Simultaneous Multiple Surface Segmentation Using Deep Learning

The task of automatically segmenting 3-D surfaces representing boundaries of objects is important for quantitative analysis of volumetric images, and plays a vital role in biomedical image analysis. Recently, graph-based methods with a global optimization property have been developed and optimized for various medical imaging applications. Despite their widespread use, these require human experts to design transformations, image features, surface smoothness priors, and re-design for a different tissue, organ or imaging modality. Here, we propose a Deep Learning based approach for segmentation of the surfaces in volumetric medical images, by learning the essential features and transformations from training data, without any human expert intervention. We employ a regional approach to learn the local surface profiles. The proposed approach was evaluated on simultaneous intraretinal layer segmentation of optical coherence tomography (OCT) images of normal retinas and retinas affected by age related macular degeneration (AMD). The proposed approach was validated on 40 retina OCT volumes including 20 normal and 20 AMD subjects. The experiments showed statistically significant improvement in accuracy for our approach compared to state-of-the-art graph based optimal surface segmentation with convex priors (G-OSC). A single Convolution Neural Network (CNN) was used to learn the surfaces for both normal and diseased images. The mean unsigned surface positioning errors obtained by G-OSC method 2.31 voxels (95% CI 2.02-2.60 voxels) was improved to $1.27$ voxels (95% CI 1.14-1.40 voxels) using our new approach. On average, our approach takes 94.34 s, requiring 95.35 MB memory, which is much faster than the 2837.46 s and 6.87 GB memory required by the G-OSC method on the same computer system.Comment: 8 page

On the resource allocation for D2D underlaying uplink cellular networks

Device-to-Device (D2D) communications has attracted research interests as an emerging technology towards 5G and beyond cellular networks. In this paper, we investigate the power allocation in D2D underlaying cellular networks with uplink channel reuse. We first develop an optimization problem to minimize the total power consumption subject to per- user Quality-of-Service (QoS) constraints. A distributed power allocation algorithm is proposed to allocate the power for both D2D and cellular users by exploiting the property of strictly non-negative inverse of a Z-matrix. It is shown that the power allocated for users can be considerably saved for low QoS requirements, especially with a large number of D2D users. The proposed algorithm is validated through simulation to realize the impacts of noise power, distance between D2D users and the number of D2D pairs in the network

An optimal power allocation for D2D communications over multi-user cellular uplink channels

Device-to-Device (D2D) communications has emerged as a promising technology for optimizing spectral efficiency, reducing latency, improving data rate and increasing system capacity in cellular networks. Power allocation in D2D communication to maintain Quality-of-Service (QoS) remains as a challenging task. In this paper, we investigate the power allocation in D2D underlaying cellular networks with multi-user cellular uplink channel reuse. Specifically, this paper aims at minimizing the total transmit power of D2D users and cellular users (CUs) sub- ject to QoS requirement at each user in terms of the required signal-to- interference-plus-noise ratio (SINR) at D2D users and base station (BS) over uplink channel as well as their limited transmit power. We first derive expressions of SINR at the D2D users and BS based on which an optimization framework for power allocation is developed. We then propose an optimal power allocation algorithm for all D2D users and CUs by taking into account the property of non-negative inverse of a Z- matrix. The proposed algorithm is validated through simulation results which show the impacts of noise power, distance between D2D users, the number of D2D pairs and the number of CUs on the power allocation in the D2D underlaying cellular networks

Development Disrupted: The Case of Afghanistan Taliban 2.0 and Lessons Learned About Foreign Aid Management

In August 2021, the United States withdrawal from Afghanistan marked the end of twenty years of attempts at liberal state building and development in that country. Despite spending trillions of dollars to create a capable, functional government, the Afghan government could not last even a week without US military and financial support. After its collapse, the Taliban immediately took over Afghanistan for the second time (Taliban 2.0). This turn of events resulted in the discontinuance of foreign aid and immediate downturn of the Afghan economy. Since then, there has been debate, among other issues, over why and how the foreign aid failed, and whether and how aid (if any) should continue to flow into the country under Taliban rule. This Article argues that foreign aid from governments and non-governmental donor agencies was not the essential problem, but it was the centralized aid and public finance management system which caused systemic corruption and waste. The monopoly of authorities, discretion over resources, and lack of downward accountability promoted a top-down, unanswerable aid and public finance management system which ultimately failed the Afghan State. With the Taliban again in power, there are two main issues that challenge the flow of foreign aid, aside from its egregious human rights record. First, the international community cannot trust a regime that has not (yet) been formally recognized or proved itself a reliable recipient; and second, the authoritarian and undemocratic leadership is pursuing the same centralized approach to management of aid and public funds. While the aid would remain humanitarian in scope, there is no assurance, as was the case in the previous regime, of any sustainable prospect of peace and in-country development. Nevertheless, the international community must find a way to meet this development challenge

Management of complete dislocation of tarsal scaphoid without fracture

Background: Injuries to the mid tarsal joints usually occur in the form of various combinations such as fracture, fracture subluxation, and fracture dislocation. Dislocations of navicular without fracture are rare injuries, minimal literatures exist, which describe the probable mechanism of injury and optimal treatment.Methods: Four patients with complete dislocation of navicular without fracture presented to us following a history of trauma. The diagnosis was confirmed by radiology and further details were studied by CT scans. One injury was open and the rest were closed. One had associated fracture of talus and two had metatarsal fracture and one was purely isolated navicular dislocation without any associated injury. All were initially stabilized in a below knee plaster of paris slab and foot end elevated. All were successfully treated surgically under spinal anesthesia with open reduction and internal fixation with Kirschner wires through a dorsomedial approach. Postoperative immobilization was continued for twelve weeks then gradual mobilization begun followed by physiotherapy.Results: All patients had good clinical results with two patients resuming their work within twelve weeks and the one with open wound took twenty weeks for resuming his original work. One with associated talar fracture later had to undergo subtalar arthrodesis for pain in the foot while weight bearing after one year of surgery for navicular dislocation. Conclusions: Open reduction and internal fixation with Kirschner wire is an effective way of managing patients with complete dislocation of tarsal navicular for early resuming of the functions and return to work

Rechargeable organic–air redox flow batteries

A rechargeable organic–air flow battery based on aqueous electrolytes is proposed and tests are conducted in a divided cell with a three-electrode configuration. Quinoxaline is used as the negative redox couple due to its low electrode potential of c.a. −0.9 V vs. Hg|HgO in aqueous electrolytes. High-surface-area nickel mesh and manganese-dioxide electrodes were employed for oxygen evolution and reduction, respectively, together with a low-cost hydroxide doped polybenzimidazole (m-PBI) separator (c.a. 20 μm). In typical alkaline electrolytes (2 M NaOH), the open-circuit voltage of the flow battery was c.a. 0.95 V, which is comparable to existing organic-based batteries. The average charge and discharge cell voltage ranges at 5–10 mA cm−2 were 1.7–1.95 V and 0.4–0.7 V, respectively. Despite using low-cost materials, average coulombic and energy efficiencies of the batteries were c.a. 81 and 25%, respectively, at 7.5 mA cm−2 over 20 cycles

Co adaptation of LiCl tolerant Solanum tuberosum L. callus cultures to NaCl stress

In this research, co-adaptation of the Calli of Solanum tuberosum, raised from petioles, to the presence of lithium (LiCl) and sodium chloride (NaCl) was studied. The cultures were adapted with LiCl in the absence of an osmotic stress and the response of adapted and unadapted calli to salinity was investigated. Undifferentiated callus growth was induced in S. tuberosum by the addition of 2 mg/l 2,4 dichlorophenoxy acetic acid (2,4-D), 0.25 mg/l kinetin to Murashige and Skoog medium. Subcultures were subjected to an incremental increase in LiCl to obtain adapted lines. Adapted and undapted calli were grown with LiCl and NaCl and the tissue content of Na+, K+, Ca2+, Mg2+ and proline levels were determined. Either 40 mM LiCl or 100 mM NaCl inhibited unadapted calli by more than 50%, while adapted calli grew normally under these conditions. The adapted calli exhibited a lower K+ content with or without salt and showed a lower accumulation of Na+ at 100 mM NaCl. The tissue K+ and Mg2+ contents decreased and their proline levels increased with salinity. A co-adaptation phenomenon is induced by LiCl that involves a regulation of K+ and Na+ contents and an accumulation of proline, which also brings about tolerance to osmotic effects of salt. This data is highly useful for devising breeding and molecular modification strategies for stress tolerance.Key words: Cations, proline, osmotic adjustment, salt tolerance, Solanum tuberosum

Search for magnetoelectric monopole response in Cr2_2O3_3 powder

Powder samples have been suggested as a pathway to fabricate isotropic magnetoelectric (ME) materials which effectively only have a pseudoscalar or monopole ME response. We demonstrate that random distribution of ME grains alone does not warrant isotropic ME response because the activation of a non-vanishing ME response requires a ME field cooling protocol which tends to induce preferred axes. We investigate the evolution of ME susceptibility in powder chromia samples for various ME field cooling protocols both theoretically and experimentally. In particular, we work out the theoretical expressions for ME susceptibility for powder Chromia in the framework of statistical mechanics where Boltzmann factors weigh the orientation of the N\'eel vector relative to the local orientation of the c-axis of a grain. Previous approximations oversimplified the thermodynamic nature of the annealing process giving rise to misleading conclusions on the role of the magnitude of the applied product of electric and magnetic fields on the ME response. In accordance with our refined theory, a strong dependence of the functional form of $\alpha$ vs. $T$ of Chromia powders on the ME field cooling protocol is observed. It shows that Chromia powder is not generically an isotropic ME effective medium but provides a pathway to realize the elusive isotropic ME response.Comment: Submitted to Physical Review

AROMA: An adapt-or-reroute strategy for multimedia applications over SDN-based wireless environments

To support new and advanced multimedia-rich applications and services while providing satisfactory user experience, the underlying network infrastructure needs to evolve and adapt. One of the key enabling technologies of the next generation (5G) networks is the integration of Software Defined Networking (SDN) within a heterogeneous wireless environment to enable interoperability and QoS provisioning. Leveraging on the features of the SDN paradigm, it is possible to introduce new solutions to handle the increasing mobile video transmission challenges with strict QoS requirements, such as: low delay, jitter, packet loss, and high bandwidth demands. However, degradation and instability perceived from video traffic makes it difficult to satisfy various end-users. In this context, this paper proposes AROMA, an Adapt-or-reROute strategy for Multimedia Applications over SDN-based wireless environments. AROMA enables QoS provisioning over multimedia-oriented SDN-based WLAN environments. The proposed solution is evaluated using a real experimental test-bed setup

Cell Lineage Determination and the Control of Neuronal Identity in the Neural Crest

The diverse cell types of complex tissues such as the blood and the brain are generated from self-renewing, multipotent progenitors called stem cells (for reviews, see Hall and Watt 1989; Potten and Loeffler 1990; Morrison et al. 1997). These stem cells must generate progeny of different phenotypes, in the correct proportions, sequence, and location. The manner in which this is accomplished is not well understood. It is clear that the local microenvironment of stem cells has an important influence on their development, as do transcription factors that act within the cells. However, the manner in which such signals and transcription factors interact to control lineage determination by multipotent stem cells is poorly understood. To address this issue, it is necessary to both alter the expression of transcription factors in stem cells and challenge the cells by altering their environment to determine their state of lineage commitment. There are relatively few experimental systems in which such combined genetic and cell biological manipulation of stern cells are feasible