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Energy harvester

Yana Kholod, Michael DeFilippo, Brittany Reed, Danielle Valdez, Grant Gillan, Dmytro Kosenkov
Excitation energy transfer (EET) determines the fate of sunlight energy absorbed by light-harvesting proteins in natural photosynthetic systems and photovoltaic cells. As previously reported (D. Kosenkov, J. Comput. Chem. 2016, 37(19), 1847), PyFREC software enables computation of electronic couplings between organic molecules with a molecular fragmentation approach. The present work reports implementation of direct fragmentation-based computation of the electronic couplings and EET rates in pigment-protein complexes within the Förster theory in PyFREC...
December 15, 2017: Journal of Computational Chemistry
Helmut Kirchhoff
Oxygenic photosynthesis is a fundamental biological process that shaped the earth's biosphere. The process of energy transformation is hosted in highly specialized thylakoid membranes that adjust their architecture in response to environmental cues at different structural levels leading to the adjustment of photosynthetic functions. This review presents structure-function dynamics ranging from the whole membrane system over the mesoscopic level (protein ensembles) down to interactions between lipids and protein complexes...
January 2018: Plant Science: An International Journal of Experimental Plant Biology
A Trey Belew, Caroline Junqueira, Gabriela F Rodrigues-Luiz, Bruna M Valente, Antonio Edson R Oliveira, Rafael B Polidoro, Luciana W Zuccherato, Daniella C Bartholomeu, Sergio Schenkman, Ricardo T Gazzinelli, Barbara A Burleigh, Najib M El-Sayed, Santuza M R Teixeira
Trypanosoma cruzi, the protozoan that causes Chagas disease, has a complex life cycle involving several morphologically and biochemically distinct stages that establish intricate interactions with various insect and mammalian hosts. It has also a heterogeneous population structure comprising strains with distinct properties such as virulence, sensitivity to drugs, antigenic profile and tissue tropism. We present a comparative transcriptome analysis of two cloned T. cruzi strains that display contrasting virulence phenotypes in animal models of infection: CL Brener is a virulent clone and CL-14 is a clone that is neither infective nor pathogenic in in vivo models of infection...
December 14, 2017: PLoS Pathogens
Chi Hao Liow, Xin Lu, Chuan Fu Tan, Kwok Hoe Chan, Kaiyang Zeng, Shuzhou Li, Ghim Wei Ho
Surface plasmon-based photonics offers exciting opportunities to enable fine control of the site, span, and extent of mechanical harvesting. However, the interaction between plasmonic photothermic and piezoresponse still remains underexplored. Here, spatially localized and controllable piezoresponse of a hybrid self-polarized polymeric-metallic system that correlates to plasmonic light-to-heat modulation of the local strain is demonstrated. The piezoresponse is associated to the localized plasmons that serve as efficient nanoheaters leading to self-regulated strain via thermal expansion of the electroactive polymer...
December 14, 2017: Small
Navendu Mondal, Apurba De, Anunay Samanta
Excitation of semiconductor quantum dots (QDs) by photons possessing energy higher than the band-gap creates a hot electron-hole pair, which releases its excess energy as waste heat or under certain conditions (when hν > 2Eg) produces multiple excitons. Extraction of these hot carriers and multiple excitons is one of the key strategies for enhancing the efficiency of QD-based photovoltaic devices. However, this is a difficult task as competing carrier cooling and relaxation of multiple excitons (through Auger recombination) are ultrafast processes...
December 13, 2017: Nanoscale
Steven A Bloomer, Kathryn E Wellen, Gregory C Henderson
BACKGROUND: Aging is characterized by increases in inflammation and oxidative stress, conditions that are exacerbated by environmental factors such as diet. In this study, we investigated the effects of a trans-fatty acid (TFA) diet on the liver in adult (25 wk) and old (60 wk) senescence-accelerated mice (SAMP8 strain) of both sexes. Our goal was to assess the effects of the diet on protein markers of inflammation and oxidative stress in the liver. METHODS: Male and female mice were placed on life-long diets containing similar amounts of total fat (17%), with differing amounts of TFA: 2% (moderate TFA group) or 0...
December 13, 2017: Lipids in Health and Disease
Björn Schulte-Herbrüggen, Guy Cowlishaw, Katherine Homewood, J Marcus Rowcliffe
INTRODUCTION: Wildlife is an important source of protein for many people in developing countries. Yet wildlife depletion due to overexploitation is common throughout the humid tropics and its effect on protein security, especially for vulnerable households, is poorly understood. This is problematic for both sustainable rural development and conservation management. METHODS: This study investigates a key dimension of protein security in a cash-crop farming community living in a wildlife-depleted farm-forest landscape in SW Ghana, a region where protein-energy malnutrition persists...
2017: PloS One
Marco A Allodi, John P Otto, Sara H Sohail, Rafael G Saer, Ryan E Wood, Brian S Rolczynski, Sara C Massey, Po-Chieh Ting, Robert E Blankenship, Gregory S Engel
Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting timescale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly-conserved tyrosine/tryptophan chain near the chromophores showing the largest changes...
December 13, 2017: Journal of Physical Chemistry Letters
Tomoyasu Noji, Mikano Matsuo, Nobutaka Takeda, Ayumi Sumino, Masaharu Kondo, Mamoru Nango, Shigeru Itoh, Takehisa Dewa
The photosynthetic light-harvesting-reaction center core complex (LH1-RC) is a natural excitonic and photovoltaic device embedded in a lipid membrane. In order to apply LH1-RCs as a biohybrid energy-producing material, some important issues must be addressed, including how to make LH1-RCs function as efficiently as possible. In addition, they should be characterized to evaluate how many active LH1-RCs efficiently work in artificial systems. We report here that an anionic phospholipid, phosphatidylglycerol (PG), stabilizes the charge-separated state (a photooxidized electron donor and reduced quinone pair, (P+QB-)) of LH1-RC (from Rhodopseudomonas palustris) and enhances its activity in photocurrent generation...
December 13, 2017: Journal of Physical Chemistry. B
Yu Ma, Jinxiu Guo, Laibing Jia, Yanbo Xie
The nanofluidic diode, as one of the emerging nanofluidic logic devices, has been used in many fields such as biosensors, energy harvesting and so on. However, the entrance effects of the nanofluidic ionic conductance were less discussed, which can be a crucial factor for the ionic conduction. Here we calculate the ionic conductance as a function of the length-to-pore ratio (L/r), which has a clear boundary between nanopore (surface dominated) and nanochannel (geometry dominated) electrically in diluted salt solution...
December 13, 2017: ACS Sensors
Jingxiu Yang, Peng Zhang, Su-Huai Wei
Cs2AgBiBr6 was proposed as one of the inorganic, stable, and non-toxic replacement of the methylammonium lead halides (CH3NH3PbI3, which is currently considered as one of the most promising light-harvesting material for solar cells). However, the wide indirect band gap of Cs2AgBiBr6 suggests that its application in photovoltaics is limited. Here, using the first principle calculation, we show that by controlling the ordering parameter at the mixed sublattice, the band gap of Cs2AgBiBr6 can vary continuously from a wide indirect band gap of 1...
December 13, 2017: Journal of Physical Chemistry Letters
Jin A Kim, Hyun-Soon Kim, Seo-Hwa Choi, Ji-Young Jang, Mi-Jeong Jeong, Soo In Lee
Carbohydrates are the primary energy source for plant development. Plants synthesize sucrose in source organs and transport them to sink organs during plant growth. This metabolism is sensitive to environmental changes in light quantity, quality, and photoperiod. In the daytime, the synthesis of sucrose and starch accumulates, and starch is degraded at nighttime. The circadian clock genes provide plants with information on the daily environmental changes and directly control many developmental processes, which are related to the path of primary metabolites throughout the life cycle...
December 11, 2017: International Journal of Molecular Sciences
Shuangxi Zhou, Wei Sheng, Fangming Deng, Xiang Wu, Zhihui Fu
In this paper, a novel approach for concrete chloride ion concentration measuring based on passive and wireless sensor tag is proposed. The chloride ion sensor based on RFID communication protocol is consisting of an energy harvesting and management circuit, a low dropout voltage regulator, a MCU, a RFID tag chip and a pair of electrodes. The proposed sensor harvests energy radiated by the RFID reader to power its circuitry. To improve the stability of power supply, a three-stage boost rectifier is customized to rectify the harvested power into dc power and step-up the voltage...
December 11, 2017: Sensors
Ieva Migliniene, Vytautas Ostasevicius, Rimvydas Gaidys, Rolanas Dauksevicius, Giedrius Janusas, Vytautas Jurenas, Povilas Krasauskas
This paper proposes an approach for designing an efficient vibration energy harvester based on a vibro-impacting piezoelectric microcantilever with a geometric shape that has been rationally modified in accordance with results of dynamic optimization. The design goal is to increase the amplitudes of higher-order vibration modes induced during the vibro-impact response of the piezoelectric transducer, thereby providing a means to improve the energy conversion efficiency and power output. A rational configuration of the energy harvester is proposed and it is demonstrated that the new design retains essential modal characteristics of the optimal microcantilever structures, further providing the added benefit of less costly fabrication...
December 12, 2017: Sensors
Jun Liu, Ankur Goswami, Keren Jiang, Faheem Khan, Seokbeom Kim, Ryan McGee, Zhi Li, Zhiyu Hu, Jungchul Lee, Thomas Thundat
The direct conversion of mechanical energy into electricity by nanomaterial-based devices offers potential for green energy harvesting 1-3 . A conventional triboelectric nanogenerator converts frictional energy into electricity by producing alternating current (a.c.) triboelectricity. However, this approach is limited by low current density and the need for rectification 2 . Here, we show that continuous direct-current (d.c.) with a maximum density of 106 A m-2 can be directly generated by a sliding Schottky nanocontact without the application of an external voltage...
December 11, 2017: Nature Nanotechnology
Sanghoon Park, Yura Kim, Hyosub Jung, Jun-Young Park, Naesung Lee, Yongho Seo
In this study, we investigated an energy harvesting effect of tensile stress using piezoelectric polymers and flexible electrodes. A chemical-vapor-deposition grown graphene film was transferred onto both sides of the PVDF and P(VDF-TrFE) films simultaneously by means of a conventional wet chemical method. Output voltage induced by sound waves was measured and analyzed when a mechanical tension was applied to the device. Another energy harvester was made with a metallic electrode, where Al and Ag were deposited by using an electron-beam evaporator...
December 11, 2017: Scientific Reports
Hang Zhang, Zhongheng Fu, Ruifeng Zhang, Qianfan Zhang, Hongzhen Tian, Dominik Legut, Timothy C Germann, Yuanqi Guo, Shiyu Du, Joseph S Francisco
Efficient flexible energy storage systems have received tremendous attention due to their enormous potential applications in self-powering portable electronic devices, including roll-up displays, electronic paper, and "smart" garments outfitted with piezoelectric patches to harvest energy from body movement. Unfortunately, the further development of these technologies faces great challenges due to a lack of ideal electrode materials with the right electrochemical behavior and mechanical properties. MXenes, which exhibit outstanding mechanical properties, hydrophilic surfaces, and high conductivities, have been identified as promising electrode material candidates...
December 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
Tjaart P J Krüger, Pavel Malý, Maxime T A Alexandre, Tomáš Mančal, Claudia Büchel, Rienk van Grondelle
Strong excitonic interactions are a key design strategy in photosynthetic light harvesting, expanding the spectral cross-section for light absorption and creating considerably faster and more robust excitation energy transfer. These molecular excitons are a direct result of exceptionally densely packed pigments in photosynthetic proteins. The main light-harvesting complexes of diatoms, known as fucoxanthin-chlorophyll proteins (FCPs), are an exception, displaying surprisingly weak excitonic coupling between their chlorophyll (Chl) a's, despite a high pigment density...
December 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yangyang Zhang, Bingwei Lu, Chaofeng Lü, Xue Feng
Self-powered implantable devices with flexible energy harvesters are of significant interest due to their potential to solve the problem of limited battery life and surgical replacement. The flexible electronic devices made of piezoelectric materials have been employed to harvest energy from the motion of biological organs. Experimental measurements show that the output voltage of the device mounted on porcine left ventricle in chest closed environment decreases significantly compared to the case of chest open...
November 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Mohsen Safaei, R Michael Meneghini, Steven R Anton
Total knee arthroplasty (TKA) is a common procedure in the United States; it has been estimated that about 4 million people are currently living with primary knee replacement in this country. Despite huge improvements in material properties, implant design, and surgical techniques, some implants fail a few years after surgery. A lack of information about in vivo kinetics of the knee prevents the establishment of a correlated intra- and postoperative loading pattern in knee implants. In this study, a conceptual design of an ultra high molecular weight (UHMW) knee bearing with embedded piezoelectric transducers is proposed, which is able to measure the reaction forces from knee motion as well as harvest energy to power embedded electronics...
September 2017: Smart Materials & Structures
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