Evaluation of Assisted Fluidization of Nanoagglomerates by Monitoring Moisture in the Gas Phase and the Influence of Gas Viscosity

We have previously reported that the fluidization of nanoparticle agglomerates can be enhanced by the addition of external force fields such as vibration, acoustic waves, centrifugal force, and magnetic particles. The criteria usually used to evaluate the enhancement in fluidization quality are the fluidized bed expansion, pressure drop, and visual appearance of the fluidized bed to determine the presence of bubbles, large heavy agglomerates and/or channeling and spouting. Here we introduce a different approach based on measuring the rate of absorption/desorption of moisture (humidification/drying) of hydrophilic fluidized nanopowders. The fluidizing gas was humidified in a controlled manner, and the amount of moisture in the gas phase was measured before and after the fluidized bed by humidity sensors. The experiments show that the amount of moisture adsorbed or desorbed by the bed of powder is larger when the fluidized bed was assisted by vibration or moving magnetic particles than when the bed was conventionally fluidized. In addition, the effect of high temperature gas on the fluidization of nanopowders was studied by using neon as a fluidizing gas at room temperature. It is shown that due to the increase in gas viscosity, the minimum bubbling velocity is increased, bubbling is reduced and a smoother fluidization is obtained

Pull-off force of coated fine powders under small consolidation

In this paper, a three-dimensional model taking into account the contact deformation and surface area coverage (SAC) of nanoadditives is proposed to predict the force required to separate two contacting particles (the pull-off force) under consolidation stress up to 10 KPa, for cornstarch, a Geldart group C powder, sparsely and densely dry-coated with nanosilica. The experimental pull-off force measurement is conducted in a Seville powder tester. Comparison of the predicted results with the experimental results indicates (1) that the pull-off force of sparsely coated cornstarch is larger than that of densely coated cornstarch due to the greater hardness and small particle radius of fumed silica; (2) there is not a continuous variation in the pull-off force with the coverage of silica; on the contrary, values of the pull-off force of sparsely coated samples are grouped in similar range, while the values of the pull-off force of densely coated samples are grouped in another range of lower values.(3) Within a range, the SAC does not have a big effect on the pull-off force for sparsely coated samples and only a slight effect for densely coated samples (4) the pull-off force increases with increasing consolidation force due to larger deformation in the contact area; (5) under consolidation stresses up to 10 KPa, the deformation of the cornstarch particles is not large enough to fully embed the nanosized silica

Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

Nations within a nation: variations in epidemiological transition across the states of India, 1990–2016 in the Global Burden of Disease Study

18% of the world's population lives in India, and many states of India have populations similar to those of large countries. Action to effectively improve population health in India requires availability of reliable and comprehensive state-level estimates of disease burden and risk factors over time. Such comprehensive estimates have not been available so far for all major diseases and risk factors. Thus, we aimed to estimate the disease burden and risk factors in every state of India as part of the Global Burden of Disease (GBD) Study 2016

Improving the flowability of cohesive pharmaceutical powders by dry particle coating

by L. Gurumurthy, Chinmay Ghoroi and R. N. Dav

Pharmaceutical nanotechnology: dry coating of micronized API powders for improved dissolution of directly compacted tablets with high drug loading

Motivated by our recent study showing improved flow and dissolution rate of the active pharmaceutical ingredient (API) powders (20 μm) produced via simultaneous micronization and surface modification through continuous fluid energy milling (FEM) process, the performance of blends and direct compacted tablets with high drug loading is examined. Performance of 50 μm API powders dry coated without micronization is also considered for comparison. Blends of micronized, non-micronized, dry coated or uncoated API powders at 30, 60 and 70% drug loading, are examined. The results show that the blends containing dry coated API powders, even micronized ones, have excellent flowability and high bulk density compared to the blends containing uncoated API, which are required for direct compaction. As the drug loading increases, the difference between dry coated and uncoated blends is more pronounced, as seen in the proposed bulk density-FFC phase map. Dry coating led to improved tablet compactibility profiles, corresponding with the improvements in blend compressibility. The most significant advantage is in tablet dissolution where for all drug loadings, the t80 for the tablets with dry coated APIs was well under 5 min, indicating that this approach can produce nearly instant release direct compacted tablets at high drug loadings.by Xi Han, Chinmay Ghoroi and Rajesh Dav

Experimental Investigation of Vibration-Induced Bulk Solids Transport and Segregation. Final Technical Report, March 28, 1995--September 26, 1996

We report experiments on the rise time T of a single large sphere within a sinusoidally vibrated bed (amplitude a) of uniform particles (diameter d). At fixed acceleration, three distinct behavioral regimes are identified both from visual observations and from the typical increase of T with frequency f. Two convective regimes separated by a critical frequency are found, and for low a and high f, a {open_quotes}non-convective{close_quotes} regime. In the latter, the bed crystallizes and a size dependent rise is evidenced. The relevance of the non-dimensional parameter a/d is shown and a scaling law is deduced which has the form f {proportional_to} d{sup {minus}1/2

Rise-time regimes of a large sphere in vibrated bulk solids

We report experiments on the rise time T of a single large sphere within a sinusoidally vibrated bed (amplitude a) of uniform particles (diameter d). At fixed acceleration, we identify three distinct behavioral regimes both from visual observations and from the typical increase of T with frequency f. We observe two convective regimes separated by a critical frequency and, for low a and high f, a "nonconvective" regime. In the latter, the bed crystallizes and a size dependent rise is evidenced. We show the relevance of the nondimensional parameter a͞d and deduce a scaling law of the form f~d 21͞2 . [ S0031-9007(97) Over approximately the last ten years, significant attention has been given to the phenomenon of size segregation in granular mixture. This is motivated in part by the fact that size segregation is often an undesirable outcome of handling and/or processing operations of bulk solids In general, a large ball placed at the bottom of a vibrated bed will rise to the surface In this paper we report the influence of the macroscopic behavior of a monodisperse bed on the rise time T of a single large sphere. Three rise regimes are identified from the specific relationship between T and the frequency f. Our results show the distinct features of two convective flows: one where heaping occurs and the other where heaping is not present. For the first time, we observe in a three-dimensional bed a dependence of T on the intruder size. This occurs when the bed becomes so compact that it crystallizes. Finally, we emphasize the relevance of the dimensionless amplitude a͞d which allows us to predict the rapid increase of T with frequency at high accelerations. The experimental system consists of a fixed acrylic cylinder of inner diameter D cyl 11.43 cm and a piston mounted onto a Bruel & Kjar shaking head. The piston motion is controlled using an accelerometer with a feedback loop. We emphasize that the bed is excited only through vibrations of the piston. If the walls were moving, the sides of the granular bed during the flight would still be subjected to the shearing motion of the vibrating walls. If the walls are fixed, one can be sure that energy is provided only when the bed is in contact with the piston. Then the shearing effect of the walls is due only to the bed motion. We note also that heaping can be observed when a bed is continuously pushed upward by a pisto