Management of retroperitoneal appendiceal perforation: a case report.

Retroperitoneal appendiceal perforation presents unique challenges in surgical management due to the complex nature of the retroperitoneal space. We present a case of a 57-year-old male with retroperitoneal appendiceal perforation, characterized by the presence of a large amount of gas in the retroperitoneal space. Emergent laparoscopic surgery was performed to address the retroperitoneal involvement. In retroperitoneal appendiceal perforation, surgical intervention and postoperative drainage are of great significance to prevent septic shock. The interconnectedness of the retroperitoneal space with other body regions is highlighted, underscoring the potential for severe complications. This case emphasizes the need for a tailored approach to managing retroperitoneal appendiceal perforation, preventing potential complications associated with this condition.

Recyclable Cholesteric Phase Liquid Crystal Device for Detecting Storage Temperature Failure.

The planar state of a cholesteric liquid crystal (CLC) often exhibits oily streak defects, which negatively impact the characteristics of precision optics, including transmission and selective reflection. In this paper, we introduced polymerizable monomers into liquid crystals and examined the effects of monomer concentration, polymerization light intensity, and chiral dopant concentration on oily streak defects in CLC. With the proposed method of heating cholesteric liquid crystals to the isotropic phase followed by rapid cooling, the oil streak defects presented in the liquid crystal can be successfully eliminated. Furthermore, a stable focal conic state can be obtained by a slow cooling process. Two stable states with different optical properties can be obtained based on the cholesteric liquid crystal at different cooling rates, which makes it possible to detect whether the stored procedure of temperature-sensitive material is qualified. These findings have widespread applications in devices that require a planar state without oily streak defects and temperature-sensitive detection devices.

Colorable Light-Scattering Device Based on Polymer-Stabilized Ion-Doped Cholesteric Liquid Crystal and an Electrochromatic Layer.

Bistable polymer-stabilized cholesteric liquid crystal (LC) devices have been extensively researched due to their energy-saving benefits. Compared to devices with merely transparent and light-scattering states, LC devices with controlled light absorption or changeable color functions are unquestionably more intriguing. In this paper, a polymer-stabilized ion-doped cholesteric LC and an electrochromic layer are used to fabricate a colorable device which can show four operating states: transparent, light-scattering, colored transparent, and colored light-scattering. The working principle and fabrication strategy are explained in detail. Based on the dielectric response of LC, the electrohydrodynamic effect of ion-doped LC, and the redox reaction of electrochromic materials, the transparent or light-scattering state and the colored or colorless state of the device can be regulated by controlling the alternating frequency and the direction of the electric field. The display performance related to the monomer, chiral dopant, and electrochromic layer is investigated. The content of monomer and chiral dopant affects the polymer network and pitch of cholesteric LC, which then affects the driving voltages and contrast ratio. The thickness of the electrochromic layer has a significant impact on the transmittance of the device's coloring and fading states. The sample with excellent operating states is obtained by optimizing the material and the construction, which can be widely applied in smart windows and energy-saving display devices.

A Deep Learning Framework for Start-End Frame Pair-Driven Motion Synthesis.

A start-end frame pair and a motion pattern-based motion synthesis scheme can provide more control to the synthesis process and produce content-various motion sequences. However, the data preparation for the motion training is intractable, and concatenating feature spaces of the start-end frame pair and the motion pattern lacks theoretical rationality in previous works. In this article, we propose a deep learning framework that completes automatic data preparation and learns the nonlinear mapping from start-end frame pairs to motion patterns. The proposed model consists of three modules: action detection, motion extraction, and motion synthesis networks. The action detection network extends the deep subspace learning framework to a supervised version, i.e., uses the local self-expression (LSE) of the motion data to supervise feature learning and complement the classification error. A long short-term memory (LSTM)-based network is used to efficiently extract the motion patterns to address the speed deficiency reflected in the previous optimization-based method. A motion synthesis network consists of a group of LSTM-based blocks, where each of them is to learn the nonlinear relation between the start-end frame pairs and the motion patterns of a certain joint. The superior performances in action detection accuracy, motion pattern extraction efficiency, and motion synthesis quality show the effectiveness of each module in the proposed framework.

Achieving a wide color gamut based on polarization interference filters in a liquid crystal display.

We propose two polarization interference filters (PIF1 and PIF2) used in the backlight unit of a liquid crystal display (LCD) to achieve a wide color gamut. Both PIF1 and PIF2 consist of two polarizers and two 720° super twisted nematic liquid crystal polymer (LCP) layers, where two polarizers are crossed in PIF1, and two polarizers are parallel in PIF2. The PIFs can eliminate unwanted cyan and yellow parts in the output spectrum, which can improve the color gamut of LCD. In our calculation, when the PIF1 is employed in the LCD with normal color filter and QD-LED backlight, the color gamut increases from 107.3% NTSC to 124.6% NTSC, which is 13.7% NTSC larger than that of the LCD with high-performance color filter. When the PIF2 is employed in the LCD with normal color filter and QD-LED backlight, the color gamut of LCD with a normal color filter is improved by 6.8% NTSC larger than that of LCD with high-performance color film, and the transfer efficiency is close to that of the LCD with high-performance color film. We define the color gamut enhancement ratio (CGER) to compare the influence of PIFs and the high-performance color filter on the color gamut enhancement performance of LCD. Compared with the high-performance color filter, the two kinds of PIFs have a higher CGER. The PIFs have a great potential for achieving a wide color gamut.

Local Self-Expression Subspace Learning Network for Motion Capture Data.

Deep subspace learning is an important branch of self-supervised learning and has been a hot research topic in recent years, but current methods do not fully consider the individualities of temporal data and related tasks. In this paper, by transforming the individualities of motion capture data and segmentation task as the supervision, we propose the local self-expression subspace learning network. Specifically, considering the temporality of motion data, we use the temporal convolution module to extract temporal features. To implement the local validity of self-expression in temporal tasks, we design the local self-expression layer which only maintains the representation relations with temporally adjacent motion frames. To simulate the interpolatability of motion data in the feature space, we impose a group sparseness constraint on the local self-expression layer to impel the representations only using selected keyframes. Besides, based on the subspace assumption, we propose the subspace projection loss, which is induced from distances of each frame projected to the fitted subspaces, to penalize the potential clustering errors. The superior performances of the proposed model on the segmentation task of synthetic data and three tasks of real motion capture data demonstrate the feature learning ability of our model.

Complementarity-Aware Attention Network for Salient Object Detection.

In this article, we tackle the saliency detection task from an interesting perspective: we focus both on salient regions (or foreground) detection and nonsalient regions (or background) detection instead of only the foreground and propose a novel complementarity-aware attention network. It is a unified framework with two branches, namely, positive attention module (PAM) and negative attention module (NAM), for the foreground and background detection, respectively. More specifically, the PAM exploits a position self-attention mechanism to enhance the discriminant ability of feature representation, which can detect most of the salient object regions. Meanwhile, the NAM is designed to detect the background regions, aiming to pop out the missing object parts and details in the prediction map produced by the PAM. By fusing these two attention modules together, NAM can provide complementary cues to assist PAM for precise object detection. Furthermore, in order to capture more multiscale contextual information, we introduce a bidirectional structure with multisupervision to the proposed complementarity-aware attention module for performance improvement. Experiments on five benchmark datasets show that the proposed framework achieves comparable results compared with the state-of-the-art saliency detection methods.

Wide viewing angle polarization interference filter using double liquid crystal layers with opposite twisted direction.

We demonstrate a wide viewing angle polarization interference filter (PIF), which consists of two crossed polarizers and double liquid crystal layers with opposite twisted direction. The polarization interference effect of the PIF is achieved by the double liquid crystal layers, and an additional compensation layer between the double liquid crystal layers can further improve the optical performance of the PIF. By using the Jones matrix method, we derive the transmittance formula of the PIF with/without compensation layer, which can be used to design any required color filter by selecting the appropriate twist angle and thickness of the liquid crystal layer. We design blue, green and red PIFs and analyze their optical performance. The proposed PIF has a wider viewing angle (±30°), and the color saturation of the PIF is also considerably high.

Inner helical waveplate with angle-insensitive retardation.

The angle-sensitivity is a serious defect of birefringent waveplate, and it draws lots of interest from researchers. In this paper, an angle-insensitive waveplate with inner helix structure is proposed. The super-twisted nematic liquid crystal polymer is used to fabricate the inner helical waveplate, and the retardation-shift is measured and analyzed. In the measured result, the retardation-shift is in the range from -0.311% to 0.194% at 45° polar angle, which is 2 orders of magnitude lower than that of the conventional waveplate. Theoretically, the retardation-shift is less than 0.5% in the polar angle range from 0° to 60°, and it will be less if the material with high refractive index is used. The analysis of the self-compensation effect explains the principle of angle-insensitivity, and the influence of tilt angle on angle-sensitivity is also investigated to guide the better design. At last, the application of the inner helical waveplate in wide color gamut display is taken as an example to show the broad application prospects.

The efficacy and safety of beta-blockers versus cyanoacrylate injection for gastric variceal bleeding: A protocol for systematic review and meta-analysis.

BACKGROUND: The benefit of beta-blockers for secondary prophylaxis of gastric variceal bleeding has limited evidence. Therefore, a systematic review and meta-analysis was conducted to systematically analyze and compare the effect of beta-blockers versus cyanoacrylate injection for patients with gastric variceal bleeding. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines will be followed to conduct the present meta-analysis. From the inception to June 2021, the Web of Science, EMBASE, PubMed, and Cochrane Library electronic databases will be searched using the key phrases "beta-blockers," "cyanoacrylate," and "gastric variceal bleeding" for all relevant English-language trials. Study included in our meta-analysis has to meet the following criteria: observational or randomized controlled trial focusing on assessing the effectiveness of beta-blockers and cyanoacrylate injection for gastric variceal bleeding; the following outcome measures are reported: bleeding from gastric variceal, overall mortality, bleed related mortality, and complications. RESULTS: This study expects to provide credible and scientific evidence for the efficacy and safety of beta-blockers versus cyanoacrylate injection for patients with gastric variceal bleeding. REGISTRATION NUMBER: 10.17605/OSF.IO/CPV9T.

Dual-path Attention Network for Compressed Sensing Image Reconstruction.

Although deep neural network methods achieved much success in compressed sensing image reconstruction in recent years, they still have some issues, especially in preserving texture details. In this paper, we propose a new dual-path attention network for compressed sensing image reconstruction, which is composed of a structure path, a texture path and a texture attention module. Motivated by the classical paradigm of image structure-texture decomposition, the structure path aims to reconstruct the dominant structure component of the original image, and the texture path targets at recovering the remaining texture details. To better bridge the information between two paths, the texture attention module is designed to deliver the useful structure information to the texture path and predict the texture region, thereby facilitating the recovery of texture details. Two paths are optimized with a unified loss function. In the testing phase, given the measurement vector of a new image, it can be well reconstructed by carrying out the well trained dual-path attention network and integrating the outputs of the structure path and the texture path. Experimental results on the SET5, SET11 and BSD68 testing datasets demonstrate that the proposed method achieves comparable or better results compared with some state-of-the-art deep learning based methods and conventional iterative optimization based methods in terms of reconstruction quality and robustness to noise.

Influences of nickel plated multi-walled carbon-nanotube on the electro-optical properties of nematic liquid crystal.

Some enhanced performances can be obtained by doping multi-walled carbon-nanotube (MWCNT) into self-organized nematic liquid crystal (NLC). However, the dispersion of MWCNT in NLC is very few, thus the enhancement is restricted. In this work, a nickel plated MWCNT (MWCNT@Ni) is synthesized to obtain a relatively high dispersion. The morphology, element and chemical bond differences between MWCNT and MWCNT@Ni are characterized. For MWCNT@Ni, there is a layer of coaxial nickel coated on the surface of MWCNT, which weakens the interaction energy between the adjacent MWCNTs and further results in a relatively high dispersion. Moreover, MWCNT@Ni has a more orderly arrangement in NLC compared with MWCNT. The results suggest that the dielectric anisotropy of MWCNT@Ni/NLC with mass fraction of 0.01 wt% is increased by ∼3.6%, and the saturation voltage is reduced by ∼7.3%. Besides, the rise time is decreased by ∼9.5% at 5 V and 1 kHz. These performances have been improved compared with MWCNT/NLC under the same mass fraction. The effect of mass fraction of MWCNT@Ni on rise time is further investigated. As a result, the rise time is decreased by ∼16.7% as MWCNT@Ni with mass fraction of 0.10 wt% is added into NLC. In general, the method to increase dispersion of dopant in NLC is proposed, which can serve as a reference to improve the performances of NLC composites.

Effect of a Dual Functional Polymer on the Electro-Optical Properties of Blue Phase Liquid Crystals.

The effects of the fluorinated monomer with an ethynyl group on the electro-optical properties of polymer-stabilized blue phase liquid crystals (PSBPLCs) were investigated in different polymer systems. In rigid polymer systems, the Kerr constant can be increased by about 27.6%, while keeping a microsecond response time. In soft polymer systems, hysteresis decreased by about 45.5% and residual birefringence can be reduced from 1.85% to 0.6%. The above phenomena exhibited dual functions of affecting the anchoring energy and the viscosity of the system simultaneously. The results provide a potential value for the ethynyl-containing monomers in PSBPLC systems.

Large aperture liquid crystal lens array using a composited alignment layer.

A liquid crystal (LC) lens array with high light control power and a large aperture using a composited alignment layer is proposed. In our design, the alignment layer is not only used for getting a uniform arrangement of LC molecule, but also for getting a lens-like refractive index distribution in the LC layer when a voltage is applied. Through simple technology processes, a tunable focal length LC lens array with a millimeter scale diameter can be achieved. Furthermore, the maximum phase difference of the proposed LC lens array can achieve 105.38π. So, the proposed LC lens array has a high light control power.

Continuously adjustable period optical grating based on flexoelectric effect of a bent-core nematic liquid crystal in planar cells.

The structures of flexodomains, which are similar to optical gratings and can be controlled by the amplitude of applied voltage and temperature, were verified through polarizing microscopy and light diffraction techniques. The properties of the optical grating induced by a bent-core nematic liquid crystal in planar cells with varied cell gaps and pretilt angles were studied. The period of optical grating decreases with the increase in the amplitude of the applied voltage and pretilt angle. In addition, the period increases with the increase in cell gap and temperature. The period of optical grating has a linear relationship with temperature. The continuously adjustable period has the potential to become an important and extended application of optical grating.

Fast Switchable Dual-Model Grating by Using Polymer-Stabilized Sphere Phase Liquid Crystal.

We demonstrated a fast switchable dual-model grating based on a polymer-stabilized sphere phase liquid crystal. To form binary periodicity layers, the polymer-stabilized sphere phase liquid crystal precursor was sequence ultraviolet cured at an isotropic and sphere phase. This grating jointly modulated both the phase and the amplitude, had six times the diffraction efficiency of that fabricated with polymer-stabilized blue phase liquid crystal. Moreover, the dual-model tunable grating shown polarization-independent and submillisecond response time, which may hold a great potential application in diffractive optics.

A gel single ion conducting polymer electrolyte enables durable and safe lithium ion batteries via graft polymerization.

Concentration polarization issues and lithium dendrite formation, which associate inherently with the commercial dual-ion electrolytes, restrict the performance of lithium ion batteries. Single ion conducting polymer electrolytes (SIPEs) with high lithium ion transference numbers (t + ≈ 1) are being intensively studied to circumvent these issues. Herein, poly(ethylene-co-vinyl alcohol) (EVOH) is chosen as the backbone and then grafted with lithium 3-chloropropanesulfonyl(trifluoromethanesulfonyl)imide (LiCPSI) via Williamson's reaction, resulting in a side-chain-grafted single ion polymer conductor (EVOH-graft-LiCPSI). The ionomer is further blended with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) by solution casting for practical use. The SIPE membrane with ethylene carbonate and dimethyl carbonate (EC/DMC = 1 : 1, v/v) as plasticizer (i.e., gel SIPE) exhibits an ionic conductivity of 5.7 × 10-5 S cm-1, a lithium ion transference number of 0.88, a wide electrochemical window of 4.8 V (vs. Li/Li+) and adequate mechanical strength. Finally, the gel SIPE is applied in a lithium ion battery as the electrolyte as well as the separator, delivering an initial discharge capacity of 100 mA h g-1 at 1C which remains at 95 mA h g-1 after 500 cycles.

Electro-optical performance of polymer-stabilized sphere phase liquid crystal displays.

Electro-optical properties of polymer-stabilized sphere phase liquid crystal (PS-SPLC) switching devices are analyzed and validated experimentally. The experimental results show the voltage-dependent transmittance curves of PS-SPLC devices. A diffraction approach, called extended anomalous diffraction approach, is proposed to fit the experimental data. Good agreement between experiment and model is obtained. The scattering model provides practical guidance for the improvement of PS-SPLC displays performance and optimization.

Dual-period tunable phase grating based on a single in-plane switching.

We proposed a dual-period phase grating using a polymer-stabilized blue phase liquid crystal (PS-BPLC). High efficiencies of 38% for the short-period phase grating and 30% for the long-period phase grating have been achieved because of the electric-field-induced rectangular-like phase profile of a PS-BPLC, which agrees quite well with the simulation results. The diffraction angle and the diffraction efficiency can be alternatively tuned by a bias voltage and intensity of applied voltage. The diffracted light of each diffraction order is elliptically polarized, and its ellipticity is larger than that induced by using the conventional nematic LCs. Such a device also shows sub-millisecond response time and holds great potential for photonics applications.

High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte.

Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known "polysulfide shuttle" effect. Here, we report a novel cell design by sandwiching a sp(3) boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batteries. The dense negative charges uniformly distributed in the electrolyte membrane inherently prohibit transport of polysulfide anions formed in the cathode inside the polymer matrix and effectively blocks polysulfide shuttling. A battery assembled with the composite separator exhibits a remarkably long cycle life at high charge/discharge rates.