Investigation of a Side-polished Fiber MZI and Its Sensing Performance

A novel all-fiber Mach–Zehnder interferometer (MZI), which consists of lateral core fusion splicing of a short section of side-polished single mode fiber (SMF) between two SMFs was proposed and demonstrated. A simple fiber side-polished platform was built to control the side polished depth through a microscope. The sensitivity of the fiber MZI structure to the surrounding refractive index (RI) can be greatly improved with the increase of the side-polished depth, but has no effect on the temperature sensitivity. The sensor with a polished depth of 44.2 μm measured RI sensitivity up to -118.0 nm/RIU (RI unit) in the RI range from 1.333 to 1.387, which agrees well with simulation results by using the beam propagation method (BPM). In addition, the fiber MZI structure also can achieve simultaneous measurement of both RI and temperature. These results show its potential for use in-line fiber type sensing application

Fabrication and Application of Iron(III)-Oxide Nanoparticle/Polydimethylsiloxane Composite Cone in Microfluidic Channels

This paper presented the fabrication and applications of an iron(III)-oxide nanoparticle/polydimethylsiloxane (PDMS) cone as a component integrated in lab on a chip. The two main functions of this component were to capture magnetic microbeads in the microfluid and to mix two laminar fluids by generating disturbance. The iron(III)-oxide nanoparticle/PDMS cone was fabricated by automatic dispensing and magnetic shaping. Three consecutive cones of 300 μm in height were asymmetrically placed along a microchannel of 2 mm in width and 1.1 mm in height. Flow passing the cones was effectively redistributed for Renolds number lower than . Streptavidin-coated magnetic microbeads which were bound with biotin were successfully captured by the composite cones as inspected under fluorescence microscope. The process parameters for fabricating the composite cones were investigated. The fabricated cone in the microchannel could be applied in lab on a chip for bioassay in the future

Decreased NPC1L1 expression in the liver from Chinese female gallstone patients

<p>Abstract</p> <p>Background</p> <p>Cholesterol gallstone disease is a very common disease in both industrialized and developing countries. Many studies have found that cholesterol gallstones are more common in women than men. The molecular mechanisms underlying the relationship between female gallstone disease and hepatic sterol transporters are still undergoing definition and have not been evaluated in humans.</p> <p>Aims</p> <p>The aim of this study is to probe for underlying hepatic molecular defects associated with development of gallstones in female.</p> <p>Methods/Results</p> <p>Fifty-seven nonobese, normolipidemic Chinese female gallstone patients (GS) were investigated with 12 age- and body mass index-matched female gallstone-free controls (GSF). The bile from the female GS had higher cholesterol saturation than that from the female GSF. The hepatic NPC1L1 mRNA levels were lower in female GS, correlated with SREBP2 mRNA. NPC1L1 downregulation was confirmed at protein levels. Consistently, immunohistochemistry showed decreased NPC1L1 expression in female GS.</p> <p>Conclusions</p> <p>The decreased hepatic NPC1L1 levels in female GS might indicate a downregulated reabsorption of biliary cholesterol in the liver, which, in turn, leads to the cholesterol supersaturation of bile. Our data are consistent with the possibility that hepatic NPC1L1 may be mediated by SREBP2.</p

1-(3,4-Dihy­droxy­phen­yl)hexan-1-one

In the title compound, C12H16O3, a fully extened hexyl carbon chain is attached to a benzene ring; the mean planes formed by the atoms in the benzene ring and the hexa­none are inclined at an angle 8.5 (2)° with respect to each other. In the crystal, inter­molecular O—H⋯O hydrogen bonds join the mol­ecules into an infinite sheet

Fractional and composite excitations of antiferromagnetic quantum spin trimer chains

Using Lanczos exact diagonalization, stochastic analytic continuation of quantum Monte Carlo data, and perturbation theory, we investigate the dynamic spin structure factor S(q, ) of the S=1/2 antiferromagnetic Heisenberg trimer chain. We systematically study the evolution of the spectrum by varying the ratio g=J_2/J_1 of the intertrimer and intratrimer coupling strengths and interpret the observed features using analytical and numerical calculations with the trimer eigenstates. The doublet ground states of the trimers form effective interacting S=1/2 degrees of freedom described by a Heisenberg chain with coupling J_eff=(4/9)J_2. Therefore, the conventional two-spinon continuum of width ∝ J_1 when g =1 evolves into to a similar continuum of width ∝ J_2 in the reduced Brillouin zone when g ⟶ 0. The high-energy modes (at ∝ J_1) for g ≈ 0.5 can be understood as weakly dispersing propagating internal trimer excitations (which we term doublons and quartons), and these fractionalize with increasing g to form the conventional spinon continuum when g is increased toward 1. The coexistence of two kinds of emergent spinon branches for intermediate values of g give rise to interesting spectral signatures, especially at g ≈ 0.7 where the gap between the low-energy spinon branch and the high energy band of mixed doublons, quartons, and spinons closes. These features should be observable in inelastic neutron scattering experiments if a quasi-one-dimensional quantum magnet with the linear trimer structure and J_2 < J_1 can be identified. We suggest that finding such materials would be useful, enabling detailed studies of coexisting exotic excitations and their interplay within a relatively simple theoretical framework.First author draf

Fractional and composite excitations of antiferromagnetic quantum spin trimer chains

Using quantum Monte Carlo, exact diagonalization, and perturbation theory, we study the spectrum of the S = 1/2 antiferromagnetic Heisenberg trimer chain by varying the ratio g = J2/J1 of the intertrimer and intratrimer coupling strengths. The doublet ground states of trimers form effective interacting S = 1/2 degrees of freedom described by a Heisenberg chain. Therefore, the conventional two-spinon continuum of width ∝ J1 when g = 1 evolves into to a similar continuum of width ∝ J2 when g → 0. The intermediate-energy and high-energy modes are termed doublons and quartons which fractionalize with increasing g to form the conventional spinon continuum. In particular, at g ≈ 0.716, the gap between the low-energy spinon branch and the high-energy band with mixed doublons, quartons, and spinons closes. These features should be observable in inelastic neutron scattering experiments if a quasi-one-dimensional quantum magnet with the linear trimer structure and J2 < J1 can be identified. Our results may open a window for exploring the high-energy fractional excitations.Published versio

Tapered microfiber MZI Biosensor for highly sensitive detection of Staphylococcus aureus

A new double-taper microfiber Mach-Zehnder interferometer (MZI) biosensor is applied for Staphylococcus aureus (S. aureus) detection. The microfiber MZI structure is fabricated by creating two tapers along a traditional single mode fiber (SMF) firstly and tapering the SMF sandwiched between two tapers into very small diameter (in the order of micrometers). The measured refractive index (RI) sensitivity of the microfiber MZI is up to 2731.1 nm/RIU in the RI range of 1.34 when the taper waist diameter was 10.2 &#x03BC;m, which is in good agreement with numerical simulation results by using the beam propagation method (BPM). The microfiber MZI functionalized with pig immunoglobulin (pig IgG) could be used to specifically binding to S. aureus. In experiment, the maximum wavelength shift of 1.408 nm was achieved when the microfiber biosensors were immersed into S. aureus with concentration of 7&#x00D7;101 CFU/mL. The limit of detection (LoD) of the microfiber biosensor for S. aureus is calculated as low as 11 CFU/mL. The proposed microfiber MZI biosensor has advantages of simple structure configuration, high sensitivity, good repeatability and specificity, wide detection range and fast detection response time (&#x003C;30 minutes) and thus was demonstrated a good application prospect in food safety inspection, biochemical sensing, diseases and medical diagnostics