Climate change and sustainable agricultural growth in the sahel region: Mitigating or resilient policy response?

The aim of this study is to provide an empirical answer to the question of whether nexus exists between climate change and sustainable agricultural growth in nine (9) countries within the Sahel region between 1990 and 2020. The study utilized Panel ARDL and Pairwise Dumitrescu Hurlin Panel Causality Tests to arrive at the following conclusions; firstly, the climate change orchestrated by change in rainfall is a very prominent factor causing reduction in sustainable agricultural growth in the Sahel region. One way feedback relationship flows from sustainable agricultural growth to greenhouse gas emission. In the light of the above, this study recommends that, in addressing the adverse effects of change in rainfall on agricultural sustainability, the policymakers in the Sahel region in particular and Africa as a whole should embark on a policy mix by embanking on mitigating policy response towards ensuring sustainable agricultural production via irrigation which is the best mode of water provisions without causing negative spilliovers on the environment. Also, the policymakers should be proactive by embarking on policies and programs that would build the resilience and adaptation of the region ahead of the future adverse effects of agriculturally induced climatic change.

Removal of Sulfide Ions from Kraft Washing Effluents by Photocatalysis with N and Fe Codoped Carbon Dots.

N and Fe codoped carbon dots (N,Fe-CDs) were fabricated from citric acid, L-glutamic acid and ferric chloride via a hydrothermal method for the photocatalytic removal of S2- from kraft washing effluents (KWE). The N,Fe-CDs were fluorescent nanoparticles (average size of 3.18 nm) and catalyzed the oxidation of S2- following a first-order kinetic model with an activation energy of 33.77 kJ/mol. The N,Fe-CDs tolerated elevated temperatures as high as 80 °C without catalyst deactivation. The N,Fe-CDs catalysts were reusable for at least four cycles, preserving over 90% of the activity. In the treatment of KWE from the kraft pulping of eucalyptus, the concentration of S2- was decreased by the N,Fe-CDs from 1.19 to 0.41 mmol/L in 6 h. Consequently, near complete remediation was obtained in 24 h. In addition, half of the chemical oxygen demand was removed after treatment with 500 mg/L of the N,Fe-CDs. In addition, the present photocatalyst was safe within a concentration of 200 mg/L, as indicated by the acetylcholinesterase inhibition test. Our findings may help develop a cleaner production process for kraft brownstock washing.

Time-Resolved Kinetic Measurement of Microalgae Agglomeration for Screening of Polysaccharides-Based Coagulants/Flocculants.

Time-resolved monitoring of microalgae agglomeration facilitates screening of coagulants/flocculants (CFs) from numerous biopolymer candidates. Herein, a filtering-flowing analysis (FFA) apparatus was developed in which dispersed microalgal cells were separated from coagulates and flocs formed by CFs and pumped into spectrophotometer for real-time quantification. Polysaccharides-based CFs for Microcystis aeruginosa and several other microalgae were tested. Cationic hydroxyethyl cellulose (CHEC), chitosan quaternary ammonium (CQA) and cationic guar gum (CGG) all triggered coagulation obeying a pseudo-second-order model. Maximal coagulation efficiencies were achieved at their respective critical dosages, i.e., 0.086 g/gM.a. CHEC, 0.022 g/gM.a. CQA, and 0.216 g/gM.a. CGG. Although not active independently, bacterial exopolysaccharides (BEPS) aided coagulation of M. aeruginosa and allowed near 100% flocculation efficiency when 0.115 g/gM.a. CQA and 1.44 g/gM.a. xanthan were applied simultaneously. The apparatus is applicable to other microalgae species including Spirulina platensis, S. maxima, Chlorella vulgaris and Isochrysis galbana. Bio-based CFs sorted out using this apparatus could help develop cleaner processes for both remediation of harmful cyanobacterial blooms and microalgae-based biorefineries.

Production of Red Pigments by a Newly Isolated Talaromyces aurantiacus Strain with LED Stimulation for Screen Printing.

Microbial pigments have been widely applied to printing in food, textile, and paper industries as a sustainable alternative to synthetic dyes. Herein, we isolated a novel Talaromyces aurantiacus strain with a strong ability to produce red pigments. We further studied pigment production conditions, stability, screen printing application, and bioactivities. Our results showed that sucrose was a favourable carbon source and the addition of l-histidine significantly enhanced the production of red pigments. Pigment production was strictly photo-regulated with effective wavelengths around 450 nm (blue light). We mixed the red pigments with cellulosic materials and explored their application potentials for screen printing on paper, cotton fabrics, and polymeric carriers. The printing density was significantly improved from 0.3 to 0.7 by overlay printing. T. aurantiacus pigments could be stably stored at pH 5-11, temperature - 10 to 70 °C, and redox potential - 200 to 300 mV. Moreover, the stable ranges were extended to pH 1-11 and temperature over 100 °C after screen-printed on paper. The red pigments exhibited antioxidant activity towards 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (IC50 10.4 mg L-1 in solution). Our results further indicated the red pigments by T. aurantiacus was environmentally friendly based on acetylcholinesterase activity assay. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01008-x.

The polycondensing temperature rather than time determines the degradation and drug release of poly(glycerol-sebacate) doped with 5-fluorouracil.

Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester that could be used as biodegradable drug carrier. We have previously prepared PGS implants doped with 5-fluorouracil (5-FU-PGSs) and found that 5-FU-PGSs exhibited an initial burst of 5-FU release during in vitro degradation. The synthesis temperature and time are two of the most important reaction conditions for polymer synthesis. Therefore, in order to establish a controllable drug-release manner, we prepared a series of 5-FU-PGS with 2% weight of 5-FU under synthesis conditions with different polycondensing temperature and time and characterized the infrared spectrum properties, in vitro degradation and drug release. Results showed that the polycondensing temperature determined the mechanical properties, degradation and drug release of 5-FU-PGSs. With the polycondensing temperature increasing, the elastic modulus and hardness of 5-FU-PGSs increased, and the mass loss and 5-FU release rate decreased. The polycondensing time had no significant influence on the mechanical property, degradation and drug release of 5-FU-PGSs. We suggest that the polycondensing temperature is the factor to control the drug-release manner.