Potential of Alkali-Silica Reactivity of Unexplored Local Aggregates as per ASTM C1260.

Alkali-silica reaction (ASR) is one of the major durability issues that affect the material degradation and structural performance, compromising the service life of concrete structures. Therefore, this study was planned to investigate the potential of ASR for locally available unexplored and vastly used aggregates, as per ASTM C1260. Aggregates from five different sources (Shalozan, Abbotabad, Orakzai, Swabi and Sada) were procured from their respective crusher sites. Mineralogical components of these aggregates were studied using the petrographic analysis. Cube, prism and mortar bar specimens were cast using mixture design in accordance with ASTM C1260 and placed in sodium hydroxide solution at 80 °C for 90 days. Identical specimens were also cured in water for the purpose of comparison. It was observed that mortar bar expansion of Orakzai aggregate was higher among the other tested aggregates and greater than 0.20% at 28 days, indicating the reactive nature according to ASTM C1260. Petrographic analysis also revealed the presence of reactive silica (quartzite) in the tested Orakzai source. It was observed that the compressive and flexural strengths of specimens exposed to ASR conducive environment was lower than the identical specimens placed in water. For instance, an approximately 9% decrease in compressive strength was observed for Orakzai aggregates exposed to ASR environment at 90 days compared to similar specimens placed in water curing. Moreover, microstructural analysis showed the development of micro-cracks for specimens incorporating Orakzai source aggregates. This study assists the construction stakeholders for the potential of unexplored local aggregates with regard to ASR before its utilization in mega construction projects.

Iron oxide nanoparticles and selenium supplementation improve growth and photosynthesis by modulating antioxidant system and gene expression of chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR) in arsenic-stressed Cucumis melo.

Current research reveals the positive role of iron oxide nanoparticles (IONPs) and selenium (Se) in extenuation of arsenic (As) induced toxicity in Cucumis melo. C. melo plants grown in As spiked soil (20 mg kg-1 As) showed reduced growth, chlorophyll (Chl) content, photosynthetic rate, stomatal conductivity and transpiration. On the other hand, the alone applications of IONPs or Se improved growth and physiochemical parameters of C. melo plants. Additionally, exogenous application IONPs and Se synergistically improved the activity of antioxidative enzymes and glyoxalase system in C. melo plants. In addition, the collective treatment of IONPs and Se reduced As uptake, enhanced rate of photosynthesis and increased gas exchange attributes of C. melo plants under As stress. Interactive effect of IONPs and Se regulated reduced glutathione (GSH), oxidized glutathione (GSSG) and ascorbate (AsA) content in C. melo plants exposed to As-contaminated Soil. IONPs and Se treatment also regulated expression of respiratory burst oxidase homologue D (RBOHD) gene, chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR). Therefore, the combined treatment of IONPs and Se may enhance the growth of crop plants by alleviating As stress.

Effect of foliar application of nano-nutrients solution on growth and biochemical attributes of tomato (Solanum lycopersicum) under drought stress.

Introduction: Drought stress has drastically hampered the growth and yield of many crops. Therefore, environmentally safe agricultural techniques are needed to mitigate drought stress impact. To this end, foliar spray of nano-nutrients solution to (NNS) alleviate harmful aspects of drought stress. Methods: In a completely randomized design (CRD) experiment, seedlings were transplanted into pots at 2-3 leaf stage, each filled with loam-compost- organic manure soil (3:1:1). Plants were divided into two groups. (a) control group (b) applied stress group. Plants at vegetative stage were treated with 100% FC for control group and 60% FC for drought group, and these levels were maintained until harvesting. Three treatments of NNS with four levels i.e., 0%, 1%, 3% and 5% were given to all the pots after two weeks of drought stress treatment with a gap of 5 days at vegetative stage. Results and discussion: Application of 1% of nano-nutrient solution displayed an improvement in shoot length, shoot fresh and dry weight, number of leaves and flowers. Leaf chlorophylls and carotenoids and total phenolics contents were found maximum while minimum electrolyte leakage was observed at 3% application compared to control. Further, 1% application of NNS increased the Leaf RWC%, total soluble sugars, flavonoids contents. 5% NNS application exhibited higher total free amino acids with minimum lipid peroxidation rate in leaves of tomato under drought. Antioxidant enzyme activities increased in a concentration dependent manner as gradual increase was observed at 1%, 3% and 5%, respectively. Overall, this study introduced a new insights on using nano-nutrient solutions to maintain natural resources and ensure agricultural sustainability.

Effects of spray dried yeast (Saccharomyces cerevisiae) on growth performance and carcass characteristics, gut health, cecal microbiota profile and apparent ileal digestibility of protein, amino acids and energy in broilers.

The aim of present study was to determine the effects of supplementation of either synbiotic or probiotic on growth performance and carcass characteristics, gut health, cecal microbiota prolife and apparent ileal digestibility of protein, amino acids, and energy in broilers. Two hundred and forty-day-old straight-run broilers (Ross 308) were allotted randomly to 1 of 5 dietary treatments including basal diet (control), supplemented with either synbiotic (Nutromax P) or probiotic (Actera), each at 0.5 and 1 g/kg of the diet for 5 weeks. The overall findings of the study indicated better (p < 0.05) growth performance of broilers by synbiotic supplementation (1 g/kg) compared with those fed probiotic (1 g/kg) supplemented and control diets. The broilers consuming diet supplemented with 1 g/kg synbiotic has an increased carcass yield in comparison with those fed control diet. The findings of gut health indicated significantly increased villus height and goblet cells, by synbiotic supplementation (1 g/kg), compared with control diet in broilers. The broilers fed 1 g/kg synbiotic supplemented diets had 18% increased protein, 9 to 31% higher amino acid, and 34% better energy digestibility, whereas 8.4% decreased protein digestibility in broilers fed probiotic (1 g/kg) supplemented compared with control diet in broilers. The broilers fed synbiotic (1 g/kg) supplemented diets had increased cecal Lactobacillus and decreased Salmonella, E. coli, and Clostridium count compared with those fed control diet. In conclusion, synbiotic supplementation (1 g/kg) resulted in improved production performance, balanced cecal microbial composition, and better digestibility of nutrients in broilers compared with those fed control and diets supplemented with probiotics.

Synergistic Effect of Bacillus thuringiensis IAGS 199 and Putrescine on Alleviating Cadmium-Induced Phytotoxicity in Capsicum annum.

Plant growth-promoting bacteria (PGPB) and putrescine (Put) have shown a promising role in the mitigation of abiotic stresses in plants. The present study was anticipated to elucidate the potential of Bacillus thuringiensis IAGS 199 and Put in mitigation of cadmium (Cd)-induced toxicity in Capsicum annum. Cadmium toxicity decreased growth, photosynthetic rate, gas exchange attributes and activity of antioxidant enzymes in C. annum seedlings. Moreover, higher levels of protein and non-protein bound thiols besides increased Cd contents were also observed in Cd-stressed plants. B. thuringiensis IAGS 199 and Put, alone or in combination, reduced electrolyte leakage (EL), hydrogen peroxide (H2O2) and malondialdehyde (MDA) level in treated plants. Synergistic effect of B. thuringiensis IAGS 199 and Put significantly enhanced the activity of stress-responsive enzymes including peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD). Furthermore, Put and microbial interaction enhanced the amount of proline, soluble sugars, and total soluble proteins in C. annum plants grown in Cd-contaminated soil. Data obtained during the current study advocates that application of B. thuringiensis IAGS 199 and Put establish a synergistic role in the mitigation of Cd-induced stress through modulating physiochemical features of C. annum plants.

Thin debris layers do not enhance melting of the Karakoram glaciers.

The assessment of meltwater sourcing from the clean and debris-covered glaciers is scarce in High Mountain Asia (HMA). The melting rate varies with the debris cover thickness and glacier orientation. The present study quantifies glacier melting rate attributed to varying thickness of debris cover in the Karakoram. We observed daily melting rates by installing ablation stakes over debris-free and debris-covered ice during a field expedition. The stakes were installed on glacier surface with debris cover thickness ranges between 0.5 and 40 cm at selected experimental sites during the ablation period (September and October 2018) and (July to August 2019). We selected three glaciers including Ghulkin, Hinarchi, and Hoper facing east, south, and north, respectively to assess the role of glacier orientation on melting rates. We observed that the debris-free ice melts faster than the debris-covered ice. Intriguingly, a thin debris layer of 0.5 cm does not enhance melting compared to the clean ice which is inconsistent with the earlier studies. The melting rate decreases as the thickness of debris cover increases at all the three selected glaciers. Furthermore, south-facing glacier featured the highest melting (on average ~ 25% more). However, the north and east-facing glaciers revealed almost same melting rates. We observed that the average degree-day factors (DDF) slightly varies within a range of 0.58-0.73 and 0.55-0.68 cm °C-1 day-1 for debris-free and 0.5 cm debris-covered ice, respectively, however, DDF largely reduces to 0.13-0.25 cm °C-1 day-1 for 40 cm debris-covered ice. We suggest continuous physical glacier ablation observations for various debris cover throughout the ablation zone to better understand the role of debris on melting.

Controlled Assembly of Cu/Co-Oxide Beaded Nanoclusters on Thiolated Graphene Oxide Nanosheets for High-Performance Oxygen Evolution Catalysts.

The use of water splitting modules is highly desired for the sustainable production of H2 as a future energy carrier. However, the sluggish kinetics and demand of high anodic potential are the bottlenecks for half-the cell oxygen evolution reaction (OER), which severely hamper the overall conversion efficiency. Although transition metal oxides based electrocatalysts have been envisioned as cost-effective and potential contenders for this quest, nevertheless, their low conductivity, instability, and limited number of active sites are among the common impediments that need to be addressed to eventually enhance their inherent catalytic potential for enhanced OER activity. Herein, the controlled assembly of transition metal oxides, that is, Cu@CuOx nanoclusters (NCs, ≈2 nm) and Co@CoOx beaded nanoclusters (BNCs, ≈2 nm), on thiol-functionalized graphene oxide (G-SH) nanosheets is reported to form novel and highly efficient electrocatalysts for OER. The thiol (-SH) functionality was incorporated by selective epoxidation on the surface of graphene oxide (GO) to achieve chemically exfoliated nanosheets to enhance its conductivity and trapping ability for metal oxides in nanoscale dimensions (≈2 nm). During the electrocatalytic reaction, overpotentials of 290 mV and 310 mV are required to achieve a current density of 10 mA cm-2 for BNCs and NCs, respectively, and the catalysts exhibit tremendous long-term stability (≈50 h) in purified alkaline medium (1 m KOH) with no dissolution in the electrolyte. Moreover, the smaller Tafel slopes (54 mV/dec for BNCs and 66 mV/dec for NCs), and a Faradic efficiency of approximately 96 % indicate not only the selectivity but also the tailored heterogeneous electrons transfer (HET) rate, which is required for fast electrode kinetics. It is anticipated that such ultrasmall metal oxide nanoclusters and their controlled assembly on a conducting surface (G-SH) may offer high electrochemical accessibility and a plethora of active sites owing to the drastic decrease in dimensions and thus can synergistically ameliorate the challenging OER process.

Ultrasmall Co@Co(OH)2 Nanoclusters Embedded in N-Enriched Mesoporous Carbon Networks as Efficient Electrocatalysts for Water Oxidation.

Metal nanoclusters (NCs, size ≤2 nm) are emerging materials in catalysis owing to their unique catalytic and electronic properties such as high surface/volume ratio, high redox potential, plethora of surface active sites, and dynamic behavior on a suitable support during catalysis. Herein, in situ growth of ultrasmall and robust Co@ß-Co(OH)2 NCs (≈2 nm) hosted in a honeycomb-like 3D N-enriched carbon network was developed for water-oxidation catalysis with extremely small onset potential (1.44 V). Overpotentials of 220 and 270 mV were required to achieve a current density of 10 mA cm-2 and 100 mA cm-2 , respectively, in alkaline medium (1 m KOH). More promisingly, at η10 =240 mV, the prolonged oxygen evolution process (>130 h) with faradaic efficiency >95 % at a reaction rate of 22 s-1 at 1.46 V further substantiated the key role of the ultrasmall supported NCs, which outperformed the benchmark electrocatalysts (RuO2 /IrO2 ) and NCs reported so far. It is anticipated that the high redox potential of NCs with regeneratable active sites and their concerted synergistic effects with the N-enriched porous/flexible carbon network are inherently worth considering to enhance the mass/charge transport owing to the nanoscale interfacial collaboration across the electrode/electrolyte boundary, thereby efficiently energizing the sluggish/challenging oxygen evolution process.

Bread wheat varieties as influenced by different nitrogen levels.

Experiment was conducted to determine the effect of different nitrogen levels on four bread wheat varieties (Triticum aestivum L.) viz. Inqilab-91, Daman-98, Dera-98 and Punjab-96 at Gomal University, Dera Ismail Khan (NWFP), Pakistan during 2000 approximatey 2001. The experiment was laid out in split plot design having four replications using a net plot size of 2 m x 5 m. Nitrogen doses used were 0, 50, 100, 150 and 200 kg/ha. The results showed that different nitrogen levels had significant effects on plant height, total number of plants/m(2), number of grains/spike, number of spike/m(2), spike weight, biological yield, grain yield and grain protein content. Maximum plant height, total number of plants/m(2), number of spikes/m(2), spike weight, biological yield and grain protein content were observed at 200 kg N/ha. Among wheat varieties Daman-98 had maximum plant height, spike weight, grains/spike, 1000-grain weight, biological yield and grain yield. Inqilab-91 had heavier grains and the most grain protein content, while Dera-98 had the maximum plant population and spikes/m(2). Grain yield and biological yield were statistically similar at doses of 150 kg N/ha and 200 kg N/ha. However, dose of 200 kg N/ha, compared to dose of 150 Kg N/ha, significantly increased the protein content.