Kernel-Elastic Autoencoder for Molecular Design

We introduce the Kernel-Elastic Autoencoder (KAE), a self-supervised generative model based on the transformer architecture with enhanced performance for molecular design. KAE is formulated based on two novel loss functions: modified maximum mean discrepancy and weighted reconstruction. KAE addresses the long-standing challenge of achieving valid generation and accurate reconstruction at the same time. KAE achieves remarkable diversity in molecule generation while maintaining near-perfect reconstructions on the independent testing dataset, surpassing previous molecule-generating models. KAE enables conditional generation and allows for decoding based on beam search resulting in state-of-the-art performance in constrained optimizations. Furthermore, KAE can generate molecules conditional to favorable binding affinities in docking applications as confirmed by AutoDock Vina and Glide scores, outperforming all existing candidates from the training dataset. Beyond molecular design, we anticipate KAE could be applied to solve problems by generation in a wide range of applications

Multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing

We demonstrate a multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing. The wider channel spacing is realized by circulating the odd-order Stokes signals in the Brillouin gain medium through a four-port circulator. The circulated odd-order Stokes signals are amplified by the Brillouin gain and thus produce even-order Stokes signals at the output. These signals are then amplified by erbium gain block to form a ring-cavity laser. Ten channels with 0.174 nm spacing that are generated at 0.5 mW Brillouin pump power and 150 mW pump power at 1480 nm can be tuned from 1556 nm to 1564 nm. The minimum optical signal-to-noise ratio of the generated output channels is 30 dB with maximum power fluctuations of ±0.5 dB

Multi-wavelength generation based on Brillouin enhanced four-wave mixing in optical fibers

An optical comb consisting of 15 lines within 30 dB was generated with an extremely simple setup, based on the combination of amplified spontaneous Brillouin scattering and 4-wave mixing in optical fibers

Insertion of the Mirena Intrauterine System for Treatment of Adenomyosis-Associated Menorrhagia: A Novel Method

SummaryObjectiveInsertion of the levonorgestrel-releasing intrauterine system Mirena is difficult in women with adenomyosis, and the device is often subsequently expelled. We used a novel insertion technique (Yang's method) to overcome this problem.Materials and MethodsThis retrospective study enrolled 273 patients with adenomyosis who were receiving Mirena for treatment of menorrhagia and/or dysmenorrhea between 2001 and 2008. Clinical outcomes and expulsion rates were compared between patients treated using conventional insertion and those treated using Yang's insertion methods.ResultsExpulsion occurred in 25.3% of patients with the conventional method, compared with 10.2% of patients with Yang's method. Hemoglobin levels and dysmenorrhea improved greatly in both groups after Mirena insertion.ConclusionYang's insertion method for levonorgestrel-releasing intrauterine system is more reliable in some difficult cases, such as patients with severe adenomyosis. This method ensures correct positioning, thus reducing the risks of uterine perforation and/or expulsion

Poly (ADP-ribose) polymerase plays an important role in intermittent hypoxia-induced cell death in rat cerebellar granule cells

<p>Abstract</p> <p>Background</p> <p>Episodic cessation of airflow during sleep in patients with sleep apnea syndrome results in intermittent hypoxia (IH). Our aim was to investigate the effects of IH on cerebellar granule cells and to identify the mechanism of IH-induced cell death.</p> <p>Methods</p> <p>Cerebellar granule cells were freshly prepared from neonatal Sprague-Dawley rats. IH was created by culturing the cerebellar granule cells in the incubators with oscillating O₂concentration at 20% and 5% every 30 min for 1-4 days. The results of this study are based on image analysis using a confocal microscope and associated software. Cellular oxidative stress increased with increase in IH. In addition, the occurrence of cell death (apoptosis and necrosis) increased as the duration of IH increased, but decreased in the presence of an iron chelator (phenanthroline) or poly (ADP-ribose) polymerase (PARP) inhibitors [3-aminobenzamide (3-AB) and DPQ]. The fluorescence of caspase-3 remained the same regardless of the duration of IH, and Western blots did not detect activation of caspase-3. However, IH increased the ratio of apoptosis-inducing factor (AIF) translocation to the nucleus, while PARP inhibitors (3-AB) reduced this ratio.</p> <p>Results</p> <p>According to our findings, IH increased oxidative stress and subsequently leading to cell death. This effect was at least partially mediated by PARP activation, resulting in ATP depletion, calpain activation leading to AIF translocation to the nucleus.</p> <p>Conclusions</p> <p>We suggest that IH induces cell death in rat primary cerebellar granule cells by stimulating oxidative stress PARP-mediated calpain and AIF activation.</p

Four-wave-mixing-assisted brillouin fiber laser with double-brillouin-frequency spacing

The generation of multiwavelength Brillouin fiber laser assisted by four wave mixing has been demonstrated. A maximum of 18 channels of laser Stokes lines are generated at a Brillouin Pump (BP) of 190 mW (similar to 22.5 dBm). The multiple peaks have a wavelength spacing of 0.176 nm (similar to 20 GHz). A tunable optical bandpass filter is incorporated to the design to suppress up to 6 dB of the noise floor hump exhibited at the multiwavelength laser spectrum while limiting the laser peaks attenuation thereby providing a much cleaner and better OSNR. (C) 2014 Elsevier Inc. All rights reserved

Structure tuned, high transmission 180° waveguide bend in 2-D planar photonic crystal

We present a high transmission, small bending radius, 180° waveguide bend based on triangular lattice air holes two-dimensional (2-D) planar photonic crystal. The desired high transmission is achieved by altering the waveguide structure at the bending region. Drop hole defects are introduced at the bending region to guide the incoming electromagnetic wave. Simulation results based on the 2-D finite difference time domain method show that normalized transmission as high as 99.4% is achieved at 1550 nm optical wavelength and it is >94% for nearly the entire optical C-band. In addition, the small bending radius enhances the suitability of our design to be used in ultra-compact photonic integrated circuits

Double Brillouin frequency shift through circulation of odd-order Stokes signal

We demonstrate a simple configuration for generating a double Brillouin frequency shift through the circulation of an odd-order Brillouin Stokes signal. It is operated based on cascaded Brillouin scattering in single-mode optical fibers that behave as the Brillouin gain media. A four-port circulator is incorporated into the setup to circulate the odd-order Brillouin Stokes signal in the fiber. It thus initiates a higher order Brillouin Stokes signal, which is double Brillouin frequency downshifted from the input signal. For the 5 km long fiber, the Brillouin pump power at 23 mW gives a clean output spectrum with 30 dB sideband suppression ratio. The output signal is 0.174 nm or ∼21.7 GHz downshifted from the input signal

Post-amplified reversed S-shaped Brillouin-erbium fiber laser

We demonstrate a Brillouin-erbium fiber laser (BEFL) based on a reversed S-shaped loop that generates multiple shifted wavelengths that utilizes two 5km long single mode fiber (SMF). At Brillouin pump power of 5mW and EDF pump power of 150 mW, up to 8 Stokes lines that are above - 10dBm and a tuning range of 35 nm, from 1542.5 nm to 1577.5 nm, are the results obtained

Reduction of stimulated Brillouin scattering threshold through pump recycling technique.

We demonstrate a simple method of stimulated Brillouin scattering (SBS) threshold reduction through a procedure of Brillouin pump recycling technique. High reflectivity optical mirror was incorporated onto our experimental structure in order to recycle the forward transmitted Brillouin pump signal back into the Brillouin gain medium thereby increasing its effective gain. In a 5.0 km single mode fiber spool, our technique reduced SBS threshold by over 48% (measured at 8.5 mW of input signal against 16.5 mW in the conventional technique under same input signal conditions). In addition, the Stokes power was amplified to 9.2 dBm by our method against 4.3 dBm measured in the conventional technique in the 5.0 km single mode fiber spool. Result of different lengths has proved that our technique considerably reduced SBS threshold compared to the conventional method of SBS characterization under same pumping schemes