Restoration models for hot working of metals and alloys are reviewed in the context of their applicability to friction stir welding (FSW) and friction stir processing (FSP). Two of these models are ...used to interpret microstructure and microtexture data for two aluminum alloys subjected to FSP. The need for further experiments and model extensions to accommodate the transients and steep gradients in the strain, strain rate and temperature experienced by materials during FSW and FSP are discussed.
Nucleotide analog inhibitors have shown clinical success in the treatment of hepatitis C virus (HCV) infection, despite an incomplete mechanistic understanding of NS5B, the viral RNA-dependent RNA ...polymerase. Here we study the details of HCV RNA replication by determining crystal structures of stalled polymerase ternary complexes with enzymes, RNA templates, RNA primers, incoming nucleotides, and catalytic metal ions during both primed initiation and elongation of RNA synthesis. Our analysis revealed that highly conserved active-site residues in NS5B position the primer for in-line attack on the incoming nucleotide. A β loop and a C-terminal membrane–anchoring linker occlude the active-site cavity in the apo state, retract in the primed initiation assembly to enforce replication of the HCV genome from the 3′ terminus, and vacate the active-site cavity during elongation. We investigated the incorporation of nucleotide analog inhibitors, including the clinically active metabolite formed by sofosbuvir, to elucidate key molecular interactions in the active site.
Nanoscale biosensors, owing to their high-sensitivity and extremely low limits-of-detection, have enabled the realization of highly complex and sophisticated miniaturized platforms for several ...important healthcare applications, the most predominant one being disease diagnosis. In particular, nanomaterial facilitated electrochemical detection of DNA hybridization has had an exceptional impact on fields such as genetics and cancerous mutation detection Here we report an ultrasensitive electrochemical platform using electrospun semi-conducting Manganese (III) Oxide (Mn2O3) nanofibers for DNA Hybridization detection. The proposed platform coalesces the inherent advantages of metal-oxide nanofibers and electrochemical transduction techniques, resulting in label-free zeptomolar detection of DNA hybridization. As proof of concept, we demonstrate zeptomolar detection of Dengue consensus primer (limit of detection: 120×10–21M) both in control as well as spiked serum samples. Our reported detection limit is superior in comparison with previously reported electrochemical DNA hybridization sensors for Dengue virus detection, spanning both labeled and label-free transductions. This ultra-sensitivity, we believe, is a result of synthesizing a low bandgap electrospun metal-oxide nanomaterial corresponding to a specific oxidation state of Manganese. This methodology can be extended for detection of any hybridization of interest by simply adapting an appropriate functionalization protocol and thus is very generic in nature.
•Zeptomolar Detection of DNA Hybridization.•Label-free Electrochemical Detection using Electrospun Low bandgap Mn2O3 Nanofiber.•Easily adaptable surface functionalization protocol for bioelectrode preparation.•Generic Biosensor Platform.•DNA Hybridization detection from control as well as spiked serum samples.
The non-linearity of Light Emitting Diodes (LEDs) has limited the efficiency of visible Light Communication (VLC) in terms of Bit Error Rate (BER). In this report, we propose a model-driven Deep ...Learning (DL) strategy for Optical Orthogonal Frequency Division Multiplexing (O-OFDM)-based VLC processes, that is employed as the Auto Encoder (AE) network system to minimize the LED non-linearity. The suggested system successfully includes communication domain knowledge into the design of the training cost function and network architecture, as opposed to the conventional fully computer-controlled autoencoder. Deep Recurrent Neural Network (Deep RNN) and Inverse Fast Fourier Transform (IFFT) are used at the emitter end to convert the binary data first into challenging I-Q codes for each O- OFDM sub-band. Then, for nonlinearity compensation and signal detection at the receiver, the symbol de-mapping is done and the demodulation is performed through a Deep RNN. DeepRNN's hidden layers are fine-tuned using the MMRFA algorithm for enhanced performance and efficiency. The proposed methodology performance is compared with the existing methods using performance metrics like BER, MSE, ACF, Power consumption, and Energy efficiency. The proposed solution outperforms several current approaches in terms of BER performances and improves operating duration, demonstrating the practicality and promise of DL in the VLC platform.
Zero hunger Swaminathan, M S
Science (American Association for the Advancement of Science),
2014-Aug-01, 2014-08-00, 20140801, Letnik:
345, Številka:
6196
Journal Article
Recenzirano
Odprti dostop
The United Nations (UN) designated 2014 as the International Year of Family Farming, recognizing that an estimated 500 million family farms, involving over 2 billion people, play a key role in food ...production and consumption worldwide. It is thus an opportune time to encourage a shift in tackling global hunger—from a “food security” focus to an agenda that promotes “nutrition security” instead. The drive to reduce hunger in the world has largely relied on crops such as wheat and rice that provide calories. But an increase in calories alone is not good enough. Improved diets and good health require bolstering nutrition.
Visible light communications (VLC) has received a lot of attention in recent studies because of its benefits over radio‐frequency (RF) communications. It is a short‐range optical wireless ...communication system that uses light‐emitting diodes (LEDs) as transmitters. Optical orthogonal frequency division multiplexing (OFDM) is an auspicious technology for VLC high‐speed data transfer. The use of OFDM in a VLC system raises the system's peak‐to‐average power ratio (PAPR). The intrinsic non‐linearity of LED is a key concern in an asymmetrically clipped DC‐biased optical OFDM (ADO‐OFDM) system due to its high PAPR. Also, conventional ADO‐OFDM modulation scheme cannot be used for accommodating different demands of services in downlink multiple access due to the restriction of direct current biased optical OFDM (DCO‐OFDM) and asymmetrically clipped optical (ACO‐OFDM) transmission on odd and even subcarriers. To tackle this issue, a modified ADO‐OFDM (MADO‐OFDM) is proposed that adjusts the numbers of subcarriers required for the transmission of ACO‐OFDM and DCO‐OFDM adaptively based on the requests of services in downlink multiple access. Also, the proposed MADO‐OFDM is integrated with a discrete Hartley Matrix transform (DisHMT) precoder and Generalized Piecewise Linear Compander (GPLD) to provide high‐speed data transmission with less PAPR. In addition, the power is allocated to the proposed MADO‐OFDM system optimally by maximizing the channel capacity based on the Aquila optimizer algorithm. The simulation results reveal that the suggested system's PAPR is reduced by 2.4 dB and 0.8 dB, respectively, compared to conventional ADO and hybrid ADO‐OFDM. It also confirms that the suggested generalized PLC can greatly increase BER without affecting the PAPR performance.
In this study, ADO‐OFDM is developed by combining a generalized space–time line code (GSTLC) precoder with a Generalized Piecewise Linear Compander (GPLC), that is, GPSTLC‐ADO‐OFDM, to achieve high‐speed data transmission with reduced PAPR. GSTLC precoder is used at the transmitter module to increase the throughput of the system by multiplying the predefined matrix and modulated data streams. The final sent signal is obtained by passing precoded GPSTLC‐ADO‐OFDM through GPLC.
The key microstructural features that control creep in advanced 9–10%Cr steels are elucidated. Conclusive evidence for the presence and coarsening of nano-scale MX carbonitrides which contribute to ...the long-term stability of these materials is presented. It is also shown that subgrain structures resulting from the martensitic transformation contribute to the basic strength by generating internal stresses through an anelastic bowing mechanism. Kinetic equations that describe the evolution of these microstructural features with time and strain, derived from exhaustive experimental measurements for two steels, are incorporated into a creep equation set based on the damage mechanics philosophy. It is shown that the anomalously high activation energy reported in the literature for creep of ferritic steels can be traced to the fact that temperature dependence of subgrain growth had been ignored hitherto. This model is shown to be able to predict creep data for two steels accurately up to tens of thousands of hours over which data are available.
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