A review on the surface modification of materials for 3D-printed diagnostic devices.

Three-dimensional (3D) printing in tissue engineering and biosensing of analytes by using biocompatible materials or modifying surface structures is an upcoming area of study. This review discusses three common surface modification techniques, viz. alkaline hydrolysis, UV light photografting, and plasma treatment. Alkaline hydrolysis involves the reaction of an alkaline solution with the surface of a material, causing the surface to develop carboxyl and hydroxyl groups. This technique can enhance the biocompatibility, surface wettability, adhesion, printability, and dyeability of materials, such as acrylonitrile butadiene styrene (ABS), polycarbonate, and polylactic acid (PLA). This review also mentions details about some of the surface-modified 3D-printed diagnostic devices. Although most of the devices are modified using chemical processes, there are always multiple techniques involved while designing a diagnostic device. We have, therefore, mentioned some of the devices based on the materials used instead of categorising them as per modification techniques. 3D printing helps in the design of sophisticated shapes and structures using multiple materials. They can, therefore be used even in the design of microfluidic devices that are very useful for biosensing. We have also mentioned a few materials for printing microfluidic devices.

Defect Enriched Tungsten Oxide Phosphate with Strategic Sulfur Doping for Effective Seawater Oxidation.

The intrinsic ability of defects within the electrocatalysts can be judiciously utilized in designing robust electrocatalysts for efficient seawater oxidation. Herein, we have fabricated a novel tungsten oxide phosphate (W12PO38.5) with optimized sulfur doping triggering the insertion of a large number of defect sites. This allows for boosted OER performance in alkaline freshwater as well as seawater, avoiding the unwanted chlorine evolution reaction. The optimized electrocatalyst achieved high current densities of 500 mA cm-2 at an overpotential of just 387 mV in fresh water and 100 mA cm-2 at 380 mV in alkaline seawater for OER. Besides the excellent catalytic performances, the developed electrocatalyst appeared to be a durable catalyst as well. An interesting electrocatalytic activation caused by the generous electronic redistribution led the electrocatalyst to achieve great stability over 100 h at a 100 mA cm-2 current density in alkaline real seawater.

New age chloride shielding strategies for corrosion resistant direct seawater splitting.

Electrocatalytic direct seawater splitting is considered to be one of the most desirable and necessary approach to produce substantial amount of green hydrogen to meet the energy demand. However, practical seawater splitting remains far-fetched due to the electrochemical interference of multiple elements present in seawater, among which chlorine chemistry is the most aggravating one, causing severe damages to electrodes. To overcome such limitations, apart from robust electrocatalyst design, electrolyte engineering along with in depth corrosion engineering are essential aspects, which needs to be thoroughly judged and explored. Indeed, extensive studies and various approaches including smart electrolyzer design have been attempted in the last couple of years on this matter. The present review offers a comprehensive discussion on various strategies to achieve effective and sustainable direct seawater splitting, avoiding chlorine electrochemistry to achieve industry-level performances.

Nickel-Vanadium-Manganese Trimetallic Nitride as Energy Saving, Efficient Bifunctional Electrocatalyst for Alkaline Water Splitting via Urea Electrocatalysis.

Hydrogen production through pure water electrolysis is often found less economic as it requires high potential for water oxidation. The presence of urea in water involving effective urea oxidation can be considered as an effective strategy to produce hydrogen economically. Herein, we develop trimetallic nickel vanadium manganese nitride porous microspheres as an efficient bifunctional electrocatalyst for both urea oxidation reaction (UOR) as well as hydrogen evolution reaction (HER) mechanisms. The optimized NiVMn nitride exhibits eye-catching UOR activity along with HER activity that required only 1.36 and -0.253 V electrode potentials, respectively, to achieve a high current density of 100 mA cm-2. Combining its bifunctional activity in UOR and HER in a two-electrode system, an energy saving by 0.26 V potential compared to water electrolysis through water oxidation can be acquired to reach 50 mA cm-2 current density. The presence of manganese(II) has a significant influence in stabilizing high valence V(V) and Ni(II), offering large number of active sites, and during UOR, the effective electronic transitions are more between Mn → Ni rather than Mn → V, leading to excellent and stable UOR performance. Indeed, the electrocatalyst and the approach offering considerable energy saving phenomena are believed to make hydrogen production more economic and sustainable.

Transition Metal Non-Oxides as Electrocatalysts: Advantages and Challenges.

The identification of hydrogen as green fuel in the near future has stirred global realization toward a sustainable outlook and thus boosted extensive research in the field of water electrolysis focusing on the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). A huge class of compounds consisting of transition metal-based nitrides, carbides, chalcogenides, phosphides, and borides, which can be collectively termed transition metal non-oxides (TMNOs), has emerged recently as an efficient class of electrocatalysts in terms of performance and longevity when compared to transition metal oxides (TMOs). Moreover, the superiority of TMNOs over TMOs to effectively catalyze not only OERs but also HERs and ORRs renders bifunctionality and even trifunctionality in some cases and therefore can replace conventional noble metal electrocatalysts. In this review, the crystal structure and phases of different classes of nanostructured TMNOs are extensively discussed, focusing on recent advances in design strategies by various regulatory synthetic routes, and hence diversified properties of TMNOs are identified to serve as next-generation bi/trifunctional electrocatalysts. The challenges and future perspectives of materials in the field of energy conversion and storage aiding toward a better hydrogen economy are also discussed in this review.

Deforestation susceptibility assessment and prediction in hilltop mining-affected forest region.

This work mainly focused on deforestation susceptibility (DS) assessment and its prediction based on statistical models (FR, LR & AHP) in the Saranda forest, India. Also, efforts had been made to quantify the effect of mining on deforestation. We had considered twenty-five (twenty present and five predicted) causative variables of deforestation, including climate, natural or geomorphological, forestry, topographical, environmental, and anthropogenic. The predicted variables have been generated from different simulation models. Also, very high-resolution, Google Earth imagery have been used in time series analysis for deforestation from 1987 to 2020 data and generated dependent variable. On deforestation analysis, it was observed that a total of 4197.84 ha forest areas were lost in the study region due to illegal mining, agricultural and tribal people allied activities. The DS results have shown that of total existing forest area, 11.22% area were under very high, 16.08% under high, 16.18% under moderate, 24.25% under low, and 32.27% falls very low categories. According to the DS assessment and predicted results, the very high susceptibility classes were found at and close to mines, agricultural, roads and settlement's surrounding sites. The sensitivity analysis results also shown that some causative variables (maximum temperature (2.95%), minimum temperature (0.51%), rainfall (2.69%), LST (4.56%), hot spot (7.36%), aspect (1.14%), NDVI (2.64%), forest density (3.78%), lithology (3.26%), geomorphology (3.00%), distance from agricultural (19.40%), soil type (2.05%), solar radiation (5.97%), LULC (3.26%), drought (3.16%), altitude (2.85%), slope (5.97%), distance from mines (18.05%), roads (2.17%), and settlements (5.18%)) were more sensitive to deforestation. Most of the sensitive parameters showed a positive correlation with DS. The AUC values of the ROC curve had shown a better fit for AHP (0.72) than (0.69) FR and LR (0.68) models for present DS results. The correlation results had shown a good inverse relationship between DS and distance from mines and foliar dust concentration. This work will espouse the future work in the effective planning and management of the mining-affected forest region and predicted deforestation susceptibility would be helpful for forest ecosystem study and policymaking.

Rhizoremediation prospects of Polyaromatic hydrocarbon degrading rhizobacteria, that facilitate glutathione and glutathione-S-transferase mediated stress response, and enhance growth of rice plants in pyrene contaminated soil.

Rhizoremediation is a strategy where pollutant degrading bacteria are augmented through plant roots using plant-microbe interaction. Therefore, for effective rhizoremediation of pyrene contaminated soil, bacterial strains were experimented for amelioration of stress response in host plant along with biodegradation ability. A total of 28 bacteria, having ability to degrade polycyclic aromatic hydrocarbons were isolated from contaminated sites and checked for their plant growth promoting attributes, such as indole acetic acid (IAA) production, phosphate solubilization, atmospheric nitrogen fixation and siderophore release. Among these isolates, Klebsiella pneumoniae AWD5 was found to degrade 60% of pyrene. While other isolates, i.e. Alcaligenes faecalis BDB4, Pseudomonas fragi DBC, Pseudomonas aeruginosa PDB1, Acinetobactor sp. PDB4 degraded 48.5%, 50.29%, 31.3% and 36% of pyrene, respectively, after 6 days of incubation. K. pneumoniae AWD5 produced 94.2 µg/ml IAA and 3.1 mM/mg/h unit of ACC deaminase, which was best among eighteen indole acetic acid producers and five of the 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing isolates. P. aeruginosa PDB1 resulted in highest phosphate solubilization activity of 875.26 ng/ml of soluble phosphate among seven phosphate solubilizers. The isolates AWD5 and PDB1 both have shown a good amount of siderophore release (56.3% and 84.3% unit). There was 19.1% increase in shoot length of rice seedlings treated with PDB1 in presence of pyrene. Similarly, 26.5% increase in the root length of AWD5 treated rice was recorded in pyrene contaminated soil. Bacterial inoculation also induced and improved the stress response in host plant, in presence of pyrene, as suggested by the superoxide dismutase, glutathione and glutathione-S-transferase activities in rice.