Optofluidic tunable broadband distributed Bragg reflector based on liquid crystal polymer composites.

A dynamically reconfigurable liquid crystal (LC) photonic device is an important research field in modern LC photonics. We present a type of continuously tunable distributed Bragg reflector (DBR) based on LC polymer composites modulated via a novel optofluidic method. LC-templated DBR films are fabricated by photopolymerization under visible standing wave interference. The influences of the incident angle, incident light intensity, and content of ethanol as a pore-forming additive on the reflection behavior are discussed in detail. Then, the LC-templated DBR films are integrated into microfluidic channels and reversibly refilled by different organic solvents. The reconfigurable characteristics of optofluidic DBRs were demonstrated by changing the average refractive index (RI) of the mixed liquids and adjusting the flow rates, resulting in the dynamic and continuous variation of the reflection band within a specific visible light band. It is anticipated that the prototype optofluidic LC device will hopefully be applied to some specific scenarios where conventional means of regulation, such as electric, optical, and temperature fields, are unsuitable and possibly boost the development of microfluidic analysis techniques based on structural color.

Reconfigurable polymer-templated liquid crystal holographic gratings via visible-light recording.

Polymer-templated nematic liquid crystal (LC) holographic gratings via visible-light recording are presented in the presence of reactive mesogens (RMs) and rose bengal (RB)/N-phenylglycine (NPG) photoinitiation systems. By optimizing the concentration of RMs in the polymer-templated LC gratings, the template after being washed out can be refilled with suitable fluidic components. And the dependence of the first-order diffraction efficiency (DE) on the concentration of RB and NPG molecules was discussed in detail. The polarization-dependency of diffraction properties was also investigated. It is revealed that the diffractive behaviors of polymer-templated LC gratings can be dynamically reconfigured by varying temperature or refilling organic solutions with different refractive index (RI). Furthermore, the potential for recording holograms using green light is explored. We expect that the reconfigurable polymer-templated LC gratings fabricated via visible-light interference would provide a facile approach to regulate the diffraction properties of holographic gratings apart from electric field, thus paving a way towards a class of novel anti-counterfeiting devices.

Real-time generation of dynamically patterned cholesteric liquid crystal fingerprint textures based on photoconductive effect.

We present a convenient approach to facilitate the real-time generation of updatable dynamically patterned cholesteric liquid crystal (CLC) fingerprint textures based on photoconductive effect. The photoconductive Bi12SiO20 (BSO) substrate acts as virtual electrode to obtain the desired states of CLCs by both electric and light fields. Owing to different boundary conditions, the switching of four states; that is, planar, fingerprint, metastable, and homeotropic states, and the rotation of fingerprint stripes can be achieved in planar alignment (PA) cell and hybrid alignment (HA) cell, respectively. With the aid of a digital micro-mirror (DMD)-based exposure system, binary and gray-scale images were successfully written and updated by light upon suitable voltages. This work provides an alternative approach to photoaddress CLC fingerprint patterns, without needing special photoalignment agents or photoresponsitive chiral dopants. We expect that it could be employed in the manipulation of nano/micro-objects by light.

Effect of the population density on belowground bud bank of a rhizomatous clonal plant Leymus secalinus in Mu Us sandy land.

Clonal propagation is the main strategy for clonal plants to adapt to wind-sand habitat, and underground bud bank could reflect the potential ability of clonal propagation. However, the effects of population density on belowground bud bank are unknown, hindering efforts in the process of dune stabilization. We investigated the horizontal density and vertical distribution of belowground bud bank of a typical rhizomatous grass Leymus secalinus, and soil water content in four dune types with different population density (dune type I: 11.2 ± 1.7 no. m-2, type II: 24.2 ± 2.6 no. m-2, type III: 40.0 ± 4.0 no. m-2, and type IV: 53.5 ± 7.2 no. m-2) in Mu Us sandy land. Our results showed that (1) total bud density of population increased markedly with increasing population density, but it did not exhibit significant difference between dune types III and IV, where density was about 130 buds m-2; and tiller bud density of population first increased, then decreased, and reached a maximum in dune type III. (2) Total bud density per individual in dune type III was significantly larger than that in other dune types (P < 0.05), whereas rhizome and tiller bud density per individual did not show significant differences in dune types II, III and IV (P > 0.05). (3) Buds tended to be concentrated at 10-30 cm soil layer in all dune types, and be buried deeper in dune types III and IV than that in dune types I and II. (4) No pronounced relationship was shown between bud density and soil water content in 10-30 cm soil layer with increasing population density. Our results suggest that moderate population density (40.0 ± 4.0 no. m-2) significantly increase the bud bank density of L. secalinus population and individual. Soil water content was not the main factor responsible for the density of L. secalinus bud bank. These results can provide important information for implementation of effective sand fixation measures and species selection for desertification control in semiarid sandy land ecosystems.

beta-Naphthoflavone protects from peritonitis by reducing TNF-alpha-induced endothelial cell activation.

ß-Naphthoflavone (ß-NF), a ligand of the aryl hydrocarbon receptor, has been shown to possess anti-oxidative properties. We investigated the anti-oxidative and anti-inflammatory potential of ß-NF in human microvascular endothelial cells treated with tumor necrosis factor-alpha (TNF-α). Pretreatment with ß-NF significantly inhibited TNF-α-induced intracellular reactive oxygen species, translocation of p67(phox), and TNF-α-induced monocyte binding and transmigration. In addition, ß-NF significantly inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. The mRNA expression levels of the inflammatory cytokines TNF-α and IL-6 were reduced by ß-NF, as was the infiltration of white blood cells, in a peritonitis model. The inhibition of adhesion molecules was associated with suppressed nuclear translocation of NF-κB p65 and Akt, and suppressed phosphorylation of ERK1/2 and p38. The translocation of Egr-1, a downstream transcription factor involved in the MEK-ERK signaling pathway, was suppressed by ß-NF treatment. Our findings show that ß-NF inhibits TNF-α-induced NF-kB and ERK1/2 activation and ROS generation, thereby suppressing the expression of adhesion molecules. This results in reduced adhesion and transmigration of leukocytes in vitro and prevents the infiltration of leukocytes in a peritonitis model. Our findings also suggest that ß-NF might prevent TNF-α-induced inflammation.

Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension--A single-center experience in Taiwan.

BACKGROUND/PURPOSE: Pulmonary endarterectomy (PEA) is a potentially curative surgical procedure for patients with chronic thromboembolic pulmonary hypertension. The aim of this study is to review our institutional experience with this operation. METHODS: We conducted a retrospective review of PEA performed at our institution between January 2005 and December 2013. The measured outcomes were inhospital complications, improvement in cardiac function and exercise capacity, and actuarial survival after PEA. RESULTS: Ten consecutive patients (7 women, 3 men) underwent PEA with a mean age of 59.9 ± 12.9 years. The preoperative New York Heart Association functional class (NYHA FC) for these patients was either Class III (n = 6) or Class IV (n = 4). The period from symptom onset to diagnosis was 34.3 ± 37.9 months, and that from diagnosis to operation was 31.4 ± 46.8 months. After PEA, the duration of intensive care unit stay and hospital stay prior to discharge were 9.7 ± 5.7 days and 18.7 ± 7.4 days, respectively. Postoperative complications included reperfusion lung edema (n = 3) and pneumonia (n = 1), and all recovered with medical therapy. After a mean follow-up of 48.4 ± 35.1 months, all patients showed marked improvements in their clinical status and were still alive without evidence of disease recurrence. CONCLUSION: With proper patient selection, the cooperation of a multidisciplinary team, and meticulous postoperative management, PEA can be conducted safely with relatively low risk at a center with limited experience with the procedure.