Application Fee (non-refundable and non-transferable)Exam FeeMember, Non-Member, Corporate MemberMemberECBA™$60$110CCBA®$125$325CBAP®$125$325
Communicating and negotiating well are essential for them. Good at using a variety of business intelligence tools to create interactive reports. It would be extremely beneficial to obtain a certification from the International Institute of Business Analysis (IIBA), such as Certified Business Analysis Professional (CBAP).
Candidates for the CBAP® designation must have completed at least 7,500 hours of business analysis work in the previous ten years. A minimum of 900 hours in four of the six BABOK® Guide Knowledge Areas were completed as part of this experience, for a total of at least 3,600 hours out of a total of 7,500 required.
Certification costs $60, which is nonrefundable. ECBA exam fees are $60, ECBA certification fees are $60, and IIBA memberships are $60. It costs $235 to take the exam for the first time, and $195 to retake it if you fail. You'll also have to pay for the required PD hours, which vary greatly depending on the course.
Yes, ECBA certification is worthwhile because there are few industry-accepted certificates that validate foundation-level business analysis knowledge and understanding. So, if you're sitting in an interview, just because you're industry certified, you'll have an advantage over your peers.
There are 150 multiple-choice questions on the exam, some of which are extremely difficult, some of which are moderately easy, and the majority of which are challenging. CBAP and CCBA tests, which are intensive, typically start with a set of difficult questions.
A business analyst can earn the highest level of competency- based certification from the IIBA by earning the CBAP. It demonstrates mastery of business analysis as well as leadership abilities. Applicants must have 7,500 hours of business analysis experience, 35 hours of professional development, and pass an exam to be considered.
|IIBA® membership fee:||$95 USD|
|Application Fee||$125 USD|
|Exam Fee – for IIBA®Members||$325 USD|
|Exam Fee – for non-IIBA® Members||$450 USD|
|Application Fee (non-refundable and non-transferable)||Exam Fee|
Because of their skill sets and expertise in business analysis, companies have been hiring more CBAP recipients in exact years. A CBAP designation holder also earns more money than a non-credentialed business analyst, so you'll have more job opportunities, more money, and global recognition with a CBAP designation.
To be considered for the CBAP®, you must have 5 years (7,500 hours) of business analysis experience, as defined by the BABOK® Guide, as well as 900 hours of experience in at least 4 of the 6 knowledge areas.
Lifting heavy items should be done carefully in order to prevent injury.
In fact, 38.5% of work-related musculoskeletal issues are related to back injury, with improper lifting being one of the main causes.
Therefore, it’s important to learn proper lifting techniques to keep yourself safe at work and at home.
This article discusses proper lifting techniques and common lifting problems, and provides useful tips.
The best lifting technique is to squat down and use the strength of your legs — instead of your back — to lift the object off of the ground.
That said, you should only lift items that you’re comfortable lifting. If you’re unsure, it’s best to ask another person for help or use other machinery (e.g., a lift).
If you’ve decided that it’s safe to lift the item by yourself, you’ll want to follow the proper lifting technique guidelines outlined by Occupational Safety and Health Administration (OSHA).
Before moving something heavy, it’s important to think and plan first.
First, look at the item that you’re about to lift and ask yourself these questions:
Taking note of your environment, the item you plan to lift, and other considerations can help you decide if this item is a one- or two-person job or requires other assistance, such as machinery.
Just like you’d warm up before a workout, you should also warm up and stretch your muscles before lifting.
Ideally, spend a few minutes doing some dynamic stretching (e.g., lunges, lower back rotations, arm circles) to prepare your muscles and get your blood flowing.
To lift safely, you first want to make sure that you’re in the right positioning.
You’ll also want to make sure that you bend your knees, squat down to grab the item, and use the strength of your legs to do most of the lifting. This can help to lower back and other muscular injury.
Here are the steps to safely lift a heavy item:
If needed, slowly take small steps to walk to the spot you plan to put the item. If it’s far, you should consider placing the item on a cart or other form of transportation.
If you need to change directions, lead with your hips and ensure your shoulders stay aligned with your hips. Continue to keep the load as close to your body as possible.
Setting an item down is the same movement as lifting but in reverse:
If the item will be placed above the ground (e.g., on a counter or table), walk up to the surface and place it gently on top. If it’s slightly lower than hip level, be sure to still bend your knees and lower your body to place the item down safely.
While no one intends to hurt themselves, it’s quite common to injure yourself while lifting heavy objects. The most common lifting problems include:
By lifting properly and avoiding these common lifting problems, you can help lower your risk of injury.
To prevent injury, consider these helpful tips:
To ensure your safety, always practice safe lifting techniques.
The best lifting techniques involve using your legs to lift heavy objects instead of your back, since your legs are some of your strongest muscles while your back is more susceptible to injury.
You’ll also want to make sure that you’re planning ahead, only lifting objects you feel comfortable lifting by yourself, and being just as mindful when you place the item down as when you lift it.
And remember, you should always ask for assistance if you have any concerns. It’s better to be safe than to risk injuring yourself.
If Army captains headed to one of the major combat training centers are looking for pointers, the officers who will challenge and evaluate them there recently shared a few.
At last month’s Maneuver Warfighter Conference on Fort Benning, Georgia, observer/controllers from each of the three major centers shared what they’ve seen, both good and bad, in units they face off against in simulated combat.
Capt. Galen King from the National Training Center at Fort Irwin, California; Capt. Andrew Mueller from the Joint Readiness Training Center at Fort Polk, Louisiana; and Capt. David Conser from the Joint Multinational Readiness Center in Germany listed key tips they hope company commanders might consider before their next rotation in the box.
“Units consistently struggle to accomplish basic tasks that enable success or survivability on the battlefield,” Conser said. Leaders, regardless of their echelon level, “do not clearly articulate the commander’s intent or concept of operation.”
Conser stressed that a CTC rotation is a rare chance for commanders to road test their unit; coming prepared and having thought through and rehearsed every detail of their mission is vital to a successful rotation.
Mueller told the audience that at the company level he’s seen a host of positive trends and challenges that seem common across formations.
On the positive side, more units are not using roads and are improving their use of high explosives. Units really know how to employ their weapons systems, and their understanding of small unit tactics has increased over past rotations, Mueller explained.
Common challenges included a lack of routine security measures, poor troop-leading procedures, a failure to prioritize tasks, and the ineffective use of terrain to conceal or maneuver. Many also had essentially nonfunctional command posts, Mueller added, and they failed to fight to, through and beyond the objective, misunderstanding the difference between movement and maneuver.
Essentially, movement is getting units and equipment, with associated logistical support, to a predetermined location. That could happen rolling down an interstate and pulling off to a sideroad before parking trucks at a range.
But maneuver uses the terrain features to gain a tactical advantage, remaining concealed until the opportune time to strike or execute a portion of the mission, whether that’s making contact with the enemy force or retaining a reconnaissance position to observe and collect information.
“Leaders aren’t comfortable maneuvering; they don’t understand transitions from movement to maneuver,” Mueller said. “So units will just do these charges across open ground and not use terrain to mask movement and stay concealed.”
Mueller advised future captains to train the doctrine at home station, ensure they’re delivering clear and concise communication, and practice that before their rotation. It’s also important to build preformatted products, such as checklists, to refer to in a pinch.
For his part, King reminded soldiers that their next rotation likely won’t be similar to the one during the counterinsurgency wars given the modern battlefield is transparent; you can see and be seen. Planners must design their process to account for brigade and division rotations, and the pace of logistics is going to strain expectations set from some Afghanistan and Iraq deployments, where everything needed was quickly available.
To replicate the operational environment the Army expects to see in future conflict, King underscored how much simulated fires have increased for units at the centers. The blue force in one rotation conducted 27 howitzer fire missions, sending more than 800 artillery rounds down range, another 400 rounds of 120mm mortars and 550 rockets from the M270 Multiple Launch Rocket System.
The red force sent more than 2,100 artillery rounds, along with nearly 500 mortar rounds and 1,827 rockets of the 122mm variety.
That’s a bit more than many saw on deployments to Iraq and Afghanistan.
Todd South has written about crime, courts, government and the military for multiple publications since 2004 and was named a 2014 Pulitzer finalist for a co-written project on witness intimidation. Todd is a Marine veteran of the Iraq War.
CLEVELAND, Ohio (WJW) — Fox 8’s Kristi Capel recently added a new member to the family named “Rocky” and while life with the puppy is going well, Kristi and her husband Hal are hungry for some helpful training tips. Jennifer Topalian is the owner of ‘The Grateful Dog‘ and she spent some time with the family to offer advice on potty training, nipping, discipline and more. To learn more about The Grateful Dog click here.
The tiny Torx- or Allen-head screws used on scope mounts have an annoying habit of stripping at just the wrong time. (Not that there is ever a right time.) This is particularly true when removing a scope mount that’s been on a gun for many years. The screws might be a little rusty, and there’s usually a bit of corrosion between the screw and the threads in the receiver. Also, it’s possible that the screws were over-tightened during installation, which can damage the head of the screw. All this adds up to screws that are very tough to remove.
When trying to remove scope mounts, using the Allen wrenches that come with new scope rings is asking for trouble. They are generally of soft steel and may strip and round the edges. They are barely acceptable for new installations when everything is new with clean threads and you are in charge of how much torque will be applied to complete the job. But when removing old screws, all bets are off. These cheap wrenches are a poor choice. Use only a good, high-quality hardened steel bit in a large-diameter screwdriver handle, like those found in the Wheeler Engineering 89-Piece Professional-Plus Gunsmithing Screwdriver Set available from Midway USA. Using a multi-bit screwdriver also allows you to keep the torque centered on the axis of the screw. With the L-shaped Allen wrenches, the tendency is for the torque to be directed off-center, that causes the wrench to tip in the screw, which leads to slipping and stripped screws and rounded wrenches.
You are only going to get one shot at this, so take the time required to get it right. Mount the gun in a gun vise so it won’t slip. Select an Allen bit that is in good shape without rounded or worn edges. Make sure the hex pocket in the screw head is clean and free from debris so the bit can enter all the way to the bottom. Insert the bit into the screw and tap it into place with a plastic-tipped hammer. A few solid whacks with the hammer on the screwdriver handle not only seats the Allen bit in the screw, but may also help loosen the screw. If the fit is at all sloppy, put a little Drive Grip or powdered rosin on the bit. Using two hands, push straight down on the top of the screwdriver with one hand, and turn with the other. Keep the screwdriver perfectly in line with the center of the screw; do not allow it to tip. Be careful about how much torque you apply, as these are small, rather delicate, screws. If the screw doesn’t loosen, back off. Try again while tapping on the screwdriver handle with a plastic hammer and applying constant torque to the handle. This is easier if you have some help. One person taps on the handle with the hammer, while the other keeps the screwdriver straight and applies the torque.
If just one of the screws is a problem, remove the rest of them first. Sometimes there is a misalignment of parts, so that puts pressure on one particular scew when all of them are tight. Removing the rest of them will often relieve that pressure, allowing the last screw to be removed.
If the screw is in a scope base that sits on a flat receiver, you can sometimes use a plastic hammer to tap on the base and turn it on the gun enough to loosen the screw. Remove all the other screws, and then tap the corner of the base so that it will drive the base counter-clockwise. It’s not necessary to turn it very far—just a partial turn will often break the screw free. Sometimes working the base back and forth with the hammer a few times will also break the screw free. Be careful about doing this on rounded receivers like the Remington 700, as tapping the mount will cam it against the receiver, jamming the screw tighter or breaking it off.
Sometimes you can do everything right, yet the screw still strips. The base I recently removed from a Remington 700 in .35 Whelen is a perfect example. The scope was installed sometime back in the late ’80s. The first three screws came free just fine—a testament to the fact that I use only high-quality bits for this kind of work—but the opening in the head of the last one stripped. I thought it could handle the amount of pressure I was applying, but it had been damaged during installation, and the head stripped.
I switched to a bit designed for a Torx-head screw that was slightly larger than the stripped hole in the screw. Keeping it straight, I tapped the screwdriver with a hammer to drive the Torx bit into the screw, effectively cutting new splines in the metal with the bit. That allowed me to remove the screw. Of course, the screw is no good anymore, and it sometimes damages the Torx bit, but a new bit is only a couple dollars at most, far less than the cost or time necessary to drill out the broken screw and re-tap the hole. I always keep a supply of screws on hand anyway, because it’s very common to need a replacement.
Sometimes nothing will work, and you must drill out the screw. Clamp the gun in a vise and use a drill press, which will supply you a lot more control than a hand-held drill. Select a bit that is slightly smaller than the head of the screw. Drill just far enough to remove the head from the screw. Once the drill bit hits the bottom of the opening, it should be centered, as it will drill to the shank of the screw. This removes the head from the shank, freeing up the base. If you are lucky, it will leave a small amount of the screw shank sticking out from the gun. If it still will not come out easily and if you have time, it wouldn’t hurt to keep this screw saturated with penetrating oil for a few days before attempting to remove it.
Use a new pair of small and high-quality Vise-Grips to clamp the screw, and try to remove it. Use a new pair, so that the teeth are clean, sharp and the jaws are perfectly aligned. Sometimes you get lucky and this works.
Drilling out the screw and re-tap ping the hole is a last resort. This is a bit tricky, and I don’t recommend that a hobby gunsmith try it on a rifle receiver until he has some experience with less-critical applications. If you lack experience with drilling out broken screws and rethreading the screw holes, a rifle receiver is not the place to learn. Take the rifle to someone who has the knowledge and the proper equipment. I have seen several ruined receivers and more than one hole drilled through the barrel by people who didn’t heed that advice.
Source: Jandré van der Walt / Unsplash
Co-authored by Zamfira Parincu and Tchiki Davis
Sometimes life throws you a curveball and you find yourself overwhelmed. Maybe you experienced a loss. Perhaps you find yourself pondering the meaning of life. Or maybe the current state of world affairs makes you feel lost. Whenever you find yourself feeling anxious or stressed, you can use grounding techniques to reconnect with yourself and the present moment. This research-based strategy may be helpful for anxiety, panic attacks, flashbacks, or even dissociation.
Grounding techniques work by “grounding” you in the present moment and pulling you away from intrusive thoughts or feelings. This refers not only to having your “feet on the ground” but also your “mind on the ground.” When you turn your attention away from thoughts, memories, or worries, you can refocus on the present moment (Fisher, 1999).
Grounding techniques are useful because they help you distance yourself from an emotional experience. When you experience negative emotions—for example, perhaps you accidentally remember a painful memory—the brain's natural instinct is to start the involuntary physiological change known as the “fight or flight” response. Although this response keeps you safe by preparing you to face, escape from, or fight danger, memories do not present a tangible danger. If you find yourself in moments like these, grounding techniques can help the body calm itself and return to the present moment.
This is one of the most common grounding techniques. It helps by grounding you to the moment and reconnecting you to all five senses by naming:
The next time you feel anxious or that you are overthinking a problem, try the 5-4-3-2-1 technique to become more present in the moment.
Guided meditation is a powerful grounding technique to reduce stress, depression and anxiety, and it can help you get out of your head and reconnect to your body. There are many types of meditation, such as the body scan, moving meditations, or loving-kindness meditation, so it’s important to try to determine which one works best for you. Meditation has been shown to reduce stress, make you calmer, promote happiness (Mineo, 2018), and even reduce symptoms of PTSD in studies with the U.S. military (Seppälä et al., 2014)
Many clinical professionals use breathing exercises to help patients be present in the moment. Focusing on breathing is a great tool for reducing stress and anxiety (Stefanaki et al., 2015). Breathing exercises work because they help you disengage from your mind and not pay attention to distracting thoughts. You can do the simple exercise below before bed, when you wake up in the morning, or before an important meeting:
First, find a comfortable and quiet place to sit or lie down. Breathe in slowly through your nose, and notice how your chest and belly rise as you fill your lungs. Then, breathe out slowly through your mouth. Do this a few times until you start to calm down.
Grounding techniques are strategies that can reconnect you with the present and may help you overcome anxious feelings, unwanted thoughts or memories, flashbacks, distressing emotions, or dissociation. You can try as many techniques as you want: The more you try, the higher the chance you’ll find at least one that works for you.
Adapted from an article published by The Berkeley Well-Being Institute.
Fox 8's Kristi Capel recently added a new member to the family named "Rocky" and while life with the new puppy is going well, Kristi and her husband Hal are hungry for some helpful puppy training tips. Jennifer Topalian is the owner of 'The Grateful Dog' and she spent some time with the family to offer advice on potty training, nipping, discipline and more. To learn more about 'The Grateful Dog' visit https://www.thegratefuldog.org/
There was a time when I was absolutely, 100% convinced that I would be that legendary mother whose child actually went to college in diapers. Both of my children were late to potty train, but one of them particularly showed major potty training resistance, to the point where I was close to tears with every pack of Pull-Ups I bought. Sound familiar? Then rest assured: You're not alone, you're not a bad parent, and there are (believe it or not) ways to get even the most stubborn toddler to use the toilet.
Just realizing that there's a wide range of "normal" when it comes to the timing of toilet training can be a relief. Most children begin to show initial signs of toilet readiness around 24 to 30 months of age, as certified potty training consultant Jacklyn Gravel tells Romper.
However, it's not at all unusual for kids to start later. "Some kids just don't want to use the potty," parenting expert Tanya Altmann, M.D., tells Romper. Dr. Altmann, a spokesperson for the American Academy of Pediatrics (AAP), adds that trying to pressure your older child to train — say, because your chosen preschool has an underwear-only policy, there's a baby on the way, or you're just done with the whole diaper thing — will only make your toddler resist even more.
Hoping to end the training struggle? Here are some expert tips that can help your resistant child join the potty party.
Dr. Altmann notes that toddlers are often too preoccupied with their playing to bother getting up and going to the bathroom. If you suspect that's the case, then try putting the potty chair in the room where your child usually plays. Better still, put a couple of them around the house (and even in the yard during warm weather) to make it easy for your child to go when they feel the urge.
Some children are fine with a steady diapers-to-Pull-Ups-to-underwear training progression; others need extra help with the transition. Begin by talking with your toddler about your expectations in simple terms.
“For example, ‘On this day we are saying goodbye to your diapers and all pee and poop will go in the potty!’” Anneliese Schlachter, a certified potty training consultant, explains to Romper. “Make everything as fun, upbeat, and exciting as possible. You want your child to feel like you're on their team and you're mastering this skill together. Then when it's time to ditch the diapers, stay as consistent as possible and make sure you as the parent [or] caregiver have realistic expectations. You're looking for progress, not perfection.”
"Make sure your child's stools are soft," Dr. Altmann advises in her book, Baby and Toddler Basics: Expert Answers to Parents' Top 150 Questions. "If he is constipated and his stools are hard, he won't want to go in the potty because pooping hurts." This can lead not only to more training delays, but also to health issues if the stool becomes impacted. Offer plenty of fiber-filled foods such as broccoli, beans, apples with skin, oranges, and oatmeal to keep your child regular, and ask your pediatrician about giving a child-safe laxative if your toddler is becoming constipated.
This is a big one, as positive support can go a long way, especially if you’re dealing with potty training resistance by a 4-year-old who is feeling behind. “I also like to remind parents to try and look for any opportunity you can to praise your child,” Gravel says. “Try to make it as specific as possible. Something like, ‘I know sometimes it feels scary for you to use the potty, but it was so brave of you to try sitting on the big potty today! Maybe tomorrow you'll get some pee in the potty too!’”
"Often, if a child is older, you know they know what to do, and they just aren't ready, spending a week at home naked and encouraging them when they have success is the best thing you can do," says Dr. Altmann. Pick a time when you don't have much to do, and just let them go around the house without pants. If your toddler starts getting that look, or starts to get squirmy, lead them to the bathroom and tell them it's time to try. After about a week, Dr. Altmann says they should be motivated to visit the potty without being prompted.
One good way to train a reluctant potty user is to stop all the reminding and nagging altogether. “Most resistance when it comes to potty training is from parental pressure — and I totally get it, we just want them to go to the freaking bathroom!” Schlachter says. “However, when we take a step back and show our children that we trust them to listen to their body, they will realize we're not going to force anything, and one day they'll just start going on their own.”
Tell your child, "I know you know when you need to poop and pee. That poop and pee wants to go in the potty, so from now on, it's your job to get it there. You don't need help." Then leave it at that. When you stop paying so much attention to their toilet habits, your child doesn't have a reason to fight back. And offer plenty of praise when your child does decide to use the potty on their own.
Bribery obviously isn’t the answer — you don’t want your little one to only go to the bathroom for the sake of a reward — but creating an association of happiness with the potty is helpful when it comes to potty training a strong-willed child. “It can also be helpful to create a fun and positive environment around using the potty,” Schlachter says. “A basket of toys specifically for potty use is usually a great motivator.”
You might even consider letting your child help choose the incentive. Rather than just offering an M&M for every potty visit, involve your child in the process. Ask your child, "What would help you remember to go poop in the potty?" and take it from there. Time-limited incentives, such as 15 minutes of playing a tablet game or painting instead of a toy or candy each time, are also great options here.
As Gravel explains, it’s easy for parents to think, “This isn’t working!” and change their whole approach to potty training at the first sign of hardship. But switching things up too quickly can be confusing for the child.
“Children love predictably and routine, even when it comes to things they may not like doing (think brushing teeth, going to the doctor, etc.),” Gravel says. “Instead of changing your methods, ease off on the pressure, questions, or reminders. Often, children who are exceptionally resistant to using the potty finally make progress when they gain the confidence in their own abilities.” If you notice any measurable progress during the first week or so, that’s a sure sign to keep going.
Agonizing over your child's training doesn't do anything to help; it just makes you a stressed-out, unhappy parent. “Potty training can feel stressful for both the child and parent, so look for ways to enjoy your child during the process,” says Gravel. “You're going to get annoyed, frustrated, or maybe even a little mad. Scheduling even 15 to 30 minutes each day to engage in an activity you and your child both enjoy together can be a nice reset for everyone.”
From my own experience, I can say that things got so much better after I adopted our pediatrician's no-big-deal attitude. I encouraged, cleaned up the messes, and trusted that everything would work out. Sure enough, one day, my resistant child told me she had to go, marched herself into the bathroom, and did her thing. Boom. Just like that. From there, it was a matter of days before she was completely trained.
Look at all the people you know. Can you tell just by looking at them who was using the toilet at age 2, and who wasn't out of diapers until 4 or 5? Of course not. Keep your perspective and your sense of humor, and you and your child will both come through this milestone smiling.
Jacklyn Gravel, certified potty training consultant
Tanya Altmann, M.D., parenting expert and spokesperson for the American Academy of Pediatrics
Anneliese Schlachter, certified potty training consultant
With a focus on healthy living, a Hispanic family a few kilometers from the U.S. capital keeps a traditional way of farming alive. The owners of Glory Fields in Maryland use techniques from the past to implement a sustainable living initiative they say is paying off so far. VOA News' Cristina Caicedo Smit has the story.
X-rays are electromagnetic waves with short wavelengths and strong penetrability in physical matter, including live organisms. Scintillators capable of converting X-rays into the ultraviolet (UV), visible or near-infrared (NIR) photons are widely employed to realize indirect X-ray detection and XEOL imaging in many fields. They include medical diagnosis, computed tomography (CT), space exploration, and non-destructive industrial material and security inspections.
Commercial bulk scintillators possess high light yield (LY) and superior energy resolution. However, they suffer from several drawbacks, such as complex fabrication procedures, expensive experimental equipment, non-tunable XEOL wavelength and poor device processability. They all produce emissions in the visible spectral range, but having XEOL in the NIR range may find more interesting applications in biomedicine. Thick crystals also generate light scattering followed by evident signal crosstalk in a photodiode array.
Recently, metal halide perovskites have been investigated for X-ray detection. Unfortunately, these materials also exhibited some intrinsic limitations, such as poor photo-/environmental- stability, heavy metal toxicity and low LY. Thus, the search for developing a new generation of scintillators is still a considerable focus of scientific research.
In a new paper published in eLight, a team of scientists, led by Professor Prasad N. Paras from the University of Buffalo, investigated the use of lanthanide-doped fluoride NSs. Their paper looked at design strategies and nanostructures that allow manipulation of excitation dynamics in a core-shell geometry.
Lanthanide-doped fluoride NSs avoid the limitations of bulk scintillators and metal halide perovskites. They also exhibit many useful properties. The core-shell structures of the lanthanide doped fluoride NSs can be tuned and designed on demand by employing a cheap and convenient wet-chemical method. The emission wavelengths can be tuned and extended to the second NIR window, benefiting from the abundant energy levels of lanthanide activators.
These NSs show superior photostability, low toxicity and convenient device processability. It makes them promising candidates for next-generation NSs and XEOL imaging. Moreover, they exhibit XEPL property, showing promising applications in biomedicine and optical information encoding. The combination of XEOL and XEPL makes them suitable for broadening the scope of their applications.
In exact years, significant advances have been made in NS development. The research team discussed design strategies and nanostructure that allow manipulation of excitation dynamics in a core-shell geometry. They also produce XEOL, XEPL, photon upconversion (UC) and downshifting (DS). It enables emission at multiple wavelengths and at varying time scales.
The fundamental working principle of XEOL imaging is to record the attenuation of X-rays after penetrating the subject with a scintillator and imaging with a camera. The scintillator screen is placed under the target to absorb the transmitted X-ray photons. A low dose of X-rays penetrating live organisms enables the application of computed tomography. Penetrating nonliving matter enables product quality and security inspection. The X-ray irradiation dose should be low enough to assure safety, while the high resolution and distinct contrast are important for image analysis.
X-ray, ionizing radiation with deep penetration depth in the human body, has been broadly studied for radiotherapy and bioimaging applications. The strong XEOL can activate the photosensitizers to generate reactive oxygen species. They directly slow or stop tumor growth by photodynamic therapy, causing inflammation and compromising microvasculature.
The XEPL in UVC range can be used for sterilization and in vivo killing of pathogens and cancer cells. Fluorides with large band-gap and facile creation of anionic defects are appropriate for generating UVC persistent luminescence. Experimental characterizations combined with first-principles calculations suggested that oxygen introduction-induced fluorine vacancies acted as electron traps.
Photodetectors have various applications in biomedical sensing, camera imaging, optical communications, and night vision. In commercial photodetectors, crystalline inorganic semiconductors are employed as photodiodes and phototransistors. They do not effectively respond to a broad scope of photon energy covering X-ray, ultraviolet-visible (UV-vis), and NIR light.
Under NIR excitation, the lanthanide-doped fluoride layer emits UV-vis light through energy-transfer UC processes. The subsequential radiation re-absorption process from lanthanide activators to the perovskite layer occurs. Visible emission from the perovskite layer is produced through recombining electrons in the CB and holes in the VB.
This nanotransducer exhibited a wide linear response to X-rays with various dose rates and UV and NIR photons at different power densities. As discussed in section 4.4, without integrating the perovskite layer, lanthanide-doped fluoride NSs can be used for the generation of XEOL, UC and DS as well, which might be possible for the realization of broadband detection in theory and need more study in the future.
Lanthanide-doped fluoride nanoparticles are suitable candidates for next-generation NSs owing to their low bio-toxicity, high photo-/environmental- stability, facile device processability, tunable XEOL and XEPL properties, and other useful features.
To promote the development of high-performance fluoride NSs and their practical applications, the team discussed the existing challenges and future multidisciplinary opportunities in this field below. Understanding the XEOL mechanism benefits the design and exploration of new fluoride NSs. At present, how the generated low kinetic energy charge carriers are transported to the luminescent centers or captured by defects and the corresponding influence factors are unclear.
The first populated nonradiative excited levels and the radiative levels of lanthanide activators are optimal when calculating or characterizing the energy differences among these charge carriers. These calculations will guide the design of energy transfer processes to match the energy differences followed by the enhanced light yield. High LY is a prerequisite for the realization of ultra-low dose rate applications.
Citation: Lanthanide doping could help with new imaging techniques (2022, September 19) retrieved 17 October 2022 from https://phys.org/news/2022-09-lanthanide-doping-imaging-techniques.html
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