Two data structures for building tetrahedralizations

A polyhedral decomposition can be unambiguously described as the collection of four primitive elements (i.e., polyhedra, facets, edges, and vertices) plus their mutual adjacency relations. We consider here the problem of representing a specific kind of polyhedral decomposition, i.e., a tetrahedralization. We describe two different representations for a tetrahedralization. The first one can only model polyhedral decompositions with tetrahedral cells, while the second one is suitable for describing any partition of a volume into polyhedral cells with triangular facets. We present two sets of primitive Euler operators, which build and manipulate such representations while maintaining their topological integrity. The use of such operators is demonstrated in connection with two algorithms for building a Delaunay tetrahedralization, which show the different hedralization, which show the different uses of the two representations.     

Efficient visual communication channels

This paper compares the efficiency of uniform quantization in the spatial domain with frequency dependent quantization in the spatial frequency domain, in the context of the end-to-end performance of visual-communication channels. Results show that the minimum data density required for informationally lossless transmission depends on the design of the image-gathering device. The information in the acquired signal, not the energy, dictates the trade-off between data transmission and visual quality. Frequency dependent quantization that maintains the information capacity of the channel while reducing the entropy of the encoded signal, improves its information efficiency. Information bit-allocation is preferable for optimized visual communication for restoration, whereas energy bit-allocation can be used only for image reconstruction.This research was supported by NASA Task Assignment NAS1-18584-90 with the Department of Mathematics, Old Dominion University, Norfolk, Virginia 23529.     

一种针对图像模糊的无参考质量评价指标

在成像模型的基础上,分析了图像模糊的原因,提出了一种为图像构造参考图像的方法,进而将结构相似度(SSIM)评价方法引入到无参考图像质量评价中,提出一种无参考结构清晰度(NRSS)的新的无参考图像质量评价方法,将其用于对模糊图像的质量评价。该方法通过低通滤波器来构造参考图像,通过计算原始图像与参考图像的结构相似度值来评价原始图像质量,很好地结合了成像系统的数学模型和结构相似度评价方法的优势,实验结果表明无参考结构清晰度评价指标能够给出和主观评价方法以及其余有参考评价方法一致的结果。     

具有多种特性的门限多代理多签名方案

为了提高多代理多签名的灵活性和实用性,在Schnorr签名的基础上,提出2个具有消息恢复特性的门限多代理多签名新方案,其中的不同类成员具有不等权限,只有指定验证者才能恢复消息并验证签名。分析结果表明,在离散对数假设和随机预言机模型下,该方案是安全的。     

基于秩相关的属性约简

针对有序尺度变量,给出了有序信息系统与有序决策表在优势关系下的粗糙集约简定义;利用粗糙集方法将对象综合排序,进而得到一组秩;根据这些秩,运用非参数统计的思想研究了两个属性子集之间的相关性,并将Spearman秩相关系数作为属性相关性度量;在不改变总体序信息情况下,给出了基于此度量对有序信息系统与有序决策表进行约简的新方法。最后通过数值例子说明该方法是可行的,且为粗糙集方法提供了统计依据。     

施威德勒型单层球面网壳结构抗火的非线性有限元分析

根据ISO-834标准升温曲线与结构钢强度和刚度随温度的变化曲线,采用非线性有限元法对不同的矢跨比的施威德勒型单层球面网壳结构进行了抗火分析,得到了一些结果,可为经济、科学的结构综合防火设计提供理论依据.     

深部开采岩体变形分析的双曲函数法

在软岩地层深部厚矿体开采条件下,给出了用于预测分析地下开采岩体移动变形的双曲正切函数模型,采用该模型对国内某地下矿山深部开采岩体移动变形进行了具体的计算分析,并与概率积分法理论分析结果和实测数据进行了对比,结果令人满意.分析结果表明,本文所提出的理论方法适用于预测分析深部矿体开采引起的岩体移动变形问题.     

Therapeutic Vaccines for HPV-Associated Oropharyngeal and Cervical Cancer: The Next De-Intensification Strategy?

The rise in human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) has prompted a quest for further understanding of the role of high-risk HPV in tumor initiation and progression. Patients with HPV-positive OPSCC (HPV+ OPSCC) have better prognoses than their HPV-negative counterparts; however, current therapeutic strategies for HPV+ OPSCC are overly aggressive and leave patients with life-long sequalae and poor quality of life. This highlights a need for customized treatment. Several clinical trials of treatment de-intensification to reduce acute and late toxicity without compromising efficacy have been conducted. This article reviews the differences and similarities in the pathogenesis and progression of HPV-related OPSCC compared to cervical cancer, with emphasis on the role of prophylactic and therapeutic vaccines as a potential de-intensification treatment strategy. Overall, the future development of novel and effective therapeutic agents for HPV-associated head and neck tumors promises to meet the challenges posed by this growing epidemic.     

NIR-Triggered Generation of Reactive Oxygen Species and Photodynamic Therapy Based on Mesoporous Silica-Coated LiYF4 Upconverting Nanoparticles

To date, the increase in reactive oxygen species (ROS) production for effectual photodynamic therapy (PDT) treatment still remains challenging. In this study, a facile and effective approach is utilized to coat mesoporous silica (mSiO₂) shell on the ligand-free upconversion nanoparticles (UCNPs) based on the LiYF₄ host material. Two kinds of mesoporous silica-coated UCNPs (UCNP@mSiO₂) that display green emission (doped with Ho³⁺) and red emission (doped with Er³⁺), respectively, were successfully synthesized and well characterized. Three photosensitizers (PSs), merocyanine 540 (MC 540), rose bengal (RB), and chlorin e6 (Ce6), with the function of absorption of green or red emission, were selected and loaded into the mSiO₂ shell of both UCNP@mSiO₂ nanomaterials. A comprehensive study for the three UCNP@mSiO₂/PS donor/acceptor pairs was performed to investigate the efficacy of fluorescence resonance energy transfer (FRET), ROS generation, and in vitro PDT using a MCF-7 cell line. ROS generation detection showed that as compared to the oleate-capped and ligand-free UCNP/PS pairs, the UCNP@mSiO₂/PS nanocarrier system demonstrated more pronounced ROS generation due to the UCNP@mSiO₂ nanoparticles in close vicinity to PS molecules and a higher loading capacity of the photosensitizer. As a result, the three LiYF₄ UCNP@mSiO₂/PS nanoplatforms displayed more prominent therapeutic efficacies in PDT by using in vitro cytotoxicity tests.     

Reduced VDAC1, Maintained Mitochondrial Dynamics and Enhanced Mitochondrial Biogenesis in a Transgenic Tau Mouse Model of Alzheimer’s Disease

Alzheimer’s disease (AD) is one of the most common forms of neurodegeneration, defined by reduced cognitive function, which is caused by the gradual death of neurons in the brain. Recent studies have shown an age-dependent rise in the levels of voltage-dependent anion channel 1 (VDAC1) in AD. In addition, we discovered an aberrant interaction between VDAC1 and P-TAU in the brains of AD patients, which led to abnormalities in the structural and functional integrity of the mitochondria. The purpose of our study is to understand the protective effects of reduced VDAC1 against impaired mitochondrial dynamics and defective mitochondrial biogenesis in transgenic TAU mice. Recently, we crossed heterozygote VDAC1 knockout (VDAC1^+/−) mice with transgenic TAU mice to obtain double-mutant VDAC1^+/−/TAU mice. Our goal was to evaluate whether a partial decrease in VDAC1 lessens the amount of mitochondrial toxicity in transgenic Tau (P301L) mice. We found that mitochondrial fission proteins were significantly reduced, and mitochondrial fusion and biogenesis proteins were increased in double-mutant mice compared to TAU mice. On the basis of these discoveries, the current work may have significance for the development of reduced-VDAC1-based treatments for individuals suffering from AD as well as other tauopathies.