An Improved Deep Residual Convolutional Neural Network for Plant Leaf Disease Detection.

In this research, we proposed a novel deep residual convolutional neural network with 197 layers (ResNet197) for the detection of various plant leaf diseases. Six blocks of layers were used to develop ResNet197. ResNet197 was trained and tested using a combined plant leaf disease image dataset. Scaling, cropping, flipping, padding, rotation, affine transformation, saturation, and hue transformation techniques were used to create the augmentation data of the plant leaf disease image dataset. The dataset consisted of 103 diseased and healthy image classes of 22 plants and 154,500 images of healthy and diseased plant leaves. The evolutionary search technique was used to optimise the layers and hyperparameter values of ResNet197. ResNet197 was trained on the combined plant leaf disease image dataset using a graphics processing unit (GPU) environment for 1000 epochs. It produced a 99.58 percentage average classification accuracy on the test dataset. The experimental results were superior to existing ResNet architectures and recent transfer learning techniques.

Co-doped carbon materials synthesized with polymeric precursors as bifunctional electrocatalysts.

The design of stable and high performance metal free bifunctional electrocatalysts is a necessity in alkaline zinc-air batteries for oxygen reduction and evolution reaction. In the present work co-doped carbon materials have been developed from polymeric precursors with abundant active sites to achieve bifunctional activity. A 3-dimensional microporous nitrogen-carbon (NC) and co-doped nitrogen-sulfur-carbon (NSC) and nitrogen-phosphorus-carbon (NPC) were synthesized using poly(2,5-benzimidazole) as an N containing precursor. The obtained sheet like structure shows outstanding ORR and OER performance in alkaline systems with excellent stability compared to Pt/C catalyst. The doped heteroatom in the carbon is expected to have redistributed the charge around heteroatom dopants lowering the ORR potential and modifying the oxygen chemisorption mode thereby weakening the O-O bonding and improving the ORR activity and overall catalytic performance. The bifunctional activity (ΔE = E j=10 - E 1/2) of an air electrode for NPC, NSC, NC and Pt/C is 0.82 V, 0.87 V, 1.06 V and 1.03 V respectively, and the NPC value is smaller than most of the reported metal and non-metal based electrocatalysts. The ORR (from onset potential) and OER (10 mA cm-2) overpotential for NPC, NSC, and NC is (290 mV, 410 mV), (310 mV, 450 mV) and (340 mV, 600 mV) respectively. In the prepared catalyst the NPC exhibited higher ORR and OER activity (NPC > NSC > NC). The doping of P in NPC is found to have a great influence on the microstructure and therefore on the ORR and OER activity.

Hierarchical Porous Carbon Microfibers Derived from Tamarind Seed Coat for High-Energy Supercapacitor Application.

The overwhelming interest in supercapacitors has led to the search for various carbonaceous materials, leading to hierarchical porous carbons. Herein, we report a natural biomass (tamarind seed)-based hierarchical porous carbon without any template and activated by a facile scheme. The tamarind seed coat-based hierarchical porous carbon possessed a unique configuration, making the material exhibit superior supercapacitor properties. A single carbon fiber hosting a distinctive micro- and mesoporous structure formed a connecting thread between the pores. This unique structure enabled high surface area and high capacitance. The highest surface area obtained by this method was 1702 m2 g-1, whereas the capacitance was 157 F g-1 in 6 M KOH. Further, an ionic liquid-based electrolyte revealed 78 F g-1 at a current density of 0.5 A g-1. Outstanding capacity retentions of 96 and 93% were obtained over 1000 cycles at a current density of 2 A g-1 for aqueous (6 M KOH) and ionic liquid (1-butyl 3-methyl imidazoliumbistrifluorosulfonylimide) electrolytes, respectively. The high charge-storage ability of the porous carbon microfibers (PCMFs) can be ascribed to the coexistence of micro- and mesopores. The power characteristics and the cyclic stability of PCMF materials were appealing in both electrolytes. The synthesis process described is amenable for large-scale applications with less complexity.

Photo-Current Enhancement in Carbon Quantum Dots Functionalized Titania Nanotube Arrays.

Highly aligned, vertically oriented, TiO2 nanotube arrays fabricated by electrochemical anodization were functionalised by carbon quantum dots (CQD) synthesized by an electrochemical reduction technique. Here, we report the photo-electrochemical properties of such TiO2 nanotubes array-CQD composite material and it has been found that the properties are significantly enhanced compared to that in pristine (bare) nanotubes. The TiO2 nanotubes were characterized by X-ray diffraction and scanning electron microscopy, whereas the CQD samples were characterized by transmission electron microscopy, optical absorption spectroscopy. CQDs synthesized under two different conditions showed a distinct size difference and corresponding absorption spectra revealed concominant shift in the absorption edges. Furthermore, the photo-electrochemical measurements were carried out with the help of photo-current, incident photon to current conversion efficiency (IPCE), Mott-Schottky plots and the impedance analysis. The photo-current data revealed 30% improvement in TiO2-CQD samples compared to bare TiO2 nanotubes samples. A higher photo-conversion efficiency was observed along with the shifting of the peak value towards visible wavelengths. The Mott-Schottky plots revealed shift in the flat-band potential in the CQD-TiO2 samples and corresponding lowering of the charge transfer resistance was observed through the impedance spectroscopy.

Synthesis and Electro-Catalytic Properties of Platinum Supported on Graphene for Methanol Oxidation.

Graphene serves as excellent support material in the synthesis of metal nanoparticle-graphene electrocatalysts. Highly active and stable Pt/Graphene electrocatalysts for the application of direct methanol fuel cells were developed. The oxygen/carbon ratio of graphene supports were tuned by various chemical methods. Pt nanoparticles with a narrow distribution of particle sizes were well dispersed on graphene. An increased catalytic activity and stability were achieved due to an increased graphitization degree of graphene when the Pt/Graphene was deoxidized during Ar/H2 reduction. The activity of Pt/Graphene towards methanol oxidation reaction and its stability was higher compared to Pt/Carbon. This study suggests a bi-functional effect of both graphitization and the oxygenated groups on the catalytic activity.

Phosphorus-doped exfoliated graphene for supercapacitor electrodes.

Graphene, a single atom thick carbon material with high surface area and electrical conductivity provides an ideal platform for designing high performance electrochemical devices. This paper reports the synthesis of phosphorous doped graphene from reduced graphene sheets, its characterization by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy and its use for supercapacitor applications. The specific capacitance was found to be 367 Fg(-1) from electrochemical measurements. These samples show a high power density of 9 kW kg(-1) and energy density of 59 Wh kg(-1) in an aqueous electrolyte solution, which is much higher than other graphene-based supercapacitors. The phosphorus-doped graphene showed a high potential for use in low cost energy storage devices.

A comparative study of nonpharmacological methods to reduce pain in neonates.

A randomized study was done to compare non pharmacological methods to reduce the pain of heel pricks in 104 stable term neonates. Non-nutritive sucking (NNS), rocking, massage, sucrose (20 percent), distilled water (DW) and expressed breast milk (EBM) were used as pain reducing agents. Duration of cry and Douleur Aiguë du Nouveau né (DAN) score were used to assess pain. Physiological parameters were also recorded before and after the stimulus. At 30 seconds after the stimulus, the pain scores were lowest in the sucrose group but this was not sustained at 1, 2 and 4 minutes. At 2 and 4 minutes pain scores were lowest in the NNS and rocking groups as compared to sucrose, distilled water, expressed breast milk and massage. The total duration of crying was also lowest in the NNS and rocking groups. Physiological parameters were comparable in all groups. Babies who were in Prechtl State 1 and 2 (sleeping) at the time of stimulus showed significantly lesser response to pain compared to babies who were awake. This was seen in all the intervention groups. In conclusion, our study suggests that rocking or giving a baby a pacifier are more effective non-pharmacological analgesics than EBM, DW, sucrose or massage for the pain of heel pricks in neonates. A calm or sleeping state before a painful procedure also appears to decrease crying and pain scores.

Caffeine in tea plants [Camellia sinensis (L) O. Kuntze]: in situ lowering by Bacillus licheniformis (Weigmann) Chester.

Tea plants (Camellia sinensis) contain 5-6% caffeine that is responsible for the stimulating effect of the beverage. As the tolerance to caffeine varies among individuals, low caffeine tea would be an ideal alternative. While assessing the potential of a few selected bacteria-Bacillus licheniformis, B. subtilis and B. firmus, to multiply on nutrient medium supplemented with glucose (5%) and tea leaf extract (2%), it was observed that only B. licheniformis could proliferate on this medium. Hence, B. licheniformis was used for further studies. Tea plants were sprayed with a suspension of B. licheniformis at a dilution of 5 x 10(8) CFU/ml containing 0.1% Tween 80 as surfactant. In situ lowering of caffeine from tea leaves was evident without affecting the quality of the other tea components. Further, there was no change in the morphological and physiological characteristics as well. It is suggested that spraying of B. licheniformis may be useful in yielding decaffeinated tea with good flavour and aroma.

Stability of native and covalently modified papain.

Covalent modification of enzymes with large polymers can produce modified enzymes which retain considerable biological activity and at the same time display resistance to denaturation by high temperatures and chaotropic agents. The cysteine protease, papain, with potential applications in industry, was covalently coupled to polymeric sucrose (mol. wt 400 kDa) at different ratios. The derivatives retained > 80% intrinsic catalytic activity with no change in pH optima and kinetic constants, indicating that the gross tertiary structure was not altered by modification. However, they displayed better thermotolerance than native papain, as indicated by their higher T50 values (6-10 degrees C) and their temperature optima being shifted by 10 degrees C. The half-life of modified papain, calculated from the rate of thermoinactivation, was prolonged by 2- to 30-fold over the native depending on the temperature and proportion of polymeric sucrose in the adducts. The increases in activation free energy of inactivation (1-10 kJ/mol) and activation enthalpy (4-78 kJ/mol) indicate stabilization of the protein and lesser inactivation due to spontaneous unfolding. In the presence of urea, modified papain showed activation, which may be due to a loosening of the 'rigid' structure, reminiscent of the property of thermophilic enzymes.