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Localized Surface Plasmon Resonance - an overview | ScienceDirect Topics

 https://t.co/mzS7vVSREJ
https://t.co/353PdAX2fa
https://t.co/3yBImjOdd4
In some cases, almost 100% of the light energy can be converted to the second harmonic frequency. These cases typically involve intense pulsed laser beams passing through large crystals, and careful alignment to obtain phase matching.
In other cases, like second-harmonic imaging microscopy, only a tiny fraction of the light energy is converted to the second harmonic—but this light can nevertheless be detected with the help of optical filters.
Generating the second harmonic, often called frequency doubling, is also a process in radio communication; it was developed early in the 20th century, and has been used with frequencies in the megahertz range. It is a special case of frequency multiplication.
An electron (purple) is being pushed side-to-side by a sinusoidally-oscillating force, i.e. the light's electric field. But because the electron is in an anharmonic potential energy environment (black curve), the electron motion is not sinusoidal.
The three arrows show the Fourier series of the motion: The blue arrow corresponds to ordinary (linear) susceptibility, the green arrow corresponds to second-harmonic generation, and the red arrow corresponds to optical rectification.
Electro-optic rectification (EOR), also referred to as optical rectification, is a non-linear optical process that consists of the generation of a quasi-DC polarization in a non-linear medium at the passage of an intense optical beam.
For typical intensities, optical rectification is a second-order phenomenon[1] which is based on the inverse process of the electro-optic effect.
It was reported for the first time in 1962,[2] when radiation from a ruby laser was transmitted through potassium dihydrogen phosphate (KDP) and potassium dideuterium phosphate (KDdP) crystals.
https://t.co/Px03xrubJ0

The term "electro-optic" is often erroneously used as a synonym for "optoelectronic".
Opto-electronics (or optronics) is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics.
In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light.
Optoelectronic devices

are electrical-to-optical

or optical-to-electrical transducers,

or instruments that use such devices in their operation.
Optoelectronics is based on the quantum mechanical effects of light on electronic materials, especially semiconductors, sometimes in the presence of electric fields.
•Photoelectric or photovoltaic effect, used in:
◦photodiodes (including solar cells)
◦phototransistors
◦photomultipliers
◦optoisolators
◦integrated optical circuit (IOC) elements
•Photoconductivity, used in:
◦photoresistors
◦photoconductive camera tubes
◦charge-coupled imaging devices
•Stimulated emission, used in:
◦injection laser diodes
◦quantum cascade lasers
•Lossev effect, or radiative recombination, used in:
◦light-emitting diodes or LED
◦OLEDs
•Photoemissivity, used in
◦photoemissive camera tube
Important applications of optoelectronics include:
•Optocoupler
•Optical fiber communications
An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light.
https://t.co/ku83nBU7Ck

An opto-isolator contains a source (emitter) of light, almost always a near infrared light-emitting diode (LED), that converts electrical input signal into light, a closed optical channel (also called dielectrical channel),
and a photosensor, which detects incoming light and either generates electric energy directly, or modulates electric current flowing from an external power supply.
The sensor can be a photoresistor, a photodiode, a phototransistor, a silicon-controlled rectifier (SCR) or a triac. Since LEDs can sense light in addition to emitting it, construction of symmetrical, bidirectional opto-isolators is possible.
An optocoupled solid-state relay contains a photodiode opto-isolator which drives a power switch, usually a complementary pair of MOSFETs.
A slotted optical switch contains a source of light and a sensor, but its optical channel is open, allowing modulation of light by external objects obstructing the path of light or reflecting light into the sensor.
Electronic equipment and signal and power transmission lines can be subjected to voltage surges induced by lightning, electrostatic discharge, radio frequency transmissions,

switching pulses (spikes) and perturbations in power supply.
Transformers and opto-isolators are the only two classes of electronic devices that offer reinforced protection — they protect both the equipment and the human user operating this equipment.
They contain a single physical isolation barrier, but provide protection equivalent to double isolation.

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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
This nonspecific cation channel opens when illuminated with blue light, depolarizing the cell [4, 6] to trigger action potentials cells with high temporal precision [5]. Since the initial discovery of ChR2, many modifications have been made to refine the kinetic properties.

For example, ChETA, engineered to address limitations of spike fidelity with ChR2, has faster temporal kinetics and can maintain reliable spike precision up to 200 Hz [7].

Halorhodopsins (NpHR), light-gated chloride pumps activated by yellow light, allow for temporally specific hyperpolarization with single spike precision [8–10].

Archaerhodopsin-3 (Arch), a yellow light-activated outward proton pump, is an increasingly popular tool for light-induced hyperpolarization to inhibit cellular activity. Arch recovers spontaneously from inactivation with a much shorter recovery time than NpHRs [11].

Arch currents continue to increase with increasing light intensity, while NpHRs saturate [11]. The increased light sensitivity of the ArchT variant, along with better membrane targeting, allows for improved neural silencing both at cell bodies and terminals [12].
LIFE
NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
During a normal pregnancy, oxidative stress enhances antioxidant mechanisms that are capable of reacting by way of enzyme activity and non-enzyme free radical deactivators. However, pregnancy is also a state in which this adaptation and balance may be easily disrupted.

There is strong evidence that a chronicin flammatory reaction combined with the presence of a local oxidizing environment may play a vital role in the etiology and development of complications during pregnancy.

In late pregnancy, damage to DNA (especially when it is caused by oxidative stress) is associated with pre-eclampsia(PE), intrauterine growth restriction (IUGR), and the death of mothers in developing countries; it largely determines pregnancy – related susceptibility to diseases

The referential values of ROS and NOS and their minimal and safe concentrations or physiologically beneficial concentrations are yet to be determined.

The measurement of oxidative stress in vivo is perceived as controversial,

as the sen-sitivity and specificity of various oxidative stress markers is unknown.. .
HEALTH
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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector.

Viral vectors are tools commonly used by molecular biologists to deliver genetic material into cells.

Viruses have evolved?

specialized molecular mechanisms

to efficiently

transport their genomes

inside the cells they infect.

Delivery of genes, or other genetic material, by a vector is termed transduction and the infected cells are described as transduced.

A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another.
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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
👍🏻


https://t.co/0ywQ1y5NDj

Pott found an association between exposure to soot and a high incidence of scrotal skin cancer in chimney sweeps. This cancer is now known as Pott's or chimney sweep cancer.

Coal contains trace amounts of naturally-occurring radioactive elements. The process of burning coal at coal-fired power plants, called combustion, creates wastes that contain small amounts of naturally-occurring radioactive material (NORM).

Fly ash particles (a major component of coal ash) can become lodged in the deepest part of your lungs, where they trigger asthma, inflammation and immunological reactions.
SONG
NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
2020 marks the start of the quantum dot revolution.

Completely ignoring the fact that "photocatalytic generation of reactive oxygen species (ROS) from quantum dots (QDs) has been widely reported."

Results: It was found that whereas singlet oxygen (1O2) was not produced by photoexcited QDs, superoxide anion(O2− )and hydroxyl radicals(OH) were generated by QDs, especially in the presence of a physiological concentration of electron donating agent including NADH.

Using cell metabolic activity assays and various probes of ROS generation, the formation of ROS in cellular environments was demonstrated.

Conclusion: Illumination of QD-treated cells and bacteria with light did affect viability. The above results, together with those of assays in the presence of various scavengers of specific ROS, indicate that the formation of ROS by QDs mainly proceeded via electron transfer.
FOR LATER READ

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Sri Krishna
Sri Krishna
@tellkrish
With @franklowery our new study on attributes of T cells that contribute to successful cell therapy in cancer patients in @ScienceMagazine today w/ colleagues @slgoff_SB, @NCI_CCR_SB @theNCI a TL;DR thread on key findings with caveats :) 1/10

has a long history of using tumor infiltrating T cells (TILs) to treat cancers since well.. before I was even born. We analyzed our most successful melanoma ACT trial for cell surface phenotypes in TIL infusion products of patients (aPD1/immunotherapy naive) /2

Surprisingly we found a CD39- TIL subset (CD39-CD69-, DN) associated with ACT-response. TBH we were expecting the opposite (CD39+). We only included CD39 bcz multiple groups (e.g. Simoni et al, 2018) had reported CD39+ as enriching for anti-tumor/neoantigen reactive T cells. /3


CD39- DN TILs RNA/epigenetics resemble stem-like memory progenitors, and in vitro were able to self-renew, and give rise to other CD39+ subsets. OTOH the most dominant subset of patient infusion products were CD39+ CD69+ (DP) and these guys were terminally differentiated.. /4


So, to clarify we specifically analyzed tumor-specific mutation-reactive Tcells. Turns out, ACT-responders had pool of neoantigen-reactive TILs in the CD39- phenotype, while non-responders did not (despite other irrelevant CD39- Tcells) -> not all CD39- T cells are bystanders /5
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Jambavan
Jambavan
@SirJambavan
https://t.co/odzm9VTdwZ

Thread for today. /0

It is fashionable for people to create sympathy to the unseen / unknown organisms. The poor things that can't stand up and fight for their own existence.

It makes for a brilliant narrative. It melts your hearts. And you get to play saviour of the oppressed by outraging. /1

But, for most part, such things are also false.

Amazon are the lungs of the world. Never mind that most of the world's oxygen production happens in open oceans. But these are harmless ones. Of course, we all love to maintain forests.

However, some things are sheer scare mongering.

For instance - take this: coral reefs will be permanently gone if mean / median temperatures raise by 1°C ..

But, really - how? Then you get a lecture on how CO2 will affect calcification.

Dig a bit deeper from another angle+

+ and you find that the earth was much much warmer during the age of Dinosaurs. So much so, that we had cold blooded lizards growing to sizes of buildings. Surely, there must have been tons of CO2 then!

And the ocean temps were quite high too.
SCIENCE
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Yardley Yeadon
Yardley Yeadon
@MichaelYeadon3
In a number of Sunday papers:
Scientific advisers said it was “hard to see” when the restrictions would end as new variants continued to emerge, delivering a potentially devastating blow to the travel industry. The prime minister said that after progress with vaccinations...

...”what we don’t want to see is all that work undone by the arrival of a new variant that is vaccine-busting”.
The idea is planted in people’s mind that this virus is mutating in such a way as to evade prior immunity. This is completely unfounded, certainly as regards immunity..

...gained naturally, after repelling the virus (which well around 99.9% of the population do, fewer, obviously in the very elderly & already ill, more in those younger & well). It’s important to appreciate that upon infection, the human immune system cuts up an infectious...

...agent into short pieces. Each of these short pieces of protein are presented to other cells in the immune system, like an identity parade. Our cells have a truly astonishing range of abilities to recognise different protein structures, and there will be some which recognise...

...each of the pieces of the invader. The cells which recognise a piece are instructed to multiply selectively so that, after a few days to a couple of weeks, our bodies contain large numbers of virus piece specific cells. These have a range of functions. Some make antibodies...
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Dr Mark D. Scherz
Dr Mark D. Scherz
@MarkScherz
It's another stunning Malagasy #dartfrog/#poisonfrog for today's #FrogOfTheDay, #42 Mantella cowani Boulenger, 1882! A highly threatened, actively conserved and managed frog from the highlands of central #Madagascar
#MadagascarFrogs
📸D.Edmonds/CalPhotos


This thread will cover only a tiny fraction of the work on Mantella cowanii because, being so charismatic and threatened, it has received quite a bit of attention.
#MadagascarFrogs

We start at the very beginning: the first specimens, two females, were collected by Reverend Deans Cowan in East Betsileo, Madagascar, and sent to London, where George Albert Boulenger described the species in 1882.
#MadagascarFrogs


Boulenger placed the species in his new genus, Mantella, along with ebenaui, betsileo, and madagascariensis. He recognised that the other Malagasy poison frogs were distinct from the Dendrobates of the Americas, although he did keep them in the Dendrobatidae.
#MadagascarFrogs

As more specimens were collected, it became clear that the species was highly variable. In 1978, Jean Guibé wrote with interest about this variability, describing a new subspecies, M. cowani nigricans—today a full species. #MadagascarFrogs
https://t.co/dwaHMbrYbj
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10-K Diver
10-K Diver
@10kdiver
1/

Get a cup of coffee.

In this thread, I'll help you understand the basics of Binomial Thinking.

The future is always uncertain. There are many different ways it can unfold -- some more likely than others. Binomial thinking helps us embrace this view.


2/

The S&P 500 index is at ~3768 today.

Suppose we want to predict where it will be 10 years from now.

Historically, we know that this index has returned ~10% per year.

If we simply extrapolate this, we get an estimate of ~9773 for the index 10 years from now:


3/

What we just did is called a "point estimate" -- a prediction about the future that's a single number (9773).

But of course, we know the future is uncertain. It's impossible to predict it so precisely.

So, there's a sense of *false precision* in point estimates like this.

4/

To emphasize the uncertainty inherent in such predictions, a better approach is to predict a *range* of values rather than a single number.

For example, we may say the index will return somewhere in the *range* of 8% to 12% (instead of a fixed 10%) per year.

5/

10 years from now, this implies an index value in the *range* [8135, 11703]:
SCIENCE

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Hinduism is a minority religion in Punjab.

During the Khalistan movement, the minority Hindus and Jains were subjected to several attacks. Hindu and Jain temples were frequently vandalized and desecrated. This thread documents a few instances.

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Durgiana Mandir is one of the oldest temples of Amritsar. According to the regional Hindu tradition, the temple was built on the spot where Lava and Kusha bound Hanuman. The temple annually attracts millions of Hindus from all over the country.


Amristsar has a very ancient Hindu history.

According to the regional Hindu tradition recorded in the "Survey of Amritsar", Amritsar got its name from Amrit immersed by Lava and Kusha in a pond.


Durgiana Mandir was rebuilt in 1921.

It was used to house the Murtis of Vishnu and Durga which were thrown out from the Parikrama of Harmandir Sahib in 1905.

Because of its presence in Amritsar, it became a frequent target of radicals during the Khalistan movement.


In 1982, in what was a completely unprovoked attack, the Dal Khalsa "activists" threw a severed cow head inside Durgiana temple.
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\u2728Anshika Sharma
✨Anshika Sharma
@Anshi_________
Low-risk, High-return stocks are what we look for relentlessly

But many of them we know but ignore
some of them don't grab financial headlines

Here are 10 low-risk, high return stocks (that we ignore):

What I mean by “high-return”?

These stocks have OUTPERFORMED the market:

💹Chart with upwards trend Since IPO
💹Chart with upwards trend Over the last 5 Years or since IPO

These are all long-term winners that will keep on winning

What do We Mean by “low-risk”?

A combination of:

❣️Great management
❣️Broad moat
❣️Financially strong
❣️High ROCE
❣️Low Disruption/Dilution/Volatility
❣️Consistent Organic Growth
❣️Assorted Customers/Suppliers
❣️Low debt

1-#CDSL

A depository is a big business and will grow continuously, Its a sustainable business
cause "Market hai toh CDSL bhi hai or rahega"


2- #Dixon

High Management Efficiency with a high ROE of 19.30%
Healthy long-term growth as Net Sales has grown by an annual rate of more than 30%
High Institutional Holdings
LOW RISK HIGH RETURN STOCKS , LOW RISK HIGH RETURN STOCKS FOR LONG TERM , LOW RISK STOCK IDEAS
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SK
SK
@sk_diary1
Kolaru Pathigam-Thevaram hymn composed by ThiruGnana Sambandar- #Thread

In Tamil Kol means planets,Aru means cut- set of songs in Kolaru Pathigam addresses all Navagrahas& last 2 lines of every song with end a plea to Bhagwan Shiva to reduce/erase the ill effects of Navagrahas


கோளறு பதிகம் - This pathigam was sung by Thirugnana Sambandar at Thirumaraikadu Kshetram -Vedaranyam,Tamilnadu

Thirugnana Sambandar & Appar(Thirunavukkarasar) travelled together to various Shiva Alayam to spread shivam & bhakti among people.They both reached Thirumaraikadu.


Thirumaraikadu(Vedaranyam) -
Appar & Sambandar were asked to enter the temple through side entrance.The main door was locked by Vedas many years ago.Appar&Sambandar sang devotional hymns praising Shiva, after which the gates opened & closed.After which main door opened for all.


After darshan of Bhagwan Shiva at Thirumaraikkadu,Sambandar received a message to travel to Madurai.
During that time, Samanam was on the rise in the Pandya Kingdom.The Pandya King converted to Samanam.The Queen Mangaiyarkkarasi was a staunch Shiva devotee and was upset.

Kularchirai Nayanar ,Chief Minister of Pandya kingdom was in agony by the turn of events.Queen requested Kulachirai Nayanar to escort Thiru gnana Sambandar to Madurai.Kularchirai Nayanar met Thiru gnana Sambandar at Thirumaraikkadu & requested him to visit Madurai.
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Erik Torenberg
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@eriktorenberg
1/“What would need to be true for you to….X”

Why is this the most powerful question you can ask when attempting to reach an agreement with another human being or organization?

A thread, co-written by @deanmbrody:


2/ First, “X” could be lots of things. Examples: What would need to be true for you to

- “Feel it's in our best interest for me to be CMO"
- “Feel that we’re in a good place as a company”
- “Feel that we’re on the same page”
- “Feel that we both got what we wanted from this deal

3/ Normally, we aren’t that direct. Example from startup/VC land:

Founders leave VC meetings thinking that every VC will invest, but they rarely do.

Worse over, the founders don’t know what they need to do in order to be fundable.

4/ So why should you ask the magic Q?

To get clarity.

You want to know where you stand, and what it takes to get what you want in a way that also gets them what they want.

It also holds them (mentally) accountable once the thing they need becomes true.

5/ Staying in the context of soliciting investors, the question is “what would need to be true for you to want to invest (or partner with us on this journey, etc)?”

Multiple responses to this question are likely to deliver a positive result.
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asif
asif
@aj_raja
PAKISTAN-INDIA WATER ISSUES – HOW INDIA STOPPED WATER IN PAKISTAN's CANALS IN 1948

Thread

After partition in 1947, the water system was also bifurcated between Pakistan n India.

India cheated Pakistan when on April 1, 1948, India suddenly n without warning stopped...
1/n


...the supply of waters flowing into Pakistan's Central Bari Doab and Dipalpur Canals.

The boundary award on the partition of the sub-continent had left the headworks of these canals in Indian territory, and in accepting it India had implied her willingness to leave...

2/n


...the historic distribution of common waters undisturbed.

India's action was therefore in flagrant disregard not only of international law n morality, but of her solemn commitments with Pakistan and a gross violation of this country's historical rights over common waters.

3/n

Faced with a threat of utter desolation of millions of acres of fertile land, Pakistan had perforce to sign a document with India in which she agreed to "India's progressively diminishing water supplies to these canals and to the West Punjab government's tapping...

4/n

...alternative resources".

A specific reservation was made in the document with regard to India's claim that she had full property rights over waters flowing into her territory, and could therefore use them as she liked.

The issue was, however, to be examined...

5/n
INDIA