How To Get Artwork From Mpmediaitemcollection

Roadmap Chapter 1 explains the iOS SDK, introducing the new options in iOS four and covers how to put in the iOS SDK. Chapter 2 kicks things off by highlighting Objective-C, which is the programming language used on the iPhone SDK. Chapter 3 looks at Xcode four, the newly released device in iOS SDK. This built-in growth setting does more than simply compile your code. It also helps you right simple errors as you type and provides fast, built-in entry to all the iPhone programming documents. Chapter 4 shifts the focus to mastering Xcode by writing code for applications and debugging with Xcode. Chapter 6 steps again to speak about consumer interplay. It covers occasions, which customers generate by touching the display with a quantity of fingers, and actions, which occur when users work together with a management object like a button or a slider. Chapter 7 finishes our have a glance at view controllers by inspecting two more-advanced potentialities. The tab bar view controller allows for modal choice between multiple pages of content material, and the navigation view controller adds hierarchy to tables. Also the universal application design idea will be lined. Chapter 8 opens the SDK toolkit by speaking about knowledge.

This consists of person input, corresponding to actions and preferences; knowledge storage, such as information; and instruments that combine input and storage, such as the devices' tackle book. In this chapter, you discover methods to retailer advanced knowledge in an SQLite database or by utilizing Core Data. Chapter 10 highlights two of the most distinctive features on the iPhone and iPad— the accelerometer and the GPS—showing how the iPhone can track movement via area. Chapter eleven covers one other of the device's strengths—media—by displaying how to do basic work with photos, films, and sound. It discusses how to play and record audio using a device's microphone and audio system. Chapter 14 examines how you can use the iPhone and iPad to interact with the web. This chapter strikes through the whole hierarchy of web communication, from low-level host connections to URLs, from internet views to modern social languages like XML and JSON. The anatomy of iOS iOS's frameworks are divided into four major layers, as shown in figure 1.4. Each of these layers incorporates a wide range of frameworks that Cocoa Touch you possibly can access when writing iOS SDK applications. Generally, you must favor the higher-level layers when you're codMedia ing . Cocoa Touch is the framework that you'll turn out to be most Core Services conversant in. It incorporates the UIKit framework—which is Core OS what we spend most of our time on on this book—and the Address Book UI framework. UIKit consists of window assist, event help, and user-interface administration, and it Figure 1.4 Apple supplies you with four layers of enables you to show each text and web pages. It additional acts as frameworks to use when your interface to the accelerometers, the digicam, the picture writing iOS applications. Media is where you can get entry to the most important audio and video protocols built into the iPhone and iPad. Its 4 graphical technologies are OpenGL ES, EAGL , Quartz (which is Apple's vectorbased drawing engine), and Core Animation . Other frameworks of note include Core Audio, Open Audio Library, and Media Player. Core Services presents the frameworks utilized in all functions.

Many of them are information related, similar to the interior Address Book framework. Core Services also contains the critical Foundation framework, which includes the core definitions of Apple's objectoriented knowledge varieties, corresponding to its arrays and sets. You can access threading, recordsdata, networking, other low-level I/O, and memory functions. Most of your programming work might be accomplished utilizing the UIKit or Foundation framework. The overwhelming majority of code in this book might be built solely using Cocoa Touch. But you'll generally have to fall again on libraries that are instead based mostly on simple C functionality. Examples embrace Apple's Quartz 2D and Address Book frameworks, in addition to third-party libraries like SQLite. Expect object creation, memory administration, and even variable creation to work differently for these non-Cocoa libraries. This will provide you with a complete fundamental software, together with a easy information set. You'll stroll by way of the code and modify it to show a list of web site bookmarks. When the person faucets the bookmark within the left pane, it's going to load the website in the right one. As you modify the code, we'll clarify intimately how the SplitViewController is constructed. Figure 7.11 reveals what the applying will look like. When you first create a split view–based application, a number of recordsdata are added to your project mechanically. Figure 7.12 exhibits the varied view parts you see when you click the SplitViewController. As you probably can see, the SplitViewController is made up of two main views. The navigation bar within the left view ought to hint that its view is a navigation controller. The object viewer in the backside corner confirms this. Notice that the view hierarchy is exactly the same as that for the navigation controller in part 7.2. The right view is loaded from one other nib referred to as DetailView.

Double-clicking the blue textual content labeled DetailView opens it and lets you modify it as you'll some other view. You'll see that later in the section whenever you add a web view to the instance software. Media Layer—Frameworks for adding audio, video, graphics and animations to your apps. Audio Toolbox Interface for audio recording and playback of streamed audio and alerts. Audio Unit Interface for opening, connecting and utilizing the iPhone OS audio processing plug-ins. AV Foundation Interface for audio recording and playback . Used in Chapter 7's Spot-On Game app and Chapter 8's Cannon Game app. Core Audio Framework for declaring data types and constants used by different Core Audio interfaces. Core Graphics API for drawing, rendering photographs, color administration, gradients, coordinate-space transformations and handling PDF documents. Media Player Finds and plays audio and video files within an app. OpenGL ES Supports integration with the Core Animation layer and UIKit views.

Subset of the OpenGL API for 2D and 3D drawing on embedded methods. Quartz Core Framework for picture and video processing, and animation utilizing the Core Animation technology. Core Services Layer—Frameworks for accessing core iPhone OS three.x services. Address Book Used to access the consumer's Address Book contacts. Core Data Framework for performing tasks associated to object life-cycle and object graph management. Core Foundation Library of programming interfaces that enable frameworks and libraries to share code and information. Introduced in Chapter 5's Favorite Twitter Searches app and used all through the book. Core Location Used to discover out the placement and orientation of an iPhone, then configure and schedule the supply of location-based occasions. Foundation Includes NSObject , plus instruments for creating graphical, event-driven apps. Also consists of design patterns and features for making your apps extra efficient. Mobile Core Services Includes commonplace types and constants. Creating a navigation controller To create a navigation controller, create a model new project utilizing the Navigation-Based Application template. You can web page through the .xib file and the Xcode listing to see what you're given. Let's start with the .xib information, whose content material you can see in figure 7.5. Mainwindow.xib contains a UINavigationController within the nib window with a UINavigationBar hidden underneath it. The primary display window accommodates a UINavigationItem and a RootViewController. The latter is a subclass of UIViewController created through Xcode, just as when you designed your individual desk controller in chapter 5. Note that this units up the usual iPhone paradigm of navigation controllers being built atop table controllers. The desk view controller's contents are instantiated by way of a second .xib file, RootViewController.xib, as proven in the table view controller's attributes window.

RootViewController.xib is a boring .xib file as a result of it incorporates solely a table view. Consider it a great instance of how pairing .xib information with view controllers can keep your program properly organized. A Tab Bar Application creates a tab bar alongside the bottom of the display screen that allows you to change between multiple views. The template does this by creating a tab bar controller and then defining what each of its views looks like. A Utility Application defines a flip-side controller that has two sides, the front facet containing an data button that permits you to name up the bottom. This is the last view controller we'll explore in chapter 7. An OpenGL ES Application is one other minimalistic software. The difference from the Window-Based Application is that it consists of GL frameworks, sends the glView messages to get it started, and otherwise units certain GL properties. We won't get to GL till chapter 13, and even then we'll only touch on it frivolously. A Split View-Based Application is a split view controller–based software that works only on the iPad. In addition, you want to autoplayback this music file 10 instances and set the delegate to self. Then inside the audio session 1#, you define the class as AVAudioSessionCategoryPlayback to inform the system that this software will use audio enjoying as a main operate. Finally, you launch the retained objects inside the dealloc 1$. Change the target to a universal utility for each iPhone and iPad. Save all the adjustments, click Build, and run it in Xcode. The text label will show the audio file's name, as proven in determine 22.three. Play with this utility a bit, and you will discover that our utility has the primary precedence in audio taking half in. When you've an incoming phone call, this application will pause playing the current music as defined within the interruption-handling methods.

In the header file, you add in a single label for the filename and three buttons for the audio taking half in control. Three strategies are defined to handle each button's contact occasion. Next, let's add the new objects to the nib file and join them to the view controller's header file. Click the MySongViewController.xib file to open it for modifying, and then open the item library. First, add a model new textual content label into the view, after which drag three buttons into the view. By default, the button's sort is a rounded rectangle. Let's change the button's attributes to a customized type and assign the background image to each button. Once it's complete, you'll see the view controller's UI, similar to the one proven in figure 22.2. Single-click the file's owner under the MySongViewController's File panel. Go to the connection inspector and ensure all four UI outlets in the file's owner are linked to new subviews. Hook up the three motion buttons and save every little thing. Now we'll move on to implement the MySongViewController.m file. There are many changes within the next step, contemplating this may be a complete audio taking half in project. You begin by initializing the media player and picker. Because the participant is being initialized with the iPodMusicPlayer method, the applying uses the global iPod player when playing media gadgets. The media picker is initialized with the MPMediaTypeAnyAudio fixed; this lets the user select any type of audio media from the iPod library. Finally, you set the category because the delegate to the MPMediaPickerController so you'll be able to reply to its actions.

The mediaPicker method known as mechanically each time the person selects an audio item from the iPod library. It receives an MPMediaItemCollection, which incorporates the audio item to be performed. The subsequent line takes this collection and provides it to the iPod media collection's queue. To disguise the picker, you name dismissModalViewControllerAnimated. The pickMedia technique shows the media picker on prime of the current view. The playMedia and stopMedia strategies are fairly self-explanatory as a result of they solely control the media participant. Use these methods as a template for implementing other media participant controls on your own. Finally, you have to make sure to release objects that you allocate. Doing so ensures that your utility doesn't use extra reminiscence than it wants and runs as effectively as attainable. In the next section, we'll discuss how to let customers document audio files. Figure 2.2 lists a variety of the many recommendations that appear in the 130-page doc IPhone Human Interface Guidelines. Points and Suggestions from the iPhone Human Interface Guidelines • Most necessary, read the doc IPhone Human Interface Guidelines. • If you're going to create net applications, additionally read the document iPhone Human Interface Guidelines for Web Applications. • Keep in mind that iPhone apps are designed in a special way from desktop apps due to the small screen. • Design your app to work well on condition that the iPhone shows only a single display screen at a time. • Keep in mind that the iPhone runs only one app at a time. Leaving an app quits the app, so be positive to save something you want immediately after it's created.

• Your app ought to be modeled after the way in which things work in the actual world. • People feel nearer to your app's interface as a result of they contact it directly . • Give individuals lists and let them contact the selection they want somewhat than requiring key stroking, if potential. • Provide suggestions to person actions—for example, use an activity indicator to level out that an app is engaged on a task of unpredictable duration. • Be consistent—for example, all the time prefer commonplace buttons and icons offered by the iPhone OS to creating your own custom-made buttons and icons. • If you do present customized icons, ensure that they're easily distinguishable from system icons. • Although you can have as many buttons as you want on alerts, you must present two. Avoid the complexity of alerts with greater than two buttons. • Your apps ought to be intuitive—the person ought to be ready to work out what to do at any given time, with minimal assist. • Support the standard iPhone gestures in the usual way. • Make your apps accessible for folks with disabilities. • If a button does something harmful, make it red. You can almost consider the AV Foundation framework as a raw API—very low stage in comparison with a variety of the different frameworks we've coated.

AV Foundation offers you all of the instruments and APIs you have to create your own options, but generally building a house from the bottom up can be a lot extra work than needed. For those who don't want a custom answer, Apple has created two normal media seize and media participant view controllers, UIImagePickerController and MPMoviePlayerController. This allows the chat shopper to periodically ping the server to verify whether the user has acquired any new chat messages. The elegant solution that Apple got here up with is called push notification. A push notification is an easy message that originates at a push provider, containing data related to a particular program. These messages can contain any number of things, together with a message, a sound file to play, a badge count, and any customized key-value pair needed for an utility. Figure 17.1 shows an instance of what a push notification would possibly seem like for an software. As you presumably can see within the determine, the push notification seems similar to a text message. The title is the title of the applying that the push notification is said to. When the consumer taps the View button, the iPhone or iPad launches the appliance that invoked the push notification. It should turn out to be obvious how this approach solves the problem of background processing for most purposes. In the case of an instant message program, users can decide to remain on-line through the chat server. That means, they will exit the applying and the server can push notifications any time they receive a new chat message. Users don't need to waste system memory having their chat shopper run within the background, pinging the server for brand spanking new messages. Push notifications are simple to incorporate in your functions, as a result of little code is required. One problem is the fact that in addition to enabling your functions for push notifications, you have to additionally create a push supplier. We'll talk about each of those aspects of the system and present you how to create a full system for sending and receiving push notifications. Push notification has been a great service since iOS three, nevertheless it solely works when the iPhone or iPad is related to the web.

How To Find Volume With Density And Volume

The tube is bent into a "U" shape and mounted on an inexpensive piezoelectric speaker. The resonance frequency of the tube is detected by a photointerrupter, amplified, and fed into the speaker; the resulting feedback circuit keeps the glass tube vibrating at its resonance frequency. A peristaltic pump and computer are used to flow samples through the tube and record the resonance frequency of the tube. Detail of the glass tube shows the path followed by a sample inside the tube as it flows into the sensor ("a"), passes the tip of the sensor ("b"), and exits the sensor ("c"). Resonance frequency of the vibrating tube vs. time as a 770 μm diameter glass bead is passed back and forth through the tube eighteen times. Each passage of the bead through the tube results in a momentary decrease in the tube's resonance frequency; this is recorded as a downward peak in the resonance frequency .

Each point on the peak (baseline "a," tip "b," and baseline "c") corresponds with the bead's location in above. The height of this peak is used to determine the buoyant mass of the bead . Histograms showing the buoyant mass of another bead weighed thousands of times in two different fluid densities. In deionized water (density 1.000 g/mL) the bead has an average buoyant mass of 3.69 ±0.12 μg, and in a sodium chloride solution (density 1.046 g/mL) the bead has an average buoyant mass of −4.42 ±0.16 μg.

The widths of these distributions—120 and 160 nanograms—provide an estimate of the resolution of our mass measurements. The four proof-of-concept samples studied here—microbeads, embryos, seeds, and biomaterials—are representative of a wide range of samples that may be analyzed in fluid using vibrating glass tube sensors. Our technique is very versatile because all objects have fundamental physical properties like mass.

Consequently, our mass sensor can be applied to problems as diverse as screening toxic substances, understanding the growth of plants, measuring the degradation of biomaterials, and many others. And unlike imaging-based measurements of size, our mass sensor is insensitive to the shape of the object. Finally, the automation, portability, and low cost of this technique make vibrating glass tubes particularly well suited for applications in the field or in resource-limited settings. When a sample passes through the vibrating tube sensor, its buoyant mass is recorded as a brief peak in the plot of resonance frequency vs. time (e.g., Fig 1C and 1D).

Once a peak is located, the height of the peak can be measured and converted to a corresponding buoyant mass value using the sensor's point mass calibration described below. Alternatively, a custom Python program can be used to fit the raw frequency measurements to an analytical equation of expected peak shape derived from Dohn et al. The resulting buoyant mass measurements were recorded and processed using a moving window average filter with a window size of five data points to slightly reduce noise in the plots of buoyant mass vs. time. Additional details about signal processing are provided in S6 Fig.

In this work, we demonstrate a simple and inexpensive sensor capable of weighing microgram-sized objects in fluid. Like the SMR, this sensor uses a change in resonance frequency to weigh an object in fluid with high precision. But unlike the SMR, this sensor can weigh samples with a large range of sizes and is extremely simple to fabricate. Our sensor consists of a short length of glass tubing bent into a "U" shape and attached to an inexpensive speaker that vibrates the glass tubing at its resonance frequency. The resulting sensor shown in Fig 1 costs about US $12 in materials and can be made in under 10 minutes. Additionally, by weighing samples in fluids of different densities, we can also use our sensor to measure the volume and density of samples in fluid.

Before using a vibrating tube to weigh a sample, the tube must first be calibrated. We calibrated the sensor shown in Fig 1A using a glass bead of known size and density in a fluid of known density . Fig 1C shows eighteen downward peaks in the resonance frequency of the tube as the bead is pumped back and forth eighteen times through the tube. The height of each peak (72 millihertz; Fig 1D) is proportional to the buoyant mass of the bead . Our homemade vibrating tube mass sensors typically have quality factors around 500, which is comparable to that of tuning forks and high enough for precise measurement of the tube's resonance frequency . To measure the density of a sample of material, both the mass and volume of the sample must be determined.

For both solids and liquids, a balance can be used to measure mass; however, methods for determining volume are different for solids and liquids. As liquids can flow and take the shapes of their containers, glassware such as a graduated cylinder or volumetric flask can be used to measure the volume of a liquid. The volume of an irregularly-shaped solid can be measured by submersion in a liquid — the difference in volume caused by addition of the solid is equal to the volume of the solid. Where mo is the absolute mass of the object, ρo is the density of the object, and ρf is the density of the fluid filling the channel. Stated in words, an object's buoyant mass is equal to its real mass minus the mass of an equivalent-volume amount of fluid.

If the object's density is less than the fluid's density, then the object has a negative buoyant mass and its passage through the tube will result in a momentary increase in the tube's resonance frequency . Finally, if the object's density equals the fluid's density, then the object will have zero buoyant mass and its passage through the tube will have no effect on the resonance frequency of the tube . Thus, the orientation of the vibrating tube with respect to gravity has no effect on its measurements. Most solid substances are irregularly shaped, which complicates volume determination. It is inaccurate, for example, to determine the volume of a powder by measuring its dimensions.

Instead of directly measuring dimensions or using glassware like a volumetric flask, it is necessary to make use of a liquid displacement method to measure the volume of an irregularly shaped solid. A graduated cylinder containing a known volume of liquid is tared. The solid is added to the cylinder, and the total mass is weighed again to determine the mass of the solid.

Addition of the solid causes an upward displacement of the liquid, resulting in a new volume reading. The volume of the solid is equal to the change in volume due to liquid displacement (i.e., the difference in liquid volume before and after adding solid). Measurements of an object's fundamental physical properties like mass, volume, and density can offer valuable insights into the composition and state of the object. However, many important biological samples reside in a liquid environment where it is difficult to accurately measure their physical properties.

To determine the density of an irregular solid in pellet form, add approximately 40 mL of water to a clean and dry 100-mL graduated cylinder. Place the cylinder on an analytical balance and tare. Add approximately 10 pellets, and record the new volume after the addition. The mass is only the pellets, as the rest have been tared. Make at least two additional sets of mass and volume measurements to calculate an average value of the density. The density for zinc was measured for three different samples.

Note that, since the measurements were made in a graduated cylinder, which is less precise than a volumetric flask, the density has lower degree of precision. Of a substance is the ratio of the mass of a sample of the substance to its volume. The SI unit for density is the kilogram per cubic meter (kg/m3).

For many situations, however, this as an inconvenient unit, and we often use grams per cubic centimeter (g/cm3) for the densities of solids and liquids, and grams per liter (g/L) for gases. Although there are exceptions, most liquids and solids have densities that range from about 0.7 g/cm3 to 19 g/cm3 . Table \(\PageIndex\) shows the densities of some common substances.

Raw resonance frequency data from repeated measurements of a single polyethylene microbead in water (from the right-hand distribution of measurements in Fig 1E). After zooming in to the filtered data , peaks corresponding to individual measurements of the microbead are visible. Zooming in further on one pair of peaks shows the ∼2 millihertz height of these peaks (corresponding to a buoyant mass of ∼3.7 μg for this microbead). The peaks come in pairs because the particular vibrating tube sensor used for this measurement had a tuning-fork shape with two vibrating "U"-shaped lobes . Table 1 lists results for the determination of the density of ethanol using a 50-mL volumetric flask.

How To Find Your Volume And Density Densities were calculated by dividing the measured mass by 50.0 mL. Table 2 lists results for the determination of the density of a sample of zinc metal using a 100-mL graduated cylinder and the liquid displacement method. Note that the measured densities are constant for both substances. Table 2, in particular, demonstrates that density is independent of the amount of substance studied.

The density of material shows the denseness of that material in a specific given area. A material's density is defined as its mass per unit volume. Density is essentially a measurement of how tightly matter is packed together. It is a unique physical property for a particular object.

The principle of density was discovered by the Greek scientist Archimedes. It is easy to calculate density if you know the formula and understand the related units The symbol ρ represents density or it can also be represented by the letter D. Ρ is the object's density m is the object's total mass V is the object's total volume Under specified conditions of temperature and pressure, the density of a fluid is defined as described above.

However, the density of a solid material can be defined in several ways. Porous or granular materials have a density of the solid material, as well as a bulk density, which can be variable. For example, if you gently fill a container with sand, and divide the mass of sand by the container volume you get a value termed loose bulk density. If you took this same container and tapped on it repeatedly, allowing the sand to settle and pack together, and then calculate the results, you get a value termed tapped or packed bulk density. Tapped bulk density is always greater than or equal to loose bulk density.

In both types of bulk density, some of the volume is taken up by the spaces between the grains of sand. The density of the sand grains, exclusive of the air between the grains, will be higher than the bulk density. The density of a substance can be used to define the substance.Water is unusual because when water freezes, its solid form is less dense than liquid water, and thus floats on top of liquid water. As an object passes through the vibrating tube sensor, the shape of each resulting peak in the tube's resonance frequency is a function of the vibrational mode and amplitude of the tube. In this work, the tubes are vibrating at their primary vibrational mode, meaning that the amplitude of vibration is highest at the tip (the bottom of the glass "U") and lowest at the base (the top of the "U").

As the particle leaves the tube (point "c" in Fig 1B) the tube's vibrational amplitude in this region decreases again, so the resonance frequency of the tube returns to baseline (point "c" in Fig 1D). General mathematical expressions for predicting this peak shape for any vibrational mode were derived by Dohn et al. Magnesium ribbon with a thickness of 250 μm (98% pure; MiniScience Inc., Clifton, NJ) was used as a model biomaterial in our degradation rate measurement studies. Roughly 1 mm sized pieces of magnesium were cut from the ribbon. The samples were polished before measurement using 600, 800, and 1200 grit silicon carbide abrasive papers to remove the native oxide layer. Flow through the sensor was controlled using the servomotor as described previously.

The resulting buoyant mass measurements are shown in Fig 4. Generally, the density of water (which is approximately about 1 gram/cubic centimeter) is taken as the standard value for calculating the density of substances. However, the SI unit of Density is measured using kilograms per cubic meter (kg/m3). Volume is an amount of space, in three dimensions, that a sample of matter occupies. The number and the phase of the molecules in the sample primarily determine the volume of a substance.

Volume will be measured in many ways in this course, but the units are usually milliliters or cubic centimeters . Methods for determining or delivering precise volumes include volumetric pipets and pycnometers; less precise methods include burets, graduated cylinders, and graduated pipets. Volume is the amount of space an object occupies while density is the mass of an object per unit volume.

You need to know the volume of an object before you can calculate its density. Calculating volume for regular objects can be done with a simple formula determined by the shape of the object. Common units for volume are cubic centimeters , cubic meters , cubic inches , and cubic feet . Once you have the volume, density is one more simple calculation away.

Common units for density are grams per cubic centimeter (g/cm3) or grams per milliliter (g/mL). Distribution of buoyant mass measurements for 474 different zebrafish embryos at 2 hours post-fertilization, obtained using our vibrating glass tube sensor. Finally, to demonstrate our technique using a biologically-relevant sample other than an organism, we used vibrating glass tubes to precisely measure the degradation rates of biodegradable materials. For many applications in medical implants, it is desirable to have materials with known degradation rates.

For example, a screw for repairing a broken bone might remain intact until the bone heals and then dissolve away. However, measuring the degradation rates of slow-degrading materials is a time-consuming and labor-intensive process. This process slows the development of new biomaterials and introduces the potential for human error. In Fig 1C a slight downward drift is visible in the baseline resonance frequency of the vibrating tube over time; the frequency is decreasing at about 2 millihertz per minute. Slow baseline frequency drift like this is common in vibrating mass sensors and is mostly due to small fluctuations in the temperature of the sensor. However, the magnitude of this drift is small compared to the duration of a peak, which is why the baseline of an individual peak in Fig 1D is relatively flat.

This demonstration illustrates the methods for measuring the density of solids and liquids. Using a volumetric flask and an analytical balance, the density of ethanol can be determined. Using a graduated cylinder, analytical balance, and water as the displaced liquid, the density of zinc metal can be determined. Additional measurements of the buoyant mass of single zebrafish embryos in water, obtained using our vibrating glass tube sensor.

By using our resonating glass tube to automatically monitor the mass of a degrading material in fluid, we can use a much smaller sample of material than would normally be required. These small (millimeter-sized) samples have a much larger surface-area-to-volume ratio than the centimeter-sized samples required by current methods. This increases the relative degradation rate of the smaller samples in fluid, making our technique capable of measuring the degradation rate of a material in hours instead of weeks or months. We used our sensors to measure the degradation rate of a sample of magnesium, a biodegradable material that has been extensively studied for potential use in medical implants .

To test this hypothesis, we used vibrating glass tubes to continuously monitor the buoyant mass of zebrafish embryos during exposure to known toxicants. Zebrafish embryos are popular vertebrate model organisms for high throughput drug discovery and screening and human disease modeling . Additionally, as marine animals, they are used extensively in assessing the toxicity of substances in aquatic environments . Current methods for assessing the health of zebrafish embryo are laborious, time-consuming, require a high degree of expertise, and can be subject to human error. Vibrating tube mass sensors could offer an economical and high-throughput alternative to these existing techniques for assessing the health of an embryo. They can also provide information on organism mass, a primary metric in toxicology that is used as a normalizing factor for dosing of toxicants .

Seeds of iceland poppy , oregano , and foxglove were obtained from Ferry-Morse and measured every 10 seconds in water until active germination was observed using the servomotor reservoir lifter described above. This estimate of single-seed mass was used along with the seed buoyant mass measurements to calculate the estimated density of each seed during imbibition and germination (Fig 3G–3I). However, there are many important samples that are too large to be weighed in the microfluidic SMR and too small to be weighed on a conventional balance. For example, fish embryos are used in a variety of developmental biology and toxicology applications .