Unveiling the efficacy of Bacillus faecalis and composted biochar in alleviating arsenic toxicity in maize.

Arsenic (As) contamination is a major environmental pollutant that adversely affects plant physiological processes and can hinder nutrients and water availability. Such conditions ultimately resulted in stunted growth, low yield, and poor plant health. Using rhizobacteria and composted biochar (ECB) can effectively overcome this problem. Rhizobacteria have the potential to enhance plant growth by promoting nutrient uptake, producing growth hormones, and suppressing diseases. Composted biochar can enhance plant growth by improving aeration, water retention, and nutrient cycling. Its porous structure supports beneficial microorganisms, increasing nutrient uptake and resilience to stressors, ultimately boosting yields while sequestering carbon. Therefore, the current study was conducted to investigate the combined effect of previously isolated Bacillus faecalis (B. faecalis) and ECB as amendments on maize cultivated under different As levels (0, 300, 600 mg As/kg soil). Four treatments (control, 0.5% composted biochar (0.5ECB), B. faecalis, and 0.5ECB + B. faecalis) were applied in four replications following a completely randomized design. Results showed that the 0.5ECB + B. faecalis treatment led to a significant rise in maize plant height (~ 99%), shoot length (~ 55%), root length (~ 82%), shoot fresh (~ 87%), and shoot dry weight (~ 96%), root fresh (~ 97%), and dry weight (~ 91%) over the control under 600As stress. There was a notable increase in maize chlorophyll a (~ 99%), chlorophyll b (~ 81%), total chlorophyll (~ 94%), and shoot N, P, and K concentration compared to control under As stress, also showing the potential of 0.5ECB + B. faecalis treatment. Consequently, the findings suggest that applying 0.5ECB + B. faecalis is a strategy for alleviating As stress in maize plants.

Modulation of sunflower growth via regulation of antioxidants, oil content and gas exchange by arbuscular mycorrhizal fungi and quantum dot biochar under chromium stress.

Chromium (Cr) toxicity significantly threatens sunflower growth and productivity by interfering with enzymatic activity and generating reactive oxygen species (ROS). Zinc quantum dot biochar (ZQDB) and arbuscular mycorrhizal fungi (AMF) have become popular to resolve this issue. AMF can facilitate root growth, while biochar tends to minimize Cr mobility in soil. The current study aimed to explore AMF and ZQDB combined effects on sunflower plants in response to Cr toxicity. Four treatments were applied, i.e. NoAMF + NoZQDB, AMF + 0.40%ZQDB, AMF + 0.80%ZQDB, and AMF + 1.20%ZQDB, under different stress levels of Cr, i.e. no Cr (control), 150 and 200 mg Cr/kg soil. Results showed that AMF + 1.20%ZQDB was the treatment that caused the greatest improvement in plant height, stem diameter, head diameter, number of leaves per plant, achenes per head, 1000 achenes weight, achene yield, biological yield, transpiration rate, stomatal conductance, chlorophyll content and oleic acid, relative to the condition NoAMF + No ZQDB at 200 mg Cr/kg soil. A significant decline in peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) while improvement in ascorbate peroxidase (APx), oil content, and protein content further supported the effectiveness of AMF + 1.20%ZQDB against Cr toxicity. Our results suggest that the treatment AMF + 1.20%ZQDB can efficiently alleviate Cr stress in sunflowers.

Design and analysis of four-jaws microgripper with integrated thermal actuator and force sensor for biomedical applications.

This research paper presents design and analysis of the multi-jaw microgripper that can manipulate microbiological organisms and species, cell probing and measurement, biomedical sample sorting, and preparation. Four jaws, actuated with a single thermal chevron actuator, can grip microbiological species ranging from 300 to 700 µm, 1 to 340 µm, 100 µm pool, and 1 to 120 µm spongy cells, respectively. Jaws are designed in such a way that they can grip regular, irregular, and spongy shaped biological species and their organelles. Parametric analysis of the microgripper exhibited that at 10 V, the efficiency of the thermal actuator is at maximum with respect to displacement, force, and temperature. To enhance displacement to voltage ratio and increase the energy efficiency, a class 3 lever mechanism has been incorporated. The amplification factors at four jaws are 17.21, 13.82, 4.02, and 4.93, respectively. For controlled application of the force to microspecies, two electrostatic force sensors have been amalgamated with jaws having capacitive sensitivities of 1.59 nf/µm, 1.91 nf/µm, 17 nf/µm, and 14.5 nf/µm, respectively. Electrothermal, static, and electrostatic analyses have been carried out with the finite element methods based software IntelliSuite®. Stress magnitudes are within the limits of structural integrity of silicon having a factor of safety 2.5. Thermal analysis revealed that at a differential voltage of 10 V, the maximum temperature goes up to 425 °C. Buckling analysis results depicted that the critical load for the thermal actuator is 241 µN with the buckling load factor greater than unity. This paper focuses on microbiological applications only; however, the designed microgripper can be used to manipulate micro-objects, microstructures, microelectronics parts, and micro assembly.