Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

If the zero-field transition in high temperature superconductors such as YBa_2Cu_3O_7-\delta is a critical point in the universality class of the 3-dimensional XY model, then the general theory of critical phenomena predicts the existence of a critical region in which thermodynamic functions have a characteristic scaling form. We report the first attempt to calculate the universal scaling function associated with the specific heat, for which experimental data have become available in recent years. Scaling behaviour is extracted from a renormalization-group analysis, and the 1/N expansion is adopted as a means of approximation. The estimated scaling function is qualitatively similar to that observed experimentally, and also to the lowest-Landau-level scaling function used by some authors to provide an alternative interpretation of the same data. Unfortunately, the 1/N expansion is not sufficiently reliable at small values of N for a quantitative fit to be feasible.Comment: 20 pages; 4 figure

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Impact of pyrene (polycyclic aromatic hydrocarbons) pollutant on metabolites and lipid induction in microalgae Chlorella sorokiniana (UUIND6) to produce renewable biodiesel

Pyrene (polycyclic aromatic hydrocarbon), an anthropogenic organic pollutant prevalent in various ecological units, receives more attention for bioremediation and energy transformation using microalgae. In this study, we have used pyrene pollutant (50–500 ppm) to evaluate the half-maximal inhibitory concentrations (IC50) of Chlorella sorokiniana and the impact on metabolites as well as the induction of lipid biosynthesis to produce renewable biodiesel. Pyrene concentration at 230 ppm (IC50) caused half-maximum inhibition for the 96 h incubation. The harvest in the stationary stage (day 16) for C. sorokiniana revealed a biomass generation of 449 ± 7 mg L−1 and 444 ± 8 mg L−1 dcw in the control medium and pyrene IC50 medium, respectively. An insignificant decline in biomass generation (1.2%) was observed due to the stress effect of the pyrene IC50 medium on metabolic biosynthesis. Although contrary to biomass generation, IC50 of pyrene assisted to induce lipid biosynthesis in C. sorokiniana. The improvement in lipid biosynthesis was observed as ~24% higher in pyrene IC50 compared to the control medium. The chemical composition of the microalgae biomass, metabolites, and lipids was examined using FTIR spectra. The extracted lipid was transesterified to produce biodiesel via methanolic-H2SO4 catalysis. The renewable biodiesel obtained was evaluated using FTIR and 1H NMR spectra. The transformation efficiency of the lipid of C. sorokiniana in biodiesel was calculated as ~81%. This research offers the incentive in lipid biosynthesis in microalgae cells using pyrene for the production of renewable and sustainable ecological biofuels along with bioremediation of pyrene. © 202

Microalgae with a truncated light-harvesting antenna to maximize photosynthetic efficiency and biomass productivity: Recent advances and current challenges

Microalgae and the associated biomass have been advocated for various eco-friendly applications. Although, microalgae are a good source of biofuels, metabolites, and value-added products, their commercial cultivation suffers from limited biomass yield due to inefficient photosynthetic efficiency. Minimizing the light-harvesting antenna size of the photosystems has been recognized as an effective mechanism to enhance photosynthetic efficiency and overall biomass productivity in microalgal cultures. Several strategies including mutagenesis, through UV radiations and chemical mutagenesis, genetic engineering, and DNA insertional mutagenesis have been employed to obtain mutant strains possessing a regulated antenna with a regulated limited number of light-harvesting molecules. However, there are still a number of challenges associated with antenna mutants that need to be addressed. This review highlights the recent developments in truncated antenna mutants of microalgae, aiming to increase the photosynthetic efficiency and biomass productivity of the respective cultures. © 2021 Elsevier Lt

Micro-pollutant Pb(II) mitigation and lipid induction in oleaginous microalgae Chlorella sorokiniana UUIND6

Green oleaginous microalgae are good candidates for the integration of heavy metal bioremediation with the generation of biofuels. To be effective, this requires a comprehensive understanding and optimization of the metal concentration that generates maximum growth along with a high yield of lipids from microalgae cells. This work follows the aforementioned strategy and involves the use of oleaginous microalgae Chlorella sorokiniana for lead mitigation and biodiesel production. The short-term effects (IC50 value at 96 h of culture) and the long-term effects (pigments and biomass) of the exposure of lead (Pb) to the growth and biochemical compositions (pigments, proteins, carbohydrates, and lipids) of microalgae have been also determined. Chlorella sorokiniana has a high half-maximal inhibitory concentration (IC50 value and higher metal bio-concentration factor (BCF) for Pb (II), which represents that this strain can be considered as a lead (Pb) hyperbioaccumulator. FTIR analysis revealed a reduction in proteins and carbohydrates under the influence of Pb while an increase in lipids has been recorded. The lipid profile based on 1H NMR and GC–MS has been followed for the quality analysis of the biodiesel produced that indicated altered lipid profiles under stress by Pb and elevated levels of SFA and MUFA. © 2021 Elsevier B.V

Hydropyrolysis of freshwater macroalgal bloom for bio-oil and biochar production: Kinetics and isotherm for removal of multiple heavy metals

In this study, hydropyrolysis was carried out using sodium carbonate to convert the green algal bloom into bio-oil, biochar, aqueous solution, and gases. The effect of supercritical conditions (400, 450, 500 °C) on the product yield, bio-oil composition, and structure, and functionalities of the biochar was determined. The high yield of biochar and bio-oil was reported at 400 °C. A significant reduction in bio-oil and increment in hydrocarbon content was reported on the elevation of temperature from 450 °C to 500 °C. After that, kinetic and isotherm analysis was investigated simultaneously to remove four heavy metals viz. Cu(II), Ni(II), Co(II), and Cd(II) from the mixture solution. Results show that kinetics data follow a pseudo-second-order kinetics model and adsorption isotherm is in better agreement with the Langmuir model, not with the Freundlich model. The maximum adsorption capacity was found 10.90, 5.74, 5.80, and 16.28 mg/g with the biochar prepared at 500 °C for Cu(II), Ni(II), Co(II), and Cd(II) metals, respectively. The current investigation provided a promising way for the utilization of freshwater algal bloom biomass for renewable products and simultaneously heavy metal removal from the water. © 2021 Elsevier B.V

Algae-based sustainable approach for simultaneous removal of micropollutants, and bacteria from urban wastewater and its real-time reuse for aquaculture

Freshwater consumption by humans has reached its peak, magnifying a dearth to freshwater availability across the world. The rising demand for freshwater has led to an interest in using purified wastewater for reuse. In this study, a novel microalgal strain Pseudochlorella pringsheimii — Ind-Jiht-1 was assessed in a pilot-scale for phyco-mitigation of various pollutants in the raw urban wastewater, including heavy metals as well as antibiotics resistant bacteria. The results appeared promising; the technology achieved an 83.2% reduction in COD, 66.7% in alkalinity and 69.6% in hardness. Moreover, almost complete reductions in total bacterial and total coliforms could be achieved. Three isolates viz., IS-2, IS-9 and IS-10, which were in the raw wastewater, could be obtained even after the 14-days microalgal-treatment of the wastewater. IS-2 was the most dominating bacterial species and able to thrive in urban wastewater even after the treatment. The treated wastewater was used to cultivate the sucker fishes. Bodyweight of the fishes was measured for evaluating their growth rates. The average survival rates of the sucker fish in the raw wastewater and treated wastewater were 0% and 84%, respectively. Results confirm that the algae-based technology not only reduces the micropollutants and bacteria from urban wastewater but also offers a platform for reuse of treated water for low-cost fish cultivation. © 2021 Elsevier B.V

Effect of catalyst and temperature on the quality and productivity of HTL bio-oil from microalgae: A review

Algae biomass has been recognized as one of the most suitable, efficient, and reliable feedstocks for bio-oil production. Among the different processes, hydrothermal liquefaction (HTL) is emerging as an effective technology for the valorization of various types of wet or dry biomass. Several factors, including temperature, retention time, and catalyst, significantly influence the overall efficiency of HTL products. The temperature ∼280 ± 40 °C is reported to be the most suitable range to achieve maximum bio-oil. Both homogeneous and heterogeneous catalysts have been used to improve bio-oil yield. For several advantages, heterogeneous catalysts are the preferred choice due to improved bio-oil generation, easy recovery, and uses. The eco-friendly approach and the reduction of heteroatoms in bio-oils make heterogeneous catalysts an ideal choice to be fortified. Alkaline catalysts have been considered most suitable to improve HTL yield. Variations in temperature and catalysts not only influence the yield of the bio-oil but also influence the characteristics of the bio-oil (e.g. high heating value, oxidative stability, gaseous emission, etc.) simultaneously. This review reveals interesting features including HTL temperature vs. yield, catalysts vs. yield, and the effect of wet and dry biomass on bio-oil properties, and finally, observations, remarks/limitations are presented for future studies. © 2021 Elsevier Lt