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1
2022 - 02 - 16
为了成功交配,许多雄蛙会坐在一起,向潜在配偶发出叫声。这时,问题就出现了——每个试图在人声鼎沸的鸡尾酒会上听清别人说话的人都会遇到:一只雌蛙是如何在背景噪音(包括其他蛙类的声音)中听到并找到自己的如意郎君呢?现在,研究人员可能找到了答案。3月5日,一篇发表在Cell Press细胞出版社旗下期刊Current Biology(《当代生物学》)上的报告显示,青蛙能做到这一点要归功于它们的肺部。当肺部膨胀时,青蛙鼓膜在特定的频率范围内降低了对环境噪音的敏感性,从而更容易关注配偶的叫声。 “从本质上讲,肺消除了鼓膜对噪音的反应,特别是对一些不在调上的‘繁殖大合唱’中所遇到的噪音。”论文主要作者、明尼苏达大学圣奥拉夫学院的Norman Lee说。 研究人员解释说,青蛙肺部所做的事情被称为“声谱对比度增强”。这是因为,与相邻频率的噪声相比,它使雄性声谱的频率尤为突出。 “这类似于某些助听器和耳蜗植入物中用于增强声谱对比度的信号处理算法。”明尼苏达大学双城校区的资深作者Mark Bee说,“人类设计这种算法,用来放大或提升语音的频率,减弱或过滤语音之间的频率,或两者兼而有之。青蛙的肺部似乎会减弱雄性交配叫声之间的频率。我们认为,这种现象发生的物理机制与降噪耳机的工作原理类似。” 科学家们早就知道,声音信号是大多数青蛙繁殖的关键。事实上,青蛙拥有一种独特的...
2
2019 - 08 - 09
今日,美国FDA批准罗氏(Roche)公司开发的NTRK,ROS1和ALK抑制剂Rozlytrek(entrectinib)上市,治疗携带NTRK基因融合的实体瘤患者,以及携带ROS1基因突变的非小细胞肺癌患者。这也是美国FDA批准的第三款“不限癌种”的抗癌疗法。自从去年Loxo Oncology/拜耳(Bayer)公司联合开发的TRK抑制剂Vitrakvi(larotrectinib)获批以来。“不限癌种”抗癌疗法得到了广大业界人士和患者的关注。还有哪些“不限癌种“疗法即将问世?“不限癌种“的抗癌疗法发展的前景如何?今天的这篇文章里,药明康德内容团队将结合公开资料,与读者分享这些问题的答案。“不限癌种“疗法的理论基础和面对的挑战我们知道,基因突变是驱动正常细胞癌变的关键。近年来高通量测序技术的进步,让我们获得了许多对癌症背后的分子生物学机理的洞见。基于这些洞见,我们对癌症的分类不再局限于癌症起源的组织,而是基于肿瘤细胞携带的特定基因变异。这一基于分子生物学生物标志物的分类方法加快了靶向疗法的开发,而“不限癌种“的抗癌疗法可以说是靶向疗法中比较特别的一个分支。这些靶向疗法的靶点在起源于不同组织的多种癌症中存在,而且”不限癌种“疗法能够在多种癌症类型中表现出卓越的疗效。例如去年获批的Vitrakvi在携带NTRK基因融合的患者中能够达到81%的总缓解率。而刚刚获得FDA批准的Rozl...
3
2019 - 08 - 01
第二看台老年性黄斑变性(AMD)、视网膜色素变性(RP)等视网膜变性疾病是目前尚无有效治疗手段的凶险致盲性眼病,也是公认的 “视力杀手”。由中南大学爱尔眼科学院院长唐仕波教授、爱尔眼科研究所副所长陈建苏教授带领团队,利用诱导多能干细胞(iPS)条件培养基和飞秒角膜透镜,联合构建高活性视网膜色素上皮细胞(RPE)的研究,不但有利于对视网膜色素上皮细胞生理特性、药物筛选等研究,还有利于构建组织工程视网膜层及其移植。这将帮助科学家开发出应用组织工程 RPE 细胞片治疗视网膜变性疾病和光感受器病变的新方法。培养高活性的视网膜细胞与年龄相关的老年性黄斑变性是发达国家 50 岁以上人群视力损害和致盲的首要病因,多达 90% 的病人无法治愈。数据显示,发达国家年龄 50 岁以上黄斑变性的发病率达 11%,目前我国的发病率接近发达国家,患病人数超过 3000 万人,并以每年 30 万人次的速度增加,成为我国现阶段 50 岁以上年龄群体发病率最高的三大眼科疾病之一,而且女性呈现出比男性更高的危险性。研究发现,未来最有希望治疗老年性黄斑变性的方式是视网膜色素上皮细胞疗法、视网膜黄斑部分的移植。那么,要采用 RPE 疗法,就需要先培养健康的视网膜细胞。陈建苏告诉科技日报记者,取出死亡时间在 3 小时内捐献者的带有部分脉络膜的视网膜组织,在解剖显微镜下可将带有部分脉络膜的 RPE 层从捐赠组织中分离出来,...
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产品名称:

EVOS™ 20X Objective, achromat, LWD, phase-contrast

上市日期: 2019-04-11
产品类别: EVOS

规格

For Use With (Equipment):EVOS® XL Core Imaging System, EVOS® XL Imaging System
Lens Type:Plan Achromat
Magnification:20X
Product Line:EVOS®
Product Size:1 each
Quantity:1 each
Type:Objective Lens


  • 产品描述
  • 产品功能
  • 产品参数

描述

This achromat objective is ideal for general applications. This is a long working distance (LWD) objective that is optimized for the imaging of slides, cell culture dishes and flasks, and microtiter plates. This is also a phase-contrast objective, making it useful for hard-to-see, translucent speciments. All EVOS® objectives offer outstanding optical performance from visible light to near infrared light. The extensive choice of objectives satisfies needs across the spectrum of magnifications and optical specifications.

Additional characteristics of this EVOS® objective:

• Magnification: 20X
• Numerical Aperture: 0.40
• Working Distance: 6.8 mm

Image Quality
Microscope objectives may be the most important components of an optical microscope because they are responsible for primary image formation. Image quality is crucial to experimental success and a requirement for publication; EVOS® objectives afford that quality across the visible spectrum to near infrared light. This performance results from years of lens manufacture perfection. EVOS® objectives have the same or better numerical apertures as any other manufacturer's in the same class, and the broad selection means you have choices for your imaging requirements.

Objective Classes

Achromat objectives are perfect for general applications, with standard correction of color and focus.

Fluorite objectives deliver excellent resolution and are made with higher numerical apertures than achromat objectives, resulting in brighter fluorescence signal and higher contrast imaging. The higher optical quality greatly reduces optical aberrations, and corrections for color and focus are at higher levels than achromat objectives. Fluorite objectives are ideally suited for fluorescence and demanding transmitted light applications, where the higher contrast make them ideally suited for color imaging.

Apochromat objectives are manufactured to the highest levels of resolution, fluorescence brightness, and contrast; chromatic aberrations are almost eliminated. They are recommended for the most demanding applications, particularly at magnifications of 60x and above. Apochromatic objectives are the best choice for the capture of color images in white light.

Brightfield Contrast versus Phase Contrast Objectives
Brightfield is the most basic form of light microscopy and is accomplished by sample absorption of light. A higher density area in a sample will absorb more light, thus increasing contrast in those areas.

Phase contrast objectives are most useful for hard to see, translucent specimens. This method of contrast is accomplished by converting phase shifts, caused by light passing through a translucent specimen, into brightness changes (i.e., contrast).

Long Working Distance versus Coverslip-Corrected Objectives
Long working distance (LWD) objectives are optimized for use through vessels with a nominal wall thickness of 0.9-1.5 mm. This includes vessels commonly used in cell culture and cell-based assays, such as slides, cell culture dishes and flasks, microtiter well plates, etc. Coverslip-corrected objectives are optimized for use through #1.5 coverslips (thickness approximately 0.17 mm). These objectives have a higher magnification/NA ratio and provide higher resolution compared to LWD objectives.

For additional choices, visit the EVOS® Objectives selection guide
Explore the entire EVOS® line of imaging systems and accessories


规格

For Use With (Equipment):EVOS® XL Core Imaging System, EVOS® XL Imaging System
Lens Type:Plan Achromat
Magnification:20X
Product Line:EVOS®
Product Size:1 each
Quantity:1 each
Type:Objective Lens


规格

For Use With (Equipment):EVOS® XL Core Imaging System, EVOS® XL Imaging System
Lens Type:Plan Achromat
Magnification:20X
Product Line:EVOS®
Product Size:1 each
Quantity:1 each
Type:Objective Lens


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