Microscopy Quotes

It is pathetic to watch the endless efforts—equipped with microscopy and chemistry, with mathematics and electronics—to reproduce a single violin of the kind the half-literate Stradivari turned out as a matter of routine more than 200 years ago.

Did you know that embryologists have recently captured the moment of conception via fluorescence microscopy? What they discovered is that at the exact moment a sperm penetrates an egg, the egg releases billions of zinc atoms that emit light. Sparks fly, literally! That miracle of conception is a microcosm that mirrors God's first four words.

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Long before the idea of scanning specimens with a small spot of light produced confocal light microscopy, the idea of using a small spot of electrons to scan surfaces had been around for as long as electron microscopy itself. A surface demarcates the boundary of a solid, and is the site of interaction with the surrounding environment, from a ball bearing to a living cell. In the mechanical world, adhesion, friction, wear, and corrosion are all dependent upon surface properties. The smooth surface of a ball bearing is crucial in the reduction of friction, but its efficiency may well be compromised by wear or corrosion.

Mary cringed every time she read a popular article that tried to explain why mitochondrial DNA is only inherited from the maternal line. The explanation usually given was that only the heads of sperm penetrate eggs, and only the midsections and tails of sperm contain mitochondria. But although it was true that mitochondria were indeed deployed that way in sperm, it wasn’t true that only the head made it into the ovum. Microscopy and DNA analyses both proved that mtDNA from the sperm’s midsection does end up in fertilized mammalian eggs. The truth was no one knew why the paternal mitochondrial DNA isn’t incorporated into the zygote the way maternal mitochondrial DNA is; for some reason it just disappears

The inventions of microscopy and telescopy shattered the boundaries of ordinary human perception and fueled the scientific revolution.

cell-specific lectin Ulex europaeus agglutinin as observed by fluorescence microscopy (Fig.1)

As a boy, I was fascinated by speed, the wild range of speeds in the world around me. People moved at different speeds; animals much more so. The wings of insects moved too fast to see, though one could judge their frequency by the tone they emitted—a hateful noise, a high E, with mosquitoes, or a lovely bass hum with the fat bumblebees that flew around the hollyhocks each summer. Our pet tortoise, which could take an entire day to cross the lawn, seemed to live in a different time frame altogether. But what then of the movement of plants? I would come down to the garden in the morning and find the hollyhocks a little higher, the roses more entwined around their trellis, but, however patient I was, I could never catch them moving. Experiences like this played a part in turning me to photography, which allowed me to alter the rate of motion, speed it up, slow it down, so I could see, adjusted to a human perceptual rate, details of movement or change otherwise beyond the power of the eye to register. Being fond of microscopes and telescopes (my older brothers, medical students and bird-watchers, kept theirs in the house), I thought of the slowing down or the speeding up of motion as a sort of temporal equivalent: slow motion as an enlargement, a microscopy of time, and speeded-up motion as a foreshortening, a telescopy of time. I experimented with photographing plants. Ferns, in particular, had many attractions for me, not least in their tightly wound crosiers or fiddleheads, tense with contained time, like watch springs, with the future all rolled up in them. So I would set my camera on a tripod in the garden and take photographs of fiddleheads at hourly intervals; I would develop the negatives, print them up, and bind a dozen or so prints together in a little flickbook. And then, as if by magic, I could see the fiddleheads unfurl like the curled-up paper trumpets one blew into at parties, taking a second or two for what, in real time, took a couple of days.

That proof required the further development of microscopy, and the work of Robert Koch.

In that respect the germ theory he espoused required more robust proof. Only the further development of microscopy, which rendered the Vibrio cholerae visible, and the experimental method, which demonstrated the role of microorganisms in inducing disease in animals, could establish the actual mechanisms of contagion. Snow painstakingly established correlation, but he was unable to prove causation.

Through painstaking microscopy, Pasteur discovered, he believed, that the disease afflicting France’s silkworms was in fact two separate diseases—pébrine and flâcherie—caused by bacteria whose role in producing these diseases he was able to demonstrate.

By 1883, then, the pathogens responsible for anthrax, tuberculosis, and Asiatic cholera had been isolated and their roles in disease causation had been demonstrated. Making use of the methodologies developed by Pasteur and Koch, scientists rapidly isolated a succession of microbes responsible for human disease—typhoid, plague, dysentery, diphtheria, scarlet fever, tetanus, and gonorrhea. The decades between 1880 and 1910 were therefore known as the “golden age of bacteriology,” when the new techniques of microscopy unraveled many of the mysteries of disease etiology, definitively proved contagionism, and established the germ theory of disease. Joseph

If I could do it all over again, and relieve my vision in the twenty-first century, I would become a microbial ecologist. Ten billion bacteria live in a gram of ordinary soil, a mere pinch held in between thumb and forefinger. They represent thousands of species, almost none of which are known to science. Into that world I would go with the aid of modern microscopy and molecular analysis. I would cut my way through clonal forests sprawled across grains of sand, travel in an imagined submarine through drops of water proportionately the size of lakes, and track predators and prey in order to discover new life ways and alien food webs. All this, and I need venture no farther than ten paces outside my laboratory building. The jaguars, ants, and orchids would still occupy distant forests in all their splendor, but now they would be joined by an even stranger and vastly more complex living world virtually without end. For one more turn around I would keep alive the little boy of Paradise Beach who found wonder in a scyphozoan jellyfish and a barely glimpsed monster of the deep.

There is a bookseller out there for every bibliophilic obsession known to humankind. You want a seventeenth-century book on microscopy with engraved illustrations on the life cycle of mosquitoes? There is a dealer who can provide you with that. You fancy rare volumes on Antarctic exploration or the history of ancient Egyptians?

Pulsed lasers produce incredibly short bursts of electromagnetic energy. For example, a pulsed femtosecond laser produces a flash of light that lasts for femtoseconds to a picosecond (a picosecond is one trillionth of a second, a femtosecond is one thousandth of a picosecond), instantly followed by another (and so on). These lasers brought about the possibility of exciting fluorophores with two photons of only half the necessary energy, but they need to arrive almost simultaneously to generate the ejection of a photon. Infrared pulsed lasers penetrate living tissue more effectively, with the advantage that fluorescence is achieved from much deeper in the tissue than normal fluorescence, where the depth of penetration is limited by multiple light scattering events. Multiphoton microscopy (mainly two photon in practice, but also feasible as three or more photons) allows imaging from as deep as a millimetre (one thousand micrometres), an improvement of several hundred micrometres over fluorescence confocal microscopy. A second advantage of two photon excitation is that it forms as a single spot in the axial plane (z axis) without the ‘hourglass’ spread of out of focus light (the point spread function) that happens with single photon excitation. This is because the actual two photon excitation will only occur at the highest concentration of photons, which is limited to the focal plane itself. Because there is no out of focus light, there is no need for a confocal pinhole, allowing more signal to reach the detector. Combined with the increased depth of penetration, and reduced light induced damage (phototoxicity) to living tissue, two photon microscopy has added a new dimension to the imaging of living tissue in whole animals. At the surface of a living brain, remarkable images of the paths of whole neurons over several hundred micrometres can be reconstructed as a 3D z section from an image stack imaged through a thinned area of the skull in an experimental animal. Endoscopes have been developed which incorporate a miniaturized two photon microscope, allowing deep imaging of intestinal epithelium, with potential to provide new information on intestinal diseases, as most of the cellular lining throughout our gut is thin enough to be imaged in this way. So far a whole range of conditions including virtually all the cancers of the digestive tract as well as inflammatory bowel disease have been investigated, reducing the need for biopsies and providing new insights as to the nature of these conditions.

It has been estimated that a career electron microscopist who spends his working days preparing, sectioning and staining, observing, and recording biological material will get through the equivalent of one cubic millimetre of tissue in a forty-year working lifetime.

Our best ability to see detail with the eye is to perceive two strands of human hair that are separated by a hair’s width. This is the limit of our resolution—the ability to see detail, measured by the distance at which two points are still distinct. Magnification without increased resolution merely produces a larger image with no increase in detail. Amazing as our own eyes are, they are poor compared with those of an eagle, where the resolution is eight times as good, enabling it to spot a rabbit at a distance of two miles.

Modern scanning probe instruments will often provide several different modes within the same instrument, including aspects of light microscopy such as near field optical scanning microscopy (NOSM) and micro tools for nanofabrication such as micro-writing devices (nanolithography), indentation probes providing exact positioning and force control, all in a specimen chamber in which both the temperature and gaseous environment can be precisely controlled. This type of scanning probe microscopy has made it possible to investigate a surface phenomenon termed surface plasmon polaritons (SPPs for short), which are surface electromagnetic waves that propagate between the interface of a metal and a dielectric (insulator). More explanation of SPPs would require a VSI on surface physics, but suffice it to say, the scanning plasmon near field microscope has made it possible to work towards practical exploitation in the applications of SPPs (which make it possible to ‘package’ light in smaller quantities than ever before) in optics, data storage, solar cells, chemical cells, and biosensors.

With the advent of nanotechnology, microfabrication has produced novel manmade constructs called metamaterials which exhibit entirely new properties in terms of their effect on light, effects which are not found in conventional materials, or even in nature itself. Early in the 21st century, a chance observation showed that an ultrathin layer of silver on a flat sheet of glass would act like a lens, and from this point, the development of the ‘perfect’ or ‘superlens’ began, with the theoretical possibility to image details such as viruses in living cells with a light microscope, bypassing Abbe’s diffraction limit. Metamaterials have been produced that make this possible, as they have a property previously unimagined in optics, and not found in nature, which is a negative refractive index.

The advent of low temperature scanning EM led to a study by Bill Wergin and colleagues from NASA in which they collected samples from different types of snow cover found in the prairies, taiga (snow forest), and alpine environments. With snow depths up to a metre, various layers occurred in which the crystals underwent a change in their microscopic shape from the original freshly fallen crystals, to the development of flat faces and sharp edges. It is this metamorphosis of lying snow that determines the likelihood of avalanches, which can be predicted from the crystal structures at various depths. Although scanning EM (electron microscopy) is hardly available as a routine assay in distant mountain regions, this work helped in the use of microwave radiology investigation of the snow water equivalent in the snow pack, as large snow crystals scatter passive microwave more than small crystals. Smaller and more rounded crystals of snow do not interlock, and can slide more easily over each other, increasing the risk of avalanches.

At one end of the scale, astronomers search the heavens for new information about the universe, whilst at the other end, microscopists chase atoms and molecules to study defects in crystals or the basic processes of life. These investigations may be separated by more than twentyfold orders of magnitude, but are nevertheless driven by the same insatiable curiosity of the human psyche to explore beyond the vision of our own eyes.

I love start gazing in morning, noon and night and anytime, I love smell of soil while raining, I love breezy air, I love twilight, I love petrol or any other natural hydrocarbon smell, I love Rain, Thunder, lightening and other space phenomenon, I love new hard copy book smell, I love taking microscopy pictures of micro organisms and soil, I love wearing white coat and I love hand shakes, small fights that leads to good memories to keep, I did not include my food or dynamic capabilities, music, those are according to situations but the things I mentioned above are my deep interests - But these things I show only If I like the person, else I ignore

From its earliest days, scanning EM proved to be a source of images that everybody could relate to, regardless of a microscopic or indeed even a scientific background. From early images showing great detail of everyday objects and animals, for example the edge of a scalpel or razor blade or the multiple compound eyes of a spider, the extra information provided by the high magnification was instantly apparent, grasping the attention of the general public in a way that transmission EM images did not (Figure 19). Today, images of bacteria, stem cells, and tumour cells are a regular sight in TV news, documentaries, newspapers, and magazines, usually brightly coloured. False or pseudo-colouring of scanning EM images is useful for highlighting specific features, as well as increasing the overall impact, which can sometimes be a little on the garish side.

So far we have considered the effects of varying the type of illumination, so at this point we can sum up how one specimen can be imaged in four separate ways. In a conventional microscope with bright field illumination, contrast comes from absorbance of light by the sample (Figure 7a). Using dark field illumination, contrast is generated by light scattered from the sample (Figure 7b). In phase contrast, interference between different path lengths produces contrast (Figure 7c), and in polarizing microscopy it is the rotation of polarized light produced by the specimen between polarizer and analyser (Figure 7d). This is ‘converted’ into an image that has colour and a three dimensional appearance by the use of Wollaston prisms in differential interference microscopy. For virtually any specimen, hard or soft, isotropic or anisotropic, organic or inorganic, biological, metallurgical, or manufactured, there will be a variety of imaging modes that will produce complementary information. Some of the types of light microscopy we have looked at above have direct parallels in electron microscopy (Chapter 4).

…the only way that we can understand the proportion and range and effect of those changes, which constitute the often undocumented daily texture of our lives (a rough, gravelly texture, like the shoulder of a road, which normally passes too fast for microscopy), is to sample early images of the objects in whatever form they take in kid-memory—and once you invoke those kid-memories, you have to live with their constant tendency to screw up your fragmentary historiography with violas of lost emotion.

In 1676, Antonie van Leeuwenhoek, the father of microscopy, was the first person in history to see bacteria. The following year, he saw his own sperm,308 and a year after that, in 1678, he discovered tiny crystals forming in the semen he had left sitting around.

Hacking human biology Quantum mechanics has the ability to provide us with more knowledge about human biology beyond better disease detection and highly targeted, needle-free therapies. Australian scientists have recently discovered a way to investigate a living cell's inner workings using a new method of laser microscopy based on the concepts of quantum mechanics. And we can use quantum computers to sequence DNA quickly then solve other health-care challenges with Big Data. This opens the possibility of specialized treatment, based on the unique genetic structure of people.

Es passa els matins enganxada al microscopi, diu, i necessita compensar-ho empaitant l'horitzó a la tarda. Creuem quatre paraules, buida el got d'aigua i segueix el seu camí escopetejada. Desapareix en tres segons i sempre em deixa pensativa perquè m'adono que jo tampoc vull passar-me la vida mirant amb microscopi, disseccionant la mostra, provant d'encertar el millor camí. Necessito no fer res, quedar-me aquí.

The focus of the work was on bite mark analysis, but it just as easily could have been shaken baby syndrome, arson investigation, hair microscopy, bullet lead analysis, polygraphs, voice spectrometry, handwriting, bloodstain pattern analysis—the list of discredited forensic techniques is considerable. The question becomes, Why? Why has junk science been accepted by courts, unanimously, for the past fifty years? How does a dentist like Levine become a world-renowned forensic scientist in a field with no basis in science? How many more Keith Harwards are there?

cell, for example, has about 2 m of DNA—a length about 250,000 times greater than the cell’s diameter. Yet before the cell can divide to form genetically identical daughter cells, all of this DNA must be copied, or replicated, and then the two copies must be separated so that each daughter cell ends up with a complete genome. The replication and distribution of so much DNA is manageable because the DNA molecules are packaged into structures called chromosomes, so named because they take up certain dyes used in microscopy (from the Greek chroma, color, and soma, body) (Figure 12.3). Each eukaryotic chromosome consists of one very long, linear DNA molecule associated with many proteins (see Figure 6.9). The DNA molecule carries several hundred to a few thousand genes, the units of information that specify an organism’s inherited traits. The associated proteins maintain the structure of the chromosome and help control the activity of the genes. Together, the entire complex of DNA and proteins that is the building material of chromosomes is referred to as chromatin. As you will soon see, the chromatin of a chromosome varies in its degree of condensation during the process of cell division. Every eukaryotic species has a characteristic number of chromosomes in each cell nucleus. For example, the nuclei of human somatic cells (all body cells except the reproductive cells) each contain 46 chromosomes, made up of two sets of 23, one set inherited from each parent. Reproductive cells, or gametes—sperm and eggs—have half as many chromosomes as somatic cells, or one set of 23 chromosomes in humans. The Figure 12.4 A highly condensed, duplicated human chromosome (SEM). Circle one sister chromatid of the chromosome in this micrograph. DRAW IT Sister chromatids Centromere 0.5μm number of chromosomes in somatic cells varies widely among species: 18 in cabbage plants, 48 in chimpanzees, 56 in elephants, 90 in hedgehogs, and 148 in one species of alga. We’ll now consider how these chromosomes behave during cell division. Distribution of Chromosomes During Eukaryotic Cell Division When a cell is not dividing, and even as it replicates its DNA in preparation for cell division, each chromosome is in the form of a long, thin chromatin fiber. After DNA replication, however, the chromosomes condense as a part of cell division: Each chromatin fiber becomes densely coiled and folded, making the chromosomes much shorter and so thick that we can see them with a light microscope. Each duplicated chromosome has two sister chromatids, which are joined copies of the original chromosome (Figure 12.4). The two chromatids, each containing an identical DNA molecule, are initially attached all along their lengths by protein complexes called cohesins; this attachment is known as sister chromatid cohesion. Each sister chromatid has a centromere, a region containing