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Solution processed semiconductor lasers have achieved much success across the nanomaterial research community, including in organic semiconductors1,2, perovskites3,4 and colloidal semiconductor nanocrystals5,6. The ease of integration with other photonic components, and the potential for upscaling using emerging large area fabrication technologies, such as roll-to-roll7, make these lasers attractive as low-cost photonic light sources that can find use in a variety of applications: integrated photonic circuitry8,9, telecommunications10,11, chemo-/bio-sensing12,13, security14, and lab-on-chip experiments15. However, for fiber-optic or free-space optical (FPO) communications and eye-safe LIDAR applications, room temperature solution-processed lasers have remained elusive. Here we report the first solution processed laser, comprising PbS colloidal quantum dots (CQDs) integrated on a distributed feedback (DFB) cavitiy, with tuneable lasing wavelength from 1.55 μm - 1.65 μm. These lasers operate at room temperature and exhibit linewidths as low as ~0.9 meV.

In the last decades, several approaches were developed to design drug delivery systems to address the multiple biological barriers encountered after administration while safely delivering a payload. In this scenario, bio-inspired and bio-mimetic approaches have emerged as promising solutions to evade the mononuclear phagocytic system while simultaneously negotiating the sequential transport across the various biological barriers. Leukocytes freely circulate in the bloodstream and selectively target the inflamed vasculature in response to injury, infection, and cancer. Recently we have shown the use of biomimetic nanovesicles, called leukosomes, which combine both the physical and biological properties of liposomes and leukocytes, respectively, to selectively deliver drugs to the inflamed vasculature. Here we report the use of leukosomes to target and deliver doxorubicin, a model chemotherapeutic, to tumors in syngeneic murine models of breast cancer and melanoma. Exploiting the inflammatory pathway responsible for recruiting immune cells to the site of injury, leukosomes exhibited increased targeting of cancer vasculature and stroma. Furthermore, delivery of doxorubicin with leukosomes enabled significant tumor growth inhibition compared with free doxorubicin in both breast and melanoma tumors. This study demonstrates the promise of using biomimetic nanovesicles for effective cancer management in solid tumors.

The use of colloidal quantum dots (CQDs) as a gain medium in infrared laser devices has been underpinned by the need for high pumping intensities, very short gain lifetimes, and low gain coefficients. Here, PbS/PbSSe core/alloyed-shell CQDs are employed as an infrared gain medium that results in highly suppressed Auger recombination with a lifetime of 485 ps, lowering the amplified spontaneous emission (ASE) threshold down to 300 µJ cm

We sought to investigate mid-term clinical outcomes and identify risk factors in one of the largest comprehensive series reported of femoro-ilio-caval (FIC) vein stent placement.Endovascular intervention with balloon angioplasty and stenting of the iliac and common femoral veins has become first-line treatment for symptomatic deep venous outflow obstruction.We conducted a single-center, retrospective analysis of 180 patients who underwent FIC stent implantation between May 2017 and May 2019; 327 procedures were performed. Our primary objective was to evaluate a composite of stent thrombosis and stent restenosis. Secondary outcomes included individual predictors of in-stent restenosis (ISR) and in-stent thrombosis (IST), primary and secondary patency, access-site complications, major bleeding, pulmonary embolism, cardiovascular death, any death, intracranial bleeding, all-cause mortality, and components of major adverse cardiac and cerebrovascular events (MACCE) in a 24-month period.A total of 327 procedures were performed for 180 patients. At 2-year follow up, 78.3% of cases remained free of any complication. Primary outcome occurred in 53 procedures (16.2%) and was highest at early (30 days) follow-up. Primary patency at 2-year follow-up was 78.43%. There were no deaths, 1 patient (0.3%) had a subdural hematoma, and 3 patients (0.9%) had MACCE. Age and post-thrombotic syndrome (PTS) were significant predictors of primary outcome. PTS and Venous Clinical Severity score (VCSS) ≥10 were found to have higher rates of thrombosis. Active smokers, the elderly, history of deep vein thrombosis (DVT), and VCSS ≥10 had a statistically significant elevated risk of ISR.Endovascular treatment with stent implantation for non-thrombotic iliac vein lesion and PTS is safe, with low morbidity, zero mortality, low complications, and persistent improvement of symptoms. Age and PTS were significant predictors of primary outcome.

A phototransistor built by the assembly of 2D colloidal semiconductor quantum wells (CQWs) on a single layer of 2D transition metal dichalcogenide (TMD) is displayed. This hybrid device architecture exhibits high efficiency in Forster resonance energy transfer (FRET) enabling superior performance in terms of photoresponsivity and detectivity. Here, a thin film of CdSe/CdS CQWs acts as a sensitizer layer on top of the MoS2 monolayer based field-effect transistor, where this CQWs-MoS2 structure allows for strong light absorption in CQWs in the operating spectral region and strong dipole-to-dipole coupling between MoS2 and CQWs resulting in enhanced photoresponsivity of one order of magnitude (11-fold) at maximum gate voltage (V-BG = 2 V) and two orders of magnitude (approximate to 5 x 10(2)) at V-BG = -1.5 V, and tenfold enhanced specific detectivity. The illumination power-dependent characterization of this hybrid device reveals that the thin layer of CQWs dominates the photogating mechanism compared to the photoconductivity effect on detection performance. Such hybrid designs hold great promise for 2D-material based photodetectors to reach high performance and find use in optoelectronic applications.

We utilized time-resolved photoluminescence (TRPL) spectroscopy to study the excitonic circular polarization (PX) from CdSe/CdMnS core/shell nanoplatelets (NPLs) with a bilayer core. This allows an extensive study of the emission dynamics as a function of magnetic field, temperature, doping concentration, and excitation wavelength. In the presence of an external magnetic field, pulsed excitation below the shell gap results in near-zero excitonic circular polarization PX at all time delays. In contrast, pulsed excitation with photon energy larger than the shell gap results in a rapid (100 ps) buildup of the excitonic circular polarization which subsequently remains constant at a level of up to 40%. We propose a model to describe the dynamics which takes into account the exchange interaction between carrier and magnetic ion (Mn) spins. The studied system exhibits a fast switchable excitonic circular polarization, implying possible applications in lasers and light emitting diodes.

Pb-chalcogenide colloidal quantum dots (CQDs) are attractive materials to be used as tuneable laser media across the infrared spectrum. However, excessive nonradiative Auger recombination due to the presence of trap states outcompetes light amplification by rapidly annihilating the exciton population, leading to high gain thresholds. Here, a binary blend is employed of CQDs and ZnO nanocrystals in order to passivate the in-gap trap states of PbS-CQD gain medium. Using transient absorption, a fivefold increase is measured in Auger lifetime demonstrating the suppression of trap-assisted Auger recombination. By doing so, a twofold reduction is achieved in amplified spontaneous emission (ASE) threshold. Finally, by integrating the proposed binary blend to a distributed feedback (DFB) resonator, single-mode lasing emission is demonstrated at 1650 nm with a linewidth of 1.23 nm (0.62 meV), operating at a low lasing threshold of ≈385 μJ cm-2 . The Auger suppression in this system has allowed to achieve unprecedented lasing emission stability for a CQD laser with recorded continuous operation of 5 h at room temperature and ambient conditions.

Achieving low-threshold optical gain for solution-processed materials is crucial for their real-life applications and deployment as gain media. However, the realization of low gain threshold in the blue region has shown to be technically an extremely challenging task using colloidal nanocrystals as a result of fast nonradiative Auger rates in smaller nanocrystals. Here, ultralow-threshold blue amplified spontaneous emission (ASE) (≈2.7 µJ cm ) accompanied with a large net modal gain coefficient of 360 cm in the blue enabled by blue-emitting (≈455–465 nm) colloidal quantum rings (QRs) of inverted type-I CdS/CdSe core/crown nanoplatelets (NPLs) is proposed and demonstrated. The synthesized QRs with controlled crown size outperform the best reported ASE thresholds and net modal gain coefficients from the solution-processed materials by ≈2.5- and ≈4-fold, respectively, in the similar blue spectral window. Utilizing this QR architecture, it is also shown that the ASE peak can be spectrally tuned by controlling the lateral size of the crown and hence quantum confinement in the lateral direction. These outstanding results support the prospects of these solution-processed QRs made of 2D hetero-NPLs in the challenging blue region as colloidal gain. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Accepted version

Solution-processed type-II quantum wells exhibit outstanding optical properties, which make them promising candidates for light-generating applications including lasers and LEDs. However, they may suffer from poor colloidal stability under ambient conditions and show strong tendency to assemble into face-to-face stacks. In this work, to resolve the colloidal stability and uncontrolled stacking issues, we proposed and synthesized CdSe/CdSe1–xTex/CdS core/multicrown heteronanoplatelets (NPLs), controlling the amount of Te up to 50% in the crown without changing their thicknesses, which significantly increases their colloidal and photostability under ambient conditions and at the same time preserving their attractive optical properties. Confirming the final lateral growth of CdS sidewalls with X-ray photoelectron spectroscopy, energy-dispersive analysis, and photoelectron excitation spectroscopy, we found that the successful coating of this CdS crown around the periphery of conventional type-II NPLs prevents the unwanted formation of needle-like stacks, which results in reduction of the undesired scattering losses in thin-film samples of these NPLs. Owing to highly efficient exciton funneling from the outmost CdS crown accompanied by the reduced scattering and very low waveguide loss coefficient (∼18 cm–1), ultralow optical gain thresholds of multicrown type-II NPLs were achieved to be as low as 4.15 μJ/cm2 and 2.48 mJ/cm2 under one- and two-photon absorption pumping, respectively. These findings indicate that the strategy of using engineered advanced heterostructures of nanoplatelets provides solutions for improved colloidal stability and enables enhanced photonic performance. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Accepted version The authors gratefully acknowledge the financial support in part from Singapore National Research Foundation under the programs of NRF-NRFI2016-08 and the Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR) of Singapore and in part from TUBITAK 114F326 and 115E679. H.V.D. also acknowledges support from TUBA. K.G. and Y.K. acknowledge support from TUBITAK BIDEB.

This paper proposes a Lyapunov based approach to design a controller in order to enhance grid stability and inertia in microgrids (MGs). This strategy is applied to Distributed Generators (DGs) which are integrated to Energy Storage System (ESS). The proposed strategy uses a simple structure to enhance the grid inertia and to damp out the power oscillations. It is to some extent analogous to that of a synchronous generator (SG) which is called a Virtual Synchronous Generator (VSG). The robustness of the proposed controller is also verified based on a time domain mathematical proof. The proposed controller effectively operates based on local information, so that there is no need for communication links. Finally, simulation results show that the transient response of the grid frequency has been improved on account of enhancing the inertia of the main grid.

A hybrid structure of the quasi-2D colloidal semiconductor quantum wells assembled with a single layer of 2D transition metal dichalcogenides offers the possibility of highly strong dipole-to-dipole coupling, which may enable extraordinary levels of efficiency in Förster resonance energy transfer (FRET). Here, we show ultrahigh-efficiency FRET from the ensemble thin films of CdSe/CdS nanoplatelets (NPLs) to a MoS

The growing number of weather-related outages in power systems highlights the role of resilience of electrical grid infrastructures. Quantifying the resiliency metric is necessary in a power system to evaluate the possible consequences of High Impact-Low Probability (HILP) events. This paper proposed a novel method to calculate a probabilistic time-dependent expected resilience metric which is obtained from combined discrete and continuous probability distribution functions. Considering uncertainties related to the load consumption and intermittent generation of Photovoltaic (PV) systems as input variables, Point Estimate Method (PEM) is applied in order to handle stochastic inherent of them and the fulfillment of the proposed probabilistic method is compared with Monte-Carlo simulation (MCS) technique. This paper analyzes the impacts of hurricane events in a Conventional Distribution System (CDS) and compares it with an Active Distribution System (ADS) using an expected resilience metric. Graph theory concept is used to evaluate restoration feasibility of costumers. The proposed Probabilistic Hurricane Resiliency Assessment (PHRA) is tested on the IEEE 37-node.

Considering a number of recent prolonged power outages caused by extreme weather conditions or more generally natural disasters, resiliency evaluation of power system is necessary for power system operators and utility owners in order to have a profound understanding of possible consequences of High Impact-Low Probability (HILP) events. This paper represents a generalized framework that could be implemented for resiliency evaluation of distribution systems against various types of natural disasters. Similar to the classic approach for reliability evaluation of distribution systems, an approach is introduced to evaluate the resiliency of distribution network. Graph theory concept is used to evaluate the probability of serving loads during a typical extreme event. IEEE 37-node and IEEE 123-node radial distribution systems are used to demonstrate the fulfillment of the proposed approach.

WOS: 000443525600107, PubMed ID: 29965729, A hybrid structure of the quasi-2D colloidal semiconductor quantum wells assembled with a single layer of 2D transition metal dichalcogenides offers the possibility of highly strong dipole-to-dipole coupling, which may enable extraordinary levels of efficiency in Forster resonance energy transfer (FRET). Here, we show ultra-high-efficiency FRET from the ensemble thin films of CdSe/CdS nanoplatelets (NPLs) to a MoS2 monolayer. From time-resolved fluorescence spectroscopy, we observed the suppression of the photoluminescence of the NPLs corresponding to the total rate of energy transfer from similar to 0.4 to 268 ns(-1). Using an Al2O3 separating layer between CdSe/CdS and MoS2 with thickness tuned from 5 to 1 nm, we found that FRET takes place 7- to 88-fold faster than the Auger recombination in CdSe-based NPLs. Our measurements reveal that the FRET rate scales down with d(-2) for the donor of CdSe/CdS NPLs and the acceptor of the MoS2 monolayer, d being the center-to-center distance between this FRET pair. A full electromagnetic model explains the behavior of this d(-2) system. This scaling arises from the delocalization of the dipole fields in the ensemble thin film of the NPLs and full distribution of the electric field across the layer of MoS2. This d(-2) dependency results in an extraordinarily long Forster radius of similar to 33 nm., Singapore National Research Foundation [NRF-NRFI2016-08]; Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR) of Singapore; TUBITAK [114F326, 115E679]; TUBA; TUBITAK BIDEB, The authors gratefully acknowledge the financial support in part from Singapore National Research Foundation under the programs of NRF-NRFI2016-08 and the Science and Engineering Research Council, Agency for Science, Technology and Research (A*STAR) of Singapore, and in part from TUBITAK 114F326 and 115E679. H.V.D. also acknowledges support from TUBA. K.G. and O.E. acknowledge support from TUBITAK BIDEB.

Whispering gallery mode (WGM) resonators are shown to hold great promise to achieve high-performance lasing using colloidal semiconductor nanocrystals (NCs) in solution phase. However, the low packing density of such colloidal gain media in the solution phase results in increased lasing thresholds and poor lasing stability in these WGM lasers. To address these issues, here optical gain in colloidal quantum wells (CQWs) is proposed and shown in the form of high-density close-packed solid films constructed around a coreless fiber incorporating the resulting whispering gallery modes to induce gain and waveguiding modes of the fiber to funnel and collect light. In this work, a practical method is presented to produce the first CQW-WGM laser using an optical fiber as the WGM cavity platform operating at low thresholds of ≈188 µJ cm−2 and ≈1.39 mJ cm−2 under one- and two-photon absorption pumped, respectively, accompanied with a record low waveguide loss coefficient of ≈7 cm−1 and a high net modal gain coefficient of ≈485 cm−1. The spectral characteristics of the proposed CQW-WGM resonator are supported with a numerical model of full electromagnetic solution. This unique CQW-WGM cavity architecture offers new opportunities to achieve simple high-performance optical resonators for colloidal lasers. NRF (Natl Research Foundation, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version

The use of a monoclonal antibody to block the neurite outgrowth inhibitor Nogo-A has been of great interest for promoting axonal recovery as a treatment for spinal cord injury. While several cellular and non-cellular assays have been developed to quantify the bioactive effects of Nogo-A signaling, demand still exists for the development of a reliable approach to characterize the effectiveness of the anti-Nogo-A antibody. In this study, we developed and validated a novel cell-based approach to facilitate the biological quantification of a Nogo-A antibody using PC-12 cells as an in vitro neuronal cell model. Changes in the mRNA levels of the neuronal differentiation markers, growth-associated protein 43 and neurofilament light-polypeptide, suggest that activation of the Nogo-A pathway suppresses axonal growth and dendrite formation in the tested cell line. We found that application of anti-Nogo-A monoclonal antibody can significantly enhance the neuronal maturity of PC-12 cells by blocking the Nogo-A inhibitory effects, providing enhanced effects on neural maturity at the molecular level. No adverse effects were observed on cell viability.

Lifted probabilistic inference methods exploit symmetries in the structure of probabilistic models to perform inference more efficiently. In lifted variable elimination, the symmetry among a group of interchangeable random variables is captured by counting formulas, and exploited by operations that handle such formulas. In this paper we generalize the structure of counting formulas and present a set of inference operators that introduce and eliminate these formulas from the model. This generalization expands the range of problems that can be solved in a lifted way. Our work is closely related to the recently introduced method of joint conversion. Due to its more fine grained formulation, however, our approach can provide more efficient solutions than joint conversion. ispartof: pages:107-122 ispartof: INDUCTIVE LOGIC PROGRAMMING: 23RD INTERNATIONAL CONFERENCE vol:8812 pages:107-122 ispartof: International Conference on Inductive Logic Programming (ILP) location:Rio de Janeiro, Brazil date:28 Aug - 30 Aug 2013 status: published

Efficient probabilistic inference is key to the success of statistical relational learning. One issue that increases the cost of inference is the presence of irrelevant random variables. The Bayes-ball algorithm can identify the requisite variables in a propositional Bayesian network and thus ignore irrelevant variables. This paper presents a lifted version of Bayes-ball, which works directly on the first-order level, and shows how this algorithm applies to (lifted) inference in directed first-order probabilistic models. Acceptence rate: 18% ispartof: pages:369-384 ispartof: Machine Learning and Knowledge Discovery in Databases, European Conference, ECML PKDD 2010 vol:6322 issue:PART 2 pages:369-384 ispartof: European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD 2010) location:Barcelona, Spain date:20 Sep - 24 Sep 2010 status: published

Information overload is no longer news; the explosive growth of the Internet has made this issue increasingly serious for Web users. Recommender systems aim at directing users through this information space, toward the resources that best meet their needs and interests. In this chapter the authors introduce their novel machine learning perspective toward the Web recommendation problem, based on reinforcement learning. Our recommendation method makes use of the Web usage and content data to learn a predictive model of users’ behavior on the Web and exploits the learned model to make Web page recommendations. Unlike other recommender systems, this system does not use the static patterns discovered from Web usage data, instead it learns to make recommendations as the actions it performs in each situation. In the proposed method the authors combined the conceptual and usage information in order to gain a more general model of user behavior and improve the quality of web recommendations. A hybrid Web recommendation method is proposed by making use of the conceptual relationships among Web resources to derive a novel model of the problem, enriched with semantic knowledge about the usage behavior. The method is evaluated under different settings and it is shown how this method can improve the overall quality of recommendations.

Various studies have indicated the value of customization and personalization in the context of e-learning systems and numerous efforts have been made in attempt to realize these goals. One significant research direction in this domain is finding effective methods for personalized course composition from a library of learning objects with respect to each learner's characteristics, goals and preferences. In this paper we employ decision support models for providing course compositions tailored to the specific characteristics of each individual learner, with an emphasis on the learning style of the learner. We show how these models can formally accommodate various features and preferences of the learner as well as how they can assist the learner in evaluating each solution by different criteria. We also propose methods for incorporating social behavior of the learners to the model in order to make use of other learners' experiences and provide higher levels of personalization for the target learner.

The development of targeted cancer treatments with increased therapeutic efficacy is still a major challenge in drug delivery. To date, nanoscale platforms are able to extend their circulation time and accumulate in the tumor through surface functionalization with polyethylene glycol and with antibodies, peptides or ligands directed against tumor biomarkers, respectively. Despite these modifications, the mononuclear phagocytic system efficiently clears these particles from circulation while opsonization proteins prevent the proper recognition between targeting ligands and target biomarkers. Additionally, most cancers are characterized by strong inflammation and increased affinity for circulating leukocytes. The surface of the leukocyte is enriched with transmembrane proteins that determine self-tolerance, adhesion, and negotiation of the inflamed vascular barrier. As result, leukocytes can efficiently recognize and infiltrate the tumor tissues. The Leukosome is a liposomal formulation based on leukocyte membranes able to provide biocompatibility, self-tolerance and targeting. The Leukosome was enriched with up to 82 different leukocyte membrane proteins in their intact native, active configuration with the appropriate post-translational modification and orientation. Among them, CD45 favored extended circulation time and avoided unspecific clearance, while Leukocyte Associated Function-1 facilitated the targeting to and permeability of the tumor inflamed vasculature. The Leukosome retained loading capabilities similar to current liposomal formulations but sustained the release of the chemotherapeutic drug for twice as long. The physical (size, surface charge and polydispersity index), chemical (surface composition and modification, loading and release kinetics), biochemical (protein content and stability), and biological (inhibition of particle clearance, tumor targeting, effect on the vascular barrier function) properties of the Leukosomes confirmed our ability to mimic the biological features and functions of leukocytes. Compared to unmodified liposomes, Leukosomes showed 5-fold increase in circulation time, 50-fold reduction of liver accumulation and 70-fold accumulation of the payload in breast, pancreatic and melanoma models in mouse. We believe this platform will provide a superior tool for the targeting and personalization of therapeutic intervention in cancer. Citation Format: Roberto Molinaro, Alessandro Parodi, Nima Taghipour, Brandon Brown, Dickson Kirui, Michael Evangelopoulos, Francesca Taraballi, Claudia Corbo, Ennio Tasciotti. The Leukosome: A biomimetic liposome for the targeting of inflamed tumor vasculature. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4586. doi:10.1158/1538-7445.AM2014-4586

Recently, engineering the surface of nanotherapeutics with biologics to provide them with superior biocompatibility and targeting towards pathological tissues has gained significant popularity. Although the functionalization of drug delivery vectors with cellular materials has been shown to provide synthetic particles with unique biological properties, these approaches may have undesirable immunological repercussions upon systemic administration. Herein, we comparatively analyzed unmodified multistage nanovectors and particles functionalized with murine and human leukocyte cellular membrane, dubbed Leukolike Vectors (LLV), and the immunological effects that may arise in vitro and in vivo. Previously, LLV demonstrated an avoidance of opsonization and phagocytosis, in addition to superior targeting of inflammation and prolonged circulation. In this work, we performed a comprehensive evaluation of the importance of the source of cellular membrane in increasing their systemic tolerance and minimizing an inflammatory response. Time-lapse microscopy revealed LLV developed using a cellular coating derived from a murine (i.e., syngeneic) source resulted in an active avoidance of uptake by macrophage cells. Additionally, LLV composed of a murine membrane were found to have decreased uptake in the liver with no significant effect on hepatic function. As biomimicry continues to develop, this work demonstrates the necessity to consider the source of biological material in the development of future drug delivery carriers. © 2015.

Lifted probabilistic inference algorithms exploit regularities in the structure of graphical models to perform inference more efficiently. More specifically, they identify groups of interchangeable variables and perform inference once for each group, as opposed to once for each variable. The groups are defined by means of constraints, so the flexibility of the grouping is determined by the expressivity of the constraint language. Existing approaches for exact lifted inference use specific languages for (in)equality constraints, which often have limited expressivity. In this article, we decouple lifted inference from the used constraint language. We define operators for lifted inference in terms of relational algebra operators, so that they operate on the semantic level (the constraints' extension) rather than on the syntactic level, making them language-independent. As a result, lifted inference can be performed using more powerful constraint languages, which provide more opportunities for lifting. We empirically demonstrate that this can improve inference efficiency by orders of magnitude, allowing exact inference where until now only approximate inference was feasible. ispartof: The Journal of Artificial Intelligence Research vol:47 pages:393-439 status: published