Enhancing Planar Inverted Perovskite Solar Cells with Innovative Dumbbell-Shaped HTMs: A Study of Hexabenzocoronene and Pyrene-BODIPY-Triarylamine Derivatives

Dumbbell-shaped systems based on PAHs-BODIPY-triarylamine hybrids TM-(01-04) are designed as novel and highly efficient hole-transporting materials for usage in planar inverted perovskite solar cells. BODIPY is employed as a bridge between the PAH units, and the effects of the conjugated π-system's covalent attachment and size are investigated. Fluorescence quenching, 3D fluorescence heat maps, and theoretical studies support energy transfer within the moieties. The systems are extremely resistant to UVC 254 nm germicidal light sources and present remarkable thermal stability at degradation temperatures exceeding 350 °C. Integrating these systems into perovskite solar cells results in outstanding power conversion efficiency (PCE), with TM-02-based devices exhibiting a PCE of 20.26%. The devices base on TM-01, TM-03, and TM-04 achieve PCE values of 16.98%, 17.58%, and 18.80%, respectively. The long-term stability of these devices is measured for 600 h, with initial efficiency retention between 94% and 86%. The TM-04-based device presents noticeable stability of 94%, better than the reference polymer PTAA with 91%. These findings highlight the exciting potential of dumbbell-shaped systems based on PAHs-BODIPY-triarylamine derivatives for next-generation photovoltaics.     

Reliable M2M/IoT data delivery from FANETs via satellite

The use of unmanned aerial vehicles (UAVs) is rising in several application fields. This work deals with the communication challenges in UAV swarms, or flying ad hoc network (FANET), when taking into account non–line‐of‐sight scenarios. The use of satellites is a necessity in such operating conditions; thus, this work provides architectural considerations and performance assessments when several (FANETs) share an uplink random access satellite channel, fed with M2M/IoT traffic generated from on‐board sensors, to be reliably delivered to a remote ground destination.     

High-Gain Chemically Gated Organic Electrochemical Transistor

Organic electrochemical transistors (OECTs) have exhibited promising performance as transducers and amplifiers of low potentials due to their exceptional transconductance, enabled by the volumetric charging of organic mixed ionic/electronic conductors (OMIECs) employed as the channel material. OECT performance in aqueous electrolytes as well as the OMIECs’ redox activity has spurred a myriad of studies employing OECTs as chemical transducers. However, the OECT's large (potentiometrically derived) transconductance is not fully leveraged in common approaches that directly conduct chemical reactions amperometrically within the OECT electrolyte with direct charge transfer between the analyte and the OMIEC, which results in sub-unity transduction of gate to drain current. Hence, amperometric OECTs do not truly display current gains in the traditional sense, falling short of the expected transistor performance. This study demonstrates an alternative device architecture that separates chemical transduction and amplification processes on two different electrochemical cells. This approach fully utilizes the OECT's large transconductance to achieve current gains of 10³ and current modulations of four orders of magnitude. This transduction mechanism represents a general approach enabling high-gain chemical OECT transducers.     

Intrinsic selectivities and yields in the catalytic hydrogenation of polyenoic fatty acid methyl esters

Precise values of the intrinsic selectivities and yields for the hydrogenation products of methyl linolenate (Ln) and methyl linoleate (L) obtained under carefully controlled conditions using a commercial Ni catalyst are presented and analyzed in detail. The existence of a preferential adsorption of Ln and a significant co-hydrogenation of its double bonds are confirmed as being the dominant features under typical vegetable oil processing conditions. It is shown that the values of the selectivities that are obtained from the classical consecutive reactions network account for the intrinsic selectivity of the catalyst only while hydrogenating feedstocks with moderate to low (<10%) contents of Ln. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Lltoral (U.N.L.)     

Analysis of network function sharing in Content Delivery Network-as-a-service slicing scenarios

Video content consumption is currently dominating the mix of traffic observed in Internet service provider (ISP) networks. The distribution of that content is usually performed by means of content delivery network (CDN) caches storing and delivering multimedia. The advent of virtualization is calling attention to the CDN providers as a use case for virtualizing the cache function. In parallel, there is a trend for sharing network infrastructures as a way of reducing deployment costs by ISPs. Then, an interesting scenario emerges when considering the possibility of sharing virtualized cache functions among ISPs which are sharing a common physical infrastructure, mostly considering that those ISPs offer similar video content catalogs to end users. Furthermore, when deciding to share the caches among ISPs, it is interesting to understand the impacts due to limiting the storage capacity at the edge sites. This paper investigates through simulations the potential efficiencies that can be achieved when sharing a virtual cache function if compared with the classical approach of independent virtual caches operated per ISP, as well as the implications of limiting the storage capacity of the caches at the edge.     

Recent Advances in Calcium-Based Anticancer Nanomaterials Exploiting Calcium Overload to Trigger Cell Apoptosis

Calcium ion is vital for the regulation of many cellular functions and serves as a second messenger in the signal transduction pathways. Once the intracellular Ca²⁺ level exceeds the tolerance of cells (called Ca²⁺ overload), oxidative stress, mitochondrial damage, and cell/mitochondria apoptosis happen. Therefore, Ca²⁺ overload has started to be deeply exploited as a new strategy for cancer therapy due to its high efficiency and satisfactory safety. This review aims to highlight the recent development of Ca²⁺-based nanomaterials (such as Ca₃(PO₄)₂, CaCO₃, CaO₂, CaH₂, CaS, and others) able to trigger intracellular Ca²⁺ overload and apoptosis in cancer therapy. The intracellular mechanisms of varied Ca²⁺-based nanomaterials and the different types of strategies to enhance Ca²⁺ overload are discussed in detail. Moreover, the design of more efficient Ca²⁺ overload-mediated cancer therapies is prospected mainly based on 1) the enhanced cellular uptake by surface modification and morphology optimization of nanomaterials, 2) the accelerated Ca²⁺ release from nanomaterials by increasing the intracellular H⁺ level and by photothermal effect, and 3) the overload maintenance by Ca²⁺ efflux inhibition, Ca²⁺ influx promotion, or promoting Ca²⁺ release from the endoplasmic reticulum.     

Artifact removal in magnetoencephalogram background activity with independent component analysis

The aim of this study was to assess whether independent component analysis (ICA) could be valuable to remove power line noise, cardiac, and ocular artifacts from magnetoencephalogram (MEG) background activity. The MEGs were recorded from 11 subjects with a 148-channel whole-head magnetometer. We used a statistical criterion to estimate the number of independent components. Then, a robust ICA algorithm decomposed the MEG epochs and several methods were applied to detect those artifacts. The whole process had been previously tested on synthetic data. We found that the line noise components could be easily detected by their frequency spectrum. In addition, the ocular artifacts could be identified by their frequency characteristics and scalp topography. Moreover, the cardiac artifact was better recognized by its skewness value than by its kurtosis one. Finally, the MEG signals were compared before and after artifact rejection to evaluate our method.     

An On-Chip Spectrum Analyzer for Analog Built-In Testing

This paper presents an analog built-in testing (BIT) architecture and its implementation. It enables the frequency response and harmonic distortion characterizations of an integrated device-under-test (DUT) through a digital off-chip interface. External analog instrumentation is avoided, reducing test time and cost. The proposed on-chip testing scheme uses a digital frequency synthesizer and a simple signal generator synchronized with a switched capacitor bandpass filter. A general methodology for the use of this structure in the functional verification of a DUT is also provided. The circuit-level design and experimental results of an integrated prototype in standard CMOS 0.5 m technology are presented to demonstrate the feasibility of the proposed BIT technique.Marcia G. Mendez-Rivera was born in Irapuato, Mexico in 1972. She received the Communications and Electronics Engineering Degree from the Universidad de Guanajuato, Guanajuato, Mexico. in 1996, the M.Sc. degree from the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Puebla, Mexico in 1998 and the M.Sc. from Texas A&M University, College Station in 2002. Her research interest is in the design and fabrication of analog and mixed-signal circuits.Alberto Valdes-Garcia born in 1978, grew up in San Mateo Atenco, Mexico. He received the B.S. in Electronic Systems Engineering degree from the Monterrey Institute of Technology (ITESM), Campus Toluca, Mexico in 1999 (with honors as the best score from all majors). Since the fall of 2000 he has been working towards the Ph.D. degree at Analog and Mixed-Signal Center (AMSC), Texas A&M University. During the spring and summer of 2000 he was a Design Engineer with Motorola Broadband Communications Sector. In the summer of 2002 he was with the Read Channel Design Group at Agere Systems where he investigated wide tuning range GHz LC VCOs for mass storage applications. During the summer of 2004 he was with the Mixed-Signal Communications IC Design Group at the IBM T. J. Watson Research Center, where worked on design and analysis of SiGe power amplifiers for millimeter wave radios. Since the fall of 2001 he has been a Semiconductor Research Corporation (SRC) research assistant at the AMSC working on the development of analog built-in testing techniques. Since the fall of 2000, Alberto has been the recipient of a scholarship from the Mexican National Council for Science and Technology (CONACYT). He represented Mexico in the 1994 Odyssey of the Mind World Creativity Contest and in the 1997 International Exposition for Young Scientists. His present research interests include built-in testing implementations for analog and RF circuits, system level design for wireless receivers and RF circuit design for UltraWideBand (UWB) communications.Jose Silva-Martinez was born in Tecamachalco, Puebla, México. He received the B.S. degree in electronics from the Universidad Autónoma de Puebla, México, in 1979, the M.Sc. degree from the Instituto Nacional de Astrofísica Optica y Electrónica (INAOE), Puebla, México, in 1981, and the Ph.D. degree from the Katholieke Univesiteit Leuven, Leuven Belgium in 1992. From 1981 to 1983, he was with the Electrical Engineering Department, INAOE, where he was involved with switched-capacitor circuit design. In 1983, he joined the Department of Electrical Engineering, Universidad Autonoma de Puebla, where he remained until 1993; He was a co-founder of the graduate program on Opto-Electronics in 1992. From 1985 to 1986, he was a Visiting Scholar in the Electrical Engineering Department, Texas A&M University. In 1993, he re-joined the Electronics Department, INAOE, and from May 1995 to December 1998, was the Head of the Electronics Department; He was a co-founder of the Ph.D. program on Electronics in 1993. He is currently with the Department of Electrical Engineering (Analog and Mixed Signal Center) Texas A&M University, at College Station, where He holds the position of Associate Professor. His current field of research is in the design and fabrication of integrated circuits for communication and biomedical application. Dr. Silva-Martinez has served as IEEE CASS Vice President Region-9 (1997–1998), and as Associate Editor for IEEE Transactions on Circuits and Systems part-II from 1997–1998 and May 2002–December 2003. Since January 2004 is serving as Associate Editor of IEEE TCAS Part-I. He was the main organizer of the 1998 and 1999 International IEEE-CAS Tour in region 9, and Chairman of the International Workshop on Mixed-Mode IC Design and Applications (1997–1999). He is the inaugural holder of the TI Professorship-I in Analog Engineering, Texas A&M University. He was a co-recipient of the 1990 European Solid-State Circuits Conference Best Paper Award.Edgar Sánchez-Sinencio was born in Mexico City, Mexico. He received the degree in communications and electronic engineering (Professional degree) from the National Polytechnic Institute of Mexico, Mexico City, the M.S.E.E. degree from Stanford University, CA, and the Ph.D. degree from the University of Illinois at Urbana-Champaign, in 1966, 1970, and 1973, respectively. In 1974 he held an industrial Post-Doctoral position with the Central Research Laboratories, Nippon Electric Company, Ltd., Kawasaki, Japan. From 1976 to 1983 he was the Head of the Department of Electronics at the Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE), Puebla, Mexico. He was a Visiting Professor in the Department of Electrical Engineering at Texas A&M University, College Station, during the academic years of 1979–1980 and 1983-1984. He is currently the TI J Kilby Chair Professor and Director of the Analog and Mixed-Signal Center at Texas A&M University. He was the General Chairman of the 1983 26th Midwest Symposium on Circuits and Systems. He was an Associate Editor for IEEE Trans. on Circuits and Systems, (1985–1987), and an Associate Editor for the IEEE Trans. on Neural Networks. He is the former Editor-in-Chief of the Transactions on Circuits and Systems II. He is co-author of the book Switched Capacitor Circuits (Van Nostrand-Reinhold 1984), and co-editor of the book Low Voltage/Low-Power Integrated Circuits and Systems (IEEE Press 1999). In November 1995 he was awarded an Honoris Causa Doctorate by the National Institute for Astrophysics, Optics and Electronics, Mexico. The first honorary degree awarded for Microelectronic Circuit Design contributions. He is co-recipient of the 1995 Guillemin-Cauer for his work on Cellular Networks. He is a former IEEE CAS Vice President-Publications. He was also the co-recipient of the 1997 Darlington Award for his work on high-frequency filters He received the Circuits and Systems Society Golden Jubilee Medal in 1999. He was the IEEE Circuits and Systems Society, Representative to the Solid-State Circuits Society (2000–2002). He is presently a member of the IEEE Solid-State Circuits Fellow Award Committee. His present interests are in the area of RF-Communication circuits and analog and mixed-mode circuit design. He is an IEEE Fellow Member since 1992.