ccem No Comments

Insect Exploration

by Travis Casagrande

 

What do you do when you have a fully intact dead insect and you also just happen to have an SEM? That’s a rhetorical question; we both know there’s only one answer.

If you’ve studied entomology (the study of insects), this may not be news to you, but like many of our users, I came from materials science and engineering. It’s safe to assume that we might not know a lot about insect facial features. So, I put one inside an electron microscope; my FIB column was temporarily broken so I had a bit of extra time. This insect was one of many that found its way into the house of one of our other staff members and the insects liked it so much that they decided to nest there. This required the services of pest control.

 


Alright, so what is this? I’ve already given you some major hints. Maybe you think it’s the eye of an insect?

 


There’s two; that’s a good sign for the eye theory.

 


Wait, there’s a 3rd? Uncertainty sets in. Let’s zoom out some more.

 


This is a wasp, but you only see part of the head here since it’s far too big for my maximum field of view. (In the electron microscopy world, insects are giants.) Now you can see the large “compound eyes” that you’re probably familiar with since they’re easily visible with your own eyes and likely the most recognizable insect facial feature.

 


These compound eyes only provide the wasp with low resolution vision. However, since they protrude outward in a dome and curve down the side of the wasp’s head, the shape gives them a very large 3-dimensional field of view, or more mathematically speaking a “high solid angle of detection”. They can also detect fast movement. [1]

 


Each domed hexagonal shape is an individual cornea that is transparent to visible light. Under the cornea is a cone lens, photoreceptor cells, and pigment cells to block excess light transmission to other units; all together forming a unit called an ommatidium. The compound eye consists of hundreds to thousands of ommatidia. [2]

 


Nature is so perfect with these hexagons, right?

 


Nope.

I found edge dislocations in the hexagonal arrangement of the ommatidia, and this is one of them. (Materials science, remember?) You can see by the angles of the blue lines how the hexagonal lattice distorts to accommodate the extra line of ommatidia. The hexagon angles and side lengths close to the dislocation site are also heavily distorted, with a few of them having only 5 sides. These dislocation “defects” weren’t uncommon either; there’s even a second one in the horizontal direction on the left edge of this image.

 


Anyway, back to the 3 domes in between the two compound eyes. So, then what are they?! I couldn’t leave this question burning in my mind for too long, so I tracked down the answer.

 

The answer: Also eyes!  Wait… what?
They are called dorsal “ocelli”, which is the plural of “ocellus” which means “simple eye”. Apparently, this extra triplet of eyes does not form an image, but they can detect variation in light intensity far more precisely than the compound eyes, and faster too because of their relative biological simplicity. These ocelli seem to be theorized to help with flight stability. Consider the pitch, yaw, and roll rotation axes in flight and how the difference in light intensity detected between each of the three ocelli would be enough to detect changes in all three of those rotational directions, assuming their environment has some directional lighting.

[image source: 2]

 
This is more than just a curiosity for science, because understanding the ocellar functions in insects can for example be applied to the engineering of flight stability controls in micro air vehicle drones. [4,5]

 

A few additional comments for those interested in the sample preparation of insects and some related SEM tips:

  • Usually you can expect an insect to be far dirtier than the one I have here, especially if you’ve found it dead on the floor. This wasp was even given to me covered with pesticide residue. I cleaned it thoroughly by ultrasonication in acetone, and then repeated with ethanol, and it seems to have been quite effective.
  • The most proper way to prepare an insect for SEM would be using a technique called “critical point drying” to displace the water and evaporate the fluid in a controlled way that won’t collapse the fine biological structures such as cell walls. This equipment is common in a biological-focused electron microscopy lab. With softer insects this is a critical technique, but the acetone/alcohol washing was good enough for the wasp, at least at low to medium magnification. If it was recently alive, it could be a little more “wet” inside and possibly off-gas once in the vacuum of the microscope chamber. A vacuum oven with gentle heating can be used to remove some of the remaining liquids to prevent contaminating the SEM chamber.
  • As you might expect, insects are non-conductive. I coated this wasp with argon-plasma sputter deposition of gold, and for much longer than I would for a typical flatter sample. I probably should have coated it even more thoroughly because there was still a fair bit of charging to deal with. Charging can be somewhat mitigated by low current operation and rapid frame averaging during image acquisition. The deeper areas and underside of the insect were still non-conductive, so it is best to use a coating method that can access the more difficult angles.
  • Since insects are huge, it’s helpful to use a large working distance because this provides a large depth of field so that most of the insect is at least somewhat in focus. High voltage also helps for larger depth of field, but sometimes will make charging effects worse. Applied to a low atomic number material, the high voltage beam can give an undesirable semi-transparency effect that prevents crisp imaging of surface textures, although this is solved by the metal coating.
    The large working distance also helps to avoid any collisions with the pole-piece, since getting to the various parts of the insect with multi-millimeter height differences requires large stage movements and a variety of tilt angles. Extra vigilance is needed to ensure that stage movements are done safely.

 

References:

[1] https://en.wikipedia.org/wiki/Compound_eye

[2] https://en.wikipedia.org/wiki/Ommatidium

[3] https://whyfiles.org/2015/fruit-fly-flight/index.html

[4] https://en.wikipedia.org/wiki/Simple_eye_in_invertebrates

[5] http://aeromav.free.fr/MAV07/session/plenary/SESSION%204/MAV07-PLEN%204-3%20Stange%20Berry%20Kleef/Stange.pdf

Samantha Stambula No Comments

COVID-19 Report – CCEM re-entering Phase 1

Hamilton will be returning to the grey zone (lockdown), and McMaster University will go back into Phase 1 of on-campus research operations. For CCEM, this means that starting Monday, March 29, the following access changes will be in effect:

  • In-person user training will not be permitted
  • In-person instrument access will no longer be allowed for external (non-McMaster) users
  • Internal (McMaster) users must be part of an approved plan for on-campus research

If you are currently booked for access or training that is affected by these policy changes, please reach out to a CCEM staff member about re-scheduling, or having your analysis performed by CCEM staff instead.

The CCEM hopes that everyone stays safe and healthy, and we look forward to easing access restrictions and re-booked for affected sessions when the situation allows. Thank you for your understanding.

For additional information, or if there are questions, please consult our COVID-19 policies, or email the Facilities Manager.

Andreas Korinek No Comments

CCEM’s new Strategic Plan 2021-2026

Over the last year, CCEM has developed a new Strategic Plan, which as been approved by the Governing Board. This plan is the result of one year of planning, consultation and envisioning the future of the centre and plots CCEM’s path into the future.

Our new Strategic Plan provides a bold vision for CCEM as a national research facility. It has been informed by feedback from the national user community, partners and CCEM management and builds on the successes and lessons from our previous Plan. The Governing Board has actively participated in shaping the plan. The strategic goals of CCEM over the next five years will strengthen CCEM’s position as a national electron microscopy research facility with international recognition for excellence that serves a growing and diverse national academic and industrial user base.

The development of the Plan has been inspired by a value proposition built on three pillars:

  • a national enabler of breakthrough materials research
  • a global leader in electron microscopy education and training
  • a provider of accessible specialized electron microscopy services

CCEM will contribute to growing the scale and scope of materials innovations that are important for the prosperity, health and security of Canadians.

Important drivers of the Strategic Plan are the following:

1. The need for new and improved materials for a more prosperous, cleaner and healthier tomorrow. Cutting-edge micro- and nano-scale imaging is a critical enabler to unlocking breakthrough materials innovations.
2. Effective national connectivity among researchers is essential for the increase of scale and pace of materials innovation in Canada.
3. The effects of the COVID-19 pandemic and the demands for equality and opportunity for all are important drivers to embrace inclusiveness, collaboration and innovative delivery of services.
4. CCEM as an MSI funded facility is expected to support leading-edge research, contribute to talent development and promote the mobilization of knowledge and transfer of technology to society through shared access by a pan-Canadian user community to specialized equipment, services and scientific personnel.

Through our EM research, training and services, we catalyze tomorrow’s materials innovations.

We have identified four strategic goals:

1. We will push the cutting-edge of materials characterization that best enables strategically important materials breakthroughs.
2. We will expand national connectivity to researchers and innovators in materials characterization, development and applications to accelerate the pace and scale of materials innovations.
3. We will re-imagine CCEM’s business model to drive impact, inclusiveness and innovation.
4. We will be Canada’s leader in education and training of the next generation of electron microscopists.

 

The new Plan can be found here

We will leverage partnerships with the user base, other research facilities and various other organizations. If you would like to discuss any opportunities to collaborate with CCEM, please contact me at korinek@mcmaster.ca, I’d be happy to discuss your ideas.

Andreas Korinek No Comments

Welcome to the CCEM blog from the Executive Director

I am Andreas Korinek, CCEM’s Executive Director. This is a new position at CCEM, I will be responsible for the business side of the centre and will be responsible for partnerships, governance and strategic direction.

My background is in interdisciplinary science, I’m a trained chemist and biochemist, and I’ve worked with scientists from many fields on projects. I also know how to code, anyone using NanoLIMS at CCEM or other McMaster core facilities is using code I’ve developed.

I’ve been at CCEM since more than 10 years, I started as a staff scientist operating the Titan LB microscope and later also the Titan HB. I’ve worked with many students and industrial customers over the years, and this has been a very fulfilling position. I got to learn about many different projects, from metals to corrosion, nuclear materials, soft materials and biological samples. During this time, I came to realize how unique CCEM is in the Canadian science landscape. The suite of instrumentation and level of science is fascinating and allows for great collaborative projects to happen.

In 2017 I became the CCEM manager and was able to implement my own philosophy on how CCEM operations should be managed. My vision is to make CCEM an open and welcoming place for anyone wishing to use microscopy in their work and learn about the different techniques and how they can be useful. I also streamlined and simplified the administrative procedures for new users and industrial clients. My goal is to provide the best possible experience at CCEM. CCEM’s team of expert staff is very diverse in gender, nationality and scientific background and they are happy to enable our users to use the instruments to their full capacity.

 

As the Acting Executive Director of CCEM, I’ve developed with the CCEM management team and the Board of Directors a new 5-year strategic plan that outlines CCEM’s growth in capabilities and our plans for collaboration and partnerships with many different stakeholders. The plan will be unveiled in a few weeks, tune in for more details later. This new plan represents an ambitious shift of CCEM from a traditional fee-for-service core facility to a research platform open for collaboration on a national scale. If you would like to find out more how you can shape the future of CCEM, send me a message, I’d be happy to discuss your ideas.

CCEM has also overhauled its governance backend and we will communicate these changes very soon. The new model aims to be inclusive and efficient and there will be many ways for users, staff, PIs and industrial clients to interact with CCEM in many ways.

Many challenges lay ahead of us. We as scientists hold the key for a better future for Canadian society and the well-being of the planet and humanity. The next decades will be spent adapting our society to the effects of global warming, the aftermath of the global pandemic and solving equity issues, just to name a few. I invite all of you to join us on this challenging journey to use science as a solution to many of these problems.

In this blog, I will regularly update you on new initiatives and policies to improve CCEM’s operations. I welcome all feedback, it will help the CCEM staff and management team to serve our user community better. CCEM staff will also post here on a variety of topics. If you would like to contribute to this blog, please send me a message, we also welcome content from users of CCEM.

ccem No Comments

COVID-19 Report – CCEM re-entering Phase 2

As the COVID-19 pandemic begins to improve in Ontario, and Hamilton returns from lockdown, McMaster University has eased restrictions for on-campus research operations. For the CCEM, this means that starting Tuesday Feb 16, the following activities are able to be resumed:

  • In-person user training for local (McMaster) users
  • In-person instrument access for external (non-McMaster) users, provided that they are able to work independently

The CCEM staff hopes that everyone continues to remain safe and healthy during this time. We look forward to resuming in-person training to all users when the situation allows. Thank you for your understanding.

For additional information, or if there are questions, please consult COVID-19 policies, or email the Acting Facilities Manager.

ccem No Comments

COVID-19 Report – CCEM Scaling Back Parts of Operations

As a result of new restrictions due to the ongoing COVID-19 pandemic, the CCEM will be scaling back parts of our operations to help ensure the safety of all staff and users of the Centre.  These new restrictions will remain in effect until further notice:

  1. CCEM will no longer be offering in-person training with our assistance from CCEM staff
  2. In-person access to the CCEM will be limited to McMaster personnel only, who are working under an approved on-campus research plan

If you already have a booking for in-person use and are external to McMaster, or are scheduled to receive in-person training, your session will have to be postponed.

Detailed CCEM COVID-19 protocols can be found on the CCEM File Server (https://ccemdata.mcmaster.ca/published/ccem-covid-19/).

The CCEM also remains open to receiving jobs for analysis by our staff.

If you have any further questions regarding our limited re-opening please contact the Acting Manager.

ccem No Comments

COVID-19 Report – CCEM entering Phase 2 of re-opening

Following McMaster’s lead, the CCEM will be moving into our Phase 2 of re-opening. What does this mean? The Centre will now be open to non-staff users that are trained to work independently and to those scheduled to receive in-person training with CCEM staff. In-person access to the CCEM requires the following:

  1. Users familiarize themselves with and follow all COVID-19 protocols in place by the CCEM, the university, and other university departments and offices – including the mandatory use of face masks for indoor, public spaces.
  2. Users book their instrument time in advance using NanoLIMS, or by arranging time with CCEM staff

Note that during this phase we are limiting instrument room occupancy to a maximum of 1 person (with an exception of 2 people for training by CCEM staff).

Detailed CCEM COVID-19 protocols can be found on the CCEM File Server (https://ccemdata.mcmaster.ca/published/ccem-covid-19/).

The CCEM also remains open to receiving jobs for analysis by our staff.

If you have any further questions regarding our limited re-opening please contact the Acting Manager.