Gold Nanoparticles with Self-Assembled Cysteine Monolayer Coupled to Nitrate Reductase in Polypyrrole Matrix Enhanced Nitrate Biosensor

We have developed here a novel, highly sensitive and selective nitrate (NO– 3) biosensor by covalent immobilization of nitrate reductase (NaR) in self-assembled monolayer (SAM) of cysteine on gold nanoparticles (GNP)-polypyrrole (PPy) modified platinum electrode. Incorporation of GNP in highly microporous PPy matrix was confirmed by morphological scanning electron microscope (SEM) images. The electrochemical behavior of the NaR modified electrode exhibited the characteristic reversible redox peaks at the potential, –0.76 and –0.62 V versus Ag/AgCl. Further, the GNP-PPy nanocomposite enhanced the current response by 2-fold perhaps by enhancing the immobilization of NaR and also direct electron transfer between the deeply buried active site and the electrode surface. The common biological interferences like ascorbic acid, uric acid were not interfering with the NO– 3 measurement at low concentration levels. This biosensor showed a wide linear range of response over the concentration of NO– 3 from 1 μM to 1 mM, with higher sensitivity of 84.5 nA μM–1 and a detection limit of 0.5 μM. Moreover, the NO– 3 level present in the nitrate-rich beetroot juice and the NO– 3 release from the lipopolysaccharide treated human breast cancer cells were estimated

Hybrid Multicarrier Random Space Vector PWM for the Mitigation the Acoustic Noise

The pulse width modulation (PWM) inverter is obvious for any industrial and power sector application. Particularly industrial drives are very keen on the industrial standards. Many modulations approached such a drives objects of DC-link consumption, harmonics suppression in lower and higher order spectrum and noise reduction. The still random PWM is a best candidate for reducing the noises on the PWM operated AC drives. There are various Random PWM (RPWM) methods has been developed and investigated for the PWM inverter fed drive noise reductions, still the shortcomings are existence on these method items of their less randomness and complex digital circuitry. These PWM dealt the spreading harmonics there by decreasing harmonic effects on the system. However, these techniques overlook the effect of acoustic noise and DC -link utilizations Therefore, in this paper mainly deals with to combined RPWM principle in space vector PWM (SVPWM) to generate random PWM generation using asymmetric frequency multi carrier called multicarrier random space vector PWM (MCRSVPWM). The SVM agreements with multicarrier (different fixed frequencies as carrier waves) which are chosen with the aid of a random binary bit generator. The proposed RSVM generated pulses with a randomized triangular carrier (4 ± 1.5 kHz), while the conventional RPWM method contains of the random pulse position with a fixed frequency triangular carrier. The simulation study is performed through MATLAB/Simulink for 3 HP asynchronous induction motor drive. The Experimental validation of proposed MCRSVPWM is tested with 2kW six switch (Power MOSFET – SCH2080KE) inverter power module fed induction motor drive.publishedVersio

A split-mouth randomized controlled trial to compare the rate of canine retraction after a soft tissue procedure compared against a corticotomy procedure for accelerated tooth movement

Background and Aim: Various methods to accelerate the orthodontic tooth movement have been used, among which corticotomy is considered to be the most common one. The suggested reasoning for such acceleration was the regional acceleratory phenomenon (RAP). Since the RAP is a property of both the hard and soft tissues, we designed a soft tissue flap procedure to compare the effects with the conventional corticotomy procedure. A split-mouth study was conducted where the two procedures were assessed in a single participant. Patients and Methods: The total sample size was calculated to be 40 with 20 participants in each group. The rate of tooth movement was the primary outcome measure, and the secondary outcomes were dentoalveolar changes, which were studied in both the conventional corticotomy and the flap-only procedure based on a cone-beam computed tomography (CBCT) wherein the alveolar bone density (BD) around canines, tipping, and rotational changes in canines, premolars, and molars were assessed. Results: Corticotomy resulted in greater canine angulation, lesser canine rotation and premolar rotation, and greater molar rotation compared with flap elevation, but these differences were statistically insignificant. Conclusion: Though the corticotomy resulted in higher BD, the differences were statistically insignificant. There was no significant difference in the rate of space closure assessed by the two techniques compared

From scrap metal to highly efficient electrodes: harnessing the nanotextured surface of swarf for effective utilisation of Pt and Co for hydrogen production

Hydrogen is considered to be the key element to achieving climate neutrality, leading to a massive demand for electrocatalysts. This work explores the transformation of metal waste into active and stable electrode materials for water splitting by modifying the surface through atomic deposition of platinum (Pt) and cobalt (Co). Our study finds that with the addition of only 28 μg cm−2 of Pt and 30 μg cm−2 of Co to metal waste, high-performance electrolysis can be achieved. We investigated discarded stainless-steel (SST), titanium (Ti), and nickel (Ni) alloys and found that they had nanotextured surfaces, consisting of 10–50 nm wide grooves, which offered an excellent platform for effective bonding of Pt or Co atoms. We demonstrate a strong synergistic relationship between the metal of the swarf surface and the metal of catalytically active centers, such that only some combinations lead to effective electrocatalysts. Furthermore, we discovered that the surface density of atomically deposited Pt or Co has a profound impact on the nanoscale morphology of the active centers, providing a mechanism for the optimization of electrocatalytic characteristics. For instance, the optimal Pt loading (28 μg cm−2) on Ti swarf yields 5–20 nm Pt nanoparticles within the grooves with exceptional hydrogen evolution reaction (HER) activity. Similarly, the optimal surface density of Co (30 μg cm−2) on Ni swarf generates ∼100 nm interlinked flakes of Co(OH)2 with outstanding oxygen evolution reaction (OER) performance. Combining these best electrodes in a full-cell electrolyser resulted in a current density of 40 mA cm−2 at 1.6 V vs. RHE and the rates of H2 and O2 production of 22.09 and 10.75 mmol min−1, respectively, with 100% faradaic efficiency with no decrease in activity in 24 hours. This study opens the door to more sustainable electrode fabrication and effective hydrogen production in alkaline water electrolysis

De novo assembly and transcriptome analysis of five major tissues of Jatropha curcas L. using GS FLX titanium platform of 454 pyrosequencing

<p>Abstract</p> <p>Background</p> <p><it>Jatropha curcas </it>L. is an important non-edible oilseed crop with promising future in biodiesel production. However, factors like oil yield, oil composition, toxic compounds in oil cake, pests and diseases limit its commercial potential. Well established genetic engineering methods using cloned genes could be used to address these limitations. Earlier, 10,983 unigenes from Sanger sequencing of ESTs, and 3,484 unique assembled transcripts from 454 pyrosequencing of uncloned cDNAs were reported. In order to expedite the process of gene discovery, we have undertaken 454 pyrosequencing of normalized cDNAs prepared from roots, mature leaves, flowers, developing seeds, and embryos of <it>J. curcas</it>.</p> <p>Results</p> <p>From 383,918 raw reads, we obtained 381,957 quality-filtered and trimmed reads that are suitable for the assembly of transcript sequences. <it>De novo </it>contig assembly of these reads generated 17,457 assembled transcripts (contigs) and 54,002 singletons. Average length of the assembled transcripts was 916 bp. About 30% of the transcripts were longer than 1000 bases, and the size of the longest transcript was 7,173 bases. BLASTX analysis revealed that 2,589 of these transcripts are full-length. The assembled transcripts were validated by RT-PCR analysis of 28 transcripts. The results showed that the transcripts were correctly assembled and represent actively expressed genes. KEGG pathway mapping showed that 2,320 transcripts are related to major biochemical pathways including the oil biosynthesis pathway. Overall, the current study reports 14,327 new assembled transcripts which included 2589 full-length transcripts and 27 transcripts that are directly involved in oil biosynthesis.</p> <p>Conclusion</p> <p>The large number of transcripts reported in the current study together with existing ESTs and transcript sequences will serve as an invaluable genetic resource for crop improvement in jatropha. Sequence information of those genes that are involved in oil biosynthesis could be used for metabolic engineering of jatropha to increase oil content, and to modify oil composition.</p

Synergy of nanocrystalline carbon nitride with Cu single atom catalyst leads to selective photocatalytic reduction of CO2 to methanol

Carbon nitride (C3N4) possesses both a band gap in the visible range and a low-lying conduction band potential, suitable for water splitting and CO2 reduction reactions (CO2RR). Yet, bulk C3N4 (b-C3N4) suffers from structural disorder leading to sluggish reaction kinetics. This can be improved by graphitisation; however, current processes in the literature, lead to a variety of graphitised C3N4 (g-C3N4), making it difficult to link the degrees of graphitisation with the functional properties. Herein, we employ complementary analyses, including electrochemical impedance, photoluminescence, and photocurrent, to elucidate structure–property–function relationships. Guided by the descriptors, we developed a facile two-step annealing method that yields nanocrystalline carbon nitride (nc-C3N4), comprising nanoscale graphitic domains within an amorphous matrix. The nanocrystalline grains of nc-C3N4 allow effective immobilisation of Cu atoms and stabilisation of low oxidation states (Cu(I)). Electron microscopy and energy-dispersive X-ray spectroscopy demonstrate that Cu is atomically dispersed. Importantly, the addition of only 0.11 wt% of copper to nc-C3N4 drastically decreases the charge recombination and resistance to change transfer. The synergy of the Cu single-atom catalyst and nanocrystalline domains in carbon nitride (Cu/nc-C3N4) leads to a remarkable 99% selectivity towards methanol production with a rate of 316 μmol gcat−1 h−1 during the photocatalytic CO2RR, which is absent in Cu/b-C3N4

Recent trends in electrochemical biosensors of superoxide dismutases

Superoxide dismutases (SODs), a family of ubiquitous enzymes, provide essential protection to biological systems against uncontrolled reactions with oxygen- and nitrogen- based radical species. We review first the role of SODs in oxidative stress and the other biological functions such as peroxidase, nitrite oxidase, thiol oxidase activities etc., implicating its role in neurodegenerative, cardiovascular diseases, and ageing. Also, this review focuses on the development of electrochemical label-free immunosensor for SOD1 and the recent advances in biosensing assay methods based on their catalytic and biological functions with various substrates including reactive oxygen species (superoxide anion radical, hydrogen peroxide), nitric oxide metabolites (nitrite, nitrate) and thiols using thiol oxidase activity. Furthermore, we emphasize the progress made in improving the detection performance through incorporation of the SOD into conducting polymers and nanocomposite matrices. In addition, we address the potential opportunities, challenges, advances in electrochemical-sensing platforms and development of portable analyzer for point-of-care applications