Effect of multiple passes of tractor with varying normal load on subsoil compaction

A field experiment was conducted on alluvial soil with sandy loam texture, in a complete randomized design, to determine the compaction of sub-soil layers due to different passes of a test tractor with varying normal loads. The selected normal loads were 4.40, 6.40 and 8.40 kN and the number of passes 1, 6, 11 and 16. The bulk density and cone penetration resistance were measured to determine the compaction at 10 equal intervals of 5 cm down the surface. The observations were used to validate a simulation model on sub-soil compaction due to multiple passes of tractor in controlled conditions. The bulk density and penetration resistance in 0–15 cm depth zone continuously increased up to 16 passes of the test tractor, and more at higher normal loads. The compaction was less in different sub-soil layers at lower levels of loads. The impact of higher loads and larger number of passes on compaction was more effective in the soil depth less than 30 cm; for example the normal load of 8.40 kN caused the maximum bulk density of 1.53 Mg/m³ after 16 passes. In 30–45 cm depth layer also, the penetration resistance increased with the increase in loads and number of passes but to a lesser extent which further decreased in the subsoil layers below 45 cm. Overall, the study variables viz. normal load on tractor and number of passes influenced the bulk density and soil penetration resistance in soil depth in the range of 0–45 cm at 1% level of significance. However, beyond 45 cm soil depth, the influence was not significant. The R² calculated from observed and predicted values with respect to regression equations for bulk density and penetration resistance were 0.7038 and 0.76, respectively.     

Phospholamban generates cation selective ion channels

Phosholamban (PLN) is involved in the contractility of cardiac muscles by regulating the intracellular calcium concentration (Ca(2+)(cyt)) of cardiac myocytes. This occurs via a modulation of the sarco-/endoplasmic CaATPase (SERCA). In spite of high-resolution structures the molecular mode of PLN action is yet not known. In the present paper we readdress the question whether PLN proteins can generate ion channel activity. Reconstitution of PLN in planar lipid bilayers reveals single channel fluctuations, which are characterized by two conductance levels, long open/closed dwell times, moderate selectivity between monovalent cations and no perceivable Ca(2+) permeability. The PLN generated channel activity could be inhibited by a PLN antibody (abPLN) implying that the channel activity is indeed due to the inherent channel function of the PLN protein.     

Fatigue crack growth simulations of homogeneous and bi-material interfacial cracks using element free Galerkin method

In this paper, quasi-static fatigue crack growth simulations of homogeneous and bi-material interfacial cracks have been performed using element free Galerkin method (EFGM) under mechanical as well as thermo-elastic load. The thermo-elastic fracture problem is decoupled into thermal and elastic problems. The temperature distribution obtained by solving heat conduction equation is used as input in the elastic problem to get the displacement and stress fields. Discontinuities in the temperature and displacement fields are captured by extrinsic partition of unity enrichment technique. The values of stress intensity factors have been extracted from the EFGM solution by domain based interaction integral approach. The standard Paris fatigue crack growth law has been implemented for the life estimation of various model problems. The results obtained by EFGM under mechanical and thermo-elastic loads were compared with those obtained by FEM using remeshing approach.     

Machine-learning classifiers for imbalanced tornado data

Learning from imbalanced data, where the number of observations in one class is significantly larger than the ones in the other class, has gained considerable attention in the machine learning community. Assuming the difficulty in predicting each class is similar, most standard classifiers will tend to predict the majority class well. This study applies tornado data that are highly imbalanced, as they are rare events. The severe weather data used herein have thunderstorm circulations (mesocyclones) that produce tornadoes in approximately 6.7 % of the total number of observations. However, since tornadoes are high impact weather events, it is important to predict the minority class with high accuracy. In this study, we apply support vector machines (SVMs) and logistic regression with and without a midpoint threshold adjustment on the probabilistic outputs, random forest, and rotation forest for tornado prediction. Feature selection with SVM-recursive feature elimination was also performed to identify the most important features or variables for predicting tornadoes. The results showed that the threshold adjustment on SVMs provided better performance compared to other classifiers.     

Sr(Ag1−xLix)2Se2 and [Sr3Se2][(Ag1−xLix)2Se2] Tunable Direct Band Gap Semiconductors

Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid-state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two-dimensional Sr(Ag_1−xLi_x)₂Se₂ layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag_1−xLi_x)₂Se₂ with x up to 0.45. In addition, a new type of intergrowth compound [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] was synthesized upon further reaction of Sr(Ag_1−xLi_x)₂Se₂ with SrSe. Both Sr(Ag_1−xLi_x)₂Se₂ and [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag_1−xLi_x)₂Se₂ can be precisely tuned via fine-tuning x that is controlled by only the flux ratio and temperature.     

On minimum metric dimension of honeycomb networks

A minimum metric basis is a minimum set W of vertices of a graph G(V,E) such that for every pair of vertices u and v of G, there exists a vertex wW with the condition that the length of a shortest path from u to w is different from the length of a shortest path from v to w. The honeycomb and hexagonal networks are popular mesh-derived parallel architectures. Using the duality of these networks we determine minimum metric bases for hexagonal and honeycomb networks.     

Synthetic study on the relationship between structure and sweet taste properties of steviol glycosides

The structure activity relationship between the C??-C?? methylene double bond on the aglycone of steviol glycosides and the corresponding impact on their sweet taste has been reported here for the first time. It has been observed that converting stevioside and rebaudioside A to their corresponding ketones by switching the doubly bonded methylene on C-17 for a ketone group actually removes the sweet taste properties of these molecules completely. Regenerating the original molecules tends to restore the sweet taste of both the steviol glycosides. Thus this C??-C?? methylene double bond in rebaudioside A and stevioside can be regarded as a pharmacophore essential for the sweetness property of these molecules.     

Chemical Composition,Antioxidant, Antibacterial,and Antibiofilm Activities of Backhousia citriodora Essential Oil

The essential oil of Backhousia citriodora, commonly known as lemon myrtle oil, possesses various beneficial properties due to its richness in bioactive compounds. This study aimed to characterize the chemical profile of the essential oil isolated from leaves of Backhousia citriodora (BCEO) and its biological properties, including antioxidant, antibacterial, and antibiofilm activities. Using gas chromatography–mass spectrometry, 21 compounds were identified in BCEO, representing 98.50% of the total oil content. The isomers of citral, geranial (52.13%), and neral (37.65%) were detected as the main constituents. The evaluation of DPPH radical scavenging activity and ferric reducing antioxidant power showed that BCEO exhibited strong antioxidant activity at IC₅₀ of 42.57 μg/mL and EC₅₀ of 20.03 μg/mL, respectively. The antibacterial activity results showed that BCEO exhibited stronger antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) than against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae). For the agar disk diffusion method, S. epidermidis was the most sensitive to BCEO with an inhibition zone diameter of 50.17 mm, followed by S. aureus (31.13 mm), E. coli (20.33 mm), and K. pneumoniae (12.67 mm). The results from the microdilution method showed that BCEO exhibited the highest activity against S. epidermidis and S. aureus, with the minimal inhibitory concentration (MIC) value of 6.25 μL/mL. BCEO acts as a potent antibiofilm agent with dual actions, inhibiting (85.10% to 96.44%) and eradicating (70.92% to 90.73%) of the biofilms formed by the four tested bacteria strains, compared with streptomycin (biofilm inhibition, 67.65% to 94.29% and biofilm eradication, 49.97% to 89.73%). This study highlights that BCEO can potentially be a natural antioxidant agent, antibacterial agent, and antibiofilm agent that could be applied in the pharmaceutical and food industries. To the best of the authors’ knowledge, this is the first report, on the antibiofilm activity of BCEO against four common nosocomial pathogens.     

4D Biofabrication of Mechanically Stable Tubular Constructs Using Shape Morphing Porous Bilayers for Vascularization Application

This study reports the fabrication of highly porous electrospun self-folding bilayers, which fold into tubular structures with excellent mechanical stability, allowing them to be easily manipulated and handled. Two kinds of bilayers based on biocompatible and biodegradable soft (PCL, polycaprolactone) and hard (PHB, poly-hydroxybutyrate) thermoplastic polymers have been fabricated and compared. Multi-scroll structures with tunable diameter are obtained after the shape transformation of the bilayer in aqueous media, where PCL-based bilayer rolled longitudinally and PHB-based one rolled transversely with respect to the fiber direction. A combination of higher elastic modulus and transverse orientation of fibers with respect to rolling direction allowed precise temporal control of shape transformation of PHB-bilayer – stress produced by swollen methacrylated hyaluronic acid (HA-MA) do not relax with time and folding is not affected by the fact that bilayer is fixed in unfolded state in cell culture medium for more than 1 h. This property of PHB-bilayer allowed cell culturing without a negative effect on its shape transformation ability. Moreover, PHB-based tubular structure demonstrated superior mechanical stability compared to PCL-based ones and do not collapse during manipulations that happened to PCL-based one. Additionally, PHB/HA-MA bilayers showed superior biocompatibility, degradability, and long-term stability compared to PCL/HA-MA.     

Catalytic reduction of 4-nitrophenol using synthesized and characterized CoS@MorphcdtH/CoS@4-MPipzcdtH nanoparticles

CoS@MorphcdtH NPs and CoS@4-MPipzcdtH NPs were synthesized by precipitation method involving three mechanisms: inclusion, occlusion, and adsorption. The synthesized NPs were characterized with the help of UV-Vis spectroscopy, FESEM-EDAX, powder x-ray diffraction, TEM, ESIMS, TG/DSC analysis. The morphology of the CoS@MorphcdtH NPs and CoS@4-MPipzcdtH NPs were hexagonal and rectangular, and the particles were in the range 7–12 nm. UV–visible spectral measurements showed surface plasmon resonance at 320 nm–340 nm with band gap of 3.65 eV–3.86 eV. The catalytically active CoSNPs called were investigated for the reduction of 4-nitrophenol (4-NP) via hydrogenation using sodium borohydride (NaBH₄) as a reducing agent. Both the CoS NPs successfully reduced 4-NP to 4- aminophenol (4-AP) in a short time, catalytic performances are almost unchanged for the first five cycles. Herein, we report the preparation and characterizations of efficient active CoS NPs consisting carbodithioic acid framework as a support/capping material, along with catalytic property.