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Free Stock Photo of ‘Glow Wire’ being shaken and moved in the darkness.
Keywords:
aura,red, beam, black, blue, blur, clean, corona, dark, darkness, energize, energy, expression, fluorescence, fuze, ghost, glo, glow, half, illuminated, illumination, incandescence, inner, layer, light, luminescence, physics, pure, radiation, ray, science, scintillation, signal, source, stick, streamer, swoosh, texture, visible, visual, waved, wire, woosh

421413     การวิเคราะห์โดยการเรืองรังสีเอกซ์     X-ray Fluorescence Analysis

การกระตุ้นอะตอม การเรืองรังสีเอกซ์ ต้นกำเนิดรังสีปฐมภูมิ หลอดรังสีเอกซ์ รังสีทุติยภูมิ หัววัดรังสีเอกซ์ ผลของเมทริกซ์ การวิเคราะห์เชิงคุณภาพและปริมาณ

(Atom excitation, X-ray fluorescence, sources of primary radiation, X-ray tube, secondary radiation, X-ray detectors, matrix effects, qualitative and quantitative analysis.)

(421413 มหาวิทยาลัยเกษตรศาสตร์)

Three papers are out online in Nature Methods that show big improvements in calcium imaging with genetically encoded sensors.  They are are based on the fluorescence intensity indicator, GCaMP.   GCaMP, first developed by Junichi Nakai, consists of a GFP that has been circularly permuted so that the N and C termini are fused and new termini are made in the middle of the protein.  Fused to one terminus is calmodulin and the other is a peptide, M13, that calmodulin (CaM) binds to in the presence of calcium. The name is supposed to look like GFP with a CaM inserted into it, G-CaM-P.  Normally the GFP is dim, as there is a hole from the outside of its barrel into the chromophore.  Upon binding calcium, this hole is plugged and fluorescence increases.

The first paper, A genetically encoded reporter of synaptic activity in vivo, from Leon Lagnado’s group, targets GCaMP2 to the outer surface of synaptic vesicles. This localization allows the fluorescence signal to be confined to the presynaptic terminal, where calcium fluxes in response to action potentials are high.  This targeting improves the response magnitude of GCaMP2 and permits the optical recording of synaptic inputs into whatever region of the brain one looks at.  They demonstrate the technique in live zebrafish.

In the second paper, Optical interrogation of neural circuits in Caenorhabditis elegans, from Sharad Ramanathan’s group, GCaMP2 has been combined with Channelrhodopsin-2 to perform functional circuit mapping in the worm.   Since the worm’s structural wiring diagram has been essentially solved, functional data could say much about how “thick” the wires between each cell are.  Unfortunately, with GCaMP2, the responses are too slow and weak to distinguish direct from indirect connections.

Finally, we have published a paper, Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators, describing the improved GCaMP3.  This indicator has between 2-10x better signal to noise than GCaMP2, D3cpv and TN-XXL, depending on the system you are using.  It’s kinetics are faster and it is more photostable than FRET indicators, and the responses are huge.  When expressed in motor cortex of the mouse, neuronal activity is easily seen directly in the raw data.  Furthermore, the sensor can be expressed stably for months, making it a potential tool for observing how learning reshapes the patterns of activity in the cortex.

Imaging of mouse motor cortex (M1) expressing the genetically-encoded calcium indicator GCaMP3 through a cortical window. After 72 days of GCaMP3 expression, large fluorescence transients can be seen in many neurons that are highly correlated with mouse running.

GCaMP3 is not perfect. It cannot reliably detect single action potential in vivo in mammals, though I doubt that any existing GECI can. Work continues on future generations of GCaMP that may achieve 100% fidelity in optical reading of the bits in the brain. However, there is considerable evidence from a number of groups that have been beta-testing the sensor, including the Tank lab of “quake mouse” fame, that it is a significant leap forward and unlocks much of the fantastic and fantasized potential of genetically-encoded calcium indicators.

Comparison of fluorescence changes in response to trains of action potentials in acute cortical slices.

I will try to post a more complete writeup of GCaMP3 for Brain Windows soon, with an unbiased eye to its strengths and weaknesses.  We worked very hard to carefully characterize this sensor’s effects on cellular and circuit properties.  If you have any questions about GCaMP3, please post them to the comments.

For further info about strategies for GECI use and optimization, check out our previous paper, Reporting neural activity with genetically encoded calcium indicators in Brain Cell Biology.

The official press release from HHMI regarding GCaMP3 is available here.

An article was published in the scientific magazine “Nature” called “Cells go fractal” on September 4th. The article reported on the findings of research done at the European Molecular Biology Laboratory (EMBL) as it was published at the ‘2009 European Molecular Biology Organization (EMBO) conference’ held in Amsterdam.

Experiments done by Sebastien Huet and Aurélien Bancaud in a research group led by Jan Ellenberg at the EMBL in Heidelberg, Germany, tracked the movement of molecules within cells, this was then compared the pattern of movement against mathematical models. It was found that, large molecules moved according to the same rules as small molecules, suggesting that their environment was therefor fractal.

The researches were able to track the behaviour of the cells by means of injecting live mouse cells in a lab dish with fluorescent molecules. They were able to track the molecules with this special type of imaging in microbiology called fluorescence microsopy. The study focused on how cells can keep track of gene activity or gene expression through chromatins in the cell nucleus.  Basically this process takes place to ensure the right molecules interact with each other at the right time and in the right place in the cells. Huet and Bancaud found that the molecules moved as if they were having to navigate obstacles (but there are no barriers, as they exist in other parts of the cell) to navigate around in the cell nucleus. When the team looked at the behaviour of different sized molecules, they saw that large molecules were obstructed to the same degree as small molecules in the cell nucleus.

It was furthermore discovered by studying how proteins, bound to different kinds of chromatin (namely Euchromatin and Heterochromatin), moved around in the cells and found that the different types of chromatin were fractal in different ways. Meaning molecules behaved differently for each type of chromatin with its own distinct fractal characteristics. All this information could be used to learn exactly how cells use a fractal structure to change the behaviour of proteins to change particular DNA sequences and skip whole other parts of the DNA sequence. It’s also expected that with insight into these fractal structures researches can learn how to better target certain areas of DNA for study or perhaps in the future even for new types of treatment for disease.

Links:
http://www.nature.com/news/2009/090904/full/news.2009.880.html
http://www.nature.com/
http://fractuality.wordpress.com/files/2009/10/cells-go-fractal.pdf

http://www.embl.de/
http://www.embo.org/

http://www.embl.de/research/units/cbb/ellenberg/members/index.php?s_personId=4421
http://www.embl.de/ExternalInfo/ellenberg/homepage/bancaud.html
http://www.embl.de/research/units/cbb/ellenberg/members/index.php?s_personId=939
http://www.embl.de/ExternalInfo/ellenberg/homepage/labmembers.html

http://en.wikipedia.org/wiki/Microbiology
http://en.wikipedia.org/wiki/Cell_(biology)
http://en.wikipedia.org/wiki/Molecule
http://en.wikipedia.org/wiki/Fluorescence_microscopy
http://en.wikipedia.org/wiki/Gene_expression
http://en.wikipedia.org/wiki/Cell_nucleus
http://en.wikipedia.org/wiki/Chromatin
http://en.wikipedia.org/wiki/Euchromatin
http://en.wikipedia.org/wiki/Heterochromatin
http://en.wikipedia.org/wiki/Protein
http://en.wikipedia.org/wiki/DNA_sequence

Depuis Dan Flavin, on sait que le tube fluorescent (souvent appelé à tort néon) est un matériel artistique de premier choix, même s’il évoque plutot au oreille du grand public l’abomination en matière d’illumination. C’est peut-être plus le fait d’une mauvaise utilisation que d’un mauvais matériel. Les œuvres de l’artiste Israélien Yochai Matos ne dérogent pas à cette tradition d’excellence du tube fluorescent. Répétons le : les fluo, du bon matos! Démonstration sur le site de l’artiste

Flame (Gate), Yochai Matos 2009 - Photo Lovis Ostenrik

Flame (Gate), Yochai Matos 2009 - Photo Lovis Ostenrik

Flame (Gate), Yochai Matos, 2009. photo Lovis Ostenrik

D’autres œuvres valent le détour : je ne vais pas vivre éternellement, coucher de soleil, éclipse, etc.

Sunset - Yochai Matos -2008

I'm not gonna live forever - Yochai Matos - 2009

Sunset - Yochai Matos - 2008

I'm not gonna live forever - Yochai Matos - 2009

Source : Flores en el Atico otra vez…

One of the most time consuming and frustrating tasks associated with fluorescence imaging in the brain is picking out your regions of interest.  Which pixels do you include in as part of the cell and which are part of the surrounding neuropil?  Often, the answer is not obvious, and even with painstaking selections you can make errors.  Eran Mukamel et. al, from Mark Schnitzer’s lab just published this Neurotechnique Automated Analysis of Cellular Signals from Large-Scale Calcium Imaging Data that aims to simplify and improve the results of ROI selection. 

The authors used a multistage approach to identify and quantify the calcium-dependent fluorescence changes of imaged neurons. First, they used principal component analysis to identify the components of the image that were likely calcium signal related and which were noise.  The sparse nature of the calcium response (calcium transients are brief and spatially confined) helped the separation from the noise. They threw the noise away.  Then they used independent component analysis to pick out which components of the calcium signal changed in a manner independent from other pieces of the signal.  These likely represent individual cells. Using this output, they performed auto-segmentation of the image into numerous individual neurons or processes and measured the fluorescence change in those regions.  In simulations of data, it resulted in superior data fidelity over hand drawing ROIs.  They also validated it with real in vivo calcium imaging.

Automated Cell Sorting Identifies Neuronal and Glial Ca2+ Dynamics from Large-Scale Two-Photon Imaging Data

Whether its neuronal imaging, high-speed motion tracking or multielectrode recordings, tremendously large data sets are currently being generated in systems neuroscience. It is simply impossible for a single post-doc to crunch all of her data without major automated computational techniques.  In calcium imaging, the resources that have been poured into the development and release of powerful new tools requires an equal effort on the data analysis end to maximize the value of this technique.  The automated algorithms presented in this paper look very promising and we will definitely be checking them out in the near future.

Chapter 9

Methods to Assess Tissue Permeability

Juan C. Ibla and Joseph Khoury

© 2006 Humana Press Inc. 999 Riverview Drive, Suite 208 Totowa, New Jersey 07512

Summary

An essential requirement for adequate organ performance is the formation of permeability barriers that separate and maintain compartments of distinctive structure. The endothelial cell lining of the vasculature defines a semipermeable barrier between the blood and the interstitial spaces of all organs. Disruption of the endothelial cell barrier can result in increased permeability and vascular leak. These effects are associated with multiple systemic disease states. The mechanisms that control barrier function are complex and their full understanding requires a multidisciplinary approach. In vivo permeability data often complement molecular findings and add power to the studies. The interaction of multiple cell types and tissues present only on mammalian models allow for testing of hypothesis and to establish the physiological significance of the results. In this chapter, we describe methods that can be used systematically to measure the permeability characteristics of several organs.

Download Full PDF

The Day-Glo Brothers

The True Story of Bob and Joe Switzer’s Bright Ideas and Brand-New Colors

By Chris Barton

Illustrated by Tony Persiani

Charlesbridge, 2009

ISBN #978-1-57091-673-1

NF picture book; ages 8-12

*Nominated for a Cybil

Even if they’d wanted to, the ancient Egyptians couldn’t have painted their pyramids a green that glowed in the desert sun. Back in 2600 BCE, there was no such color.

Later in the book:

By accident, Joe and Bob had invented a totally new color. To their amazement it glowed in both daylight and ultraviolet light. The called this new color Fire Orange, and Joe used their newfound know-how to create other colors–glowing reads, yellows, greens, and more. Meanwhile, Bob looked for ways these “Day-Glo” colors could be used. World War II provided lots of them.

It’s hard to imagine a world without the Day-Glo colors in shocking greens, blazing oranges, and screaming yellows. But before World War II, those colors didn’t exist. This fascinating picture book, chock full of well-explained information, traces the invention of Day-Glo paint and the two men who developed it following an inopportune accident in the ketchup factory by one brother and an interest in magic by the other.

Explanations about light, fluorescence, and refraction fit nicely into the narrative of the brothers’ lives as Barton details the steps of their progress. The quality writing in this glowing nonfiction makes the story readable and the interesting stages along the way keep the pace brisk.

Bright endpapers reflect the Day-Glo colors and welcome the reader to something special inside. The illustrations begin in black and white and color is gradually added to the stylistic art until the Day-Glo colors appear in screaming brilliance in the final spreads. Additional information follows the story, along with an author’s note and how he heard of the Switzer brothers.

The Charlesbridge Publishers site has a fun interactive link and explanation of fluorescence and Day-Glo along with links to the source information.

Activity 1

Research fluorescence and daylight fluorescence. Find out how ultraviolet makes colors glow.

This site gives an explanation about the visible light spectrum.

Here’s another site for understanding visible light. 

Activity 2

Find out about what makes up white light and how this light makes a rainbow. Here’s an explanation of how rainbows form.

Make your own rainbow.

Learn more about Chris Barton.  He blogs, too!  Buy the book!

National Science Standards: properties of objects and materials; light, heat, electricity, and magnetism.

See an in-depth review at Fuse 8 Production

Abby (the) Librarian also has a review.

Scientists at Heidelberg University, Germany have developed a new technique for localization microscopy, the “spectral precision distance microscopy” (SPDM). Using visible light, this method allows a single molecule resolution of celullar structures down to the range of few nanometer, about 20 times better than the conventional optical resolution. The researchers invented a new instrument which is a combination of the world’s fastest nano light microscope for 3D cell analysis and the new SPDM technique. Prof. Christoph Cremer of the Kirchhoff Institute of Physics and his team were able to show that SPDM can be realized by common fluorescent dyes, such as the green fluorescent protein (GFP) which can be switched on and off by means of light, as long as certain photophysical conditions are fulfilled. This can be achieved via the so-called “reversible photobleaching” of the dye. So far, only special fluorescent dyes could be used as temporally convertible light signals. According to Cremer there are millions of specimens containing gene constructs with dyes from the GFP group available in biomedical laboratories all over the world. They could be put into immediate use for this new kind of localization microscopy.
www.uni-heidelberg.de

Researchers at the University of California, Berkeley, US have developed the CellScope – a new microscope that can be attached to a common mobile phone with a camera to take color images of microorganisms. The CellScope consists of compact microscope lenses fitted in a holder, which is positioned in front of the mobile phones camera. By using an off-the-shelf phone with a 3.2 megapixel camera, the researchers were able to achieve a spatial resolution of 1.2 micrometers. In this way they were able to capture bright field images of Plasmodium falciparum, the parasite that causes malaria in humans and sickle-shaped red blood cells. They were also able to take fluorescent images of Mycobacterium tuberculosis, the bacterium that causes TB in humans. The development of CellScope moves a major step forward in taking clinical microscopy out of specialized laboratories and into field settings for disease screening and diagnoses. “The same regions of the world that lack access to adequate health facilities are, paradoxically, well-served by mobile phone networks,” said Dan Fletcher, UC Berkeley associate professor of bioengineering and head of the research team. “We can take advantage of these mobile networks to bring low-cost, easy-to-use lab equipment out to more remote settings.”
www.berkeley.edu

CellScope prototype configured for fluorescent imaging (taken by David Breslauer, UC Berkeley)

As with all things that might attract someone’s attention, it is amazing how many details can be discovered about any subject.

In the case of phytoplankton, I find it fascinating that these small organisms can not be observed by the naked eye, but their presence is rather easily detectable from space. As an example, you may want to look at the links on the right side of this page, under ‘Science’ and click on the link ‘Global fluorescence‘, where you will find a NASA publication on how the microscopically small phytoplankton cells can be observed with satellites.

Fluorescence? Fluorescence is light which is emitted from an object, a short time after that same object had absorbed light of a shorter wavelength (so fluoresced light is a bit more reddish then the slightly more blueish light which was absorbed).

Well, in case of phytoplankton, fluorescence is one way in which the light energy (from the sun) which was absorbed, can be safely dissipated if it could not be used by the phytoplankton to support their immediate energetic needs. So it is a loss factor, and it can be used to measure how efficient the cells are carrying out their life supporting functions. Knowing this efficiency is as valuable to the ability to judge the health of phytoplankton as is a cardiogram for a physician when he examines a patient.

For many years, I was so facinated by this phenomenon, that I wanted to learn as much as possible about it. Then, after learning how to measure this emitted light, and used it to understand under which condition phytoplankton feels well (or not), I wanted to dig deeper into this phenomenon.  It ended up in a situation, where I had collected enough nifty details, that, when put together as mathematical equations in a model, I hoped that the equotion would allow me to create signals exactly such as observed in nature, and when so, that I could ‘look’ at the invisible processes which were now made visible by equations. Since the equations were a reflection of existing structures, the whole effort helped me to better understand how the whole energy generating machinery was functioning. Anyhow, I wrote it up for fun, long after I left science, and I put it here for those who wish to understand why we can see phytoplankton from space, and those who study phytoplankton and wish to understand some more details.

Just click the link below:

From Electrons to Biomass

Do note, that if you are one of the few who opens this link above, you join most probably only a few people on this earth who are interested in the most fundamental processes of our earth!

Un laboratoire de l’Institut central d’expérimentation animale de l’Université Keio au Japon, vient de servir de lieu de naissance à un singe fluorescent. Son père était fluorescent, il est fluorescent, la grande première n’est pas d’arriver à implanter une protéine fluorescente dans le génome d’un être vivant, mais que ce gène soit transmis à la génération suivante. On connait la capacité des Japonais à inventer toute sorte de jeux, mais cette fois ce n’est pas pour des raisons ludiques que cet animal a été génétiquement modifié. Les expériences conduite sur le Marmouset ouvrent la voie à des manipulations génétiques ; l’étape suivante est l’implantation de maladies – parkinson, sclérose latérale amyotrophique. L’utilité de ces recherches est contesté par certains scientifiques, qui font remarquer que cette espèce de singe est plus éloignée des humains que d’autres. Quoique… Certains humains se sentent proches du singe et ne se privent pas de le faire savoir !

La molécule intégré au patrimoine génétique du Marmouset a été piqué sur une méduse. Il faut allumer une lampe à ultra-violet pour observer son singe vert luire dans la nuit.

Plus d’info par ici

Together with his research team, Professor Vasilis Ntziachristos from the Helmholtz Zentrum Munich, Germany and the Technical University Munich, Germany developed a new technology to make light audible. The technique, called multi-spectral opto-acoustic tomography (MSOT), combines light and ultrasound to visualize fluorescent proteins that are seated several centimeters deep into living tissue.
The researchers used a genetically modified adult zebra fish which carried fluorescent pigments in its tissue. They illuminated the fish from multiple angles using flashes of laser light that are absorbed by the fluorescent pigments in the fish. The pigments absorb the light, a process that causes slight local increases of temperature, which in turn result in tiny local volume expansions. This happens very quickly and creates small shock waves. In effect, the short laser pulse gives rise to an ultrasound wave that the researchers pick up with an ultrasound microphone. To analyze the resulting acoustic patterns, a computer is attached. The computer uses specially developed mathematical formulas to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image. In the future this technology may facilitate the examination of tumors or coronary vessels in humans.
www.helmholtz-muenchen.de/en

Multi-spectral opto-acoustic tomography or MSOT allows the investigation of subcellular processes in live organisms.

By: Laurie Neilsen

When many people think of UV lights or black lights, they think of posters in college dorm rooms, or spooky Halloween displays. Ultraviolet light, however, is an important subject of scientific study. Occupying the segment of the electromagnetic wavelength spectrum between 10 nm and 400 nm, Ultraviolet light is invisible to the human eye. UV lights are often referred to as “black” lights because of this.

The Ultraviolet Flashlights available from Educational Innovations emit long-wave UV light at 385 nm. When the invisible ultraviolet light shines on a fluorescent substance, the light reflected back is slightly less energetic. The loss of energy lengthens the wavelength of the light, bringing it above 400 nm, and into the visible spectrum. Materials which have this reaction to UV light are all around us in our daily lives.

I went home one day with one of our 51-bulb Long-Wave UV Flashlights to make note of what in my apartment does and does not fluoresce. Some were items I expected, like white paper. Many of my books and many of the labels on products throughout my home glowed brightly under the UV light. Likewise, many white fabrics also fluoresced, including dryer sheets and some old insulation around our doorways. The text on one of my posters seemed to nearly jump off the paper, even though it is not a poster designed to make college students say “whoa.”

I was not surprised to find that many items commonly called “neon” glow under a blacklight. There were several Lego pieces which glowed quite brightly, usually the headlights on the vehicles. Any brightly colored labels or plastic packaging lit up, as did some clear plastic packages. I was surprised to see that some of the glasses in my cupboard seemed to glow faintly, usually those with thick bottoms.

A trip into my pantry revealed a few surprises. Both shortening and canola oil reacted to the light, as did tonic water. The bright packaging of my cheese snacks reacted, but the cheese snacks themselves did not glow as brightly as I thought they might. I knew that liquid detergent is reactive to UV light, but I use powder detergent. Although it did not all glow, there were several brightly glowing particles within the detergent. I wonder if this is what is used to make white clothes look whiter.

I looked into my jewelry box to see that a few of the beads were glowing. I have a necklace from the people who bring us our Real Cool Bugs. Mine has a green chafer beetle in it, whose eyes apparently react to UV light. It looked as if I had somehow turned its little headlights on.

As I wandered through the apartment, I noticed that the dust (in what I thought was a pretty clean apartment) was glowing under the UV light. I turned the flashlight on my skin, and saw that I fluoresce as well. Perhaps I should get out in sunlight a little more often.

Remembering far too many crime shows from television, I turned the light on my floor. I saw something glowing brightly on one of the rugs. With the lights on, there appeared to be nothing there. I am assuming the crime that took place there involved a ball of fur escaping the confines of my cat’s stomach. I then made the grave mistake of turning the light on my tub and sink in the bathroom. Do yourself a favor, and never look at your tub in the dark with a UV light. I’m hoping soap scum was the reason for the streaks and spots that I saw. If I ever want to sleep again, that was just soap scum.

Having explored most of my home, I turned the UV light onto the walls. I could clearly see the spots where holes in the plaster walls were filled in, and possibly painted over with new paint. The old paint on the walls had no reaction at all to the light, despite being white paint. Newer paint has brighteners that cause a reaction to UV light. Considering how old the house is, and how much the plaster walls tend to break apart in big chunks when drilled into, a UV light could be a handy tool in finding places where a hole might be easier to drill.

Science is about asking questions and finding answers. Therefore, the Scientific Process requires a healthy dose of curiosity. Send your students on their own ultraviolet scavenger hunts, and see what they find. The answers may surprise you.

The Fluorescence Education Center, also referred to as the Fluorescence Foundation, will host two courses on the principles of fluorescence techniques to be held from:
June 29 – July 2, 2009 in Genova, Italy
and
September 14-17, 2009 in Madrid, Spain

The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications.

Topics addressed in this course include:

- Basic Definitions and Principles of Fluorescence
- Fluorescence Polarization
- Time-resolved Fluorescence
- Instrumentation
- Data Manipulation and Data Analysis
- Non-Linear Microscopy Including SHG
- GFP Fluorescence and Photoactivation
- Confocal and Multiphoton Fluorescence Microscopy
- FCS, Fluorescence Correlation Spectroscopy
- FLIM, Fluorescence Lifetime Imaging
- Single Molecule Imaging
- Image Processing and Deconvolution Approaches

www.fluorescence-foundation.org

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Theabove mogok ruby belong to .03-o.0 around CT, No Mong Htsu heated rubies. Right now 2.29CT ruby for sale being dotted around silk inclusions, a bit calcite inclusions, a bit bubbles inside, and dotted short needel incsions

http://shouten.tripod.com/index.html

in the Japanese homepage, 2.29CT ruby showed. We do not mind SSEF or gubelin certificate as for this ruby

http://members.at.infoseek.co.jp/kazuochocholatt/index-30.html

In that, mandaley jaydiet is also contained, stocked.

For gemstones customers please forget about used cars in the same space,

I handle only Burma ruby and sapphires unheated, no other stones such as Mong Hstsu rubies, srilankan rubies, sapphires–I just handle used cars and only Burma ruby and sapphires

http://www.apsara.co.uk/content/view/41/27/

The above is very nice site for Mogok gems inclusions. and very easy recognition.

We can go anyway you like as certified. Nobody buy ours gems unless certified, not our certifiy, but you must certify in your contry

La fluorescenza è la propietà che hanno determinate sostanze, di riemettere a frequenza più bassa le radiazioni ricevute, in particolare di assorbire la luce ultravioletta ed emettere nello spettro del visibile.

Vediamo un esempio pratico:

prendiamo un foglio di carta formato A4 e scriviamo  con degli evidenziatori: giallo, verde, arancione e fucsia.

Illuminiamo il foglio con una lampada di Wood……ed ecco cosa vediamo:

gli evidenziatori che emettono nel visibile sono il giallo, il verde, e l’ arancione, il fucsia pochissimo….e perchè quest’ ultimo emette pochissmo??

Penso che ci siano 2 ipotesi (o più):

la prima è che ci sono pochissimi colori fluorescenti,

la seconda è che la mia lampada non ha la frequenza giusta per eccitare le sostanze presenti nel fucsia…

Sicuramente molti di voi, avranno notato però anche altro:

il foglio bianco emette nel blu…..questo è dato dalla presenza nel foglio di determinate sostanze, chiamate sbiancanti ottici, che sono presenti anche nei detersivi per il bucato, e che hanno il compito di donare al foglio o ai capi, quello che viene definito “più bianco non si può“.

In assenza di queste sostanze i fogli ed i capi apparirebbero gialli, quest’ ultimi anche se appena lavati, cosa non molto gradevole a vedersi.

Ora però proviamo ad eliminare il blu del foglio per concentrarci sugli evidenziatori, utilizzando un programma di fotoritocco eliminiamo la componente del colore che non ci interessa.

Ecco il risultato:

ora il fucsia si vede leggermente di più, il giallo è distinguibile dal verde,  l’ arancione è  arancione e non rosa come sembrava.

Infine la prova del 9: poniamo un filtro taglia UV (non fa passare UV), per vedere cosa succede:

Si vede chiaramente che l’ emissione, dei colori al di sotto del filtro è molto minore rispetto ai circostanti.

La  fluorescenza viene spesso usata in ambito bio-medico, ad esempio quando vengono eseguite biopsie e quindi preparati istologici, in cui si mettono in evidenza particolari antigeni tramite anticorpi “coniugati” con particolari sostanze fluorescenti: i fluorocromi.

Successivamente si osserva al microscopio illuminando il preparato in diascopia (dall’ alto), con luce UV,  saranno quindi visibili solo le porzioni che contengo gli antigeni riconsciuti dagli anticorpi.

Nella foto seguente, un glomerulo renale, in caso di LES.

Da: www.patologinfiore.it

Altri esempi in ambito bio-medico, possono essere le proteine denaturate, che sono autofluorescenti, oppure i tessuti che sono stati sottoposti a livelli glicemici elevati per lunghi periodi, anch’ essi autofluorescenti.

Alla prossima.

Here is an example:

take a sheet of A4 paper and write with highlighters: yellow, green, orange and fuchsia. 

Enlighten the sheet with a black light …… and that’s what we see:

the markers that emit in the visible are yellow, green, and orange, fuchsia very little …. and why’ s very little?

I think there are 2 cases (or more):

The first is that there are very few fluorescent colors,

the second is that my lamp does not have the right frequency to excite the substances in fuchsia …

Surely many of you have noticed but even more:

emits a clean sheet in the blue ….. this is the presence in the form of certain substances, called optical brighteners, which are also present in laundry detergents, which are responsible for donating the sheet or to the dress, that which is defined as “more white you can not.”

In the absence of these sheets and dress appear yellow, even if just washed but not very pleasant to see.

But now we try to eliminate the blue sheet to focus on the markers, using a photo editing program to remove part of the color that we are not interested.

Here’s the result:

fuchsia now you see a little more, the yellow is distinguishable from the green, the orange is orange, not pink as it seemed.

Finally, the proof of 9: we put a UV filter size (it does not pass UV), to see what happens:

It is clear that the issue, the colors below the filter is much smaller than the surrounding.

The  fluorescence is often used in bio-medical, for example, when biopsies are performed and then histological preparations, which highlight specific antigens using antibodies “married” with special fluorescent substances: the fluorochromes.

Subsequently observed under the microscope illuminating the preparation in diascopia (from high), with UV light, will be visible only the portions that contain antigens recognized by antibodies.

In the photo below, a renal glomeruli, in the case of LES. 

Other  examples in bio-medical, may be the denatured proteins, which are autofluorescence, or tissues that have been subjected to high blood sugar levels for long periods, also they autofluorescence.

To the next.

The “Superresolution” research network, founded by the German Ministry of Education and Sciences, demonstrated a new widefield microscopy technology with resolutions better than 20 nanometers. The method is based on special dyes, which’s fluorescence can be optically and reversibly switched on and off in aqueous solutions. The dyes are bond to cellular structures by using a functional group. By switching the dyes on and off, the fluorescence emission is separated in time until only those dye molecules fluoresce that have enough distance to allow their localization as single molecules. After several thousand switching cycles, a total image is constructed (dSTORM – direct stochastic optical reconstruction microscopy). Involved in the project were the work groups of Prof. Dr. M. Sauer and Prof. Dr. J. Mattay (University of Bielefeld, Germany ), Prof. Dr. K.-H. Drexhage (University of Siegen, Germany), Prof. Dr. J. Enderlein (University of Goettingen, Germany), and Prof. Dr. S. Hell (Max Planck Institute of Biophysical Chemistry, Goettingen, Germany).
www.biophotonik.org

Cytoskeleton of a fixed cell. Left: Fluorescence image at standard conditions. Right: dSTORM image using molecular switches.