and why proper arrangement of acceptor/anchoring groups within a conjugated dye frame is important in suppressing improper charge recombination in DSSCs are discussed. Separating the electron acceptor from the anchoring unit in the donor–acceptor‐type organic dye would be a promising strategy to reduce recombination and improve photocurrent generation. A guiding light : All‐organic dyes have shown promising potential as an effective sensitizer in DSSCs. Their chemical nature decisively affects the current generation and open‐circuit voltage. Several molecular design strategies of all‐organic dyes to improve DSSC performance as well as factors for the improvement of photocurrent generation and reduction of improper recombination are discussed (see figure).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97444/1/5220_ftp.pd

Flexible transit routing model considering passengers’ willingness to pay

This paper proposes an alternative flexible transit model with two levels of bus stops, A level and B level. A-level bus stops are fixed, while B-level bus stops are flexible and provide service only when passengers indicate a strong willingness to pay (WTP). This fare structure encourages passengers to choose bus stops with their mobile phones or computers. An optimization model of 0-1 integer-programming is formulated based on whether certain B-level stops can be serviced. With a numerical example, we compare the performance of the proposed traversing method and a tabu search algorithm, both of which are adapted to solve the model. Finally, a real case is provided to evaluate the proposed transit system against comparable systems (e.g., a fixed-route transit system and a taxi service), and the result shows that the flexible transit routing model will help both passengers and bus companies, thus creating a win-win situation

Synthetic strategies to nanostructured photocatalysts for CO2 reduction to solar fuels and chemicals

Artificial photosynthesis represents one of the great scientific challenges of the 21st century, offering the possibility of clean energy through water photolysis and renewable chemicals through CO2 utilisation as a sustainable feedstock. Catalysis will undoubtedly play a key role in delivering technologies able to meet these goals, mediating solar energy via excited generate charge carriers to selectively activate molecular bonds under ambient conditions. This review describes recent synthetic approaches adopted to engineer nanostructured photocatalytic materials for efficient light harnessing, charge separation and the photoreduction of CO2 to higher hydrocarbons such as methane, methanol and even olefins

Trends in template/fragment-free protein structure prediction

Predicting the structure of a protein from its amino acid sequence is a long-standing unsolved problem in computational biology. Its solution would be of both fundamental and practical importance as the gap between the number of known sequences and the number of experimentally solved structures widens rapidly. Currently, the most successful approaches are based on fragment/template reassembly. Lacking progress in template-free structure prediction calls for novel ideas and approaches. This article reviews trends in the development of physical and specific knowledge-based energy functions as well as sampling techniques for fragment-free structure prediction. Recent physical- and knowledge-based studies demonstrated that it is possible to sample and predict highly accurate protein structures without borrowing native fragments from known protein structures. These emerging approaches with fully flexible sampling have the potential to move the field forward

Search for hidden-charm tetraquark with strangeness in e+e−→K+Ds∗−D∗0+c.c.e^{+}e^{-}\rightarrow K^+ D_{s}^{*-} D^{*0}+c.c.

We report a search for a heavier partner of the recently observed $Z_{cs}(3985)^{-}$ state, denoted as $Z_{cs}^{\prime -}$, in the process $e^{+} e^{-}\rightarrow K^{+}D_{s}^{*-}D^{* 0}+c.c.$, based on $e^+e^-$ collision data collected at the center-of-mass energies of $\sqrt{s}=4.661$, 4.682 and 4.699 GeV with the BESIII detector. The $Z_{cs}^{\prime -}$ is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate $K^+$ recoil-mass spectra, which are probed for a potential contribution from $Z_{cs}^{\prime -}\to D_{s}^{*-}D^{* 0}$ ($c.c.$). We find an excess of $Z_{cs}^{\prime -}\rightarrow D_{s}^{*-}D^{*0}$ ($c.c.$) candidates with a significance of $2.9\sigma$, after considering systematic uncertainties, at a mass of $(4123.5 \pm 0.7_{\mathrm{stat.}} \pm 1.1_{\mathrm{syst.}}) \mathrm{MeV}/c^{2}$. As the data set is limited in size, the upper limits are evaluated at the 90% confidence level on the product of the Born cross section and the branching fraction of $Z_{cs}^{\prime-}\rightarrow D_{s}^{*-}D^{* 0}$, $\sigma^{\rm Born}\cdot\mathcal{B}$ at the three energy points, under different assumptions of the $Z_{cs}^{\prime -}$ mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV. Under various mass and width assumptions, the upper limits of $\sigma^{\rm Born}\cdot\mathcal{B}$ are found to lie in the range of $2\sim6$, $3\sim7$ and $3\sim6$ pb at $\sqrt{s}=4.661$, 4.682 and 4.699 GeV, respectively. The larger data samples that will be collected in the coming years will allow a clearer picture to emerge concerning the existence and nature of the $Z_{cs}^{\prime -}$ state.Comment: 17 pages, 7 figure

Measurement of the C ⁣PC\!P-even fraction of D0→K+K−π+π−D^0\to K^+K^-\pi^+\pi^-

A determination of the $C\!P$-even fraction $F_+$ in the decay $D^0 \to K^+K^-\pi^+\pi^-$ is presented. Using $2.93$ fb$^{-1}$ of $e^+e^-\to\psi(3770)\to D\bar{D}$ data collected by the BESIII detector, one charm meson is reconstructed in the signal mode and the other in a $C\!P$ eigenstate or the decay $D\to K_{S, L}^0\pi^+\pi^-$. Analysis of the relative rates of these double-tagged events yields the result $F_+ = 0.730 \pm 0.037 \pm 0.021$, where the first uncertainty is statistical and the second is systematic. This is the first model-independent measurement of $F_+$ in $D^0 \to K^+K^-\pi^+\pi^-$ decays.Comment: 13 pages, 5 figure