Treatment of breast deformity with free deep inferior epigastric perforator flap secondary to pectoralis major flap harvesting

SummaryHead and neck cancer is less common in women than in men. Free tissue transfer is the first choice in reconstructive option for head and neck tumor. Pedicle pectoralis major (PM) flap was a common option in head neck reconstruction in the past, but has become the salvage procedure when free flap fails. However, it is not suitable for female patients because of severe breast deformity and induced psychosocial distress. We present a female patient who had breast deformity due to PM flap reconstruction and was successfully treated with free deep inferior epigastric perforator (DIEP) flap. A 48-year-old woman had squamous cell carcinoma in the left side buccal mucosa, T2N0M0, stage II s/p wide excision with partial resection of maxilla and marginal resection of mandible. Free anterolateral thigh flap had been tried but in vain, then alternatively salvaged with a pedicle PM flap 3 years earlier. She presented with malposition of the left breast, nipple retraction, and high riding. We adequately released the contracture and reconstructed with a free DIEP flap. The free DIEP flap survived completely and restored a balanced breast with good shape and symmetry at 1-year follow-up. Although PM flap is a good modality in head and neck reconstruction, it should be used cautiously especially in female patients. The free DIEP flap is not only suitable for breast reconstruction in breast cancer patient, but also a good choice for a different purpose of breast reconstruction such as this patient with breast deformity due to PM flap harvest

Coexistence of multiuser entanglement distribution and classical light in optical fiber network with a semiconductor chip

Building communication links among multiple users in a scalable and robust way is a key objective in achieving large-scale quantum networks. In realistic scenario, noise from the coexisting classical light is inevitable and can ultimately disrupt the entanglement. The previous significant fully connected multiuser entanglement distribution experiments are conducted using dark fiber links and there is no explicit relation between the entanglement degradations induced by classical noise and its error rate. Here we fabricate a semiconductor chip with a high figure-of-merit modal overlap to directly generate broadband polarization entanglement. Our monolithic source maintains polarization entanglement fidelity above 96% for 42 nm bandwidth with a brightness of 1.2*10^7 Hz/mW. We perform a continuously working quantum entanglement distribution among three users coexisting with classical light. Under finite-key analysis, we establish secure keys and enable images encryption as well as quantum secret sharing between users. Our work paves the way for practical multiparty quantum communication with integrated photonic architecture compatible with real-world fiber optical communication network

Solving Nonlinear Parabolic Equations by a Strongly Implicit Finite-Difference Scheme

We discuss the numerical solution of nonlinear parabolic partial differential equations, exhibiting finite speed of propagation, via a strongly implicit finite-difference scheme with formal truncation error $\mathcal{O}\left[(\Delta x)^2 + (\Delta t)^2 \right]$. Our application of interest is the spreading of viscous gravity currents in the study of which these type of differential equations arise. Viscous gravity currents are low Reynolds number (viscous forces dominate inertial forces) flow phenomena in which a dense, viscous fluid displaces a lighter (usually immiscible) fluid. The fluids may be confined by the sidewalls of a channel or propagate in an unconfined two-dimensional (or axisymmetric three-dimensional) geometry. Under the lubrication approximation, the mathematical description of the spreading of these fluids reduces to solving the so-called thin-film equation for the current's shape $h(x,t)$. To solve such nonlinear parabolic equations we propose a finite-difference scheme based on the Crank--Nicolson idea. We implement the scheme for problems involving a single spatial coordinate (i.e., two-dimensional, axisymmetric or spherically-symmetric three-dimensional currents) on an equispaced but staggered grid. We benchmark the scheme against analytical solutions and highlight its strong numerical stability by specifically considering the spreading of non-Newtonian power-law fluids in a variable-width confined channel-like geometry (a "Hele-Shaw cell") subject to a given mass conservation/balance constraint. We show that this constraint can be implemented by re-expressing it as nonlinear flux boundary conditions on the domain's endpoints. Then, we show numerically that the scheme achieves its full second-order accuracy in space and time. We also highlight through numerical simulations how the proposed scheme accurately respects the mass conservation/balance constraint.Comment: 36 pages, 9 figures, Springer book class; v2 includes improvements and corrections; to appear as a contribution in "Applied Wave Mathematics II

Engineered Biomaterials to Enhance Stem Cell-Based Cardiac Tissue Engineering and Therapy

Cardiovascular disease is a leading cause of death worldwide. Since adult cardiac cells are limited in their proliferation, cardiac tissue with dead or damaged cardiac cells downstream of the occluded vessel does not regenerate after myocardial infarction. The cardiac tissue is then replaced with nonfunctional fibrotic scar tissue rather than new cardiac cells, which leaves the heart weak. The limited proliferation ability of host cardiac cells has motivated investigators to research the potential cardiac regenerative ability of stem cells. Considerable progress has been made in this endeavor. However, the optimum type of stem cells along with the most suitable matrix-material and cellular microenvironmental cues are yet to be identified or agreed upon. This review presents an overview of various types of biofunctional materials and biomaterial matrices, which in combination with stem cells, have shown promises for cardiac tissue replacement and reinforcement. Engineered biomaterials also have applications in cardiac tissue engineering, in which tissue constructs are developed in vitro by combining stem cells and biomaterial scaffolds for drug screening or eventual implantation. This review highlights the benefits of using biomaterials in conjunction with stem cells to repair damaged myocardium and give a brief description of the properties of these biomaterials that make them such valuable tools to the field.Anwarul Hasan acknowledges the startup grant and the University Research Board (URB) grant from American University of Beirut, Lebanon, and the National Council for Scientific Research (CNRS) grant, Lebanon, as well as the Farouk Jabre interdisciplinary research award. Arghya Paul acknowledges the University of Kansas New Faculty General Research Fund for support and assistance with this work. The authors also acknowledge an investigator grant provided by the Institutional Development Award (IDeA) from the National Institute of General Medical Sciences (NIGMS) of the NIH Award Number P20GM103638-04 (to A.P.). R.W. acknowledges the financial support from NIGMS (NIH, T32-GM008359) Biotechnology Predoctoral Research Training Program

Virus-Free and Live-Cell Visualizing SARS-CoV-2 Cell Entry for Studies of Neutralizing Antibodies and Compound Inhibitors

新型冠状病毒SARS-CoV-2在全球蔓延，给全球公共卫生带来严重威胁。快速研制疫苗、抗体和治疗药物成为科学界面临的重大挑战。由于SARS-CoV-2的高度传染性，采用病毒感染模型进行中和抗体及小分子抑制剂的药效评估需要在高等级生物安全实验室中进行，且常需要数天时间才能完成检测，限制了抗体和药物筛选的效率。发展快速、可视、不依赖于活病毒的新冠病毒入胞检测探针和细胞模型，对于加速新冠病毒抗体和药物的研究有重要意义。夏宁邵教授团队通过CHO真核表达系统高效表达制备出C端融合抗酸荧光蛋白Gamillus的重组新冠病毒spike蛋白STG。STG经SEC分子筛和冷冻电镜确认呈现与天然病毒刺突高度相似的三聚体结构，且与ACE2有很高的亲和力（18.2nM）。STG具备良好的细胞相容性和荧光性质，研究者进一步开发了可定量测定感染恢复期血清、疫苗免疫血清中和抗体（入胞阻断抗体）水平的CSBT检测方法。除了抗体检测评估方面的应用外，该研究发展的探针和模型还可用于筛选分析抑制新冠病毒入胞及胞内转运的小分子化合物。 我校博士后张雅丽，博士生王邵娟、巫洋涛，博士后侯汪衡、袁伦志和深圳市第三人民医院沈晨光博士为共同第一作者。厦门大学夏宁邵教授、袁权教授、程通教授为该论文共同通讯作者。The ongoing corona virus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2 infection, has resulted in hundreds of thousands of deaths. Cellular entry of SARS-CoV-2, which is mediated by the viral spike protein and ACE2 receptor, is an essential target for the development of vaccines, therapeutic antibodies, and drugs. Using a mammalian cell expression system,a genetically engineered sensor of fluorescent protein (Gamillus)-fused SARS-CoV-2 spike trimer (STG) to probe the viral entry process is developed.In ACE2-expressing cells, it is found that the STG probe has excellent performance in the live-cell visualization of receptor binding, cellular uptake, and intracellular trafficking of SARS-CoV-2 under virus-free conditions. The new system allows quantitative analyses of the inhibition potentials and detailed influence of COVID-19-convalescent human plasmas, neutralizing antibodies and compounds, providing a versatile tool for high-throughput screening and phenotypic characterization of SARS-CoV-2 entry inhibitors. This approach may also be adapted to develop a viral entry visualization system for other viruses.This study was supported by National Natural Science Foundation of China (81993149041 for N.X.; 81902057 for Y.Z.; 81871316 and U1905205 for Q.Y.), the National Science and Technology Major Project of Infectious Diseases (No. 2017ZX10304402‐002‐003 for T.C. and No. 2017ZX10202203‐009 for Q.Y.), the National Science and Technology Major Projects for Major New Drugs Innovation and Development (No. 2018ZX09711003‐005‐003 for T.C.), the Science and Technology Major Project of Fujian (2020YZ014001), the Science and Technology Major Project of Xiamen (3502Z2020YJ01), and the Guangdong Basic and Applied Basic Research Foundation (2020A1515010368 for C.S.). 该研究得到了国家自然科学基金、传染病防治国家科技重大专项、福建省应急科技攻关项目和厦门应急科技攻关项目的支持

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data