Name: a strain gauge monitor (sgm) for continuous valve gape measurements in bivalve molluscs in response to laboratory induced diel-cycling hypoxia and ph
Uploaded: 2018-08-01T14:00:00.000+00:00
Duration: 7 min 59 s
Description: Watch this Scientific Journal Video about A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH at JoVE.co

我们感谢梅林达 Forseth 拍摄牡蛎的照片和测量他们在 ImageJ 的打呵欠宽度。我们感谢丹尼斯 Breitburg 水族馆与昼夜循环缺氧和周期性 pH 条件的接触。我们感谢史密森环境研究中心, Edgewater, 马里兰, 为实验空间。低氧实验由国家海洋和大气管理中心资助, 为海岸海洋研究资助号。NA10NOS4780138 和史密森亨特登基金对丹尼斯 Breitburg。在缺氧实验过程中, 阀门的打呵欠测量是由华盛顿学院为埃尔卡 t. 波特提供的一项师资增强补助金资助的。

1. 气门打呵欠装置的惠斯通电桥的施工
注: 应变表名义上为1000ω, 所以要完全平衡和空桥, 所有组件应为1000Ω。
<ol><li>如图 1所示, 焊锡两 1 kΩ精密电阻, 然后再到976ω电阻和100Ω10转电位器。典型的应变计范围是几个ω在1000ω有名无实, 因此只有这种抵抗需要被匹配。使用固定的976Ω电阻和可调电阻 (10 转电位器) 为此目的。</li>
	<li>将可变臂的一侧和 1 kΩ电阻的一侧连接到与双壳式应变计的接头上, 如图 1所示。</li>
	<li>将桥的顶部和底部连接到电源, 以便为桥提供偏置电流, 如图 1所示。</li>
	<li>将桥中点连接到前置放大器和数据记录器, 如图 1所示。这将记录双壳的反应, 因为它的打呵欠运动调节应变计的电阻。</li>
	<li>在双壳类应变计附加后, 通过调整10匝电位器, 直到数据记录仪输入的电压为零, 才能使桥变空。使用单独的 BNC 连接器和手持电压表为此目的。 注意: 零值输出意味着在数据记录器上可以使用非常高的增益, 而不会使输入饱和, 从而测量出非常精确的电压 (打哈欠响应)。 注: 我们的多通道设置使用分立元件手工焊接在一个标准的电子产品 "性能板"。这可以很容易地正式在一个非常便宜的电路板, 很少额外的努力。</li>
</ol>2. 昼夜循环缺氧和周期性 pH 值的一般设置
<ol><li>保持牡蛎与已知的低疾病患病率61在 75 L 水族馆在 14 h 光以下:10 h 黑暗周期, 7 天每星期48, 并且暴露他们到周期性变化在 [做] 模仿昼夜循环缺氧如发现在自然7, 8. 在14小时的光线下, 在罗德岛2米深的一个晴朗的日子里模拟光的水平, 马里兰61。</li>
	<li>在实验室中建立昼夜循环缺氧和周期性 pH 值, 并对其进行长期实验. (2015)49. 在每个水族馆操作 [做] 和 pH 值, 并在任何时候保持在预先确定的水平。为避免因食物限制而关闭阀门, 请将浮游植物62添加到水族馆。通过调节每个水族馆中的 [做] 来补偿任何潜在的藻类分解吸收。</li>
</ol>3. 双壳类驯化
<ol><li>在进行打呵欠实验之前, 将牡蛎适应昼夜循环缺氧大约一周。</li>
</ol>4. 建立昼夜循环缺氧高原阶段
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57404/57404fig2.jpg"> 图 2.[ 做 ] 每天都在实验中纵以产生昼夜循环缺氧 .在这里, 2 个连续的昼夜周期显示, 其中的打呵欠测量被采取.每个昼夜周期包含四个 [做] 阶段: a = 过饱和 (SS), b = normoxia 在过饱和以后, c = 低高原 (LP), d = normoxia 在低高原以后。对于低高原, 严重缺氧 ([做] = 0.6 毫克/升) 与控制或循环 pH 值表示有一个粗黑线, 轻度缺氧 (做) = 1.7 毫克/升) 与循环 pH 值与一条细灰色线和 normoxia ([做] = 7.3 毫克/升) 与虚线。灰色方框表示两天内有10小时的暗间隔。<a href="/files/ftp_upload/57404/57404fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<ol><li>为了创造昼夜循环缺氧, 在四个连续的阶段 (做) 保持恒定的时间内调整 [做]: 2 h 过饱和, 6 h normoxia 在过饱和, 4 h 低高原 (normoxia 在控制情况下) 和 2 h normoxia 在低以后高原阶段。</li>
	<li>在低高原阶段, 保持常氧治疗常数在 [做] 7.3 毫克/升, 轻度低氧治疗常数在 a [做] 1.7 毫克/升和严重缺氧治疗恒定在 [做] 0.6 毫克/升。</li>
	<li>对于严重缺氧, 在低海拔地区运行两个 ph 处理,即严重缺氧, 控制 ph 值保持在7.8 和严重缺氧的周期性 ph 值, 其中 ph 值从7.8 到7.0 在低高原期间。用周期性 ph 值进行轻度低氧治疗, ph 值从7.8 循环到7.0。如果需要, 用恒定的 pH 值进行第二次轻度缺氧治疗。</li>
</ol>5. 高原阶段之间的 [做] 向上/向下倾斜
<ol><li>计划在四恒定的阶段之间的斜坡向上或向下采取2小时, 除了从 normoxia 后的斜坡, 过饱和后到低高原阶段, 这需要3小时. 通常, 缺氧已被发现发生深夜或凌晨小时在夏天7,8;因此, 保持在黑暗中的低高原阶段, 以及从它向上或上升的时期, 总长度的黑暗10小时。</li>
	<li>重复昼夜循环缺氧61周4-5 天。</li>
	<li>在过饱和之前, 在向上的阶段添加带有传感器的牡蛎, 并在关闭它们后将它们移除, 两天后, 它们就会经历两个完整的昼夜周期 (图 2), 并附有传感器。</li>
</ol>6. 制作传感器电缆
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57404/57404fig3.jpg"> 图 3.双壳通用应变计阀传感器.( a)应变计传感器, (b)附着在牡蛎上的应变计, 显示两个阀门之间的应变计回路(c)安装在牡蛎上的应变计传感器。<a href="/files/ftp_upload/57404/57404fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<ol><li>通过将两个 32 AWG (7/40) 导线 (见材料表) 拧成所需的颜色 (图 3a), 构造气门打呵欠传感器电缆。将所需的打哈欠传感器电缆的长度缩短两倍,即两次从水族馆到通用的长度, 再加一点额外的。</li>
	<li>有两个人站在对面, 每一个都持有电缆的一端。</li>
	<li>将一把剪刀的手柄滑过电缆, 以便在电缆中间有一把剪刀由电缆持有。保持电缆在紧张的时刻 (它不能松懈)。</li>
	<li>让两个人拧电缆相反的方向保持电缆在紧张。当电缆开始扭曲时, 中间的剪刀 (提供重量) 会下沉, 电缆两端都可以相互缠绕。</li>
	<li>把电缆的两端放在一起, 把它们高高举起, 不要让剪刀与电缆接触地面或松弛。电缆拧完后, 切断另一端的电缆, 因此有4条电缆引线, 每一端有两个。</li>
	<li>或者, 为了加快这一步, 让一个人拿着一根夹在一端的导线的钻头, 保持电线上的张力, 并通过转动钻头拧紧电线。</li>
	<li>从双绞线的每一端的导线上剥去2厘米的绝缘。</li>
</ol>7. 焊接传感器
<ol><li>锡暴露的电缆。</li>
	<li>在传感器电缆一端的两个引线上的焊料 Dsub 连接器男性卷曲针脚, pretinning 针脚并插入电缆。</li>
	<li>然后, 通过将收缩油管放在每个引线上来隔离引线。选择比电缆引线直径大得多的收缩油管。用热枪收缩热收缩。收缩油管现在应该紧紧包裹在导线周围。 注 : 在实验期间 , 这两条引线在惠斯通电桥上。</li>
	<li>将传感器电缆的剩余端焊接到1000Ω应变计的两个触点上, 其余两个引线上的尺寸为 13.5 mm * 5.5 毫米网格 (图 3a)。</li>
	<li>向传感器电缆添加传感器标识标记 (图 3a)。</li>
</ol>8. 密封传感器
注: 应变计在海水中迅速腐蚀, 因此必须密封良好。密封的质量影响传感器的使用寿命。
<ol><li>将应变计密封在 PCT-2A 胶带上, 将15毫米胶带留在传感器两侧的长端和2毫米 (图 3a)。将 PCT-2A 胶带连接到应变计的下侧后, 在传感器引线上添加快速凝胶, 并将电缆的连接端打开。</li>
	<li>将与底部一块相同尺寸的第二片 PCT-2A 胶带连接到传感器的顶部, 并将两片胶带与中间的应变计连接在一起。不要让快速凝胶流动的任何地方以外的线索和传感器电缆。</li>
	<li>要改进密封, 请在传感器周围的两片胶带的边缘添加 PCT-2A 胶带的薄条。对传感器的三个暴露边缘执行此项。</li>
	<li>重复步骤6.1 到8.4 十一次, 用传感器构造12个传感器电缆, 一个用于惠斯通电桥上的每个通道。 注:应变计的成功密封是影响海水中双壳式打呵欠传感器生存的关键变量, 是传感器输出中偶尔出现的 "跳跃"。早期的试验没有上述密封技术, 导致早期传感器腐蚀和随后的故障, 或快速漂移超出测量范围。未来的改进应该包括改进密封的技术。</li>
</ol>9. 将气门打呵欠传感器附着在双壳体上 (图 3b, c)
<ol><li>在低高原阶段之前, 从昼夜循环缺氧水族馆中去除牡蛎。</li>
	<li>用指甲油在每个锦葵的清洁干燥壳上写一个识别号。</li>
	<li>将密封应变片连接到活C 锦葵的清洁干燥阀 (图 3b, C), 使用水族馆密封胶使传感器在运行后被拆卸。在壳体 (图 3c) 上, 将在牡蛎右侧 (平) 阀上的引线连接在上面, 并将应变计 (图 3b) 的环放在阀门上, 以免阻碍阀门的开启 (图 3b)。将传感器剩余的自由端粘附在左阀上。 注: 观察证实, 牡蛎通常在传感器到位时打开阀门。</li>
	<li>这并不重要的是, 传感器周围的粘接方式, 但是, 如果一些引线粘在左阀和一些正确的阀门上, 信号的方向将被改变。在奔跑结束时, 信号的方向从双壳的强制关闭变得清楚。对于所有的双壳贝类, 将应变计部分与传感器粘合在一起会导致相同的阀侧, 从而使打呵欠响应信号的变化方向一致。</li>
	<li>在密封传感器并将其附加到牡蛎的过程中的每个步骤中, 定期检查传感器电阻, 以确保它停留在读数电子的范围内, 并检查在处理过程中是否有潜在的传感器损坏。</li>
	<li>连接12个牡蛎到12个传感器, 以填补所有12通道的通用。</li>
	<li>将牡蛎添加到不同的水族馆, 就在过饱和高原阶段之前。</li>
</ol>10. 阀门数据存储器和复用器的设置
<ol><li>将传感器连接到双壳结构上, 然后将电缆与通用 (图 1) 中的每个传感器 (总共12个桥) 相连, 并连接到数据存储器。</li>
	<li>设置数据记录器采样周期每2.5 秒读一次, 然后平均十五年代。 注意: 此处使用的数据存储器上的62k 示例内存允许12小时无人值守操作。如果需要, 可以选择更大的 dataloggers 和更快的取样速率。</li>
	<li>将传感器连接到双壳, 并使用在通用上的电位器表盘, 将每个传感器的打哈欠信号零。</li>
	<li>如有必要, 如在较高的矿化度中, 在传感器响应中周期性地校正每个传感器, 以便传感器保持在惠斯通电桥的通用 (-25 到 +25 mV) 输出的范围内。在惠斯通电桥与数据存储器输入之间, 选用了通用的测距范围。</li>
</ol>11. 双壳贝类在昼夜循环缺氧中的应用
<ol><li>在水族馆密封剂固化后 (约30分钟), 将双壳贝类返回到含水的含氧保温桶中, 至少5小时, 以使水族馆的密封胶在试验中沉没前浸出。</li>
	<li>放置牡蛎在水族馆期间在上升阶段到过饱和 (SS) 高原 (图 2)。</li>
</ol>12. 用打呵欠传感器回收双壳贝类
<ol><li>当从水族馆恢复牡蛎与昼夜自行车 hypoxiaat 两天期间结束时, 使用您的手指触发牡蛎关闭, 并产生一个关闭信号的传感器电压。这样, 可以记录闭合信号的方向和大小。</li>
	<li>如果传感器值大于闭合值的½, 则将牡蛎定义为打开。如果传感器值小于½的结束值, 则将牡蛎定义为已关闭。 注: 东方牡蛎在中间范围内不太开放。</li>
</ol>13. 原始阀门的目瞪口呆数据的线性化
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57404/57404fig4.jpg"> 图 4。牡蛎原始的打呵欠数据的线性化。(a) 14 h 光:10 h 暗相, (b)在两天期间内有严重缺氧 ([做] 0.6 毫克/升), (c)一只牡蛎的原始打呵欠数据时间序列。数据的线性漂移是由传感器的腐蚀引起的, 在后处理中必须去除, (d)后处理后的打呵欠数据时间序列(e)近似实时。为了确定闭合穗的大小和方向, 牡蛎在奔跑结束时被触发关闭。不同传感器之间的震级不同。<a href="/files/ftp_upload/57404/57404fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<ol><li>视觉识别牡蛎的打呵欠活动, 并使用封闭 (或开放, 无论哪个较长) 的双壳贝类的阶段, 以确定仪器漂移。如果电子表格软件中的语句使用零 (例如, = (单元格 > 5、1 (true)、0 (false)) 的一个和打开值来标记闭合的值, 则可用。</li>
	<li>移除最短的相位, 并对剩余的原始数据运行线性回归。使用回归方程进行线性化实验数据 (图 4)。必须对每个传感器分别进行线性化。 注:传感器漂移是线性过短 (分钟) 和长 (天) 时间刻度和漂移量的变化, 从传感器到传感器。漂移通常可以忽略在短时间跨度, 如一个小时, 其中只有偶尔线性漂移已经注意到。传感器漂移要求对每个传感器分别进行气门打呵欠和传感器的刻度校准, 并且在数据后处理时必须对每个传感器进行线性化。</li>
</ol>14. 传感器校准: 实际的打呵欠宽度与传感器 mV
在一个侧面实验中, 传感器电压可以校准为实际的打呵欠宽度的牡蛎。
<ol><li>在水族馆里, 用一个打呵欠的传感器设置一个牡蛎。开始打呵欠录音。通过触摸来触发牡蛎关闭。不久后, 牡蛎将再次开放。</li>
	<li>当牡蛎打开时, 拍照时, 每次拍照时都要记下打呵欠装置的传感器电压。跟踪哪张照片与哪个哈欠仪器在读。在照片中放置参照刻度, 在同一水平的阀门上。</li>
	<li>使用 ImageJ 等开源图像处理程序, 分析每张照片 (mm) 中牡蛎打开的距离。</li>
	<li>比较实际的打呵欠宽度和传感器电压, 并运行回归分析。这给出了实际开启状态的校准, 进一步的传感器测量可以与双壳的实际打呵欠宽度有关。 注:虽然这表明, 打呵欠宽度与传感器电压呈线性关系, 但在实际中, 这个过程花费太长时间, 没有进行低氧打呵欠实验。对于缺氧的打呵欠实验, 重要的是要清除牡蛎的必要时间从他们的水族馆, 以装备他们的传感器, 并返回到水族馆。在某些实验中, 对角宽度的测量可能是很重要的, 应遵循上述标定技术。</li>
</ol>

我们没有什么可透露的。

典型的研究集中在连续, 延长的时间期间低氧气条件和反应, 经常被测量作为生存, 动物。然而, 目前我们对动物对昼夜循环缺氧的行为反应的理解最小为63。因此, 更多的研究应该集中在反应昼夜循环缺氧的有机体的行为, 这在夏天经常发生在许多河口7,8。
在此, 我们提出了一种连续测量双壳贝类对昼夜循环缺氧和?...

缺氧,即溶解氧浓度足够低, 对生物和生态过程产生负面影响, 但通常功能上定义为 [做] < 2 毫克/升1, 缺氧 (功能上定义为 0.0-0.2 毫克/升)在世界沿海水域、河口和深海2、3发生频繁和严重的情况, 并经常因增加富营养化4、5而加剧。随着缺氧和缺氧程度的增加, 动物对生境的影响和生境质量的丧失。预计气候变化会恶化缺氧和缺氧6。
在许多分层, 营养丰富的河口, 如美国切萨皮克湾, 季节性持续缺氧可以战胜和可能发生年复一年2年。此外, 昼夜的低氧循环经常出现在诸如切萨皮克湾和其他地点的河口, 并发生在夜间或清晨7,8的凌晨时间。
大多数研究的重点是持续暴露的有机体对低 [做] 和对他们的耐受性缺氧和缺氧9,10,11,12,13,14.此外, 研究还观察了物种分布、丰度和物种组成的大规模转移, 以响应延长的低 [做]4,15。通常对低 [做] 非常敏感的物种, 死于大众,16将剩下的物种转移到一个年轻的, 规模较小, 短命的动物群中, 例如, 在路易斯安那州-德克萨斯大陆架生态系统4上发现。
行为变化通常在社区崩溃之前 17和研究报告了有机体的行为反应到延长的低 [做]4,16,17,18,19 ,20,21,22,23,24,25。然而, 这些研究并不侧重于生物体对缺氧昼夜循环暴露的反应以及河口 [做] 可用性的波动性。
昼夜在浅水河口的循环缺氧已得到越来越多的认识, 因为研究监测 [做] 更频繁的过程中的天数与 sondes 在河口16,26。水可以保持缺氧几个小时, 在夜间或清晨小时, 当没有氧气的光合作用在夜间, 但高耗氧呼吸7,16。研究还发现, 潮汐影响低条件下的昼夜循环, 当低潮与夜间27的结束相吻合时, 观测到最极端的极小值。只有在几个小时的缺氧后才会回到 normoxia7,16,28在每天的周期。
为了确定锦葵对昼夜循环缺氧和 ph 值的行为反应, 我们监测了暴露于实验室诱导的昼夜循环和周期性 pH 值的牡蛎瓣膜的开启和关闭。双壳贝类的打呵欠反应已被用来检测恶劣的环境条件。在反应污染物29、30、31、有毒藻类32、33、34、热污染35、36的情况下, 双壳贝类阀门关闭,37、食物数量减少38,39,40, 哺养的政权39,41, 再现37,42, 光周期43,44、ph 值45、46、ph 值和溶解氧的总和47均已测定。例如, 打呵欠技术包括直接观测48,49,13, 连续测量使用簧片开关和磁铁 (Dreissena 显示器)50, 或光纤传感器51需要清水。此外, 磁铁和磁场强度霍尔传感器已用于研究贻贝角52,53,54,55和高频电磁感应系统这可以测量两个电线圈之间的不同距离, 被粘在阀门已使用56,57,58,59。电磁感应系统需要高压源, 必须将电源输送到外壳52的两侧。该系统还可作为 "MOSSELMONITOR" (http://mosselmonitor.nl/) 提供商业用途。
在紧张的研究预算, 我们建立了一个廉价的应变计监测 (通用), 以持续测量牡蛎目瞪口呆的实验室诱导昼夜循环的 [做] 和 pH 值, 在低能见度条件下。我们的系统也比竞争系统简单得多, 允许许多动物在实验中进行检测。我们想确定 C 的行为反应. 锦葵昼夜循环严重 ([做] = 0.6 毫克/升) 缺氧与控制 ph 值 (ph = 7.8) 和循环 ph 值 (ph = 7.8-7.0), 并对轻度 ([做] = 1.7 毫克/升) 缺氧的目瞪口呆反应。此外, 我们想确定牡蛎是否能够迅速响应在昼夜周期的变化, 以及他们如何反应时, normoxia 返回后, 缺氧事件。也许牡蛎是最佳地适应迅速地波动的环境在许多河口16,27在他们居住的地方被发现。虽然有更多复杂的阀门目瞪口呆显示器可用, 但通用提供了一种廉价的技术, 允许连续测量阀门在水中的目瞪口呆, 即使在低能见度条件。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57404/57404fig1.jpg"> 图 1。用于气门打呵欠装置的惠斯通电桥.<a href="/files/ftp_upload/57404/57404fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
用于监测双壳类打呵欠的应变计传感器是聚酰亚胺支持下的一种曲折模式的电阻膜。少量的应变调节传感器的电阻。当呵欠导致传感器的电阻发生变化时, 双壳贝类会弯曲应变片。我们使用了一个零位, 平衡, 惠斯通电桥每双壳的通道, 如图 1所示, 以测量传感器电阻的变化。惠斯通电桥由电位器清零, 允许数据存储器使用相当高的增益。惠斯通电桥是一种标准方法, 用于准确测量未知电阻, 使用与已知电阻标准和电压表的比值。这个非常老技术的历史在 Ekelof (2001)60被谈论。我们集成了12通道, 每一个都有自己的惠斯通电桥和零电位计, 进入应变仪显示器 (通用) 单元。

<table><tbody><tr><td>Campbell CR 10x data logger</td><td>Campbell Scientific, Logan, Utah</td><td></td><td>Or other data logger. At Campbell the CR 10X has been replaced with the CR 1000</td></tr><tr><td>Campbell CR 10x multiplexer</td><td>Campbell Scientific, Logan, Utah</td><td></td><td>Data logger needs to have space for 12 channels</td></tr><tr><td>Dsub connector male crimp pins</td><td>TE Connectivity</td><td>205089-1</td><td>pins for gape sensor leads</td></tr><tr><td>PCA tape</td><td>Micro Measurements Corp, NC</td><td></td><td>To seal the strain gauge</td></tr><tr><td>Duro Quick Gel</td><td>Ace Hardware</td><td></td><td>Superglue</td></tr><tr><td>SG13/1000-LY43 or LY41</td><td>Omega Engineering Inc., Stanford, CT</td><td></td><td>Strain gauges</td></tr><tr><td>32 AWG (7/40) teflon Alpha wires</td><td>AlphaWire, Elizabeth, NJ</td><td>2840/7</td><td>Sensor cables, different colors are available</td></tr><tr><td>1/16&quot; heat shrink tubing</td><td>Qualtek</td><td>B01A3QKKO6</td><td>To seal the leads of the sensor cable</td></tr><tr><td>Weller WES51 Analog Soldering Station</td><td>Amazon</td><td></td><td>Lots of soldering, need a good soldering iron. https://www.amazon.com/Weller-WES51-Analog-Soldering-Station/dp/B000BRC2XU/ref=sr_1_23?s=hi&amp;amp;ie=UTF8&amp;amp;qid=1505654295&lt;br/&gt; &amp;amp;sr=1-23&amp;amp;keywords=soldering+iron</td></tr><tr><td>Rosin Soldering Flux Paste</td><td>Amazon</td><td></td><td>Needed for soldering</td></tr><tr><td>60-40 Tin Lead Rosin Core Solder Wire</td><td>Amazon</td><td></td><td>Needed for soldering</td></tr><tr><td>Aquarium sealant</td><td>Home Depot</td><td></td><td>Attach sensors to bivalve</td></tr><tr><td>PC Laptop</td><td></td><td></td><td>Any old PC to run Campbell gape program</td></tr><tr><td>heat gun</td><td>Amazon</td><td></td><td>shrink shrink tubing</td></tr><tr><td>Drill</td><td>Hardware store, Amazon</td><td></td><td>for twisting wires to make sensor cables</td></tr><tr><td>AC to DC power module</td><td>Acopian</td><td>DB15-30</td><td>Wheatstone bridge power supply</td></tr><tr><td>Poteniometer</td><td>Clarostat</td><td>733A</td><td>Wheatsone bridge nulling</td></tr><tr><td>isolating BNC connector</td><td>Sterren Electronics</td><td>&quot;200-148</td><td>Wheatstone bridge output for multimeter</td></tr><tr><td>Fused AC receptical panel module</td><td>Adam technologies</td><td>IEC-GS-1-200</td><td>Wheatstone bridge power supply connector</td></tr><tr><td>976 ohm 1% resistor</td><td>Vishay Dale</td><td>CMF50976R00FHEB</td><td>Wheatstone bridge resistor</td></tr><tr><td>1 kohm 1% resistor</td><td>Vishay Dale</td><td>CMF501K0000FHEB</td><td>Wheatstone bridge resistor</td></tr><tr><td>Potentiometer scale dial</td><td>Kilo International</td><td>462</td><td>10 turn dial for nulling potentiometer</td></tr><tr><td>DB25 male panel connector</td><td>TE connectivity</td><td>1757819-8</td><td>Data logger connector on Wheatstone bridge</td></tr><tr><td>DB25 female panel connector</td><td>TE connectivity</td><td>1757819-8</td><td>Sensor connector to Wheatstone bridge</td></tr><tr><td>perforated circuit board</td><td>Vector electronics</td><td>64P44WE</td><td>circuit board for mounting of bridge components</td></tr><tr><td>enclosure</td><td>Hammond Manufacturing</td><td>1444-29</td><td>Enclosure for sensor readout electronics</td></tr></tbody></table>

a strain gauge monitor (sgm) for continuous valve gape measurements in bivalve molluscs in response to laboratory induced diel-cycling hypoxia and ph

研制了一种成本低廉、基于实验室的应变计阀, 用于监测双壳软体动物在昼夜循环缺氧时的气门打呵欠行为。一座惠斯通电桥连接到与牡蛎壳相连的应变计 (锦葵)。记录的信号允许的开放和关闭的双壳贝类将连续记录在两天期间的实验性昼夜循环缺氧和昼夜循环变化的 pH 值。在这里, 我们描述了一个用于开发廉价的应变计监视器的协议, 并在一个示例实验室实验中描述了如何使用它来测量东部牡蛎 (锦葵) 的气门打呵欠行为, 以应对昼夜循环缺氧和pH 值的周期性变化。对周期性严重缺氧 (0.6 毫克/升) 溶解氧条件下的牡蛎进行了气门打呵欠测量, pH 值、周期性轻度缺氧 (1.7 毫克/升) 条件和常氧 (7.3 毫克/升) 条件下无周期性变化。我们证明, 当牡蛎遇到重复的昼夜周期, 他们迅速关闭他们的壳, 以应对严重缺氧和关闭的时间滞后到轻度缺氧。当 normoxia 恢复时, 它们又迅速地打开了。牡蛎没有反应周期性的 pH 条件叠加在昼夜循环严重缺氧。在氧条件降低时, 三个以上的牡蛎同时关闭。我们证明, 牡蛎对昼夜循环缺氧的反应, 这必须考虑当评估的行为, 双壳贝类溶解氧。该阀可用于评估双壳软体动物对溶解氧或污染物的变化的反应。密封技术, 以更好地密封的阀门打哈欠应变计从海水需要进一步改进, 以提高传感器的寿命。

暴露在不间断的常氧河口水中的牡蛎 (在日常周期的低高原阶段没有缺氧) 大部分时间都是开放的, 只是很少短暂关闭 (图 5)。当他们关闭从牡蛎到牡蛎不同。Loosanoff 和 Nomejko 194644和希金斯 198039也发现了这种模式。牡蛎也没有反应在黑暗和轻的阶段的区别。
<img alt="Figure...

Watch this Scientific Journal Video about A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH at JoVE.co

A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

基于实验室诱导的昼夜循环缺氧和 pH 值的双壳软体动物连续气门目瞪口呆测量用应变计监测仪 (通用)

了解双壳悬浮馈线对环境变量 (如溶解氧) 的行为反应, 可以解释一些生态系统过程。我们开发了一个价格低廉, 以实验室为基础的应变计监测仪 (锦葵) 来测量牡蛎、牡蛎、昼夜循环缺氧和周期性 pH 值的气门打呵欠反应。

An inexpensive, laboratory-based, strain gauge valve gape monitor (SGM) was developed to monitor the valve gape behavior of bivalve molluscs in response ...

a-strain-gauge-monitor-sgm-for-continuous-valve-gape-measurements

Universidad San Sebastian

Research

JoVE Journal

Environment

A Strain Gauge Monitor (SGM) for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

8.9K 次观看.  University of Baltimore. 了解双壳悬浮馈线对环境变量 (如溶解氧) 的行为反应, 可以解释一些生态系统过程。我们开发了一个价格低廉, 以实验室为基础的应变计监测仪 (锦葵) 来测量牡蛎、牡蛎、昼夜循环缺氧和周期性 pH 值的气门打呵欠反应。

视频: A Strain Gauge Monitor SGM for Continuous Valve Gape Measurements in Bivalve Molluscs in Response to Laboratory Induced Diel-cycling Hypoxia and pH

A Simple Approach to Manipulate Dissolved Oxygen for Animal Behavior Observations

The ability to manipulate dissolved oxygen (DO) in a laboratory setting has significant application to investigate a number of ecological and organismal behavior questions. The protocol described here provides a simple, reproducible, and controlled method to manipulate DO to study behavioral response in aquatic organisms resulting from hypoxic and anoxic conditions. While performing degasification of water with nitrogen is commonly used in laboratory settings, no explicit method for ecological (aquatic) application exists in the literature, and this protocol is the first to describe a protocol to degasify water to observe organismal response. This technique and protocol were developed for direct application for aquatic macroinvertebrates; however, small fish, amphibians, and other aquatic vertebrates could be easily substituted. It allows for easy manipulation of DO levels ranging from 2 mg/L to 11 mg/L with stability for up to a 5 min animal-observation period. Beyond a 5 min observation period water temperatures began to rise, and at 10 min DO levels became too unstable to maintain. The protocol is scalable to the study organism, reproducible, and reliable, allowing for rapid implementation into introductory teaching labs and high-level research applications. The expected results of this technique should relate dissolved oxygen changes to behavioral responses of organisms.

This article describes a simple and reproducible protocol to manipulate dissolved oxygen conditions in a laboratory setting for animal behavior studies. This protocol may be used in both teaching and research laboratory settings to evaluate organismal response of macroinvertebrates, fishes, or amphibians to changes in dissolved oxygen concentration.

一个简单的方法来操作的动物行为观察溶解氧

The ability to manipulate dissolved oxygen (DO) in a laboratory setting has significant application to investigate a number of ecological and organismal ...

科研

环境科学

Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage&#160;and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design.

There has been renewed interest in developing polymer valves. Here, the objectives are to demonstrate the feasibility of modifying a commercial pulse duplicator to accommodate tri-leaflet geometries and to define a protocol to present polymer valve hydrodynamic data in comparison to native and prosthetic valve data collected under near-identical conditions.

协议相对液力评估的三单张聚合物阀

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of ...

生物工程

Quantitative and Temporal Control of Oxygen Microenvironment at the Single Islet Level

Simultaneous oxygenation and monitoring of glucose stimulus-secretion coupling factors in a single technique is critical for modeling pathophysiological states of islet hypoxia, especially in transplant environments. Standard hypoxic chamber techniques cannot modulate both stimulations at the same time nor provide real-time monitoring of glucose stimulus-secretion coupling factors. To address these difficulties, we applied a multilayered microfluidic technique to integrate both aqueous and gas phase modulations via a diffusion membrane. This creates a stimulation sandwich around the microscaled islets within the transparent polydimethylsiloxane (PDMS) device, enabling monitoring of the aforementioned coupling factors via fluorescence microscopy. Additionally, the gas input is controlled by a pair of microdispensers, providing quantitative, sub-minute modulations of oxygen between 0-21%. This intermittent hypoxia is applied to investigate a new phenomenon of islet preconditioning. Moreover, armed with multimodal microscopy, we were able to look at detailed calcium and KATP channel dynamics during these hypoxic events. We envision microfluidic hypoxia, especially this simultaneous dual phase technique, as a valuable tool in studying islets as well as many ex vivo tissues.

Microfluidic oxygen control confers more than just convenience and speed over hypoxic chambers for biological experiments. Especially when implemented via diffusion through a membrane, microfluidic oxygen can provide simultaneous liquid and gas phase modulations at the microscale-level. This technique enables dynamic multi-parametric experiments critical for studying islet pathophysiology.

氧微环境中的单个胰岛水平的定量和临时控制

Simultaneous oxygenation and monitoring of glucose stimulus-secretion coupling factors in a single technique is critical for modeling pathophysiological ...

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

A flow-through device for using the biodeposition method to quantify filtration and feeding behavior of bivalve mollusks was modified for shipboard use. A two-dimensional gimbal table built around the device isolates the apparatus from boat motion, thereby allowing the accurate quantification of bivalve filtration variables at offshore shellfish aquaculture sites.

海上双壳贝类悬浮饲料定量装置的设计与应用

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves ...

Microalgae Cultivation and Biomass Quantification in a Bench-Scale Photobioreactor with Corrosive Flue Gases

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for microalgal cultivation with temperature, pH, and gas composition and flow rate control. At bench-scale, photobioreactors are advantageous to researchers studying microalgal properties, productivity, and growth optimization. At industrial scales, photobioreactors can maintain product purity and improve production efficiency. The video describes the preparation and use of a bench-scale photobioreactor for microalgal cultivation, including the safe use of corrosive gas inputs, and details relevant biomass measurements and biomass productivity calculations. Specifically, the video illustrates microalgal culture storage and preparation for inoculation, photobioreactor assembly and sterilization, biomass concentration measurements, and a logistic model for microalgal biomass productivity with rate calculations including maximum and overall biomass productivities. Additionally, since there is growing interest in experiments to cultivate microalgae using simulated or real waste gas emissions, the video will cover the photobioreactor equipment adaptations necessary to work with corrosive gases and discuss safe sampling in such scenarios.

Bench-scale, axenic cultivation facilitates microalgal characterization and productivity optimization before subsequent process scale-up. Photobioreactors provide the necessary control for reliable and reproducible microalgal experiments and can be adapted to safely cultivate microalgae with the corrosive gases (CO2, SO2, NO2) from municipal or industrial combustion emissions.

具有腐蚀性烟气的台式光生物反应器中的微藻培养和生物量定量

Photobioreactors are illuminated cultivation systems for experiments on phototrophic microorganisms. These systems provide a sterile environment for ...

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an area of productive research with over 1,400 published animal studies in just the last 5 years. Numerous techniques have been developed for quantifying smooth muscle activity of the stomach, small intestine, and colon. In vitro and ex vivo techniques offer powerful tools for mechanistic studies of GI function, but outside the context of the integrated systems inherent to an intact organism. Typically, measuring in vivo smooth muscle contractions of the stomach has involved an anesthetized preparation coupled with the introduction of a surgically placed pressure sensor, a static pressure load such as a mildly inflated balloon or by distending the stomach with fluid under barostatically-controlled feedback. Yet many of these approaches present unique disadvantages regarding both the interpretation of results as well as applicability for in vivo use in conscious experimental animal models. The use of dual element strain gages that have been affixed to the serosal surface of the GI tract has offered numerous experimental advantages, which may continue to outweigh the disadvantages. Since these gages are not commercially available, this video presentation provides a detailed, step-by-step guide to the fabrication of the current design of these gages. The strain gage described in this protocol is a design for recording gastric motility in rats. This design has been modified for recording smooth muscle activity along the entire GI tract and requires only subtle variation in the overall fabrication. Representative data from the entire GI tract are included as well as discussion of analysis methods, data interpretation and presentation.

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

The in vivo measurement of smooth muscle contractions along the gastrointestinal tract of laboratory animals remains a powerful, though underutilized, technique. Flexible, dual element strain gages are not commercially available and require fabrication. This protocol describes the construction of reliable, inexpensive strain gages for acute or chronic implantation in rodents.

的微型双元应变计测量加工和植入<em&gt;体内</em&gt;胃肠收缩鼠害。

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an ...

Impedance Pneumography for Minimally Invasive Measurement of Heart Rate in Late Stage Invertebrates

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by environmental temperature, this has the potential to alter thermal physiological performance in a variety of marine organisms. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography to understand how cardiac performance in late stage invertebrates changes under acute thermal stress. The protocol presents a minimally invasive technique that allows for real-time collection of heart rate during a temperature ramping experiment. Data are easily manipulated to generate an Arrhenius plot that is used to calculate Arrhenius break temperature (ABT), the temperature at which heart rate begins to decline with increasing temperatures. This technique can be used in a variety of late stage invertebrates (i.e., crabs, mussels, or shrimps). Although the protocol focuses solely on the impact of temperature on cardiac performance, it can be modified to understand the potential for additional stressors (e.g., hypoxia or hypercapnia) to interact with temperature to influence physiological performance. Thus, the method has potential for wide-ranging applications to further understand how marine invertebrates respond to acute changes in the environment.

Measuring heart rate during a thermal challenge provides insight into physiological responses of organisms as a consequence of acute environmental change. Using the American lobster (Homarus americanus) as a model organism, this protocol describes the use of impedance pneumography as a relatively noninvasive and nonlethal approach to measure heart rate in late stage invertebrates.

晚期无脊椎动物中心率微创测量的阻抗肺造影

Temperatures in oceans are increasing rapidly as a consequence of widespread changes in world climates. As organismal physiology is heavily influenced by ...

Supramaximal Intensity Hypoxic Exercise and Vascular Function Assessment in Mice

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by international guidelines for patients suffering from cardiovascular diseases, more specifically, lower extremity artery diseases, where the patients' walking capacity is considerably altered, affecting their quality of life. 
Traditionally, both low continuous exercise and interval training have been used. Recently, supramaximal training has also been shown to improve athletes' performances via vascular adaptations, amongst other mechanisms. The combination of this type of training with hypoxia could bring an additional and/or synergic effect, which could be of interest for certain pathologies. Here, we describe how to perform supramaximal intensity training sessions in hypoxia on healthy mice at 150% of their maximal speed, using a motorized treadmill and a hypoxic box. We also show how to dissect the mouse in order to retrieve organs of interest, particularly the pulmonary artery, the abdominal aorta, and the iliac artery. Finally, we show how to perform ex vivo vascular function assessment on the retrieved vessels, using isometric tension studies.

High-intensity training in hypoxia is a protocol that has been proven to induce vascular adaptations potentially beneficial in some patients and to improve athletes&#39; repeated sprint ability. Here, we test the feasibility of training mice using that protocol and identify those vascular adaptations using ex vivo vascular function assessment.

小鼠低血压运动的下位强度及血管功能评估

Exercise training is an important strategy for maintaining health and preventing many chronic diseases. It is the first line of treatment recommended by ...

行为学

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

The isolated microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of factors that control vessel diameter, and thus, perfusion resistance1-5. This is a classic experimental preparation that was, in large measure, initially described by Uchida et al.15 several decades ago. This initial description provided the basis for the techniques that was extensively modified and enhanced, primarily in the laboratory of Dr. Brian Duling at the University of Virginia6-8, and we present a current approach in the following pages. This preparation will specifically refer to the gracilis arteriole in a rat as the microvessel of choice, but the basic preparation can readily be applied to vessels isolated from nearly any other tissue or organ across species9-13. Mechanical (i.e., dimensional) changes in the isolated microvessels can easily be evaluated in response to a broad array of physiological (e.g., hypoxia, intravascular pressure, or shear) or pharmacological challenges, and can provide insight into mechanistic elements comprising integrated responses in an intact, although ex vivo, tissue. The significance of this method is that it allows for facile manipulation of the influences on the integrated regulation of microvessel diameter, while also allowing for the control of many of the contributions from other sources, including intravascular pressure (myogenic), autonomic innervation, hemodynamic (e.g., shear stress), endothelial dependent or independent stimuli, hormonal, and parenchymal influences, to provide a partial list. Under appropriate experimental conditions and with appropriate goals, this can serve as an advantage over in vivo or in situ tissue/organ preparations, which do not readily allow for the facile control of broader systemic variables. 
The major limitation of this preparation is essentially the consequence of its strengths. By definition, the behavior of these vessels is being studied under conditions where many of the most significant contributors to the regulation of vascular resistance have been removed, including neural, humoral, metabolic, etc. As such, the investigator is cautioned to avoid over-interpretation and extrapolation of the data that are collected utilizing this preparation. The other significant area of concern with regard to this preparation is that it can be very easy to damage cellular components such as the endothelial lining or the vascular smooth muscle, such that variable source of error can be introduced. It is strongly recommended that the individual investigator utilize appropriate measurements to ensure the quality of the preparation, both at the initiation of the experiment and periodically throughout the course of a protocol.

The ex vivo Isolated Skeletal Microvessel Preparation for Investigation of Vascular Reactivity

An ex vivo preparation is described for isolation of the largest gracilis muscle resistance arterioles for interrogation of both vascular responses to vasoactive stimuli and the assessment of basic structural properties via passive wall mechanics.

“体外骨骼肌微血管制备离体血管反应性的调查

The isolated  microvessel preparation is an ex vivo preparation that allows for examination of the different contributions of  factors that control vessel ...

生物学

Mechano-Node-Pore Sensing: A Rapid, Label-Free Platform for Multi-Parameter Single-Cell Viscoelastic Measurements

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer metastasis. Conventional methods for measuring these properties, such as atomic force microscopy (AFM) and micropipette aspiration (MA), capture rich information, reflecting a cell's full viscoelastic response; however, these methods are limited by very low throughput. High-throughput approaches, such as real-time deformability cytometry (RT-DC), can only measure limited mechanical information, as they are often restricted to single-parameter readouts that only reflect a cell's elastic properties. In contrast to these methods, mechano-node-pore sensing (mechano-NPS) is a flexible, label-free microfluidic platform that bridges the gap in achieving multi-parameter viscoelastic measurements of a cell with moderate throughput. A direct current (DC) measurement is used to monitor cells as they transit a microfluidic channel, tracking their size and velocity before, during, and after they are forced through a narrow constriction. This information (i.e., size and velocity) is used to quantify each cell's transverse deformation, resistance to deformation, and recovery from deformation. In general, this electronics-based microfluidic platform provides multiple viscoelastic cell properties, and thus a more complete picture of a cell's mechanical state. Because it requires minimal sample preparation, utilizes a straightforward electronic measurement (in contrast to a high-speed camera), and takes advantage of standard soft lithography fabrication, the implementation of this platform is simple, accessible, and adaptable to downstream analysis. This platform's flexibility, utility, and sensitivity have provided unique mechanical information on a diverse range of cells, with the potential for many more applications in basic science and clinical diagnostics.

Presented here is a method to mechanically phenotype single cells using an electronics-based microfluidic platform called mechano-node-pore sensing (mechano-NPS). This platform maintains moderate throughput of 1-10 cells/s while measuring both the elastic and viscous biophysical properties of cells.

机械节点孔传感:用于多参数单细胞粘弹性测量的快速、无标记平台

Cellular mechanical properties are involved in a wide variety of biological processes and diseases, ranging from stem cell differentiation to cancer ...