A Blockchain-Based Spatial Crowdsourcing System for Spatial Information Collection Using a Reward Distribution.

Due to the increasing relevance of spatial information in different aspects of location-based services, various methods are used to collect this information. The use of crowdsourcing due to plurality and distribution is a remarkable strategy for collecting information, especially spatial information. Crowdsourcing can have a substantial effect on increasing the accuracy of data. However, many centralized crowdsourcing systems lack security and transparency due to a trusted party's existence. With the emergence of blockchain technology, there has been an increase in security, transparency, and traceability in spatial crowdsourcing systems. In this paper, we propose a blockchain-based spatial crowdsourcing system in which workers confirm or reject the accuracy of tasks. Tasks are reports submitted by requesters to the system; a report comprises type and location. To our best knowledge, the proposed system is the first system that all participants receive rewards. This system considers spatial and non-spatial reward factors to encourage users' participation in collecting accurate spatial information. Privacy preservation and security of spatial information are considered in the system. We also evaluated the system efficiency. According to the experiment results, using the proposed system, information accuracy increased by 40%, and the minimum time for reviewing reports by facilities reduced by 30%. Moreover, we compared the proposed system with the current centralized and distributed crowdsourcing systems. This comparison shows that, although our proposed system omits the user's history to preserve privacy, it considers a consensus-based approach to guarantee submitted reports' accuracy. The proposed system also has a reward mechanism to encourage more participation.

An Interoperable Architecture for the Internet of COVID-19 Things (IoCT) Using Open Geospatial Standards-Case Study: Workplace Reopening.

To safely protect workplaces and the workforce during and after the COVID-19 pandemic, a scalable integrated sensing solution is required in order to offer real-time situational awareness and early warnings for decision-makers. However, an information-based solution for industry reopening is ineffective when the necessary operational information is locked up in disparate real-time data silos. There is a lot of ongoing effort to combat the COVID-19 pandemic using different combinations of low-cost, location-based contact tracing, and sensing technologies. These ad hoc Internet of Things (IoT) solutions for COVID-19 were developed using different data models and protocols without an interoperable way to interconnect these heterogeneous systems and exchange data on people and place interactions. This research aims to design and develop an interoperable Internet of COVID-19 Things (IoCT) architecture that is able to exchange, aggregate, and reuse disparate IoT sensor data sources in order for informed decisions to be made after understanding the real-time risks in workplaces based on person-to-place interactions. The IoCT architecture is based on the Sensor Web paradigm that connects various Things, Sensors, and Datastreams with an indoor geospatial data model. This paper presents a study of what, to the best of our knowledge, is the first real-world integrated implementation of the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) and IndoorGML standards to calculate the risk of COVID-19 online using a workplace reopening case study. The proposed IoCT offers a new open standard-based information model, architecture, methodologies, and software tools that enable the interoperability of disparate COVID-19 monitoring systems with finer spatial-temporal granularity. A workplace cleaning use case was developed in order to demonstrate the capabilities of this proposed IoCT architecture. The implemented IoCT architecture included proximity-based contact tracing, people density sensors, a COVID-19 risky behavior monitoring system, and the contextual building geospatial data.

PET imaging of EGFR expression using an 18F-labeled RNA aptamer.

OBJECTIVE: Epidermal growth factor receptor (EGFR) is a theranostic biomarker for a variety of cancer types. The aim of the present study was to develop an 18F radiolabeled EGFR targeting RNA aptamer, and to investigate its ability to visualize and quantify EGFR in xenograft models. METHODS: Biolayer interferometry binding assay was used to detect the binding affinity of the alkyne-modified EGFR aptamer MinE07 (denoted as ME07) with recombinant human wild-type EGFR protein and the mutant EGFRvIII protein. Cy5-conjugated ME07 was used for flow cytometry and immunofluorescence staining, and an Alexa Fluor 488-labeled EGFR antibody (ab193244) was used as a control. 18F-Fluorobenzoyl (FB) azide was employed as a synthon to produce 18F-FB-ME07 via click chemistry, and the cellular uptake and internalization characteristics of 18F-FB-ME07 were investigated. Static PET scans, 60-min dynamic scans, and biodistribution study of 18F-FB-ME07 were performed in three types of tumor models. RESULTS: The Kd values of ME07 to wtEGFR and EGFRvIII proteins were 0.3 nM and 271 nM respectively. The A431, U87MG, and HCT-116 cells showed strong, weak, and negative binding with Cy5-ME07, which is consistent with EGFR expression level in these cells. Peak cell uptake values of 18F-FB-ME07 in A431, U87MG and HCT-116 cells were 2.86%, 2.19% and 0.88% of the added dose respectively. The mean internalization of 18F-FB-ME07 in these cells were 60.02%, 53.1%, and 52.8% of the total accumulated radioactivity. In static PET imaging, despite high uptake in the liver and kidneys, 18F-FB-ME07 showed reasonable accumulation in A431 tumors (1.02 ± 0.13 %ID/g at 30 min after injection). Of note, the uptake of 18F-FB-ME07 in A431 xenografts was significantly higher than that in U87MG and HCT-116 xenografts. In A431 xenografted mice, the tumor/blood ratio was 3.89 and the tumor/muscle ratio reached 8.65. CONCLUSIONS: We for the first time generated an aptamer-derived EGFR targeting PET tracer 18F-FB-ME07, which showed highly selective targeting ability in mouse tumor models expressing different levels of EGFR. Our results suggest that 18F-FB-ME07 is a potential EGFR targeting molecular imaging probe for future clinical translation.

Correction to: PET imaging of EGFR expression using an 18F-labeled RNA aptamer.

The original version of this article contained a mistake in the first paragraph of "Cell uptake and internalization of 18F-FB-ME07" section. The text "The specific activity was 7.4-14.8 kBq/nmol" should have been "The specific activity was 7.4-14.8 Mbq/nmol".

Community-Based Groundwater Monitoring Network Using a Citizen-Science Approach.

Water level monitoring provides essential information about the condition of aquifers and their responses to water extraction, land-use change, and climatic variability. It is important to have a spatially distributed, long-term monitoring well network for sustainable groundwater resource management. Community-based monitoring involving citizen scientists provides an approach to complement existing government-run monitoring programs. This article demonstrates the feasibility of establishing a large-scale water level monitoring network of private water supply wells using an example from Rocky View County (3900 km(2) ) in Alberta, Canada. In this network, community volunteers measure the water level in their wells, and enter these data through a web-based data portal, which allows the public to view and download these data. The close collaboration among the university researchers, county staff members, and community volunteers enabled the successful implementation and operation of the network for a 5-year pilot period, which generated valuable data sets. The monitoring program was accompanied by education and outreach programs, in which the educational materials on groundwater were developed in collaboration with science teachers from local schools. The methodology used in this study can be easily adopted by other municipalities and watershed stewardship groups interested in groundwater monitoring. As governments are starting to rely increasingly on local municipalities and conservation authorities for watershed management and planning, community-based groundwater monitoring provides an effective and affordable tool for sustainable water resources management.

Implementation and Evaluation of Four Interoperable Open Standards for the Internet of Things.

Recently, researchers are focusing on a new use of the Internet called the Internet of Things (IoT), in which enabled electronic devices can be remotely accessed over the Internet. As the realization of IoT concept is still in its early stages, manufacturers of Internet-connected devices and IoT web service providers are defining their proprietary protocols based on their targeted applications. Consequently, IoT becomes heterogeneous in terms of hardware capabilities and communication protocols. Addressing these heterogeneities by following open standards is a necessary step to communicate with various IoT devices. In this research, we assess the feasibility of applying existing open standards on resource-constrained IoT devices. The standard protocols developed in this research are OGC PUCK over Bluetooth, TinySOS, SOS over CoAP, and OGC SensorThings API. We believe that by hosting open standard protocols on IoT devices, not only do the devices become self-describable, self-contained, and interoperable, but innovative applications can also be easily developed with standardized interfaces. In addition, we use memory consumption, request message size, response message size, and response latency to benchmark the efficiency of the implemented protocols. In all, this research presents and evaluates standard-based solutions to better understand the feasibility of applying existing standards to the IoT vision.

GeoCENS: a geospatial cyberinfrastructure for the world-wide sensor web.

The world-wide sensor web has become a very useful technique for monitoring the physical world at spatial and temporal scales that were previously impossible. Yet we believe that the full potential of sensor web has thus far not been revealed. In order to harvest the world-wide sensor web's full potential, a geospatial cyberinfrastructure is needed to store, process, and deliver large amount of sensor data collected worldwide. In this paper, we first define the issue of the sensor web long tail followed by our view of the world-wide sensor web architecture. Then, we introduce the Geospatial Cyberinfrastructure for Environmental Sensing (GeoCENS) architecture and explain each of its components. Finally, with demonstration of three real-world powered-by-GeoCENS sensor web applications, we believe that the GeoCENS architecture can successfully address the sensor web long tail issue and consequently realize the world-wide sensor web vision.

Locally optimal detection of image watermarks in the wavelet domain using Bessel K form distribution.

A uniformly most powerful watermark detector, which applies the Bessel K form (BKF) probability density function to model the noise distribution was proposed by Bian and Liang. In this paper, we derive a locally optimum (LO) detector using the same noise model. Since the literature lacks thorough discussion on the performance of the BKF-LO nonlinearities, the performance of the proposed detector is discussed in detail. First, we prove that the test statistic of the proposed detector is asymptotically Gaussian and evaluate the actual performance of the proposed detector using the receiver operating characteristic (ROC). Then, the large sample performance of the proposed detector is evaluated using asymptotic relative efficiency (ARE) and "maximum ARE." The experimental results show that the proposed detector has a good performance with or without attacks in terms of its ROC curves, particularly when the watermark is weak. Therefore, the proposed method is suitable for wavelet domain watermark detection, particularly when the watermark is weak.

Retained interface gentian violet ink in Descemet stripping endothelial keratoplasty.

PURPOSE: To present a case of a patient who underwent right Descemet stripping endothelial keratoplasty (DSEK) in whom the gentian violet ink used to mark and orient the donor corneal graft had persisted at the host-graft interface. METHODS: A 57-year-old woman with progressive corneal edema from Fuchs endothelial dystrophy in her right eye underwent a combined phacoemulsification/posterior chamber intraocular lens insertion and DSEK. The host endothelium was stripped in a central 9.0-mm diameter. The endothelial graft was harvested to a depth of 400 µm. The anterior stromal flap was lifted, and the stromal side of the endothelial graft was peripherally marked with a dotted "7" using a Codman gentian violet marker pen and a dot was placed at the center to aid centration. The graft was inserted and centrally positioned. The superior clear corneal wound was closed with 3 × 10/0 nylon interrupted sutures. The patient was instructed to lie face up for the first 48 hours. RESULTS: At 1 week, the graft was well positioned and the central gentian violet mark was not present but the peripheral markings were noted. At 14 months, the cornea was clear with an unaided visual acuity of 20/25 and best-corrected visual acuity of 20/20 but the superior peripheral markings persisted at the graft-host interface. Specular microscopy demonstrated a cell density of 1900 cells per square millimeter. CONCLUSIONS: Gentian violet ink marking used in DSEK operations may persist at the graft-host interface. Small, peripheral markings will minimize the risk of interference with central vision, ink-induced inflammation, and endothelial damage.

New generation Sensor Web Enablement.

Many sensor networks have been deployed to monitor Earth's environment, and more will follow in the future. Environmental sensors have improved continuously by becoming smaller, cheaper, and more intelligent. Due to the large number of sensor manufacturers and differing accompanying protocols, integrating diverse sensors into observation systems is not straightforward. A coherent infrastructure is needed to treat sensors in an interoperable, platform-independent and uniform way. The concept of the Sensor Web reflects such a kind of infrastructure for sharing, finding, and accessing sensors and their data across different applications. It hides the heterogeneous sensor hardware and communication protocols from the applications built on top of it. The Sensor Web Enablement initiative of the Open Geospatial Consortium standardizes web service interfaces and data encodings which can be used as building blocks for a Sensor Web. This article illustrates and analyzes the recent developments of the new generation of the Sensor Web Enablement specification framework. Further, we relate the Sensor Web to other emerging concepts such as the Web of Things and point out challenges and resulting future work topics for research on Sensor Web Enablement.

Intrastromal injection of antibiotic agent in the management of recalcitrant bacterial keratitis.

Intrastromal injection is a novel method of delivering an antibiotic agent directly to the site of keratitis. Although intrastromal antifungal agents have been used to manage refractory fungal keratitis, the experience with intrastromal antibiotic agents for bacterial keratitis is more limited. We report a case of refractory bacterial keratitis treated with an intrastromal antibiotic agent and discuss the potential for the clinical use of this modality.

Tight orbit syndrome: a previously unrecognized cause of open-angle glaucoma.

PURPOSE: To describe a new syndrome of tight orbit and intractable glaucoma with a poor visual prognosis. METHODS: A retrospective observational case series of six patients seen at two centres between 2001 and 2007 assessing intraocular pressure (IOP), best-corrected visual acuity and visual field. RESULTS: Three men and three women, ranging in age at diagnosis from 14 to 53 years, demonstrated similar orbital features and progressive visual field loss despite intensive management with medication and laser and operative surgery. Highest IOPs ranged from 30 to 50 mmHg. Trabeculectomy and/or glaucoma drainage devices were attempted in five patients but all failed. One patient underwent orbital decompression with achievement of IOP control. Final IOP at last follow-up was variable; only two patients achieved IOP in the normal range, with the rest ranging from 25 to 40 mmHg. All patients had advanced visual field loss. CONCLUSION: Tight orbit syndrome presents a serious clinical challenge. Despite maximum medical therapy and surgical intervention IOP is difficult to control, resulting in progressive visual field loss.

Self-tonometry in glaucoma management--past, present and future.

Glaucoma is the leading cause of irreversible blindness in the world. Diagnosis and management of glaucoma is significantly associated with intraocular pressure, but contemporary office-based measurements are not sufficient to discover diurnal changes and spikes, nor do they demonstrate the effect of medication and compliance. Patient-directed self-tonometry can be taken throughout the day and is therefore the subject of much discussion and research. In this article we review the history of self-tonometry devices and present technologies for the future.

Histopathology of a functioning mitomycin-C trabeculectomy.

The ideal trabeculectomy bleb is diffuse, normally vascularized and characterized by microcystic change in the overlying conjunctiva. We compare and contrast the histopathology of a normally functioning mitomycin-C trabeculectomy site obtained from an eye enucleated for iris melanoma with abnormal blebs discussed in the literature. Representative sections of the normally functioning bleb were examined under the light microscope. The conjunctiva is composed of a uniform three-layered non-keratinizing stratified squamous epithelium overlying a single layer of oedematous basal cells. The conjunctival stroma consisted of loose connective tissue, traversed by capillaries and scattered small cystic spaces lined by endothelial cells. There were no goblet cells and few inflammatory cells and fibroblasts. The scleral trapdoor was evident as a cleft in the scleral wall in communication with the anterior chamber at the surgically created sclerostomy. Because the histopathological findings in our case correlate well with this clinical appearance, we conclude that whereas augmentation with anti-metabolites, such as mitomycin-C, can be associated with significantly altered conjunctival histopathology and consequent hypotony, but, if used carefully, normal architecture is conserved.

Orbital cellulitis as a postoperative complication of sub-Tenon anaesthesia in cataract surgery.

Orbital cellulitis is a rarely reported sight-threatening complication of sub-Tenon anaesthesia. We report a case of orbital cellulitis in a patient who had received sub-Tenon anaesthesia for routine cataract surgery. We discuss the potential under-reporting of complications of sub-Tenon anaesthesia that had a delayed presentation, and the possible association between the use of hyaluronidase in the anaesthetic mixture and orbital cellulitis following sub-Tenon anaesthesia.