Berg adder (Bitis atropos) envenoming: an analysis of 14 cases

Introduction: The berg adder (Bitis atropos) is a little-studied, lesser-known viperid snake found in southern Africa and there is limited information available regarding the manifestations of envenoming.

Materials and methods: This observational series of 14 cases documents features of berg adder envenoming over a period of 16 years (1987–2003).

Clinical features of envenomed patients: All 14 patients developed local cytotoxic effects. Thirteen patients developed systemic effects manifesting and documented in varying degrees. These include (1) prominent vomiting (2) disturbances in cranial nerve function (anosmia and altered taste, an ophthalmological triad of ptosis, mydriasis and visual disturbances including loss of accommodation, and dysphagia) (3) a global decrease in motor power where mechanical ventilation was often required for respiratory failure and (4) hyponatraemia (lowest value recorded 111?mmol/L), sometimes with associated convulsions.

Discussion: The full range of polypeptides present in berg adder venom is yet to be characterised. However, two closely related phospholipases A₂ (PLA₂; PLA₂-1 and PLA₂-2) have been purified from the venom of B. atropos and clinical evidence suggests that a natriuretic peptide is also possibly present. Envenoming results in distinctive, sometimes life-threatening, manifestations.     

基于SIMD技术的可重构去块滤波器结构

由于去块滤波运算数据量庞大的特点以及视频解码实时性的要求,近年来,去块滤波运算的硬件加速器已逐渐成为研究的热点。从兼顾系统的灵活性与性能的角度出发,设计了一种可重构去块滤波器。与传统的支持单一标准的去块滤波硬件加速器相比,该滤波器具有以下优点：实现了一种滤波算法可配置的滤波器结构,从而可以支持多个视频编码标准;采用了基于SIMD单指令多数据流技术,实现滤波数据全并行运算,使硬件高度规整,易于芯片布局布线;设计了1个4级可配置的流水线,重构为不同视频标准的去块滤波器,复用硬件资源,提高了硬件利用率和系统数据吞吐量。用这种架构实现了1个同时支持H264、AVS、VP8、RealVideo 4种标准的多标准去块滤波加速器,时钟频率为200 MHz,能够用于多标准高清视频的实时滤波处理。     

基于重写归纳技术的串行加法器的描述和验证

在用重写系统描述逻辑位，门电路，位串和自然数的基础上，对半加器，全加器和串行加法器等基本硬件电路的逻辑功能进行了刻画，并用基于重写归纳的推理技术证明了所有描述的正确性，为用重写技术正确描述和验证复杂硬件电路奠定了基础。最后给出与其他类似工作的分析和比较。     

TURBT术治疗T1T2期膀胱癌91例

目的:分析两种手术方法对T1T2期膀胱癌的治疗效果。方法:根据病史、体格检查、B超、3D-CT、膀胱镜活组织检查确诊的T1T2期膀胱癌152例,采用TURBT术(经尿道膀胱肿瘤切除术)91例,膀胱局部切除术61例,分析比较治疗效果。结果:两种手术方法疗效无显著特异性,患者生存率与肿瘤病理分期有直接相关性。结论:T1T2期膀胱癌采用TURBT术与采用膀胱局部切除术疗效相当,但TURBT费用低,创伤少,便于再次手术,有推广意义。     

CCR4表达与胆囊癌细胞GBC-SD侵袭和转移的关系

目的：探讨趋化因子CCR4对人胆囊癌细胞GBC-SD增殖、周期、侵袭和迁移运动能力的影响。方法应用Western b1ot法检测人不同胆囊癌细胞株中CCR4的表达水平;慢病毒感染胆囊癌细胞GBC-SD;siRNA-CCR4沉默CCR4基因;Western b1ot法鉴定干扰效果。胆囊癌细胞GBC-SD分为三组：GBC-SD、GBC-SD/CCR4-RNAi和GBC-SD/contro1细胞,CCR4配体CCL17对这三组细胞进行作用。采用CCK8法检测三组细胞的增殖能力;流式细胞仪检测细胞周期;Transwe11小室运动侵袭试验检测细胞迁移和侵袭能力;Western b1ot法检测CCR4基因沉默后,对其相应配体CCL17和CCL22蛋白表达的影响。结果沉默CCR4基因,对胆囊癌细胞GBC-SD的细胞周期及增殖均无影响,但能显著抑制GBC-SD细胞的侵袭及运动迁移能力,CCR4基因的沉默对肿瘤细胞CCL17和CCL22基因的表达无影响。结论胆囊癌细胞GBC-SD表达趋化因子受体CCR4,CCR4可以促进胆囊癌细胞GBC-SD的侵袭和转移。     

Severe Puff Adder (Bitis arietans) Envenomation with Coagulopathy

Background: The puff adder (Bitis arietans) is a highly toxic venomous snake that is responsible for a large proportion of the venomous snakebites in sub-Saharan Africa, where it is indigenous. Puff adder bites in North America result from snakes in captivity. Although thrombolytic enzymes are present in puff adder venom, significant coagulopathy has not been previously reported with a confirmed puff adder envenomation.

Results: We report a serious puff adder envenomation to the finger, characterized by severe swelling, local tissue necrosis, hypotension, thrombocytopenia, severe coagulopathy, and hemorrhage. Fifteen vials of South Africa polyvalent antivenom were administered, beginning 4.5 hours post-envenomation, with step-wise improvement in hematological abnormalities. Other treatments included vasopressors, ventilatory support, leeches, transfusion, and eventual digit amputation. After a prolonged hospital course, the patient had a good outcome.

Conclusions: Puff adder envenomation causes tissue necrosis, hypotension, coagulopathy, thrombocytopenia, and spontaneous bleeding. Severe coagulopathy may occur. Physicians treating severe cases should be prepared to administer at least 15 vials of antivenom if needed.     

Programmable matter by folding

Programmable matter is a material whose properties can be programmed to achieve specific shapes or stiffnesses upon command. This concept requires constituent elements to interact and rearrange intelligently in order to meet the goal. This paper considers achieving programmable sheets that can form themselves in different shapes autonomously by folding. Past approaches to creating transforming machines have been limited by the small feature sizes, the large number of components, and the associated complexity of communication among the units. We seek to mitigate these difficulties through the unique concept of self-folding origami with universal crease patterns. This approach exploits a single sheet composed of interconnected triangular sections. The sheet is able to fold into a set of predetermined shapes using embedded actuation. To implement this self-folding origami concept, we have developed a scalable end-to-end planning and fabrication process. Given a set of desired objects, the system computes an optimized design for a single sheet and multiple controllers to achieve each of the desired objects. The material, called programmable matter by folding, is an example of a system capable of achieving multiple shapes for multiple functions.     

Successful treatment of presumed death‐adder neurotoxicity using anticholinesterases

We present the first reported case in Australia of anticholinesterases being used successfully in conjunction with antivenom to treat neurotoxicity following death‐adder envenomation. A 49‐year‐old man was bitten by his pet death adder. He developed significant neurotoxicity due to delayed presentation and suboptimal first aid. Following one ampoule of polyvalent antivenom which produced an allergic reaction, administration of neostigmine and atropine facilitated aeromedical evacuation without the need for mechanical ventilation. After three ampoules of monovalent death‐adder antivenom at the receiving hospital, antivenom supplies were exhausted. Further neostigmine and atropine resulted in complete resolution of paralysis, allowing discharge. Anticholinesterases may reduce the dose of antivenom required to treat death‐adder envenomation. They may also be of use in cases of allergic reactions to antivenom, and in reducing the need for endotracheal intubation.     

Exotic snakebite: Envenomation by an African puff adder (Bitis arietans)

We report an envenomation by the African puff adder (Bitis arietans), an exotic snake in the United States. The patient developed swelling and ecchymoses in the affected extremity, and cutaneous necrosis of the envenomated fingertip. There was no significant coagulopathy. He received 20 vials of specific antivenin (Schlangengift-Immunserum Behring Zentralafrika, Behringwerke, Marburg, Germany) and debridement of devitalized finger tissue. The only permanent sequelae were cutaneous scarring and permanent loss of the fingernail on the envenomated finger. Exotic snakebite is a rare presenting problem in emergency departments. The initial approach to a patient envenomated by an exotic venomous snake is discussed. Use of antivenin and supportive care are emphasized.     

From the Cover: Origami tubes assembled into stiff,yet reconfigurable structures and metamaterials

Thin sheets have long been known to experience an increase in stiffness when they are bent, buckled, or assembled into smaller interlocking structures. We introduce a unique orientation for coupling rigidly foldable origami tubes in a “zipper” fashion that substantially increases the system stiffness and permits only one flexible deformation mode through which the structure can deploy. The flexible deployment of the tubular structures is permitted by localized bending of the origami along prescribed fold lines. All other deformation modes, such as global bending and twisting of the structural system, are substantially stiffer because the tubular assemblages are overconstrained and the thin sheets become engaged in tension and compression. The zipper-coupled tubes yield an unusually large eigenvalue bandgap that represents the unique difference in stiffness between deformation modes. Furthermore, we couple compatible origami tubes into a variety of cellular assemblages that can enhance mechanical characteristics and geometric versatility, leading to a potential design paradigm for structures and metamaterials that can be deployed, stiffened, and tuned. The enhanced mechanical properties, versatility, and adaptivity of these thin sheet systems can provide practical solutions of varying geometric scales in science and engineering.Introducing folds into a thin sheet can restrict its boundaries, cause self-interaction, and reduce the effective length for bending and buckling of the material (1–4). These phenomena make thin sheets practical for stiff and lightweight corrugated assemblies (5, 6); however, such systems tend to be static, i.e., functional in only one configuration. For creating dynamic structures, origami has emerged as a practical method in which continuous thin sheet panels (facets) are interconnected by prescribed fold lines (creases). Existing origami patterns and assemblages can easily be deployed; however, they tend to be flexible and need to be braced or locked into a fixed configuration for a high stiffness-to-weight ratio to be achieved (7–10). The zipper-coupled system is different because it is stiff throughout its deployment without having to be locked into a particular configuration.Origami principles have broad and varied applications, from solar arrays (11) and building façades (12) to robotics (13), mechanisms in stent grafts (14), and DNA-sized boxes (15). The materials and methods used for fabricating, actuating, and assembling these systems can vary greatly with length scale. On the microscale, metallic and polymer films or, more often, layered composites consisting of stiff and flexible materials can be folded by inducing current, heat, or a chemical reaction (16, 17). Large-scale origami structures can be constructed from thickened panels connected by hinges and can be actuated with mechanical forces (11, 18, 19). The kinematic motion, functionality, and mechanical properties of the origami are governed largely by the folding pattern geometry. For example, rigid origami systems are defined as those having a kinematic deformation mode in which movement is concentrated along the fold lines, whereas the panels remain flat (20, 21). Among various rigid folding patterns, the Miura-ori has attracted attention for its folding characteristics (22, 23), elastic stiffness properties beyond rigid folding (24, 25), geometric versatility (26, 27), and intrinsic material-like characteristics (28, 29).The zipper-coupled tubes introduced here are derived from the Miura-ori pattern and can undergo the same type of rigid kinematic deployment. All other deformations are restrained as they require stretching and shear of the thin sheets. Thus, the structure is light and retains a high stiffness throughout its deployment. It has only one flexible degree of freedom and can be actuated by applying a force at any point (Fig. 1 and Movie S1). To explore unique mechanical properties of the zipper tubes, we introduce concepts of eigenvalue bandgaps and cantilever analyses to the field of origami engineering. Zipper assemblages can be fabricated with a variety of materials and methods. We envision applications of these assemblages will range in size from microscale metamaterials that harness the novel mechanical properties to large-scale deployable systems in engineering and architecture (Movies S2–S4).Open in a separate windowFig. 1.Deployment and retraction sequence of a zipper-coupled tube system. This origami has only one flexible motion through which it can deform, and thus it is deployed by actuating only on the right end. See Movie S1 for complete simulation.This paper is organized as follows. First, the Miura-ori pattern is introduced, and the geometries of three fundamental coupling orientations are discussed. Next, we demonstrate how the system stiffness changes as we assemble two sheets into a tube and then two tubes into the unique zipper-coupled tubes. The fundamental coupling orientations are then studied as deployable cantilevers that can carry perpendicular loads. Next, we discuss cellular assemblages, geometric variations, and practical applications that can be created from coupled tubes, and we conclude with some final remarks.