Solvent-free production of thermoplastic lignocellulose from wood pulp by reactive extrusion.

A novel acylation approach suited to rapid bulk thermoplasticization of lignocellulose without solvents was previously demonstrated by the authors in benchtop batch studies. The method relies upon a benzethonium chloride/sulfuric acid functionalizing agent at low concentrations to act as a wetting agent for the wood pulp, similar to an ionic liquid, yet binds to the lignocellulose ester as a flow aid in the final thermoplastic. The present investigation evaluates the approach in a residence time-limited (45-90 s) continuous twin-screw reactor, where intensive mixing and heat were found to yield high acylation. The modified lignocellulose exhibited desired thermoplasticity by being melt moldable without the need for plasticizers and maintained much of the excellent stiffness of cellulose, demonstrating a maximum flexural modulus of 5.4 GPa and tensile modulus of 1.8 GPa. The influence of extrusion conditions on thermoplasticity was examined by a Design of Experiments (DOE) analysis.

Dried and Redispersible Cellulose Nanocrystal Pickering Emulsions.

The effect of tannic acid (TA) and water-soluble cellulose derivatives on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. The potential to both fully dry CNC-stabilized emulsions and to redisperse the dried emulsions in water is demonstrated. When CNCs are mixed with excess adsorbing polymer, either methyl cellulose or hydroxyethyl cellulose, followed by emulsification with corn oil, oil-in-water emulsions can be transformed without oil leakage into solid dry emulsions via freeze-drying. However, these dry emulsions exhibit droplet coalescence within the solid matrix and thus cannot be redispersed. Addition of TA (after emulsification) imparts dispersibility to the dried emulsions due to complexation between the cellulose derivatives and TA which condenses the "shell" around the oil droplets. When dried emulsions with TA are placed in water, the emulsion droplets redisperse readily without the need for high energy mixing, and minimal change in emulsion droplet size is observed by Mastersizer and confocal microscopy. Therefore, the simple addition of two sustainable components to CNC Pickering emulsions (i.e., TA and methyl cellulose or hydroxyethyl cellulose) has led to the first dried and redispersible CNC-based emulsions with oil content as high as 94 wt %. These processing abilities will likely extend the use of these surfactant-free, "green", and potentially edible emulsions to new food, cosmetic, and pharmaceutical applications.

Functional heterogeneity of osteoclasts: matrix metalloproteinases participate in osteoclastic resorption of calvarial bone but not in resorption of long bone.

Data in the literature suggest that site-specific differences exist in the skeleton with respect to digestion of bone by osteoclasts. Therefore, we investigated whether bone resorption by calvarial osteoclasts (intramembranous bone) differs from resorption by long bone osteoclasts (endochondral bone). The involvement of two major classes of proteolytic enzymes, the cysteine proteinases (CPs) and matrix metalloproteinases (MMPs), was studied by analyzing the effects of selective low molecular weight inhibitors of these enzymes on bone resorption. Mouse tissue explants (calvariae and long bones) as well as rabbit osteoclasts, which had been isolated from both skeletal sites and subsequently seeded on bone slices, were cultured in the presence of inhibitors and resorption was analyzed. The activity of the CP cathepsins B and K and of MMPs was determined biochemically (CPs and MMPs) and enzyme histochemically (CPs) in explants and isolated osteoclasts. We show that osteoclastic resorption of calvarial bone depends on activity of both CPs and MMPs, whereas long bone resorption depends on CPs, but not on the activity of MMPs. Furthermore, significantly higher levels of cathepsin B and cathepsin K activities were expressed by long bone osteoclasts than by calvarial osteoclasts. Resorption of slices of bovine skull or cortical bone by osteoclasts isolated from long bones was not affected by MMP inhibitors, whereas resorption by calvarial osteoclasts was inhibited. Inhibition of CP activity affected the resorption by the two populations of osteoclasts in a similar way. We conclude that this is the first report to show that significant differences exist between osteoclasts of calvariae and long bones with respect to their bone resorbing activities. Resorption by calvarial osteoclasts depends on the activity of CPs and MMPs, whereas resorption by long bone osteoclasts depends primarily on the activity of CPs. We hypothesize that functionally different subpopulations of osteoclasts, such as those described here, originate from different sets of progenitors.

Role of metronidazole in improving response and specific drug sensitivity in advanced pulmonary tuberculosis.

One hundred and thirty-seven patients of advanced pulmonary tuberculosis were randomly allocated to receive metronidazole 400mg tid (76) or placebo (61) for 2 months in a single blind study. All received streptomycin 0.75 g,INH 30 mg and rifampicin 450 mg daily as standard antitubercle treatment. There were no significant pretreatment differences, among both groups. Compared to placebo group there was superior clinical improvement in metronidazole treated group at 4 and 8 weeks (81% vs 53%-P less than 0.05; 87% vs 72%-P less than 0.05 respectively), greater sputum reduction at 4 weeks (49% vs 9%-P less than 0.001) greater radiologic improvement at 4 weeks (60% vs 43%-P less than 0.01) and a better antituberculous drug sensitivity. Metronidazole seems to have beneficial adjuvant role in the drug treatment of tuberculosis. This may improve response in advanced cases.

Bombay experience in intensive respiratory care over 6 years.

The experience of the intensive respiratory care in 930 cases treated from 1983 for 4 years and in 404 cases over the next 2 years is reported. The background operational problems are stressed. Those between age 10 and 50 years did significantly better (p less than 0.05). The survival over the first 4 years in IPPR cases was 16.3% and in non IPPR group 71.8%; over the next 2 years, the former group, survival was 32.4 and 36.3%. The survival in asthmatic patients was high (76%). In cases with organophosphorus poisoning (without IPPR), survival was 81% while in IPPR group it was 29%. In 1988, the results in this group were better due to more aggressive management. In autopsy data on 85 cases, infection was not a major feature in those dying within 24 hours. The survival in COPD cases showed significant relation to age (p less than 0.05), initial arterial pO2 below 60 mm (p less than 0.01) and arterial pH below 7.3 (p less than 0.01). In cases with pneumonia (also asthma) younger cases did better (p less than 0.05) as also those with pneumonia and initial pO2 above 60 mm (p less than 0.01) and pH above 7.3 (p less than 0.001). When pneumonia was community acquired, survival (64.8%) was better than when it was hospital acquired (24%; p less than 0.01). Only the need for IPPR affected survival in trauma group. The major cause of death was infection with Klebsiella, Pseudomonas, Staphylococci and other gram--ve organisms. It is concluded that with proper planning and training, the IRCU does provide a useful mode of treatment in selected patients with respiratory problems.