Ultra-compact acousto-optic modulation using on-chip integrated Bragg gratings on lithium niobate-chalcogenide hybrid platform.

An ultra-compact and efficient acousto-optic modulator based on a thin-film lithium niobate-chalcogenide (ChG) hybrid platform was designed and realized. In this approach, π phase-shift Bragg grating has an ultra-short effective interaction length of only ∼ 300 µm and a compact footprint of 200 × 300 µm2. The strong microwave-acoustic coupling and superior photo-elastic property of the ChG allow us to achieve a half-wave voltage of Vπ = 1.08 V (4.07 V) for the π phase-shift Bragg grating (waveguide Bragg grating), corresponding to VπL = 0.03 V·cm (0.09 V·cm). This acousto-optic modulator exhibits a compact size, and low power consumption, and can be used for on-chip optical interconnects and microwave photonics.

Wearable strain sensor integrating mechanoluminescent fiber with a flexible printed circuit.

This paper reports an optical strain sensor that integrates a self-powered mechanoluminescent (ML) elastic fiber with a flexible circuit. The inclusion of an alumina nanoparticle as the additive results in seven-fold enhancement of ML intensity while maintaining flexibility of 120% strain. The sensor facilitates the detection of strain and stretching speed. It attains a sensitivity of 0.0022 lx/(1% strain) and a resolution of 0.2% strain, respectively. We have successfully applied it to detect bending motions of the finger, wrist, and elbow. This wearable strain sensor holds promise for diverse applications in wearable technology.

Near infrared luminescence properties and mechanism of high bismuth-doped SiO2-Al2O3-La2O3 glass.

This research investigated the wideband near-infrared spectroscopy characteristics of 60SiO2-25Al2O3-10La2O3 glass doped with high levels of bismuth up to 5 mol%. The near-infrared radiation range was explored under excitation wavelengths of 488 nm, 532 nm, 808 nm, and 980 nm, resulting in near-infrared radiation spanning from 1000 nm to 1800nm with Full Width at Half Maximum (FWHM) values of 313.0 nm, 336.3 nm, 296.2 nm, and 262.9 nm, respectively. Notably, the sample exhibited a lifetime of 1.473 ms when pumped at 808 nm, corresponding to a stimulated cross-section of σe=3.35 × 10-21 cm2. Through an in-depth investigation of the luminescence properties, the underlying physical mechanism behind the near-infrared luminescence was revealed. The emissions observed at approximately 1150 nm and 1300 nm were attributed to the aluminum-related bismuth active center (BAC-Al) and the silicon-related bismuth active center (BAC-Si), respectively. Furthermore, it is postulated that the emission at the 1150 nm band originates from the 3P1, 3P2 →3P0 transition of Bi+ and the 2D3/2 → 4S3/2 transition of Bi°, while the emission at the 1300 nm band may be linked to mixed valence states of Bi3+. This work will find potential applications in broadband near-infrared optical devices.

Amorphous TiO2 shells: an Essential Elastic Buffer Layer for High-Performance Self-Healing Eutectic GaSn Nano-Droplet Room-Temperature Liquid Metal Battery.

Gallium-based alloy liquid metal batteries currently face limitations such as volume expansion, unstable solid electrolyte interface (SEI) film and substantial capacity decay. In this study, amorphous titanium dioxide is used to coat eutectic GaSn nanodroplets (eGaSn NDs) to construct the core-shell structure of eGaSn@TiO2 nanodroplets (eGaSn@TiO2 NDs). The amorphous TiO2 shell (~6.5 nm) formed a stable SEI film, alleviated the volume expansion, and provided electron/ion transport channels to achieve excellent cycling performance and high specific capacity. The resulting eGaSn@TiO2 NDs exhibited high capacities of 580, 540, 515, 485, 456 and 426 mAh g-1 at 0.1, 0.2, 0.5, 1, 2 and 5 C, respectively. No significant decay was observed after more than 500 cycles with a capacity of 455 mAh g-1 at 1 C. In situ X-ray diffraction (in situ XRD) was used to explore the lithiation mechanism of the eGaSn negative electrode during discharge. This study elucidates the design of advanced liquid alloy-based negative electrode materials for high-performance liquid metal batteries (LMBs).

Electrically Tunable Lenses for Imaging and Light Manipulation.

Optofluidics seamlessly combines optics and microfluidics together to construct novel devices for microsystems, providing flexible reconfigurability and high compatibility. By taking advantage of mature electronic fabrication techniques and flexible regulation of microfluidics, electrically actuated optofluidics has achieved fantastic optical functions. Generally, the optical function is achieved by electrically modulating the interfaces or movements of microdroplets inside a small chamber. The high refractive index difference (~0.5) at the interfaces between liquid/air or liquid/liquid makes unprecedented optical tunability a reality. They are suitable for optical imaging devices, such as microscope and portable electronic. This paper will review the working principle and recent development of electrical optofluidic devices by electrowetting and dielectrophoresis, including optical lens/microscope, beam steering and in-plane light manipulation. Some methods to improve the lens performance are reviewed. In addition, the applications of electrical microfluidics are also discussed. In order to stimulate the development of electrically controlled liquid lens, two novel designs derived from electrowetting and dielectrophoresis are introduced in this paper.

An Antifatigue Liquid Metal Composite Electrode Ionic Polymer-Metal Composite Artificial Muscle with Excellent Electromechanical Properties.

Ionic polymer-metal composites (IPMC), one of the most popular materials in the field of artificial muscle research, have attracted much attention because of their high flexibility, low drive voltage (<10 V), high force density, large deformation, and so forth. However, the results show that the serious electrode fatigue crack and water loss of traditional IPMC greatly decrease its fatigue life and limit the practical application. In this study, we developed a novel liquid metal composite electrode. A layer of eutectic gallium-indium alloy (EGaIn) liquid metal was applied to the surface of the platinum electrode of the IPMC using a mask. Because of the good self-healing performance of the liquid metal, it is expected to solve the above problems of resistance increase and water loss caused by cracks. It turns out that the prepared EGaIn/Pt-IPMC exhibits a driving force up to 120 mN and maximum fatigue life of about 25,000 s at a driving voltage of 3 V. Compared with the best work reported, the fatigue strength of EGaIn/Pt-IPMC was increased by about 210%, and the maximum driving force of EGaIn/Pt-IPMC prepared by a single-layer basement membrane was between the IPMC prepared by 4-6 layer basement membrane. The electromechanical properties were significantly improved, and it is expected to realize a series of bionic applications.

Electrically generated optical waveguide in a lithium-niobate thin film.

This paper reports an electrically generated optical waveguide for the transverse-magnetic wave. The waveguide is formed in a z-cut single-crystal lithium-niobate (LN) thin film by the electro-optic effect, where the extraordinary refractive index (RI) of the LN film is increased by a voltage applied to patterned electrodes that define the waveguide geometry. Such a waveguide can be made to exist or disappear by turning on or off the applied voltage. A straight waveguide and an S-bend waveguide with an RI contrast of ∼0.004 are generated at a voltage of 200 V. The propagation loss of the generated waveguide measured at the wavelength 532 nm is 1.8 dB/cm. Electrically generated optical waveguides could fulfill useful functions in photonic integrated circuits, such as reconfigurable cross connect and switching that require wavelength-independent and mode-independent operation.

Aberration-free aspherical in-plane tunable liquid lenses by regulating local curvatures.

Aberration is a long-standing problem of fixed focal lenses and a complicated lens set is usually required to compensate for aberration. It becomes more challenging for tunable lenses. This paper reports an original design of an in-plane optofluidic lens that enables compensation for spherical aberration during the tuning of focal length. The key idea is to use two arrays of electrode strips to symmetrically control the two air/liquid interfaces by the dielectrophoretic effect. The strips work together to define the global shape of the lens interface and thus the focal length, whereas each strip regulates the local curvature of the interface to focus the paraxial and peripheral arrays on the same point. Experiments using a silicone oil droplet demonstrate the tuning of focal length over 500-1400 µm and obtain a longitudinal spherical aberration (LSA) of ∼3.5 µm, which is only 1/24 of the LSA (85 µm) of the spherical lens. Fine adjustment of the applied voltages of strips allows even elimination of the LSA and enabling of the aberration-free tunable lenses. It is the first time that local curvature regulation is used to compensate for the aberration within one in-plane liquid lens. This simple and effective method will find potential applications in lab-on-a-chip systems.

Antiproliferative activity of plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) in human gastric carcinoma cells is facilitated via activation of autophagic pathway, mitochondrial-mediated programmed cell death and inhibition of cell migration and invasion.

PURPOSE: Gastric cancer causes high mortality rates across the globe, mainly due to late diagnosis and the unavailability of effective chemotherapeutic agents. This study evaluated the anticancer potential of plumbagin against gastric cancer cells as well as its effects on autophagic and apoptotic pathways, cell migration and invasion. METHODS: MTT assay was used for cell viability assessment. Acridine orange (AO)/ethidium bromide (EB) and annexin V/propidium iodide (PI) staining were used for the detection of apoptosis. Autophagy was demonstrated by electron microscopy. Transwell assay was used for cell migration and invasion. Western blotting was used for the detection of protein expression. RESULTS: The results showed that plumbagin could considerably inhibit the proliferation of AGS gastric cancer cells (IC50;8 µM). The anticancer activity of plumbagin against AGS cells was found to be due to the induction of autophagy and apoptosis. Plumbagin-induced apoptosis and autophagy were also associated with alteration in apoptosis (Bax and Bcl-2) and autophagy (LC3I, II, and Beclin 1) - related protein expressions. The effects of plumbagin on the migration and invasion of AGS cells were also investigated by transwell assays and the results showed that plumbagin inhibited both the migration and invasion of AGS cells at IC50. CONCLUSIONS: These results indicate that plumbagin significantly inhibits the growth of gastric cancer in vitro and could prove beneficial in the management of gastric cancer and needs further research including in vivo studies.

Multilayered PdSe2/Perovskite Schottky Junction for Fast, Self-Powered, Polarization-Sensitive, Broadband Photodetectors, and Image Sensor Application.

Group-10 transition metal dichalcogenides (TMDs) with distinct optical and tunable electrical properties have exhibited great potential for various optoelectronic applications. Herein, a self-powered photodetector is developed with broadband response ranging from deep ultraviolet to near-infrared by combining FA1- x Cs x PbI3 perovskite with PdSe2 layer, a newly discovered TMDs material. Optoelectronic characterization reveals that the as-assembled PdSe2/perovskite Schottky junction is sensitive to light illumination ranging from 200 to 1550 nm, with the highest sensitivity centered at ≈800 nm. The device also shows a large on/off ratio of ≈104, a high responsivity (R) of 313 mA W-1, a decent specific detectivity (D*) of ≈1013 Jones, and a rapid response speed of 3.5/4 µs. These figures of merit are comparable with or much better than most of the previously reported perovskite detectors. In addition, the PdSe2/perovskite device exhibits obvious sensitivity to polarized light, with a polarization sensitivity of 6.04. Finally, the PdSe2/perovskite detector can readily record five "P," "O," "L," "Y," and "U" images sequentially produced by 808 nm. These results suggest that the present PdSe2/perovskite Schottky junction photodetectors may be useful for assembly of optoelectronic system applications in near future.

Continuous artificial synthesis of glucose precursor using enzyme-immobilized microfluidic reactors.

Food production in green crops is severely limited by low activity and poor specificity of D-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) in natural photosynthesis (NPS). This work presents a scientific solution to overcome this problem by immobilizing RuBisCO into a microfluidic reactor, which demonstrates a continuous production of glucose precursor at 13.8 µmol g-1 RuBisCO min-1 from CO2 and ribulose-1,5-bisphosphate. Experiments show that the RuBisCO immobilization significantly enhances enzyme stabilities (7.2 folds in storage stability, 6.7 folds in thermal stability), and also improves the reusability (90.4% activity retained after 5 cycles of reuse and 78.5% after 10 cycles). This work mimics the NPS pathway with scalable microreactors for continuous synthesis of glucose precursor using very small amount of RuBisCO. Although still far from industrial production, this work demonstrates artificial synthesis of basic food materials by replicating the light-independent reactions of NPS, which may hold the key to food crisis relief and future space colonization.

Optofluidic Tunable Lenses for In-Plane Light Manipulation.

Optofluidics incorporates optics and microfluidics together to construct novel devices for microsystems, providing flexible reconfigurability and high compatibility. Among many novel devices, a prominent one is the in-plane optofluidic lens. It manipulates the light in the plane of the substrate, upon which the liquid sample is held. Benefiting from the compatibility, the in-plane optofluidic lenses can be incorporated into a single chip without complicated manual alignment and promises high integration density. In term of the tunability, the in-plane liquid lenses can be either tuned by adjusting the fluidic interface using numerous microfluidic techniques, or by modulating the refractive index of the liquid using temperature, electric field and concentration. In this paper, the in-plane liquid lenses will be reviewed in the aspects of operation mechanisms and recent development. In addition, their applications in lab-on-a-chip systems are also discussed.

Dielectrophoresis-actuated liquid lenses with dual air/liquid interfaces tuned from biconcave to biconvex.

This paper reports an electrically reconfigurable optofluidic lens with two air-liquid (silicone oil) interfaces actuated by dielectrophoretic (DEP) force. Initially, a symmetric biconcave air-liquid lens is formed by the surface tension in a microfluidic chip. Then, the DEP force deforms the air-liquid interfaces from biconcave to biconvex, tuning the focal length from -0.5 mm to infinite to +0.5 mm. The wide tunability of the focal length results from the large refractive index difference (∼0.4 at the air-liquid interface), which is only 0.1 in previous liquid-liquid lenses. In the experiment, the lens achieves an ƒ number of 0.91 while consuming only 6.7 nJ per circle. Some asymmetric working states, such as concave-convex and plano-convex lenses, have also been demonstrated. Compared with continuous liquid flow-sustained lenses, this stationary liquid lens holds promise of better compatibility and higher scalability. Its wide tunability, low power consumption and easy operation make it suitable for light manipulation in microfluidic networks.

Dielectrophoresis-actuated in-plane optofluidic lens with tunability of focal length from negative to positive.

This paper reports a tunable in-plane optofluidic lens by continuously tuning a silicone oil-air interface from concave to convex using the dielectrophoresis (DEP) force. Two parallel glasses are bonded firmly on two sides by NOA 81(Norland Optical Adhesive 81) spacers, forming an open microfluidic channel. An ITO (indium tin oxide) strip and another unpatterned ITO layer are deposited on two glasses as the top and bottom electrodes. Initially, a capillary concave liquid-air interface is formed at the end of the open channel. Then the DEP force is enabled to continuously deform the interface (lens) from concave to convex. In the experiment, the focal length gradually decreases from about -1 mm to infinite and then from infinite to around + 1 mm when the driving voltage is increased from 0 V to 260 V. Particularly, the longitudinal spherical aberration (LSA) is effectively suppressed to have LSA < 0.04 when the lens is operated in the focusing state. This work is the first study of in-plane tunable lenses using the DEP force and possesses special merits as compared to the other reported tunable lenses that are formed by pumping different liquids or by temperature gradient, such as wide tunability, no need for continuous supply of liquids, low power consumption (~81 nJ per switching) due to the capacitor-type driving, and the use of only one type of liquid. Besides, its low aberration makes it favorable for light manipulation in microfluidic networks.

Planar polarization-routing optical cross-connects using nematic liquid crystal waveguides.

This paper presents the device design and performance analysis of a novel design of planar optical cross-connect (OXC) using nematic liquid crystal (NLC) waveguides. It employs N × N switching matrix in cross-bar fabric. In each unit cell, the input light is set in either the transverse electric (TE) mode or the transverse magnetic (TM) mode by electrically reorienting the NLC in the waveguide. The light then enters a passive waveguide and is routed to different paths depending on the polarization state (TE/TM mode). A sample device of 8 × 8 OXC is analyzed for performance estimation, which predicts a maximum on-chip insertion loss of 3 dB, an average cross-talk of -40 dB, ~1 ms switching time, and 2 mm × 2 mm footprint. The proposed OXC is unique in the switching mechanism of polarization-dependent routing and allows non-blocking switching with high compactness and broad bandwidth. It is potential for optical circuit switching in data centers and optical communication networks.

Review of Recent Patents and Developments in Skeletal Muscle Regeneration.

Skeletal muscle is a highly-specialized tissue that is capable of contractile function and able to withstand and adapt to daily mechanical and physiological stress. Musculoskeletal disorders, including muscular dystrophies, result in chronic pain and disability, reduced quality of life, burden on family, and increased healthcare costs. Although several mechanisms have been identified for muscle injury and regeneration, mechanisms of these diseases are poorly understood, and targeted and effective pharmacologic treatment(s) are not available. More research is needed in this area in order to develop effective treatment regimens. The purpose of this review is to discuss known mechanisms of muscle injury and repair, and highlight some recent patents and research developments for treatment of skeletal muscle disorders.

Electrically controlled polarization rotator using nematic liquid crystal.

Here we report a planar polarization rotator using a nematic liquid crystal waveguide, which is subject to a gradient electric field in parallel to the waveguide substrate plane. The fabricated polydimethylsiloxane (PDMS) device has demonstrated the electrically-controlled polarization rotation at a switching time of 70 ms and a propagation loss of 9 dB/cm at 532 nm. The unique features such as planar form, electric control, and soft material allows integration into planar lightwave circuits and flexible photonics.

Optofluidic tunable lenses using laser-induced thermal gradient.

This paper reports a new design of optofluidic tunable lens using a laser-induced thermal gradient. It makes use of two straight chromium strips at the bottom of the microfluidic chamber to absorb the continuous pump laser to heat up the moving benzyl alcohol solution, creating a 2D refractive index gradient in the entrance part between the two hot strips. This design can be regarded as a cascade of a series of refractive lenses, and is distinctively different from the reported liquid lenses that mimic the refractive lens design and the 1D gradient index lens design. CFD simulation shows that a stable thermal lens can be built up within 200 ms. Experiments were conducted to demonstrate the continuous tuning of focal length from initially infinite to the minimum 1.3 mm, as well as the off-axis focusing by offsetting the pump laser spot. Data analyses show the empirical dependences of the focal length on the pump laser intensity and the flow velocity. Compared with previous studies, this tunable lens design enjoys many merits, such as fast tuning speed, aberration-free focusing, remote control, and enabling the use of homogeneous fluids for easy integration with other optofluidic systems.

[Sarcomatoid malignant mesothelioma: a clinicopathologic and immunohistochemical analysis of 22 cases].

OBJECTIVE: To elaborate on the clinical and pathologic features of sarcomatoid malignant mesothelioma (SMM), its diagnostic criteria and differential diagnoses. METHODS: Twenty-two cases of SMM retrieved from in-house and consultation files (between January 2009 to September 2013) were reviewed with emphasis on the clinicopathologic characteristics, immunophenotypes and the prognostic impact. RESULTS: The mean age of the patients was 54 years (ranged from 24-73 years). There was no sexual predilection and the majority of the patients did not have history of asbestos exposure. Overall, 14 tumors developed in the pleura and 8 cases arose from the peritoneal cavity. Clinically, patients presented signs and symptoms in accord with the location of the tumors, notably coughing, shortness of breath, and chest pain for patients with pleural origin, and nausea, abdominal distention and abdominal pain for those with peritoneal primary. In most cases, CT and MRI scan demonstrated lobulated masses (8/11). However, diffuse infiltrative growth patterns were observed exclusively in a minority of pleural cases (3/11). No visceral lesion was observed in any case. Histologically, 19 cases had either fibrosarcomatous or undifferentiated pleomorphic sarcoma-like appearance. Two cases were consistent with desmoplastic mesothelioma. One case contained osteosarcomatous element. All cases expressed pan-cytokeratin (AE1/AE3), and most cases were also positive for D2-40 (15/20). The staining of calretinin (9/21) and WT1 (10/14) was generally weak and focal. They were all negative for TTF-1, napsin A, SP-A, p63 and CD34. Follow-up information (range from 1 to 36 months) was available in 11 cases, 6 of which were alive with unresectable tumor, 1 patient with recurrent disease and 4 patients succumbed to disease. The overall survival was 5 months (mean 8 months). CONCLUSIONS: The diagnosis of SMM is achieved by comprehensive evaluation of medical history, imageological and pathological findings. Since calretinin immunoreactivity is infrequently observed in SMM, application of pan-cytokeratin and D2-40 immunostains offers a reasonable alternative for diagnosis. Diagnosis of SMM can be made by excluding a variety of spindle cell neoplasms with overlapping features, such as sarcomatoid carcinoma, synovial sarcoma, solitary fibrous tumor and fibrous pleuritis.

A distributed fiber vibration sensor utilizing dispersion induced walk-off effect in a unidirectional Mach-Zehnder interferometer.

We propose and experimentally demonstrate a novel ultra-long range and sensitive distributed fiber vibration sensor. Only one unidirectional Mach-Zehnder interferometer (MZI) is employed in this scheme as the sensing element. In this sensor structure, we utilize chromatic dispersion-induced walk-off effect between the vibration signals sensed by two distributed feedback (DFB) lasers at different wavelengths to locate the vibration position. Vibration signals with frequencies up to 9 MHz can be detected and the spatial resolution of 31 m is achieved over 320 km of the standard single mode fiber. Monitoring multiple vibration sources can also be realized using this scheme.