Sunday 2 July 2023

Hayfever - Airborne allergens under the microscope

 A day of sneezing and irritated eyes again, now that it has rained in Milton. Here is what I found in the air and put under the microscope - masses of pollen grains, fungal spores and even starch grains! The sample is from a comparable day last week, when I rinsed a roughly 30cm x 30cm (1 square foot) piece of fine netting that had been on the washing line for 18 hours!

The various types are shown with numbered examples on the following figures, using the labelling:

  1. Pollen grains from flowering plants stained red and can vary a lot in shape and size
  2. Pollen grains from grass - are stained red, plain ovals with a single pore, and can vary in size
  3. Fungal spores - generally brown, beige or grey, ranging from lage paddle shapes to small ovals
  4. Fragments of fungal hyphae - look like broken brown twigs
  5. Starch grains - variable sizes, transparent, circular to oval with a hint of a central marking

Air sample at 200x magnification showing pollen, fungal spores and fragments, and starch grains 01
From the first picture above you can get an idea of the abundance of pollen and fungal spores in 1/600 of the collected material. The spiky pink pollen comes from a plant in the daisy family.

For us hayfever sufferers, our problem is compounded by the fact that all these very small particles stick quite readily to our hair, faces and clothes. Our symptoms can be triggered if even if just a few become loose when we move indoors or go to bed, hence the advice to wash hair and change outer clothes frequently if you do suffer badly from hayfever. Thank heavens that many of our cars have pollen filters!

I calculated that overall my total sample from a small piece of netting contains about
  • 7,200 pollen grains
  • 42,000 fungal spores 
  • 600 starch grains
Hayfever is when our own immune system becomes sensitive to airborne dust, pollen, spores, hair, for example, treating them as a threat and trying to protect us.  Unfortunately, our eyes and noses are the areas most likely to be exposed and react. What's more, each one of us develops our own typical allerge to one or more of the many different particles in the air.

I can manage with taking hayfever tablets daily during the main hayfever season, and eyedrops when it is particularly bad on the eyes. I only need to avoid going out on particularly bad days. Many others suffer much more seriously and find their lives dramatically impaired. In those cases it is worth seeing if your doctor or health system offer both a service to identify your specific allergens and a possible corresponding desensitisation program. two useful lins in the UK are:
There is also another side to being able to capture and identify pollens and spores - in forensics, when trying to match a person or vehicle to a crime location. Here, the fact that pollen and spores are so pernicious and will be very specific to locations helps, as illustrated in a fantastc book by Patricial Wiltshire 'Traces' -

Airborne particles. I hadn't really realised how abundant they are! My sympathy if you are a hayfever sufferer.

For your interest, below are some more images from the airborne pollen sample.

Air sample at 200x magnification showing pollen, fungal spores and fragments, and starch grains 02

The caplet shaped pollens are from the same family as Cow Parsley.

Air sample at 400x magnification showing pollen, fungal spores and fragments, and starch grains 03

The largest pollen grain (1) is similar to Hazel pollen. The grass pollen (2, bottom) has a visible single pore.

Air sample at 400x magnification showing pollen, fungal spores and fragments, and starch grains 04

The large pollen grain (1) is very characteristic for pines, the two black circles within it are trapped air bubbles. The starch grain (5) is on the large side. Starch in airborne dust most likely comes from decayed plants and very small grains can come from some pollens. The fungal fragments (4) would also have come from dried decaying plants and soil.


Wednesday 22 March 2023

Reviving UK-DE trade - Some notes on a March 2023 Trade mission

Tower Bridge London at night

Executive Summary

Six German companies specialising in innovative building transformations, modernisations and restoration attended 2 days of talks and bilateral information exchanges in London on 20-21 March before continuing with site visits in the following days. Key messages from both UK and DE side were 1. Shared interests in working and collaboration between companies in the sector. 2. The difficulties in finding skilled craftspersons and apprentices. 3. Cross-border hurdles impacting on collaborations and the need to find suitable solutions to ameliorate them. 4. Deep frustration at the lack of political action in the UK  

The trade mission was a German BMWK Ministry ( event organised and enabled by Europartnerships ( It was held at both the German Embassy, London and the Institute of Practitioners in Advertising (IPA), both at Belgrave Square.

Day 1. Talks in a secure environment

Hearing that I was the sole person allowed to bring in a laptop for the day's event at the German Embassy, with special dispensation from the Chancellor, I was only mildly disappointed to find out that it was not the German Chancellor, but the almost equally eminent embassy's Chancellor. I am unable for obvious reasons to reveal the other stringent security restrictions and precautions we had to undergo before we could reach our meeting room, but we were in the hands of the extremely professional and courteous and friendly staff throughout. 

We were warmly greeted and had a good outline of the current situation re post Brexit trade and UK politics by the Deputy head of Economics Mariko Higuchi ( The directors of the six german companies were then provided with advice on a wide variety of relevant topics. These ranged from basic cultural differences, via the new tax issues arising through crossborder trade, to the impact of visas, BIM and onsite Health and Safety on doing business in the UK. Key message to emerge, life is simpler if you have partners in both countries.

Compliments to the speakers, Marc Lehnfeld (Director GTAI, Sven Riemann (Marketing AHK - a long standing and witty contributor at past events, Martin Werhahn (Tax Services AHK, and Robert Hunt (associate Konduit Ltd, who proved himself to be one of the rare breed of  0.5% of british in the UK who could definitely speak German.

Though retired, my role for Europartnerships over the years has been to come in as meeting's chair for the two days, to ensure the fair timing of talks takes us agreeably through to breaks and mealtimes, without bias and on time.

Six different personalilities, skills and businesses

We (the delegates) made our way to the Motel One, Tower Hill, afterwards to meet up at 4:30 to go through the six comapny presentations in a relaxed manner. This is a crucial and really helpful stage for me. It gives me a chance to get to know not only their businesses and objectives, but the different personalities, something cemented in The Dean Swift pub, close to Tower Bridge later that evening. It helps with supporting them on the following day.

I'll try to give some single line summaries of the six different companies and their services:
  • Felix Graf of Felix Graf GmbH: A family business with a a strong link with its community and employees, that has grown to specialise in the interior fittings for the hotel and catering industry.
  • Lars Krauss of Greengineers: Consultants and specialist planning services to provide tailored sustainable solutions that meet their client's needs.
  • Jörn Brennscheidt of Hokon. Making impossible stairways possible!
  • Thomas Schubert of Ingeneurbüro für Kirchenbau, Glocken und Denkmalpflege. Rebuilding and recovering churches, community buildings and creating welcoming communal places.
  • Christian Schulte of Mühlenhof Restaurierungen GmbH. Sympathetic and authentic restaurations of historic windows, doors, floors, panelling and furniture in collaboration with architects and art historians.
  • Peter Spor of Tischlerei Spor GmbH & Co KG. A traditional joinery and carpentry company whose expertise include dry wall construction and the repair and build of solid wooden floors.
Most of the companies already have international experience and are english speakers, with several having completed projects in the UK prior to Brexit.

Day 2. Presentations and key issues.

Day 2 was held at the Institue of Practitioners in Advertising (IPA, almost opposite to the German Embassy, on the other side of Belgrave Square, a long standing and friendly venue for Europartnerships.

Over 70 UK architects and other companies in the construction and restoration sector had expressed an interest and a substantial number filled the larger conference room upstairs at the IPA. This time it was the turn of Markus Knauf (Head of the Economics Department at the German Embassy and Mark Dodsworth, director of Europartnerships (  to welcome the guests, as well as thanking Petra Riemenschneider and team at Europartnerships for their herculean efforts in organising the event.

For once, technology was on our side as the first of the mornings talks, by Marie-Theres Sobik of Thyssen ( on "The vocational training system in Germany" was given remotely using Teams. A training system that had a century of experience behind it, contrasting with the mixed and changing approaches in the UK. Circumstances had prevented Marie-Theres from being able to attend and her physical presence was sorely missed by me and the Europartnerships team. Like Sven mentioned above, she had been a stalwart and bright, constructive presence at many previous events in the past. Afterwards, Michael Schienke of Vorbild Architecture ( and Sven Riemann (AHK reversed yesterday's role and enlightened the british audience on cultural differences across the channel, revealing that in Germany too, there was a diversity of regional prides, traditions and ways of doing things.

Our six german companies then had their turn in the spotlight. Gradually, the audience came alive with shared experiences and questions not only to the companies, but also about how to overcome some of the hurdles presented since Brexit. After all, the UK had fallen out of the list of top 10 trading partners with Germany. Here, the presentations given to us at the embassy proved invaluable; problems with taxation through the transfer of goods several times back and forth across the UK-EU borders could be overcome to some degree with professional assistance and sometimes even at a final null cost calculation. Building partnerships with one member in the EU and the other in the UK was a good route to take, each familiar with their own ideosyncratic bureaucracies, regulations and regional issues and helping solve the border transitions of goods and services.

What I understood was, that the greatest regret was the loss of access to the Erasmus program, with some UK delegates speaking of the way it had helped their careers. In turn, the German companies had young staff who would leap at the chance to gain experience in the UK. A representative from one of the UK bodies in the industry implored the German Embassy to seek more routes to collaboration in the training of up and coming craftspeople in the construction and in the restoration sectors. Apparently there were promising comments from the government - but at present little action.

We ended the day with a buffet lunch and many individual discussions between attendees and the german company representatives, followed by the longer one-to-ones from pre-arranged appointments.

My personal feeling at the end of the day was, that there were opportunities and an interest in longer term collaboration between the two countries in innovative building transformations, modernisation and restoration, despite the hurdles raised by Brexit. 

From the german companies' point of view, it was an insight into the opportunities that might exist, possible partners to contact when back home, as well as a better knowledge of the potential barriers. Ultimately, it would be their judgement whether it would be worth their time and investment in trying to enter the UK market.

Sunday 19 March 2023

Creamed Honey crystal microscopy using LOCA - Method

Crystals of creamed honey (sourece Honigmanufaktur Meerbusch). 40x objective, industrial microscope camera, transmitted light, crossed polarisation filters and quarter wave plate.

I returned from a family vsit to Germany with a small jar of creamed honey, made by Honigmanufaktur Meerbusch ( Coming to the bottom of the jar, of this very smooth, cream like honey, I looked for the best way to visualise and measure the honey crystals. Through experimentation, a simple method for producing a thin layer of honey crystals and mounting in LOCA  was developed. Samples were best observed between crossed polarisation filters with a quarter wave plate.


I tried several methods to get a thin layer of the sugar crystals.

  1. Taking a small drop on a slide, covering with a cover slip and pressing hard. Not very successful,
  2. Small drop of honey on a slide mixed with some oil then pressed with a cover slip. Partially successful, giving areas with some thinner layers. see figures 1 & 2
  3. Small drop of honey mixed with isopropanol - too viscous too smear.
  4. Making a thin streak of honey across the width of a slide and trying to spread it as you would a blood smear, pulling a thin film behind another angled slide. Honey too viscous to be spread.
  5. Making a thin streak and  using an angled other slide to smear it thinly. Unsuccessful - the smear was of a viscous thin layer solution wihout many crystals until the place where the dragging slide was pulled off, There a slip of thick crystals remained.
  6. The final approach was a modification of method 5. Making a thin streak and  using an angled other slide to smear it thinly at first and then reducing the pressure over a 2 cm stretch of the slide. SUCCESS! there was an area of the smear that was thick enough to leave crystals yet thin enough to have them at almost a single layer. A drop of LOCA was placed on the thin area, a cover slip added and pressed. The slide was set by exposure to a hand held UV torch for 60 seconds and then cleaned according to the method published by Gordon Brown, 2020, creating a permanent slide.
Slides were photographed using a Reichert Zetopan microscope witha 40x objective and a Chinese 5 megapixel objective camera and the software ToupView. Lighting techniques used were standard brightfield, use of crossed polarisation filters without and then with a quarter wave filter. A series of images at different focus through the sample were taken and combined in a focus stack using Picolay.


Method 2. The sample of honey mixed with sunflower oil had areas that were thin enough to see defined crystals. There were planar, needle and fragmentary types. However the sample was still fairly thick.

Figure 1. Creamed honey crystals. Method 2. Mixed with sunflower oil, 40x objective, between crossed polarisation filters. Field of view 250 µm.

Figure 2. Creamed honey crystals. Method 2. Mixed with sunflower oil, 40x objective, between crossed polarisation filters plus quarter wave plate. Field of view 250 µm.

Method 6. Sample spread as a smear of increasing thickness on slide and mounted in LOCA. More parts of the slide could be found where the layer of crystals was thin enough to resolve individual crystals.

The crystals in this cream honey are extrememly thin and show little contrast in transmitted light (figure 3). Greater contrast of the crystals against background is achieved using polarisation. Their thinness is also reflected in the fact that they appear in pale colourless shades between crossed polars (figure 4). The planar like crystals have 120 degree angles reflecting molecular sugar. There are also small needle like crystals. 

Whilst the contrast is less with the inclusion of a half wave plate (figure 5), it does reveal crystals missed under just crossed polars. making this the preferred method for photography.

The images reveal that most of the crystals are smaller than 20 µm in diameter. The result is consistent with the cream like nature of this honey.

Figure 3. Method 6, sample spread and mounted in LOCA. 40 x objective. Normal transmitted light. 

Figure 4.  Creamed honey crystals. Method 6, sample spread and mounted in LOCA. 40 x objective, between crossed polarisation filters.

Figure 5. Creamed honey crystals. Method 6, sample spread and mounted in LOCA. 40 x objective, between crossed polarisation filters plus quarter wave plate.


Honey is liquid in the beehive, where it is kept at about 35 degrees C by the bees themselves. When stored at home after purchasing, honey will begin to crystallise from the bottom of the jar upwards if the room temperture is cooler than 35 degrees C. The rate of crystallisation is dependent on the fructose/glucose ratio; more fructose, the slower crystalisation occurs. 

Particle size has an impact of the mouth feel of foods. Larger grains feel coarse and the food 'grainy', whilst particles smaller than 20 µm impart a creamy texture in chocolate, for example. 

Honey with coarse crystals can be liquified again by warming if desired.

On the other hand, a smooth, cream honey can be deliberately created. Liquid honey is seeded with 10% of its volume of existing cream honey or large honey crystals that have been blended into sufficiently small particles. The added crystals are stirred into the liquid honey and the mixture left to stand for a week or more by which time the honey becomes saturated with small crystals and is turned into a cream honey.

Useful references and links

Monday 13 March 2023

Feathers under the microscope

The unexpected finding for me personally, on identifying feathers under the microscope, was that it was the downy feathers or down parts of feathers that can be key to identification. 

A fellow microscopist and I in Milton had missed being able to attend an Iceni meeting in Norfolk a couple of weekends ago on the topic of feathers. So later in the day, we got together to have a go ourselves. In addition to some feathers we had, we were able to borrow some from my neighbours here in Hall End.

Selection of feathers

That doesn't mean that the flight feathers are uninteresting. A closer look at the rigid part of the pheasant feather reveals the hooking mechanism on the barbules. These are the fine filaments that create the interlocking between the regular rows of  barbs radiating from the main feather stem.

Pheasant feather at 40x, 100x and 400x magnification, showing hooks and notches on barbules

Downy barbs can not only be found on (surprise surprise) down, but also on the bases of other feathers on a bird. Looked at closely, the barbs have fine filamentous barbules with distinctive nodes that can be seen at higher magnification. Below are some of the examples that we discovered.

Pheasant down at 40x, 100x and 400x magnification

Macaw down at 40x, 100x and 400x magnification

Goldfinch down at 40x, 100x and 400x magnification

Possible swan down at 40x, 100x and 400x magnification

Unknown down, possily pigeon at 40x, 100x and 400x magnification

Just to add a bit of colour, I had a go at making a stitched image of a peacock's feather, using the software Image View (which is very like Toupe View). Normally I would take separate pictures and use Hugin to stitch them together. Image View allows you to do the stitching automatically by moving the sample in rows or columns. The second attampt sort of worked, as shown below.

Eye of a peacock feather scanned with Imave View at about 40 magnification, equivalent to about 8 images stitched together.

All in all, it was a very enjoyable exercise and occupied a Sunday afternoon plus a bit extra for picture editing.

Useful identification guides for feathers under the microscope:

Microscopy of Feathers: Carla J. Dove & Sandra L. Koch, 2011. A Practical Guide for Forensic Feather Identification.  THE MICROSCOPE • Vol 59:2, pp 51-71.

Tim G. Brom, 1986. Microscopic identification of feathers and feather fragments of Palearctic birds. Bijdragen tot de Dierkunde, 56 (2): 181-204