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Peng Cao, Xiaodong Su, Xiaowei Pan, Zhenfeng Liu, Wenrui Chang, Mei Li
Around photosystem II (PSII), the peripheral antenna system absorbs sunlight energy and transfers it to the core complex where the water-splitting and oxygen-evolving reaction takes place. The peripheral antennae in plants are composed of various light-harvesting complexes II (LHCII). Recently, the three-dimensional structure of the C2 S2 M2 -type PSII-LHCII supercomplex from Pisum sativum (PsPSII) has been solved at 2.7-Å resolution using the single-particle cryo-electron microscopy method. The large homodimeric supercomplex has a total molecular weight of >1400 kDa...
March 14, 2018: Biochimica et Biophysica Acta
Kelsey H Elliott, Samantha A Brugmann
Molecular signals are the guiding force of development, imparting direction upon cells to divide, migrate, differentiate, etc. The mechanisms by which a cell can receive and transduce these signals into measurable actions remains a 'black box' in developmental biology. Primary cilia are ubiquitous, microtubule-based organelles that dynamically extend from a cell to receive and process molecular and mechanical signaling cues. In the last decade, this organelle has become increasingly intriguing to the research community due to its ability to act as a cellular antenna, receive and transduce molecular stimuli, and initiate a cellular response...
March 13, 2018: Developmental Biology
Alexandra J Townsend, Francesco Saccon, Vasco Giovagnetti, Sam Wilson, Petra Ungerer, Alexander V Ruban
Non-photochemical quenching (NPQ) of chlorophyll fluorescence is the process by which excess light energy is harmlessly dissipated within the photosynthetic membrane. The fastest component of NPQ, known as energy-dependent quenching (qE), occurs within minutes, but the site and mechanism of qE remain of great debate. Here, the chlorophyll fluorescence of Arabidopsis thaliana wild type (WT) plants was compared to mutants lacking all minor antenna complexes (NoM). Upon illumination, NoM exhibits altered chlorophyll fluorescence quenching induction (i...
March 13, 2018: Biochimica et Biophysica Acta
Changlong Liu, Lin Wang, Xiaoshuang Chen, Jing Zhou, Weiwei Tang, Wanlong Guo, Jin Wang, Wei Lu
The present work reports on a graphene-like material that is promising for photodetection applications due to its high optical absorption and layer-dependent properties. To date, only narrowband photodetectors have been realized; therefore, extending the working wavelength is becoming more imperative for applications such as high-contrast imaging and remote sensing. In this work, we developed a novel detection technique that provides enhanced performance across the infrared and terahertz bands by using an antenna-assisted top-gated black phosphorus phototransistor...
March 16, 2018: Nanoscale
Kai Sun, Deqiang Yang, Sihao Liu, Tianming Yang
In this paper, a wide-band low cross polarization antenna with a structure of microstrip line coupling to slot line as the balun is proposed. The radiation part of the antenna is fed by two pairs of parallel transmission line via a transition from a slot line which is coupled by a microstrip line. Because it is fed by parallel transmission lines, which is balanced-fed structure, the antenna can achieve an improved low cross-polarization performance. The height of the antenna is 0.146λ0 (λ0 is the wavelength of lowest frequency)...
2018: PloS One
Ya-Li Zhang, Xiao-Bin Fu, Hong-Chun Cui, Lei Zhao, Ji-Zhong Yu, Hong-Liang Li
As one of the main lepidopteran pests in Chinese tea plantations, Ectropis obliqua Warren (tea geometrids) can severely decrease yields of tea products. The olfactory system of the adult tea geometrid plays a significant role in seeking behaviors, influencing their search for food, mating partners, and even spawning grounds. In this study, a general odorant-binding protein (OBP) gene, EoblGOBP2 , was identified in the antennae of E. obliqua using reverse transcription quantification PCR (RT-qPCR). Results showed that EoblGOBP2 was more highly expressed in the antennae of males than in females relative to other tissues...
March 15, 2018: International Journal of Molecular Sciences
Saroj R Tripathi, Paul Ben Ishai, Kodo Kawase
The applications of terahertz (THz) waves have been increasing rapidly in different fields such as information and communication technology, homeland security and biomedical engineering. However, study on the possible health implications due to various biological effects induced by THz waves is relatively scarce. Previously, it has been reported that the human sweat ducts play a significant role in the interaction of the THz wave with human skin due to its coiled structure. This structure imposes on them the electromagnetic character of a helical antenna...
March 1, 2018: Biomedical Optics Express
Qike Wang, Yidan Shang, Douglas S Hilton, Kiao Inthavong, Dong Zhang, Mark A Elgar
The elaborate bipectinate antennae of male moths are thought to increase their sensitivity to female sex pheromones, and so should be favoured by selection. Yet simple filamentous antennae are the most common structure among moths. The stereotypic arrangements of scales on the surface of antennae may resolve this paradox. We use computational fluid dynamics techniques to model how scales on the filamentous antennae of moths affect the passage of different particles in the airflow across the flagellum in both small and large moths...
March 14, 2018: Proceedings. Biological Sciences
Xiaofeng Yi, Jian Zhang, Tiehu Fan, Baofeng Tian, Chuandong Jiang
Magnetic resonance sounding (MRS) is a novel geophysical method to detect groundwater directly. By applying this method to underground projects in mines and tunnels, warning information can be provided on water bodies that are hidden in front prior to excavation and thus reduce the risk of casualties and accidents. However, unlike its application to ground surfaces, the application of MRS to underground environments is constrained by the narrow space, quite weak MRS signal, and complex electromagnetic interferences with high intensities in mines...
March 13, 2018: Sensors
Lisa V Poulikakos, Prachi Thureja, Alexia Stollmann, Eva De Leo, David J Norris
Chiral metallic nanostructures can generate evanescent fields which are more highly twisted than circularly polarized light. However, it remains unclear how best to exploit this phenomenon, hindering the optimal utilization of chiral electromagnetic fields. Here, inspired by optical antenna theory, we address this challenge by introducing chiral antenna parameters: the chirality flux efficiency and the chiral antenna aperture. These quantities, which are based on chirality conservation, quantify the generation and dissipation of chiral light...
March 13, 2018: Nano Letters
Samantha K Rowbotham, Soren Blau, Jacqueline Hislop-Jambrich
The term 'B.A.S.E jump' refers to jumping from a building, antenna, span (i.e., bridge) or earth (i.e., cliff) structure, and parachuting to the ground. There are numerous hazards associated with B.A.S.E jumps which often result in injury and, occasionally, fatality. This case report details the skeletal trauma resulting from a fatal B.A.S.E jump in Australia. In this case, the jumper impacted the ground from a fall of 439m in a feet-first landing position, as a result of a partially deployed parachute, under extreme vertical deceleration...
February 27, 2018: Forensic Science International
Kuang Zhang, Hao Yu, Xumin Ding, Qun Wu
In this paper, a holographic metasurface possessing beam scanning capability at fixed frequency is presented. The desired radiation beam is obtained by using a reference wave to excite a sinusoidally-modulated impedance surface, which is equivalent to the interference pattern between the radiation wave and reference wave. By changing the bias voltage of varactor diodes loaded on the sub-wavelength unit cells, the variation range of the modulated impedance can be tuned, resulting in the change of radiation angle...
March 5, 2018: Optics Express
Miguel V Drummond, Vanessa C Duarte, André Albuquerque, Rogério N Nogueira, Leontios Stampoulidis, Georg Winzer, Lars Zimmermann, Stephen Clements, Javad Anzalchi
The design and dimensioning of a photonic-aided payload for a multi-beam high-throughput communications satellite is a complex problem in which the antenna, RF and photonic subsystems must be considered as a whole for achieving best performance with lowest mass and power consumption. In this paper, we propose and dimension the receiving stage of a communications satellite comprising a phased array antenna (PAA) feeding a multibeam photonic beamforming system (PBS). The PBS uses a single wavelength and resorts to heterodyne detection such that the retrieved beams are frequency downconverted...
March 5, 2018: Optics Express
Okan Yurduseven, Daniel L Marks, Thomas Fromenteze, David R Smith
We present a reconfigurable, dynamic beam steering holographic metasurface aperture to synthesize a microwave camera at K-band frequencies. The aperture consists of a 1D printed microstrip transmission line with the front surface patterned into an array of slot-shaped subwavelength metamaterial elements (or meta-elements) dynamically tuned between "ON" and "OFF" states using PIN diodes. The proposed aperture synthesizes a desired radiation pattern by converting the waveguide-mode to a free space radiation by means of a binary modulation scheme...
March 5, 2018: Optics Express
Stephan Block, Srdjan S Aćimović, Nils Odebo Länk, Mikael Käll, Fredrik Höök
Fluorescence correlation spectroscopy (FCS) has provided a wealth of information on the composition, structure, and dynamics of cell membranes. However, it has proved challenging to reach the spatial resolution required to resolve biophysical interactions at the nm-scale relevant to many crucial membrane processes. In this work, we form artificial cell membranes on dimeric, nanoplasmonic antennas, which shrink the FCS probe volume down to the ~20 nm length-scale. By analysing the autocorrelation functions (ACFs) associated with the fluorescence bursts from individual fluorescently tagged lipids moving through the antenna "hot spots", we show that the confinement of the optical readout volume below the diffraction limit allows the temporal resolution of FCS to be increased by up to 3 orders of magnitude...
March 12, 2018: ACS Nano
Steven Ger Nyanjom, Cyrus Tare, Fred Wamunyokoli, George Fredrick Obiero
Tsetse flies (Glossina) are vectors of African trypanosomiasis. Olfaction plays a critical role in Glossina behavior, including larviposition, feeding, and reproduction. Odorant receptors (ORs) are important in insect chemoreception as they bind volatile odorants and transport them to olfactory receptor neurons to elicit behavioral response. To better understand Glossina chemoreception, we used quantitative polymerase chain reaction to examine the expression levels of ORs in female and male Glossina morsitans morsitans Wiedemann, 1850 (Diptera: Glossinidae) antennae and legs...
February 26, 2018: Journal of Medical Entomology
Karl H Schoenbach
This article is based on my presentation at the D'Arsonval Ceremony at the Joint Annual Meeting of the Bioelectromagnetics Society and the European BioElectromagnetics Association in Hangzhou, China, in June of 2017. It describes the pathway from the first studies on the effects of intense, nanosecond pulses on biological cells to the development of medical therapies based on these effects. The motivation for the initial studies of the effects of high voltage, nanosecond pulses on mammalian cells was based on a simple electrical circuit model, which predicted that such pulses allow us to affect not just the plasma membrane but also the subcellular structures...
March 12, 2018: Bioelectromagnetics
Waleska Vera, Jan Bergmann
The grape weevil, Naupactus xanthographus Germar (Coleoptera: Curculionidae), is a polyphagous insect native to southern South America that causes considerable damage in grape and other fruit species. In this study, the morphology and ultrastructure of the antennae and the antennal sensilla of N. xanthographus were investigated using scanning electron microscopy and transmission electron microscopy. The antennae consist of a scape, a pedicel, a funicle, and a zone called the "club," which are all formed by a total of 12 antennomers...
March 12, 2018: Microscopy Research and Technique
Christopher McCleese, Zhanqian Yu, Nopondo Ndoh Esemoto, Charles Kolodziej, Buddhadev Maiti, Srijana Bhandari, Barry D Dunietz, Clemens Burda, Marcin Ptaszek
Excitonically-coupled bacteriochlorin (BC) dimers constitute a primary electron donor (special pair) in bacterial photosynthesis and absorbing units in light-harvesting antenna. However, the exact nature of the excited state of these dyads is still not fully understood. Here, we report a detailed spectroscopic and computational investigation of a series of symmetrical bacteriochlorin dimers, where the bacteriochlorins are connected either directly or by a phenylene bridge with variable length. The excited state of these dyads is quenched in high-dielectric solvents, which we attribute to photoinduced charge transfer...
March 10, 2018: Journal of Physical Chemistry. B
Leng-Duei Koh, Jingjie Yeo, Yeong Yuh Lee, Qunya Ong, Mingyong Han, Benjamin C-K Tee
The present review will introduce the basic concepts of silk-based electronics/optoelectronics including the latest technological advances on the use of silk fibroin in combination with other functional components, with an emphasis on improving the performance of next-generation silk-based materials. It also highlights the patterning of silk fibroin to produce micro/nano-scale features, as well as the functionalization of silk fibroin to impart antimicrobial (i.e. antibacterial) properties. Silk-based bioelectronics have great potential for advanced or futuristic bio-applications including e-skins, e-bandages, biosensors, wearable displays, implantable devices, artificial muscles, etc...
May 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
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