procedure for your own materials should be determined by trials; in practice almost no two materials grind alike. Avoid overfilling vials as this greatly reduces grinding efficiency.

If at first the sample doesn’t grind as intended, try these strategies:

•Reduce the overall weight of the sample. (Some fibers and thin films may grind best in the Small vial with a sample weight of 100-200 mg.)

•Reduce the size of the individual pieces to ¼ or 1/8 inch (6 to 3 mm).

•Increase the precooling time. (20 minutes of precooling is about the maximum necessary for most samples to reach LN temperatures.)

•Grind longer. (30 minutes of actual grinding time is the maximum recommended for one run, due to the LN capacity of the tub, but you can top off the LN and repeat the run if necessary.)

When handling chilled samples or vials, or touching parts of the Freezer/Mill that have been chilled by LN, always wear protective gloves.

6.22 Size of Sample Pieces

The size of sample pieces is important. For uniform results in Small vials we recommend most samples be cut into pieces smaller than ¼ inch (6 mm). Very tough samples such as fresh bone should be cut smaller, down to 1/8 inch (3 mm). Samples can be cut proportionately larger for Mid-Size and Large Vials. In any case the size of the pieces should be controlled, and consistent from sample to sample. There are several reasons for this:

•The more irregular the size of the sample pieces, the more difficult it is to predict the results. Uniform procedures work better with uniform samples.

•Thin fibers and films in particular can very difficult to cryogrind unless they are cut into small pieces first. Wads of long fibers and crumpled balls of film take up extra room and can be elastic, even at LN temperatures.

•Tough samples in large pieces can be very difficult to grind, and in rare cases may damage the vial. A large, wedge-shaped piece of bone or a tough polymer can act as a wedge to push a moving impactor through the side of the polycarbonate tube.

6.23Putting a Sample into the Vial at Room Temperature

Most Freezer/Mill samples do not have to be kept cold all the time, and can be loaded at room temperature. To load a vial, first assemble it halfway by pushing an end-plug into a center cylinder. Add the sample and impactor to the vial, and close it with the other end-plug. Shake the vial to make sure the impactor has room to move back and forth.

6.24 Putting a Cold Sample into the Vial and Keeping it Cold

Some samples must be kept cold, such as plant or animal tissue being prepared for RNA extraction. When a sample is cold, and must be kept cold throughout the grinding process, the loading procedure is more elaborate.

Assemble a center cylinder and end-plug, as in 6.23, then chill the end-plug and about an inch of the cylinder in a shallow liquid nitrogen bath. The vial racks with the 6870L and 6870S

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SPEX SamplePrep LLC

9.24.07

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Allied Telesis 6870 manual Size of Sample Pieces, Putting a Sample into the Vial at Room Temperature
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6870 specifications

The Allied Telesis 6870 is a robust Layer 3 Ethernet switch designed for high-performance networking in enterprise environments. Incorporating advanced features and technologies, it serves as a vital component in managing complex network infrastructures, ensuring seamless connectivity, reliability, and enhanced performance.

One of the standout characteristics of the 6870 is its support for a high number of Gigabit Ethernet ports. With multiple SFP and SFP+ ports, the switch allows for flexibility in connecting various devices, while also facilitating the use of different physical media. This capability is crucial for organizations that demand versatile connection options, particularly when managing diverse networking equipment.

The switch is equipped with advanced Layer 3 routing capabilities, allowing it to perform IP routing functions in addition to standard Ethernet switching. Suitable for traffic management, the switch supports protocols such as OSPF, RIP, and static routing, enabling efficient and intelligent path selection in larger networks. This functionality is essential for optimizing bandwidth usage and maintaining an efficient data flow throughout the network.

Another highlight of the Allied Telesis 6870 is its support for VLANs (Virtual Local Area Networks). VLANs enable network segmentation, improving security and performance by isolating different segments of traffic. This capability is further enhanced by the switch's support for advanced features like Ingress/Egress Rate Limiting and Quality of Service (QoS). These features allow network administrators to prioritize critical applications and ensure that bandwidth is allocated effectively.

The switch also incorporates the innovative Allied Telesis Autonomous Management Framework (AMF), which simplifies device management and network configuration. With AMF, administrators can manage multiple switches as a single logical entity, reducing operational complexity and minimizing downtime. This technology supports zero-touch provisioning, enabling rapid deployment and configuration of network devices.

Security is another key aspect of the 6870, with features such as Access Control Lists (ACLs) and IEEE 802.1X port-based authentication. These measures help protect the network from unauthorized access and ensure that only authenticated devices can connect to the network.

In summary, the Allied Telesis 6870 is a versatile and powerful switch that meets the demands of modern enterprise networks. With its comprehensive feature set, including high-performance routing, VLAN support, and advanced management capabilities, it offers a reliable solution for organizations seeking to optimize their network infrastructure. Whether for deploying new services or managing existing traffic, the 6870 stands out as a formidable choice for network administrators.
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