Biochar Synthesis from Mineral- and Ash-Rich Waste Biomass,Part 1: Investigation of Thermal Decomposition Mechanism during Slow Pyrolysis

Synthesizing biochar from mineral- and ash-rich waste biomass (MWB), a by-product of human activities in urban areas, can result in renewable and versatile multi-functional materials, which can also cater to the need of solid waste management. Hybridizing biochar with minerals, silicates, and metals is widely investigated to improve parent functionalities. MWB intrinsically possesses such foreign materials. The pyrolysis of such MWB is kinetically complex and requires detailed investigation. Using TGA-FTIR, this study investigates and compares the kinetics and decomposition mechanism during pyrolysis of three types of MWB: (i) mineral-rich banana peduncle (BP), (ii) ash-rich sewage sludge (SS), and (iii) mineral and ash-rich anaerobic digestate (AD). The results show that the pyrolysis of BP, SS, and AD is exothermic, catalyzed by its mineral content, with heat of pyrolysis 5480, 4066, and 1286 kJ/kg, respectively. The pyrolysis favors char formation kinetics mainly releasing CO₂ and H₂O. The secondary tar reactions initiate from ≈318 °C (BP), 481 °C (SS), and 376 °C (AD). Moreover, negative apparent activation energies are intrinsic to their kinetics after 313 °C (BP), 448 °C (SS), and 339 °C (AD). The results can support in tailoring and controlling sustainable biochar synthesis from slow pyrolysis of MWB.     

Investigations on the mechanism of the hypocholesterolemic action of diethylhexyl phthalate in rats

The plasticizer di(2-ethylhexyl)phthalate (DEHP), used widely in the manufacture of food packages and medical plastic devices, depressed serum cholesterol (40%) and proliferated hepatic mitochondria (100%) when administered in the diet (2%, w/w) to the rat. Microsomes isolated from the livers of animals administered DEHP showed lowered specific activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase (50%). The incorporation of acetate but not of mevalonate into hepatic cholesterol was decreased (52%) in these animals. The release of bile acids was greatly enhanced (100%), and the activity of cholesterol 7 alpha-hydroxylase, the regulatory enzyme in the pathway of bile acid formation, was stimulated (70%) on DEHP administration. Even though the capacity of mitochondria to oxidize the side chain of cholesterol was not enhanced in DEHP-fed animals, the larger population of mitochondria would ensure that the amount of cholesterol oxidized per gram of liver was significantly higher.     

Soleus H-reflex modulation after motor incomplete spinal cord injury: effects of body position and walking speed

Objective:

To examine position-dependent (semireclined to standing) and walking speed–dependent soleus H-reflex modulation after motor incomplete spinal cord injury (SCI).

Participants:

Twenty-six patients with motor incomplete SCI (mean: 45 ± 15 years) and 16 noninjured people (mean: 38 ± 14 years).

Methods:

Soleus H-reflexes were evoked by tibial nerve stimulation. Patients were tested in semireclined and standing positions (experiment 1) and in midstance and midswing positions (experiment 2).

Results:

H-reflexes were significantly greater after SCI in all positions compared with noninjured people (P < 0.05). Position-dependent modulation from semireclined to standing (normally observed in noninjured people) was absent after SCI. In SCI patients, H-reflex modulation was not significantly different at 1.2 m/s compared with 0.6 m/s treadmill walking speed; in noninjured people, H-reflex modulation was significantly greater at 1.2 m/s compared with 0.6 m/s treadmill walking speed. There was a significant positive correlation between modified Ashworth scores, a clinical measure of spasticity and soleus H-reflex amplitudes tested in all positions. A significant negative correlation was also found between H-reflexes in standing and midstance positions and the amount of assistance patients required to walk.

Conclusions:

An improvement in position-dependent and walking speed–dependent reflex modulation after SCI may indicate functional recovery. Future studies will use H-reflex testing to track changes as a result of therapeutic interventions.