TF30042: The database is full. Contact your Team Foundation Server administrator. Event Log from data base server: MSSQLSERVER: Could not allocate space for object 'dbo.tblNotificationQueue'.' PKtblNotificationQueue' in database 'TfsReal-Time collection' because the 'PRIMARY' filegroup is full. Public, non-restricted data depicting National Register spatial data processed by the Cultural Resources GIS facility. Last minor update, September 2020.
Bausch & Lomb commercialised the first soft contact lenses, made from a hydrogel, in 1971. The next generation of lenses incorporated silicone-containing polymers to increase comfort. Now, some researchers have turned their attention to ‘smart’ contact lenses, exploiting miniaturised electronics and transparent conducting materials. In future, it may be that our lenses won’t just improve vision, but will also monitor biomarkers of disease by measuring levels of sugars and proteins in our tears.
Smart lenses for continuously monitoring glucose are a major research area. In recent years, continuous glucose monitors (CGM) have entered the market, providing patients with more data and allowing tighter control over glucose levels. But CGM have drawbacks: most require inserting electrodes under the skin, which can be painful and can cause skin problems.
Gregory Herman’s team at Oregon State University (OSU), US, are using flexible, transparent sensors to monitor glucose levels in the tears of Type 1 diabetes patients. Ultimately, the researchers want to expand the sensors to detect a range of tear biomarkers to identify ocular disorders such as dry eye disease, diabetic retinopathy and glaucoma, cancers and multiple sclerosis.
The group’s technology was developed initially for consumer electronics. While working in industry, Herman and two colleagues developed a semiconductor based on indium gallium zinc oxide (IGZO) that produced higher resolution displays on televisions, smartphones and tablets while saving power and improving touch-screen sensitivity. In 2009, Herman moved to OSU, where he began investigating biomedical applications.
‘These biosensors probably won’t put blood labs out of business,’ says Herman. ‘But I think that we can do a lot of diagnostics using information that can be extracted from tear drops in the eye.’
Herman’s team created a biosensor containing a transparent sheet of IGZO field-effect transistors (FETs) and glucose oxidase, an enzyme that breaks down glucose.1,2 The enzyme oxidises any glucose present, resulting in a pH change, which triggers a response in the electrical current flowing through the IGZO transistor. ‘We use field effect sensing which measures changes in the electric field near a surface, which in turn changes the conductivity of the semiconductor material,’ Herman says.
However, glucose concentrations in the eye are much lower than in blood or interstitial fluid under skin so lens biosensors have to be much more sensitive. To address this problem, the team uses colloidal nanosphere lithography to minimise the size of the semiconductor molecule (amorphous indium gallium) in the active layer.The resulting closely packed, hexagonal nano-networks can detect subtle glucose changes in tear fluid. ‘This scaleable technique improves sensing by about two to three times order of magnitude - so well within the range of detecting glucose in tears,’ says Herman.
Their goal is to integrate the sensor in a contact lens where it operates as part of an artificial pancreas. The sensor could transmit real-time glucose information to a wearable pump that delivers the hormones needed to regulate blood sugar: insulin and glucagon.
The team is investigating using a capacitor to store charge and power the sensors. ‘The capacitor could be charged using radiofrequency communications,’ explains Herman. ‘As the sensors would be very small and would not run all the time, ideally they would not use a lot of power.’
In theory, Herman says more than 2500 biosensors - each measuring a different bodily function - could be embedded in one millimetre square patch of an IGZO contact lens. ‘We can integrate an array of sensors into the lens and also test for other things: stress hormones, uric acid, pressure sensing for glaucoma, and characteristic protein biomarkers of cancer risk. We can monitor many compounds in tears – and since the sensor is transparent, it doesn’t obstruct vision; more ‘real estate’ [area] is available for sensing on the contact lens.’
Once they are fully developed, the biosensors could transmit vital health information to smartphones and other Wi-Fi or Bluetooth-enabled devices. However, Herman says it could be a year or more before a prototype bio-sensing contact lens is ready for animal testing.
Dual purpose lenses
Researchers in South Korea are also working on contact lenses to monitor glucose in tears, but their devices are also designed to measure high intraocular pressure. Intraocular pressure is the largest risk factor for glaucoma, a leading cause of blindness. The team – led by Jang-Ung Park at Ulsan National Institute of Science and Technology and Hong Kyun Kim at Kyungpook National University - has demonstrated real-time glucose detection on a live rabbit eye and in vitro wireless monitoring of intraocular pressure of a bovine eyeball. Their sensor measures both glucose and intraocular pressure simultaneously based on different electrical responses.
‘This study can be used to diagnose diabetes and glaucoma by implementing two types of transparent electronic sensors in the production of smart contact lens sensors,’ says Park. ‘We are now a step closer to the implementation of a fictional idea for a smart contact lens like in the films Minority Report and Mission: Impossible.’
The sensor’s key components are graphene and a graphene-silver nanowire (AgNW) hybrid structure, which has enhanced electrical and mechanical properties while still maintaining transparency and ‘stretchability’. The team integrated the sensors with resistance, inductance and capacitance circuits and placed them onto soft contact lenses. All the components are transparent, with slightly visible spiral antenna. The circuits operate at a radio frequency so power sources are not required, the team adds.
To monitor intraocular pressure, the team placed a layer of silicone elastomer between two inductive spirals made of graphene-AgNW hybrid electrodes in a sandwich structure.3 High-intraocular pressure increases the radius of curvature of the cornea. As pressure rises, the cornea stretches and the dielectric layer in the sensor - an electrically non-conductive layer - starts to thin, and this increases the capacitance of the circuit. At the same time, the spiral coils also start to expand and this increases the inductance. The sensor embedded in the contact lens transmits the changes in both to the wireless antenna.
Whereas inductance and capacitance vary with structural changes in the device, allowing the detection of intraocular pressure, the circuit’s resistance responds to molecular binding. To detect glucose, the team use glucose oxidase immobilised on channels in the graphene using a pyrene linker. The enzyme catalyses oxidation of glucose to gluconic acid and reduction of water to hydrogen peroxide. Hydrogen peroxide, a reducing agent in the system, is oxidised to produce oxygen, protons and electrons. The concentration of charge carriers in the channel, and thus the drain current, increases at higher concentration of glucose, and this affects the resistance in the circuit, which can be detected and measured.
Although the team admits that the precise diagnosis of glucose may require further sensor development, they say that the contact lens sensor should be sufficient for screening for prediabetes anddaily glucose monitoring. They also expect that the simple pyrene-chemistry involved would allow for a multiplexed array of graphene sensors, tuned to detect numerous disease-related biomarkers in tear fluid.
According to the team, the sensors still worked when the lens changed shape, and when exposed to various substances in human tears. Furthermore, since the electronic sensor is inserted into a soft contact lens, they claim it should feel comfortable and note that the rabbit did not show any abnormal behaviour when wearing the lens.
Autofocus lens
Another area of research of interest are lenses that focus themselves within milliseconds. These could be life-changing for people with presbyopia or age-related far-sightedness, in which the eye’s lens gets stiffer so making it difficult to focus on close objects.
Presbyopia affects more than 1bn people worldwide, half of whom do not have adequate correction, says Hongrui Jiang of the University of Wisconsin, Madison, US. And while glasses, conventional contact lenses and surgery provide some improvement, these options all involve the loss of contrast and sensitivity, as well as difficulty with night vision. Jiang wants to design contacts that continuously adjust along with a person’s own cornea and lens to restore better vision.
The project requires overcoming several engineering challenges. These include designing the lens, algorithm-driven sensors and miniature electronic circuits that adjust the shape of the lens, plus creating a power source. All of these then need to be embedded in a soft, flexible material that fits over the eye.
In their latest study, Jiang’s team has been investigating image sensors.4 ‘The sensors must be extremely small and capable of acquiring images under low-light conditions, so they need to be exquisitely sensitive to light,’ he says.
The team took their inspiration from the retina of elephant nose fish, which live in dark, muddy rivers. The fish can spot predators even in murky waters because of their uniquely shaped retina, which comprises a series of parabolic or cup-like structures with reflective sidewalls that help gather light and intensify the particular wavelengths needed for the fish to see.
The researchers created a device with thousands of very small light collectors; shaped like fingers, the insides of these glass collectors are lined with deep cups coated with reflective aluminum. Incoming light hits the fingers and then is focused by the reflective sidewalls. Jiang’s team tested the device’s ability to enhance images using a lab-designed mechanical eye model. They found it enhanced image intensity without consuming power.
In separate studies, the researchers have designed and lab-tested a couple of different approaches for the contact lens material. For one approach, they formed a liquid lens from a droplet of silicone oil and water. The droplet sits in a chamber on top of a flexible platform. A pair of electrodes produces an electric field that modifies the surface tension of each liquid differently, resulting in forces that squeeze the droplet into different focal lengths. The team reported that their lens is able to focus on objects as small as 20µm, roughly the width of the thinnest human hair.
In another approach, the team have tried to mimic the compound eyes of insects, which contain thousands of individual microlenses. Each micolens points in different directions to capture a specific part of a scene. Jiang’s team developed a flexible array of artificial microlenses. ‘Each microlens is made out of a forest of silicon nanowires,’ Jiang explains. ‘Together, the microlenses provide even greater resolution than the liquid lens.’
In order to change focus, the contact lens will also need to be equipped with an extremely small, thin power source. Jiang’s working solution is a solar cell that converts solar energy into electricity, and also stores energy within a network of nanostructures. It works much the way a conventional solar panel does, but the addition of storage capability within a single device is novel, according to Jiang. The device still needs tweaking, but the team is optimistic that it will be powerful enough to drive the lens yet small enough to fit the space available.
A prototype for clinical testing may still be five to ten years off, Jiang says. Once it’s available, however, it may not cost much more than conventional contact lenses. ‘There's a huge market for this and with mass production, the cost is not likely to be a barrier,’ he believes.
Google lens Public interest in smart contact lenses was first triggered back in early 2014 when Google announced it was testing lens technology to measure glucose levels in tears. Later that year, Novartis announced that it would license the technology from Google. Its eye care unit, Alcon, set up a collaboration with Verily Life Sciences, Google’s life science division, created in in 2015. But the promised clinical trials have stalled. According to its website, Verily is still working with Alcon on a glucose-sensing lens and an accommodating contact lens for people with age-related far-sightedness. Verily is responsible for the integrated circuits, sensors and wireless communication, and has been working on ‘the technical challenges of significant miniaturisation for autonomous sensing systems and dramatic reduction of power consumption to permit tiny batteries’. Alcon’s focus is biocompatible materials, optics and clinical development. In November 2016, Novartis said it was abandoning a goal to start clinical trials of the autofocus lens in that year. Alcon’s spokeswoman says the glucose-sensing lens is in early clinical development with clinical trials planned in the near future, but there isn’t a definitive timeline. She adds that they are pleased with the steady progress, and are moving at a pace expected in the proof-of-concept development phase. Oregon State University’s Gregory Herman says the Verily/Alcon prototype sensor is not fully transparent. ‘It’s an amperometric sensor [based on electrochemistry rather than a field effect] and you can see the chips. That means it has to be off to the side of the contact lens,’ he explains. ‘Another issue is the signal is dependent on the size of the sensor and you can only make it so small or you won’t be able to get a usable signal. With an FET sensor, you can actually make it smaller and enhance the output signal by doing this.’ |
Full Contact Details
References
1 G. Herman et al, Nanoscale, 2016, 8, 18469.
2 G. Herman et al, ACS Appl. Mater. Interfaces, 2016, 8, 7631.
3 Jang-Ung Park et al, Nature Communications; DOI: 10.1038/ncomms14997.
4 H. Jiang et al, PNAS; DOI: 10.1073/pnas.1517953113.
This section describes likely causes of and possible solutions for the error messages that appear on the control panel. If a message not described here appears, act according to the message.
Message | Causes | Solutions |
|---|---|---|
'Authentication has failed.' | The entered login user name or login password is not correct. | Contact the user administrator. |
'Authentication has failed.' | The machine cannot perform authentication. | Contact your administrator. |
'Authentication with the destination has failed. Check settings. To check the current status, press [Scanned Files Status].' | The entered user name or password was invalid. |
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'Cannot communicate with PC. Contact the administrator.' | WSD (Device) protocol or WSD (Scanner) protocol is disabled. | Contact your administrator. |
'Cannot detect original size. Select scan size.' | The original placed on the exposure glass is a nonstandard size. |
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'Cannot find the specified path. Please check the settings.' | The destination computer name or folder name is invalid. | Check whether the computer name and the folder name for the destination are correct. |
'Cannot find the specified path. Please check the settings.' | An antivirus program or a firewall is preventing the machine connecting to your computer. |
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'Cannot start scanning because communication was failed.' | Scan Profile is not set on the client computer. | Set Scan Profile. For details about how to do this, see 'Changing a Scan Profile', Scanner Reference. |
'Cannot start scanning because communication was failed.' | The [Take no action] setting has been selected on the client computer, forcing the client computer to remain inactive when it receives scan data. | Open scanner properties, click the [Events] tab, and then select [Start this program] as the computer's response on receipt of scan data. For details, see your operating system's Help. |
'Cannot start scanning. Check the setting(s) on the PC.' | The Scan Profile might be incorrectly configured. | Check the Scan Profile configuration. |
'Cannot write on the memory storage device. Check the memory storage device and machine settings.' | The memory device is faulty, or the file name contains a character that cannot be used. |
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'Cannot write on the memory storage device because remaining free space is insufficient.' | The memory device is full and scan data cannot be saved. Even if the memory device appears to have sufficient free space, data might not be saved if the maximum number of files that can be saved is exceeded. |
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'Cannot write on the memory storage device because the device is write-protected.' | Section symbol on mac. The memory device is write-protected. | Unlock the write-protection on the memory device. |
'Captured file exceeded max. number of pages per file. Cannot send the scanned data.' | The maximum number of pages per file has been exceeded. | Reduce the number of pages in the transmitted file, and then resend the file. See 'Storage function', Scanner Reference. |
'Connection with LDAP server has failed. Check the server status.' | A network error has occurred and connection has failed. Try the operation once more. |
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'Could not send the data because the PC timed out before it was sent.' | A time out occurred when using WSD Scanner. Time outs occur when too much time passes between scanning an original and sending its data. The followings are likely causes of time outs: Astrill vpn download iphone.
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'Destinations to which encrypted files will be sent contain users without certificates or with invalid certificates. Check the destinations.' | The destination's S/MIME certificates are invalid or cannot be found. | Contact your administrator. |
'Destinations to which encrypted files will be sent contain users that could not be verified by the certificates. Check the destinations.' | S/MIME certificates are valid, but the Certificate Authority could not be found for the destination. | Contact your administrator. |
'Entered user code is not correct. Please re-enter.' | You have entered an incorrect user code. | Check the authentication settings, and then enter a correct user code. |
'Exceeded max. E-mail size. Sending E-mail has been cancelled. Check [Max. E-mail Size] in Scanner Features.' | The file size per page has reached the maximum e-mail size specified in [Scanner Features]. |
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'Exceeded max. No. of results to display. Max.: n' (A figure is placed at n.) | Search results have exceeded the max. displayable number. | Search again after changing the search conditions. |
'Exceeded max. data capacity. Check scanning resolution, then press Start key again.' | The scanned data exceeded maximum data capacity. | Specify the scan size and resolution again. Note that it may not be possible to scan very large originals at a high resolution. See 'Relationship between Resolution and Scan Size', Scanner Reference. |
'Exceeded max. data capacity. Check the scanning resolution, then reset original(s).' | The scanned original exceeded maximum data capacity. | Specify the scan size and resolution again. Note that it may not be possible to scan very large originals at a high resolution. See 'Relationship between Resolution and Scan Size', Scanner Reference. |
'Exceeded max. number of alphanumeric characters for the path.' | The maximum number of specifiable alphanumeric characters in a path has been exceeded. | The maximum number of characters which can be entered for the path is 256. Check the number of characters you entered, and then enter the path again. |
'Exceeded max. number of alphanumeric characters.' | The maximum enterable number of alphanumeric characters has been exceeded. | Check the maximum number of characters which can be entered, and then enter it again. See 'Values of Various Set Items for Transmission/Storage/Delivery Function', Scanner Reference. |
'Exceeded max. number of files which can be sent at the same time. Reduce the number of the selected files.' | The number of files exceeded the maximum number possible. | Reduce the number of files, and then send them again. |
'Exceeded max. number of files which can be used in Document Server at the same time.' | The maximum number of files that can be stored in the Document Server has been exceeded. | Check the files stored by the other functions, and then delete unneeded files. For details about how to delete files, see 'Deleting a Stored Document', Copy and Document Server Reference. |
'Exceeded max. number of pages per file. Do you want to store the scanned pages as 1 file?' | The file being stored has exceeded the maximum number of pages for one file. | Specify whether to store the data or not. Scan the pages that were not scanned, and then store them as a new file. See 'Storing Files Using the Scanner Function', Scanner Reference. |
'Exceeded max. number of standby files. Try again after the current file is sent.' | The maximum number of standby files was exceeded. | There are 100 files waiting in the sending queue for e-mail, Scan to Folder, or delivery functions. Wait until files have been sent. |
'Exceeded max. number of stored files. Cannot send the scanned data as capturing files is unavailable.' | Too many files are waiting to be delivered. | Try again after they have been delivered. |
'Exceeded max. page capacity per file. Press [Send] to send the scanned data, or press [Cancel] to delete.' | The number of scanned pages exceeded maximum page capacity. | Select whether to send the data so far. |
'Exceeded max. page capacity per file. Press [Write] to write the scanned data to the memory storage device, or press [Cancel] to delete.' | The scan could not be completed because the maximum number of pages that can be scanned by this machine was exceeded during writing to the Memory device. | Reduce the number of documents to be written to the memory device, and then try again. |
'Exceeded maximum number of file to store. Delete all unnecessary files.' | Too many files are waiting to be delivered. | Please try again after they have been delivered. |
'Exceeded time limit for LDAP server search. Check the server status.' | A network error has occurred and connection has failed. |
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'Invalid certificates or no S/MIME certificates were found.' | The destination's S/MIME certificates are invalid or cannot be found. | Contact your administrator. |
'LDAP server authentication has failed. Check the settings.' | The user name and password differ from those set for LDAP Authentication. | In [System Settings], under [Administrator Tools], check the settings of LDAP server. For details, see 'Programming the LDAP server', Network and System Settings Reference. |
'Memory is full. Cannot scan. The scanned data will be deleted.' | Because of insufficient hard disk space, the first page could not be scanned. | Try one of the following measures:
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'Memory is full. Do you want to store scanned file?' | Because there is not enough free hard disk space in the machine for storing in the Document Server, only some of the pages could be scanned. | Specify whether to use the data or not. |
'Memory is full. Press [Write] to write the current scanned data to the memory storage device, or press [Cancel] to delete.' | The scan could not be completed because there was insufficient hard disk memory at the time of saving to the memory device. | Select whether or not to save the scanned document to the memory device. |
'Memory is full. Scanning has been cancelled. Press [Send] to send the scanned data, or press [Cancel] to delete.' | Because there is not enough free hard disk space in the machine for delivering or sending by e-mail while storing in the Document Server, only some of the pages could be scanned. | Specify whether to use the data or not. |
'Memory storage device not detected. Insert the device.' | There is no memory device inserted. | Insert a memory device, or check to see whether the memory device is properly inserted in the media slot. |
'No paper. Load paper of one of the following sizes.' | No paper is set in the specified paper tray. | Load paper of the sizes listed in the message. See 'Loading Paper', About This Machine. |
'Now loading WSD.. Please wait.' | WSD scanner function is being prepared. | Wait a while. |
'Only one memory storage device can be used in one time. Please remove all other memory storage devices to resume writing.' | Only one memory device can be connected at a time. | Insert one memory device only in the media slot. |
'Original is being scanned by another function. Switch to the following function, then press the Stop key to cancel scanning or press the Start key to continue.' | A function of the machine other than the Scanner function is being used such as the Copier function. | Cancel the job in progress. For example, press [Exit], and then press the [Copy] key. Next, press the [Clear/Stop] key. When the message 'The Clear / Stop key was pressed. Are you sure you want to stop scanning?' appears, press [Stop]. |
'Output buffer is full. Sending the data has been cancelled. Please try again later.' | Too many jobs are in standby state, and sending was canceled. | Retry sending after sending jobs in standby state completes. |
'SMTP authentication E-mail address and Administrator E-mail address mismatch.' | The SMTP authentication e-mail address and the administrator's e-mail address do not match. | Contact your administrator. |
'Scanner journal is full. Please check Scanner Features.' | 'Print & Delete Scanner Journal' in [Scanner Features] is set to [Do not Print: Disable Send], and Scanner Journal is full. | Print or delete Scanner Journal. For details, see 'General Settings', Scanner Reference. |
'Selected file is currently in use. File name cannot be changed.' | You cannot change the name of a file whose status is 'Waiting..' or that is being edited with DeskTopBinder. | Cancel transmission ('Waiting..' status cleared) or the DeskTopBinder setting, and then change the file name. |
'Selected file is currently in use. Password cannot be changed.' | You cannot change the password of a file whose status is 'Waiting..' or that is being edited with DeskTopBinder. | Cancel transmission ('Waiting..' status cleared) or the DeskTopBinder setting, and then change the password. |
'Selected file is currently in use. User name cannot be changed.' | You cannot change the sender's name whose status is 'Waiting..' or that is being edited with DeskTopBinder. | Cancel transmission ('Waiting..' status cleared) or the DeskTopBinder setting, and then change the user name. |
'Sending the data has failed. The data will be resent later.' | A network error has occurred and a file was not sent correctly. | Wait until sending is retried automatically after the preset interval. If sending fails again, contact the network administrator. |
'Some invalid destination(s) contained. Do you want to select only valid destination(s)?' | The specified group contains e-mail destinations and Scan to Folder destinations, either of which are incompatible with the specified transmission method. | In the message that appears at each transmission, press [Select]. |
'Some of selected files are currently in use. They could not be deleted.' | You cannot delete a file which is waiting to be transmitted ('Waiting..' status displayed) or whose information is being changed with DeskTopBinder. | Cancel transmission ('Waiting..' status cleared) or the DeskTopBinder setting, and then delete the file. |
'Some page(s) are near blank. To cancel, press the Stop key.' | The first page of the document is almost blank. | The original's blank side might have been scanned. Be sure to place your originals correctly. |
'The entered file name contains invalid character(s). Enter the file name again using any of the following 1 byte characters. ' 0 to 9 ', ' A to Z ', ' a to z ', ' . - _' | The file name contains a character that cannot be used. | Check the file name set at the time of scanning. For details about characters that can be used in file names, see 'Specifying the File Name', Scanner Reference. |
'The selected file(s) contained file(s) without access privileges. Only file(s) with access privileges will be deleted.' | You have tried to delete files without the authority to do so. | The files can be deleted by the file administrator. To delete a file which you are not authorized to delete, contact your administrator. |
'Transmission has failed. Insufficient memory in the destination hard disk. To check the current status, press [Scanned Files Status].' | Transmission has failed. There was not enough free space on the hard disk of the SMTP server, FTP server, or client computer at the destination. | Allocate sufficient space. |
'Transmission has failed. To check the current status, press [Scanned Files Status].' | While a file was being sent, a network error occurred and the file could not be sent correctly. | If the same message appears again after scanning again, the cause could be a mixed network, or else network settings were changed during WSD scanner transmission. Check with your system administrator. |
'Updating the destination list has failed. Try again?' | A network error has occurred. | Check whether the server is connected. |
'Updating the destination list.. Please wait. Specified destination(s) or sender's name has been cleared.' | A specified destination or sender's name was cleared when the destination list in the delivery server was updated. | Specify the destination or sender's name again. |
'Updating the destination list.. Please wait. Specified destination(s) or sender's name has been cleared.' | The destination list is being updated from the network using Web Image Monitor. | Wait until the message disappears. Do not switch off the power while this message is displayed. Depending on the number of destinations to be updated, there may be some delay before you can resume operation. Operations are not possible while this message is displayed. |
'You do not have the privileges to use this function.' | The logged in user name does not have permission for the selected function. | Contact your administrator about the permission for the required function. |
'Contains invalid character(s). Please re-enter.' | The file name contains a character that cannot be used. | Check the file name specified at the time of scanning. The file name specified in the Sending Scan Files to Folders function cannot contain the following characters: / : * ? ' < > | Zan image printer crack. The file name cannot start or end with a period '.'. |
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