These lectures has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/ocular-ultrasound/❤❤
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Ocular Ultrasonography (Ocular USG/ Ophthalmic USG), ophthalmic ultrasound/ ophthalmic ultrasonography/ ocular ultrasound/ Ultrasound of eye and orbit
PRESENTATION LAYOUT
Introduction
History
Physics
Principles & instrumentation
Terminologies
Indications & contraindications
Methods - A-Scan - B-Scan
Interpretation
Definition
Ultrasound Waves are acoustic waves that have frequencies greater than 20 KHz
The human ear can respond to an audible frequency range, roughly 20 Hz - 20 kHz
......................
For Further Reading
Clinical Procedures in Optometry by J. D. Barlett, J. B. Eskridge & J. F. Amos
Ophthalmic Ultrasound: A Diagnostic Atlas by C. W. DiBernardo & E. F. Greenberg Internet
These lectures has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh
This lecture is based on post-graduate students of Ophthalmology (DO, DCO, MCPS, FCPS, MS) and optical principle of LASER, construction of laser and laser tissue interaction has cover the lecture
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/ocular-ultrasound/❤❤
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Ocular Ultrasonography (Ocular USG/ Ophthalmic USG), ophthalmic ultrasound/ ophthalmic ultrasonography/ ocular ultrasound/ Ultrasound of eye and orbit
PRESENTATION LAYOUT
Introduction
History
Physics
Principles & instrumentation
Terminologies
Indications & contraindications
Methods - A-Scan - B-Scan
Interpretation
Definition
Ultrasound Waves are acoustic waves that have frequencies greater than 20 KHz
The human ear can respond to an audible frequency range, roughly 20 Hz - 20 kHz
......................
For Further Reading
Clinical Procedures in Optometry by J. D. Barlett, J. B. Eskridge & J. F. Amos
Ophthalmic Ultrasound: A Diagnostic Atlas by C. W. DiBernardo & E. F. Greenberg Internet
These lectures has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh
This lecture is based on post-graduate students of Ophthalmology (DO, DCO, MCPS, FCPS, MS) and optical principle of LASER, construction of laser and laser tissue interaction has cover the lecture
spectrophotometer.pptx,DNA/RNA Quantification,clinical diagnosis, protein ana...Parthvi Soni
Spectrophotometry is a powerful analytical technique that plays a crucial role in scientific research and industrial applications. By measuring the absorbance of light by a sample, spectrophotometers provide valuable information about the concentration and characteristics of substances. Understanding the principles, components, and applications of spectrophotometry enables scientists and professionals to utilize this technique effectively for a wide range of analyses. As technology advances, spectrophotometry continues to evolve, offering greater precision, versatility, and efficiency in the pursuit of scientific knowledge and innovation.
These lecture has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh
These lectures has prepared for postgraduate student (Ophthalmology) according to the curriculum of Bangladesh College of Physician and Surgeons (BCPS) and Bangabondhu Sheikh Mujib Medical University (BSMMU) Bangladesh
Light Amplification by Stimulated Emission of Radiation. Its basic principle of working, features or characteristics, types, applications, hazards caused by LASER and future scopes.
This lecture is based on medical students those are preparing for postgraduate degree namely FCPS/MS/MD/ any any subject coz hypertension is a systemic disease and by seeing the ocular fundus we can asses the general condition of blood vessels in major organ.
This lecture is based on post-graduate students of Ophthalmology (DO, DCO, MCPS, FCPS, MS) and optical principle of GAT has to know for a student to use the instrument friendly
This lecture is based on post-graduate medical students of all subject those who are students MS/MD/FCPS of different subject on Central Tendency and Dispersion.
This is the 5 th lecture on "Research Methodology through zoom. The lecture was based on postgraduate Medical students those are different courses of FCPS/MS/MD/PhD (any Specialty)
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
The Gram stain is a fundamental technique in microbiology used to classify bacteria based on their cell wall structure. It provides a quick and simple method to distinguish between Gram-positive and Gram-negative bacteria, which have different susceptibilities to antibiotics
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
2. Laser vs Light
Laser Light
Stimulated Emission Spontaneous emission
Monochromatic Polychromatic
Highly energized Poorly energized
Parallelism Highly divergence
Coherence Non Coherence
Can be sharply focussed Can’t be sharply focussed
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3. History of Laser
• 1960: The first laser was built by Theodore Maiman using a
ruby crystal medium.
• 1963: The first clinical ophthalmic use of Laser in human
• 1968: L Esperance developed the Argon Laser
• 1971: Neodymium Yttrium aluminum garnet (Nd:YAG) and
Krypton Laser develop
• 1983: Torkel developed the Excimer Laser
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4. What is laser?
Laser is the acronym of
• L: Light
• A: Amplification by
• S: Stimulated
• E: Emission of
• R: Radiation
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5. Laser physics
• Laser as electromagnetic waves emitting radiant energy in tiny
package called quanta/photon. Each photon has a characteristic
frequency and its energy is proportional to its frequency
• Three basic ways for photons and atoms to interact.
i. Absorption
ii. Spontaneous Emission
iii. Stimulated Emission
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7. Properties of laser
1) Laser is monochromatic
2) A particular laser has single wavelength
3) This depends on the medium used
4) It cannot be white
5) It is always coloured, i,e green, blue-green etc
6) It is coherent, i,e each wave (photon) is in the same phase as
the next.
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8. Properties of laser
7) It is collimated, i, e rays (photon) are exactly parallel
8) Polarization: The photons vibrate in the same plane
9) It produces bright light
10) It produces intense heat & energy at short distance
11) Laser can burn, coagulate, evaporate & disrupt
12) It can be concentrated in a very small area
(Ref: Manual of Optics & Refraction PM Mukherjee Page: 2.3.4)
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9. Properties of laser
• The light emitted from a laser is monochromatic, that is, it
is of one wavelength (color). In contrast, ordinary white light
is a combination of many different wavelengths (colors).
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10. Properties of laser
• Lasers emit light that is highly directional. Laser light is
emitted as a relatively narrow beam in a specific
direction. Ordinary light, such as coming from the sun, a light
bulb, or a candle, is emitted in many directions away from the
source.
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11. Properties of laser
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The light from a laser is said to be coherent, which
means the wavelengths of the laser light are in phase
in space and time
13. Different issues to know to understand laser
In order to understand the basic principle of a
laser, it is
instructive to first consider a
passive resonator ("cavity"),such as an
arrangement of mirror that creates a closed path
for a light beam.
The simplest configuration is made with only
two mirror, one being flat and one being curved.
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14. Different issues to know to understand laser
However, its optical power will decay, as some energy is lost in
every resonator round trip. A so-called gain medium can now be
inserted that, when supplied with energy ("pumped").
If the gain g is lower than the resonator losses l, the power
decay is only slowed down. For g = l, the optical power stays
constant; and for g > l, the power rises with each round trip.
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15. Different issues to know to understand laser
• The latter condition can not be maintained
forever; sooner or later, the high intra cavity
intensity will saturate the gain.
• In the steady state, as reached after some time,
the gain will be exactly sufficient to compensate
for the resonator losses. We then have
continuous-wave laser operation with constant
optical power and g = l.
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16. • For extracting a laser beam as a useful
output of the device, the left mirror, for
example, acts as an output coupler,
transmitting some percentage (say 10%)
of the intra cavity power.
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17. Different issues to know to understand laser
1.Spontaneous absorption- electron will move from
low energy level to high energy level by absorbing
photon
2.Spontaneous radiation- electron will move from
high energy level to low one by releasing photon
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22. Three basic components of Laser
A Laser medium
• e,g solid, liquid or gas
Exciting method
• Light or electricity
Optical cavity (Laser tube)
• Around the medium acts as a resonator
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23. Construction of Laser
• Laser consists of a cylinder that may be solid or
hollow; latter is filled with gas, liquid or a
combination.
• These substances should have ability to absorb
energy in one form and emit a new type of more
useful energy. The energy can be thermal,
mechanical, light or electrical. The process of
conversion is called lasing.
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24. Construction of Laser
A cavity of the cylinder has two concave
mirrors at each end. One of them is fully
reflective. The mirrors are coated with thin
film of dielectric that reflects light close to
the wavelength of the laser light. The other
mirror is located on the other of the tube.
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25. • The focal length of each mirror almost
coincides with the centre of the tube The
second mirror is partially reflective and is
considered to be leaky.
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26. Construction of Laser
There are two slanting windows that close
each end of the tube.
The cavity or the rod is surrounded by
source of energy that raises the energy
level of the atoms within the cavity to a
high level in a very unstable state.
This is called population inversion.
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27. The next step is spontaneous decay of the
energized atom to a lower energy level.
This phenomena is the basis behind the
release of high energy in the form of light
that is converted to suitable wavelength.
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28. Construction of Laser
• Thus, to summarized, there are 2 steps:
1) Population inversion in active medium
2) Amplification of appropriate wavelength.
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29. The energy stored in the laser material, i,
e, gas, liquid or solid, is released in a
narrow beam of monochromatic light.
This light is a source of high thermal
energy, which is used in ophthalmology
for various purposes.
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30. Previously, we discuss that one mirror is
partially transparent, some of the light is
allowed to leave the tube.
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31. • This light will be coherent (the wave fronts in
phase),
• monochromatic (one wave length) and
• collimated (all the rays parallel).
Light is produced continuously, and such a laser
is said to be operating in continuous-wave (CW)
mode.
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32. Laser mode
Laser light is generally regarded as being
coherent, as a practical level not all the light
waves are preciously parallel as they resonate
between the two mirrors of the Laser tube.
Cross-section of laser beam at different points
along its path reveals that it is very slightly
divergent, and that it is more intense at certain
points (called transverse electromagnetic modes)
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33. Transverse mode are not so important when
energy is delivered diffusely (retinal
photocoagulation)
But for photo disruption (YAG) it is important to
have precisely focused energy a greater
disruptive effect and, consequently, the effects of
transverse modes need to be considered.
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34. Units of
wavelength
Unit Symbol Length
Centimeter cm 10-2 meter
Angostrom 10-8 meter
Nanometer nm 10-9 meter
Micrometer μm 10-6 meter
36. The effects of laser energy on ocular tissues
depend upon the:
Wavelength.
pulse duration of laser light and the
absorption characteristic of the tissue in
questions (largely determined by the pigments
contained within it).
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37. Effects of laser energy on tissue
The effects can be
1) Thermal
2) Photochemical
3) Ionizing effect
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38. Thermal effect
Light energy is converted into heat energy if the wavelength
coincides with the absorption spectrum of the tissue pigment
on which it falls and if the pulse duration is between a few
microsecond and 10 s
Melanin in the retina absorb most of the visible spectrum &
xanthophyll strongly absorb blue light, and hemoglobin absorb
blue, green and yellow wavelength.
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39. Thermal effect
In the retina, heat is transferred to the adjacent layers of the
retina to cause a 10-20 degree rise in tissue temp. The result is
photocoagulation and a localized burn.
When visible or infrared light raises the tissue temp to 100 deg
water vaporizes and causes tissue disruption.
Example: Carbon di oxide. Argon laser.
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40. Photochemical effect
When a pulse duration of 10 s or more is required to cause
damage, the mechanism is the formation of free radical ions
which are highly reactive and toxic to cells.
Shorter wavelengths ( blue & UV) causes damage at lower
levels of irradiance and are therefore more harmful.
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41. Ionisation
Photon energy delivered in a nanosecond or less may be
sufficient to strip electrons from molecules to form a collection
of ions and electrons called a plasma.
A plasma has a very high temperature and rapidly expands to
cause a mechanical shock wave sufficient to displace tissue.
Energy released as photons may produce a flush.
Example: Nd-YAG & Argon-fluoride excimer laser
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42. • When the laser energy exceeds the
threshold for causing tissue damage, the
mechanism of any damage depends
largely upon the duration of exposure.
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43. Laser tissue interaction
Laser
Tissue
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Thermal effect
i. Photocoagulation
ii. Photodisruption
iii. Photovaporization
Photochemical
i. Photo radiation
ii. Photoablation
Ionizing
Effect
46. Photoablation
Breaks the chemical bonds that hold tissue together essentially
vaporizing the tissue e,g, photorefractive keratectomy. Argon-
Fluoride (ArF) excimer Laser.
Usually
Visible wavelength: Photocoagulation
Ultraviolet: Photo ablation
Infra red: Photodisruption & Photocoagulation
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47. Photo ablation
• Vaporization of tissue to CO2 and water occurs when it’s temp
rise 60 – 100 deg or greater.
• Commonly used CO2
• Absorbed by water of cells
• Visible vapor (vaporization)
• Heat Cell disintegration
• Cauterization Incision
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48. Photochemical effect
• Photo radiation
• Also called photo dynamic Therapy (PDT)
• Photochemical reaction following visible/infrared light
particularly after administration of exogenous chromophore
Commonly used photosensitizer:
• Hematoporphyrin
• Benzaporphyrin derivatives
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49. Uses of Laser in ophthalmology
Mode Lesion Tissue treated
Photocoagulat
ion
Thermal burn Retina & TM
Photoablation Breakdown of chemical bonds
without thermal change
Cornea
Photodisruptio
n
Breakdown of form plasma
resulting in disruption of tissue
PCO
Photovaporiza
tion
Vaporization of fluid from the
tissue to cut
Small tumor
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50. Commonly used Laser in Ophthalmology
Laser Wave
length
Effect
Argon Laser Green
Argon Laser Blue
514 nm
488 nm
Photocoagulation
Photocoagulation
Nd YAG single frequency
Nd YAG double frequency
1064 nm
532 nm
Photodisruption
Photocoagulation
Diode Laser 810 nm Photocoagulation
Excimer Laser 193 nm Photoablation
Ruby Laser 550 nm Photocoagulation
Krypton Laser Red
Krypton Laser Yellow
647 nm
568 nm
Photocoagulation
Photocoagulation
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51. Modes of Laser Operation
• Continuous Wave Laser: It deliver their energy in a continuous
stream of photons
• Pulse Laser: Produce energy pulses of a few ten of micro to
few mili second
• Q Switches Laser: Deliver energy pulses of extremely shorter
duration (nanosecond)
• A mode locked Laser: Emits a train of short duration pulses
(picosecond)
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