Supercapacitors are one of the key devices for energy‐storage applications. They have energy densities much higher than those of conventional capacitors and possess much better power delivery ...capabilities than batteries. This makes them unique devices that can outperform both batteries and conventional capacitors under special circumstances. Nanocarbons are the main electrode materials for supercapacitors. Abundant sources of nanocarbons and facile processes of modification have led to the fabrication of cheap electrodes. In this review, we focus on the capacitance performance of highly porous activated carbons and attempt to determine the role of different pores. Elaborate discussions are presented on individual contributions from micro‐ and mesopores and their mutual dependence. This article also presents a comparative performance report for both random and ordered porous nanocarbons. Novel carbon materials, such as carbon nanotubes and graphene, and their contributions in this context are discussed. We summarize key techniques for the functionalization of nanocarbons and their pseudocapacitive charge‐storage mechanisms. Nanocarbon composites with redox‐active transition‐metal oxides and conducting polymers are highlighted along with their impact as electrode materials. Ideal composite structures are highlighted and an attempt is made to determine an ideal future electrode structure for capacitors with high energy and power density.
Super power! The capacitance performance of highly porous activated carbons is described and the elucidation of the role of different pores is attempted (see picture). Elaborate discussions are also presented on the individual contributions from micro‐ and mesopores and their mutual dependence. An ideal electrode can be realized when a charge transportation pathway is obtained through the mesopores that channel ions to the micropores available on the surface.
Cellular networks have been engineered and optimized to carrying ever-increasing amounts of mobile data, but over the last few years, a new class of applications based on machine-centric ...communications has begun to emerge. Automated devices such as sensors, tracking devices, and meters, often referred to as machine-to-machine (M2M) or machine-type communications (MTC), introduce an attractive revenue stream for mobile network operators, if a massive number of them can be efficiently supported. The novel technical challenges posed by MTC applications include increased overhead and control signaling as well as diverse application-specific constraints such as ultra-low complexity, extreme energy efficiency, critical timing, and continuous data intensive uploading. This article explains the new requirements and challenges that large-scale MTC applications introduce, and provides a survey of key techniques for overcoming them. We focus on the potential of 4.5G and 5G networks to serve both the high data rate needs of conventional human-type communication (HTC) subscribers and the forecasted billions of new MTC devices. We also opine on attractive economic models that will enable this new class of cellular subscribers to grow to its full potential.
The main obstacles to achieving high electrochemical energy density while retaining high power density are the trade-offs of energy versus power and gravimetric versus volumetric density. Optimizing ...structural parameters is the key to circumvent these trade-offs. We report here the synthesis of carbon nanotube (CNT)-bridged graphene 3D building blocks via the Coulombic interaction between positively charged CNTs grafted by cationic surfactants and negatively charged graphene oxide sheets, followed by KOH activation. The CNTs were intercalated into the nanoporous graphene layers to build pillared 3D structures, which enhance accessible surface area and allow fast ion diffusion. The resulting graphene/CNT films are free-standing and flexible with a high electrical conductivity of 39 400 S m–1 and a reasonable mass density of 1.06 g cm–3. The supercapacitors fabricated using these films exhibit an outstanding electrochemical performance in an ionic liquid electrolyte with a maximum energy density of 117.2 Wh L–1 or 110.6 Wh kg–1 at a maximum power density of 424 kW L–1 or 400 kW kg–1, which is based on thickness or mass of total active material.
Fractional frequency reuse (FFR) is an interference management technique well-suited to OFDMA-based cellular networks wherein the bandwidth of the cells is partitioned into regions with different ...frequency reuse factors. To date, FFR techniques have been typically been evaluated through system-level simulations using a hexagonal grid for the base station locations. This paper instead focuses on analytically evaluating the two main types of FFR deployments - Strict FFR and Soft Frequency Reuse (SFR) - using a Poisson point process to model the base station locations. The results are compared with the standard grid model and an actual urban deployment. Under reasonable special cases for modern cellular networks, our results reduce to simple closed-form expressions, which provide insight into system design guidelines and the relative merits of Strict FFR, SFR, universal reuse, and fixed frequency reuse. Finally, a SINR-proportional resource allocation strategy is proposed based on the analytical expressions and we observe that FFR provides an increase in the sum-rate as well as the well-known benefit of improved coverage for cell-edge users.
Interference management techniques are critical to the performance of heterogeneous cellular networks, which will have dense and overlapping coverage areas, and experience high levels of ...interference. Fractional frequency reuse (FFR) is an attractive interference management technique due to its low complexity and overhead, and significant coverage improvement for low-percentile (cell-edge) users. Instead of relying on system simulations based on deterministic access point locations, this paper instead proposes an analytical model for evaluating Strict FFR and Soft Frequency Reuse (SFR) deployments based on the spatial Poisson point process. Our results both capture the non-uniformity of heterogeneous deployments and produce tractable expressions which can be used for system design with Strict FFR and SFR. We observe that the use of Strict FFR bands reserved for the users of each tier with the lowest average \sinr provides the highest gains in terms of coverage and rate, while the use of SFR allows for more efficient use of shared spectrum between the tiers, while still mitigating much of the interference. Additionally, in the context of multi-tier networks with closed access in some tiers, the proposed framework shows the impact of cross-tier interference on closed access FFR, and informs the selection of key FFR parameters in open access.
An ultrathin V2O5 layer was electrodeposited by cyclic voltammetry on a self‐standing carbon‐nanofiber paper, which was obtained by stabilization and heat‐treatment of an electrospun ...polyacrylonitrile (PAN)‐based nanofiber paper. A very‐high capacitance of 1308 F g−1 was obtained in a 2 M KCl electrolyte when the contribution from the 3 nm thick vanadium oxide was considered alone, contributing to over 90% of the total capacitance (214 F g−1) despite the low weight percentage of the V2O5 (15 wt%). The high capacitance of the V2O5 is attributed to the large external surface area of the carbon nanofibers and the maximum number of active sites for the redox reaction of the ultrathin V2O5 layer. This ultrathin layer is almost completely accessible to the electrolyte and thus results in maximum utilization of the oxide (i.e., minimization of dead volume). This hypothesis was experimentally evaluated by testing V2O5 layers of different thicknesses.
An ultrathin film of V2O5 is electrodeposited on the surface of carbon nanofibers to obtain a high surface area with an improved electrode conductivity. This provides a high pseudocapacitance of 1308 F g−1 with respect to the effective contribution from the deposited oxide layer. The schematic shows the distribution of V2O5 throughout the nanofiber. The graph shows the dependence of the specific capacitance on the deposited amount of V2O5.
The Trade Policy Review Mechanism (TPRM) has been an integral part of the GATT/WTO since 1989 and shoulders a fundamental responsibility in making the regime more transparent. This paper asks: how ...has the TPRM responded to demands from developing countries for information and transparency? The paper uses a typology of information systems to explain the evolution of surveillance in the trade regime and asks whether the TPRM was assigned the functions of an ideal-type information system. The paper, then, evaluates the performance of the TPRM against its given mandate of increasing transparency to promote improved adherence with trade rules. It presents, for the first time, empirical evidence on the content of reports and the participation of countries, to highlight persisting content- and participation-related challenges. It discusses the capacity challenges within the WTO Secretariat and briefly outlines efforts made by developing countries to boost surveillance capacity at home. The paper ends by outlining priorities for monitoring in the trade regime: generating specific information that developing countries need, supporting domestic capacity for surveillance (including from non-official sources), and concentrating on improved peer review and follow-up procedures. Monitoring and surveillance is the rising agenda of the WTO.Pascal Lamy1
If symptomatic in infants, the autosomal recessive disease lysosomal acid lipase deficiency (LAL-D; sometimes called Wolman disease or LAL-D/Wolman phenotype) is characterized by complete loss of LAL ...enzyme activity. This very rare, rapidly progressive form of LAL-D results in severe manifestations leading to failure to thrive and death, usually by 6 months of age. We report results from 2 open-label studies of enzyme replacement therapy with sebelipase alfa, a recombinant human LAL, in infants with LAL-D: the phase 2/3 Survival of LAL-D Infants Treated With Sebelipase Alfa (VITAL) study (NCT01371825) and a phase 2 dose-escalation study (LAL-CL08 CL08; NCT02193867). In both, infants received once-weekly intravenous infusions of sebelipase alfa.
The analysis population contained 19 patients (9 in VITAL; 10 in CL08). Kaplan-Meier estimates of survival to 12 months and 5 years of age were 79% and 68%, respectively, in the combined population, and the median age of surviving patients was 5.2 years in VITAL and 3.2 years in CL08. In both studies, median weight-for-age, length-for-age, and mid-upper arm circumference-for-age z scores increased from baseline to end of study. Decreases in median liver and spleen volume over time were noted in both studies. Short-term transfusion-free hemoglobin normalization was achieved by 100% of patients eligible for assessment in VITAL, in an estimated median (95% confidence interval CI) time of 4.6 (0.3-16.6) months. In CL08, short-term transfusion-free hemoglobin normalization was achieved by 70% of patients eligible for assessment, in an estimated median (95% CI) time of 5.5 (3.7-19.6) months. No patient discontinued treatment because of treatment-emergent adverse events. Most infusion-associated reactions (94% in VITAL and 88% in CL08) were mild or moderate in severity.
The findings of these 2 studies of infants with rapidly progressive LAL-D demonstrated that enzyme replacement therapy with sebelipase alfa prolonged survival with normal psychomotor development, improved growth, hematologic parameters, and liver parameters, and was generally well tolerated, with an acceptable safety profile.
Breast and/or ovarian cancer (BOC) are among the most frequently diagnosed forms of hereditary cancers and leading cause of death in India. This emphasizes on the need for a cost-effective method for ...early detection of these cancers. We sequenced 141 unrelated patients and families with BOC using the TruSight Cancer panel, which includes 13 genes strongly associated with risk of inherited BOC. Multi-gene sequencing was done on the Illumina MiSeq platform. Genetic variations were identified using the Strand NGS software and interpreted using the StrandOmics platform. We were able to detect pathogenic mutations in 51 (36.2%) cases, out of which 19 were novel mutations. When we considered familial breast cancer cases only, the detection rate increased to 52%. When cases were stratified based on age of diagnosis into three categories, ⩽40 years, 40-50 years and >50 years, the detection rates were higher in the first two categories (44.4% and 53.4%, respectively) as compared with the third category, in which it was 26.9%. Our study suggests that next-generation sequencing-based multi-gene panels increase the sensitivity of mutation detection and help in identifying patients with a high risk of developing cancer as compared with sequential tests of individual genes.
Cholestane-3β,5α,6β-triol (3β,5α,6β-triol) is formed from cholestan-5,6-epoxide (5,6-EC) in a reaction catalysed by cholesterol epoxide hydrolase, following formation of 5,6-EC through free radical ...oxidation of cholesterol. 7-Oxocholesterol (7-OC) and 7β-hydroxycholesterol (7β-HC) can also be formed by free radical oxidation of cholesterol. Here we investigate how 3β,5α,6β-triol, 7-OC and 7β-HC are metabolised to bile acids. We show, by monitoring oxysterol metabolites in plasma samples rich in 3β,5α,6β-triol, 7-OC and 7β-HC, that these three oxysterols fall into novel branches of the acidic pathway of bile acid biosynthesis becoming (25R)26-hydroxylated then carboxylated, 24-hydroxylated and side-chain shortened to give the final products 3β,5α,6β-trihydroxycholanoic, 3β-hydroxy-7-oxochol-5-enoic and 3β,7β-dihydroxychol-5-enoic acids, respectively. The intermediates in these pathways may be causative of some phenotypical features of, and/or have diagnostic value for, the lysosomal storage diseases, Niemann Pick types C and B and lysosomal acid lipase deficiency. Free radical derived oxysterols are metabolised in human to unusual bile acids via novel branches of the acidic pathway, intermediates in these pathways are observed in plasma.
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•Free radical derived oxysterols metabolised to unusual bile acids.•Metabolism proceeds via novel branches of the acidic pathway.•Bile acids with:- 3β,5α,6β-triol; 3β,7β-diol-5-ene or 3β-ol-5-en-7-one in A/B-ring.•Unusual bile acids found in plasma from patients with NPC, NPB and LALD.•Intermediates in the biosynthesis of unusual bile acids found in plasma.
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