A Novel Lossless ECG Compression Algorithm for Active Implants.

A low complexity lossless ECG compression algorithm for active implants is proposed in this paper. The algorithm is based on adaptive length encoding by combining linear prediction with delta encoding. The algorithm is tested on forty-eight segments of 30-min ECG signals obtained from MIT-BIH Arrhythmia Database. The results show that with the data segment length of 33 and the predictor order of 2, the average compression rate of the algorithm reaches 2.43 and there is no difference between the reconstructed signal and the original one. It implies that it can realize the lossless compression with a high compression ratio. Meanwhile, the low complexity makes this novel algorithm suitable for ECG monitoring applications of active implants.

Fast and blind chromatic dispersion estimation with one sample per symbol.

We propose a fast and blind chromatic dispersion (CD) estimation method by one sample per symbol after coherent detection. The CD estimation process is non-data aided, without the iterative scanning to obtain the CD values. Moreover, we identify that the proposed CD estimation method is transparent to the used modulation format and robust to the transmission impairments, including amplified spontaneous emission (ASE) noise and fiber nonlinearity. When the 35-GBaud DP-16QAM signal with a roll-off factor of 0.1 is transmitted over standard single mode fiber (SSMF) with a range from 320-km to 560-km, the error of CD estimation is less than 150-ps/nm under the condition of 8192 symbols used.

Research Progress on the Anti-Disproportionation of the ZrCo Alloy by Element Substitution.

Hydrogen-induced disproportionation (HID) during the cycles of absorption and desorption leads to a serious decline in the storage capacity of the ZrCo alloy, which has been recognized as the biggest obstacle to its application. Therefore, the prerequisite of a ZrCo application is to solve its anti-disproportionation problem in the field of rapid hydrogen isotope storage. Beyond surface modification and nanoball milling, this work systematically reviews the method of element substitution, which can obviously improve the anti-disproportionation. From a micro angle, as hydrogen atoms that occupy the 8e site in the ZrCoH3 lattice are instable and are considered to be the driving force of disproportionation, researchers believe that element substitution by changing the occupation of hydrogen atoms at the 8e site can improve the anti-disproportionation of the alloy. At present, Ti/Nb substitutions for the Zr terminal among substitute elements have an excellent anti-disproportionation performance. In this work, up-to-date research studies on anti-disproportionation and its disproportionation mechanism of the ZrCo alloy are introduced by combining experiments and simulations. Moreover, the optimization of the alloy based on the occupation mechanism of 8e sites is expected to improve the anti-disproportionation of the ZrCo alloy.

Anchoring carbon nanotubes and post-hydroxylation treatment enhanced Ni nanofiber catalysts towards efficient hydrous hydrazine decomposition for effective hydrogen generation.

For effective hydrogen generation with remarkable durability, carbon nanotubes (CNTs) grown on Ni nanofibers and their post hydroxylation treatment engendered active Ni nanofiber catalysts an efficient decomposition of hydrous hydrazine with a turnover frequency (TOF) of 19.4 h-1 and an activation energy down to 51.05 KJ mol-1.

Activation and Disproportionation of Zr2Fe Alloy as Hydrogen Storage Material.

As a hydrogen storage material, Zr2Fe alloy has many advantages such as fast hydrogen absorption speed, high tritium recovery efficiency, strong anti-pulverization ability, and difficulty self-igniting in air. Zr2Fe alloy has lower hydrogen absorption pressure at room temperature than LaNi5 alloy. Compared with the ZrVFe alloy, the hydrogen release temperature of Zr2Fe is lower so that the material can recover hydrogen isotopes at lower hydrogen concentration efficiently. Unfortunately, the main problem of Zr2Fe alloy in application is that a disproportionation reaction is easy to occur after hydrogen absorption at high temperature. At present, there is little research on the generation and influencing factors of a disproportionation reaction in Zr2Fe alloy. In this paper, the effects of temperature and hydrogen pressure on the disproportionation of Zr2Fe alloy were studied systematically. The specific activation conditions and experimental parameters for reducing alloy disproportionation are given, which provide a reference for the specific application of Zr2Fe alloy.

Lead Iodide Thin Film Crystallization Control for High-Performance and Stable Solution-Processed Perovskite Solar Cells.

PbI2 thin film crystallization control is a prerequisite of high-quality perovskite thin film for sequentially solution-processed perovskite solar cells. An efficient and simple method has been developed by adding HCl to improve perovskite thin film quality, and an efficiency of 15.2% is obtained. This approach improves coverage, uniformity, and stability of pervoskite thin film.

Precise identification and manipulation of adsorption geometry of donor-π-acceptor dye on nanocrystalline TiO2 films for improved photovoltaics.

Adsorption geometry of dye molecules on nanocrystalline TiO2 plays a central role in dye-sensitized solar cells, enabling effective sunlight absorption, fast electron injection, optimized interface band offsets, and stable photovoltaic performance. However, precise determination of dye binding geometry and proportion has been challenging due to complexity and sensitivity at interfaces. Here employing combined vibrational spectrometry and density functional calculations, we identify typical adsorption configurations of widely adopted cyanoacrylic donor-π bridge-acceptor dyes on nanocrystalline TiO2. Binding mode switching from bidentate bridging to hydrogen-bonded monodentate configuration with Ti-N bonding has been observed when dye-sensitizing solution becomes more basic. Raman and infrared spectroscopy measurements confirm this configuration switch and determine quantitatively the proportion of competing binding geometries, with vibration peaks assigned using density functional theory calculations. We further found that the proportion of dye-binding configurations can be manipulated by adjusting pH value of dye-sensitizing solutions. Controlling molecular adsorption density and configurations led to enhanced energy conversion efficiency from 2.4% to 6.1% for the fabricated dye-sensitized solar cells, providing a simple method to improve photovoltaic performance by suppressing unfavorable binding configurations in solar cell applications.

Thermal assisted oxygen annealing for high efficiency planar CH3NH3PbI3 perovskite solar cells.

We report investigations on the influences of post-deposition treatments on the performance of solution-processed methylammonium lead triiodide (CH3NH3PbI3)-based planar solar cells. The prepared films were stored in pure N2 at room temperature or annealed in pure O2 at room temperature, 45°C, 65°C and 85°C for 12 hours prior to the deposition of the metal electrodes. It is found that annealing in O2 leads to substantial increase in the power conversion efficiencies (PCEs) of the devices. Furthermore, strong dependence on the annealing temperature for the PCEs of the devices suggests that a thermally activated process may underlie the observed phenomenon. It is believed that the annealing process may facilitate the diffusion of O2 into the spiro-MeOTAD for inducing p-doping of the hole transport material. Furthermore, the process can result in lowering the localized state density at the grain boundaries as well as the bulk of perovskite. Utilizing thermal assisted O2 annealing, high efficiency devices with good reproducibility were attained. A PCE of 15.4% with an open circuit voltage (VOC) 1.04 V, short circuit current density (JSC) 23 mA/cm(2), and fill factor 0.64 had been achieved for our champion device.

Significant enhancement in photocatalytic reduction of water to hydrogen by Au/Cu2 ZnSnS4 nanostructure.

Enhanced photocatalytic activities by Au core Novel Au/Cu2 ZnSnS4 core/shell nanoparticles (NPs) are synthesized for the first time via wet chemistry approach. The insertion of Au core into CZTS NPs dramatically enhances light absorption due to surface plasmon resonance effect, especially in the Vis-NIR region. Au/CZTS core/shell NPs show much higher photocatalytic activities for hydrogen evolution compared with other CZTS nanostructures.

Improvement in light harvesting in a dye sensitized solar cell based on cascade charge transfer.

Dye sensitized solar cells (DSSCs) offer the potential of being low-cost, high-efficiency photovoltaic devices. However, the power conversion efficiency is limited as they cannot utilize all photons of the visible solar spectrum. A novel design of a core-shell photoanode is presented herein where a thin shell of infrared dye is deposited over the core of a sensitized TiO2 nanofiber. Specifically, a ruthenium based dye (N719) sensitized TiO2 nanofiber is wrapped by a thin shell of copper phthalocyanine (CuPc). In addition to broadening the absorption spectrum, this core-shell configuration further suppresses the electron-hole recombination process. Instead of adopting the typical Förster resonance energy transfer, upon photons being absorbed by the infrared dye, electrons are transferred efficiently through a cascade process from the CuPc to the N719 dye, the conduction band of TiO2, the FTO electrode and finally the external circuit. Concurrently, photons are also absorbed by the N719 dye with electrons being transferred in the cell. These additive effects result in a high power conversion efficiency of 9.48% for the device. The proposed strategy provides an alternative method for enhancing the performance of DSSCs for low-cost renewable energy in the future.

Plasma cell myeloma presenting as abnormal uterine bleeding.

We report a case of a 53-year-old woman who presented with anemia and abnormal uterine bleeding. Endometrial and cervical biopsies revealed infiltration by large atypical cells, which were characterized as neoplastic plasma cells. Further investigations revealed systemic plasma cell dyscrasia (i.e., plasma cell myeloma). We therefore report a case of plasma cell myeloma, initially presenting as abnormal uterine bleeding.

Negative charge at amino acid 149 is the molecular determinant for substrate specificity of lecithin: cholesterol acyltransferase for phosphatidylcholine containing 20-carbon sn-2 fatty acyl chains.

We previously described a point mutation in human LCAT (E to A at residue 149; hE149A) that demonstrated greater activity with phosphatidylcholine (PC) substrate containing 20:4 in the sn-2 position compared with the wild-type enzyme [hLCAT; Wang et al. (1997) J. Biol. Chem. 272, 280-286], resulting in a human enzyme with the substrate specificity similar to that of rat LCAT. The purpose of the present study was to explore the molecular basis for the role of amino acid 149 in determining fatty acyl substrate specificity. In the first experiment, the reverse mutation in rat LCAT (rA149E) converted substrate specificity of rat LCAT toward that of the human enzyme, demonstrating that the mutation was context independent and reversible. In the second experiment, we found that hE149A compared with hLCAT demonstrated higher activity with PC species containing 20-carbon, but not 18-carbon, sn-2 fatty acyl chains. The increased activity of hE149A was due to an increase in apparent V(max) but not to apparent K(m) or LCAT binding to the PC surface. Substitution of different amino acids in the 149 position of hLCAT showed that activation of the enzyme with sn-2 20:4 containing PC substrate was only observed when the negative charge at residue 149 was removed. We conclude that the negative charge at amino acid 149 of LCAT is a critical determinant for the specificity of the enzyme for PC containing 18- vs 20-carbon sn-2 fatty acyl chains.

[Anatomical study and three dimensional image characteristic analysis of basicranial artery and its clinical significance].

OBJECTIVE: To observe and measure the inside diameter of basicranial arteries, the angulation of main arteries, the three dimensional image characteristic of internal carotid arteries and the anatomical variation of Willis circle. METHODS: The arteries of 30 formalin-fixed adult heads were injected with latex after which the caliber and characteristic of cerebral arteries were observed and measured. The three dimensional image characteristic of internal carotid arteries and its branches were measured using 3D-DSA. RESULTS: (1) Main artery caliber: origin of internal carotid artery (Left 5.12 +/- 1.48 mm; Right 5.11 +/- 1.42 mm); origin of middle cerebral artery (Left 2.93 +/- 1.44 mm; Right 2.92 +/- 1.46 mm); origin of anterior cerebral artery (Left 2.63 +/- 1.33 mm; Right 2.61 +/- 1.32 mm); origin of vertebral artery (Left 4.37 +/- 1.21 mm; Right 3.22 +/- 1.64 mm); origin of basilar artery (4.45 +/- 1.28 mm); origin of posterior cerebral artery (Left 2.62 +/- 1.36 mm; Right 2.61 +/- 1.22 mm). (2) The angulation of main arteries: C1, 2 of ICA and C4, 5 of ICA (Left 32 +/- 22 degrees; Right 36 +/- 28 degrees ); ICA and ACA (Left 43 +/- 26 degrees; Right 46 +/- 28 degrees). (3) The results show that anatomical and three dimensional image characteristic of internal carotid arteries have no difference (P > 0.05). (4) The anatomical variation of Willis circle: Type O (56.7%); Type A (16.7%); Type P (20.0%); Type AP (6.7%). CONCLUSIONS: It is helpful to measure the inside diameter of basicranial arteries for the selection of various catheter in interventional neuroradiology, to observe the angulation of main arteries and the three dimensional image characteristic of internal carotid arteries for the moulding of various catheter in endovascular therapy and to master the anatomical variation of Willis circle for decreasing complications of endovascular treatment and judging prognosis of cerebrovascular diseases.