AbstractThis study demonstrates the importance of selecting an appropriate liquid-to-solid ratio (L∶S) for batch sorption study (BSS) of bentonite (BE). The current recommended L∶S is 20 for BSS of ...soils and sediments, which works well for most of the soils/sediments. However, for expansive soil like BE, L∶S=20 was found to be inadequate due to the formation of thick gel like consistency preventing proper interaction of metal ion with solid surface. This resulted in considerable underestimation of sorption capacity of BE. Effort was made to identify appropriate L∶S for BE for which there is no specific guideline available in the literature. Under controlled pH condition and Pb2+ as the model heavy metal ion, it was noted that the sorption capacity of BE increases with L∶S beyond 20 and with an increase in initial metal ion concentration. The highest percentage removal of Pb2+ was observed at L∶S=50 and lowest at L∶S=100 for initial concentration greater than 300 mg/L. The minimum L∶S possible for BE is 20, below which the interaction between the solution and soil solids becomes difficult due to formation of a thick gel like consistency. The interaction of BE with Pb2+ was further investigated from the results of field emission scanning electron microscopy (FESEM) integrated with energy dispersive X-ray spectroscopy (EDX). Fourier transform infrared (FTIR) spectrometer was used to identify the variations in interaction between the Pb2+ ions and functional group present on BE for various L∶S. It was concluded that for all practical purposes, L∶S=50 is a suitable ratio for determining sorption capacity of expansive soil like BE.
•Explores the utility of a harmful weed, water hyacinth (WH) for soil reinforcement.•Effect of density is significant in case of lower moisture content soil–fiber composite.•WH fiber modified the ...brittle behavior of soil to ductile behavior of soil–fiber composite.•WH fiber content of 0.5–0.75% is found to mobilize maximum compressive strength.
Growing awareness of sustainability in construction has increased attention toward increase in use of natural fibers for soil reinforcement applications. Researchers have explored the utility of natural limited life fibers such as jute, reed and sisal for soil reinforcement. In this study, an attempt was made to demonstrate the use of local weed named water hyacinth (Eicchornia crassipes) as soil reinforcement. A series of unconfined compression strength (UCS) tests was conducted on silty sand reinforced with randomly distributed fiber. These series of tests aim to study influence of different fiber content, soil density and moisture content. The stress–strain response of fiber reinforced soil shows the increase in post peak strength and ductility. This was mainly attributed due to presence of cellulose content. The effect of soil density on increased strength due to inclusion of fiber is significant in case of lower moisture content.
A graphite/phenol formaldehyde resin composite bipolar plate was developed for fuel cell applications. The electrical conductivity of the composite was measured with the help of a four-probe ...technique. A basic model was modified to predict the electrical conductivity of the plate for a wide range of graphite content. The model was highly dependent on the shape factor and orientation factor of the conductive graphite filler in the composite. The concept of digital image processing was used to quantitatively determine the shape and orientation factors of the bipolar plate. The experimental values of the electrical conductivities were well predicted by the model. The most effective in-plane and through-plane electrical conductivities, at 75% graphite content, were found to be 165 and 103.3
S
cm
−1, respectively.
Domperidone (DOM) is a dopamine- receptor (D(2)) antagonist, which is widely used in the treatment of motion-sickness. The pharmacokinetic parameters make DOM a suitable candidate for transdermal ...delivery. The purpose of the present investigation was to develop transdermal delivery systems for DOM and to evaluate their physicochemical characteristics, in vitro release an ex vivo permeation through rat abdominal skin and their mechanical properties.
Bilayered matrix type transdermal drug delivery systems (TDDS) of DOM were prepared by film casting technique using hydroxypropyl methyl cellulose as primary and Eudragit RL 100 as secondary layers. Brij-35 was incorporated as a solubilizer, d-limonene and propylene glycol were employed as permeation enhancer and plasticizer respectively. The prepared TDDS were extensively evaluated for in vitro release, moisture absorption, moisture content, water vapor transmission, ex vivo permeation through rat abdominal skin, mechanical properties and stability studies. The physicochemical interaction between DOM and polymers were investigated by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR).
All the formulations exhibited satisfactory physicochemical and mechanical characteristics. The optimized formulation F6 showed maximum cumulative percentage of drug release (90.7%), permeation (6806.64 µg) in 24 hrs, flux (86.02 µg /hr/cm(2)) and permeation coefficient of 0.86x10(-2) cm/hr. Values of tensile strength (4.34 kg/mm(2)) and elastic modulus (5.89 kg/cm(2)) revealed that formulation F6 was strong but not brittle. DSC and FTIR studies showed no evidence of interaction between the drug and polymers. A shelf life of 2 years is predicted for the TDDS.
Domperidone bilayered matrix type transdermal therapeutic systems could be prepared with the required flux and suitable mechanical properties.
Bilayered buccoadhesive patch for systemic administration of felodipine was developed using hydroxy propyl methyl cellulose as primary layer and Eudragit RLPO as secondary layer. In vitro drug ...permeation studies through porcine buccal membrane and buccal absorption studies in human volunteers were performed. Six formulations were developed by solvent casting technique and evaluated for in vitro drug release, moisture absorption, mechanical properties, surface pH, in vitro broadhesion and in vitro permeation of felodipine through porcine buccal membrane from bilayered buccal patch. Formulation BB4 showed a drug release of 94.6% with zero order release profile and permeated 41.6% of drug with a flux of 0.113 mg h super(-1)cm super(-2) through porcine buccal membrane. Formulation BB4 showed 3.42 N and 1.63 mJ peak detachment force and work of adhesion respectively. The physicochemical interactions between felodipine and polymer was investigated by Fourier transform infrared (FTIR) Spectroscopy. According to FTIR the drug did not show any evidence of an interaction with the polymer. A stability study of optimized patch BB4 was done in natural human saliva; it was found that both drug and buccal patches were stable in human saliva. The results indicate that suitable bilayered buccoadhesive patches with desired permeability could be prepared.
Drug efflux by intestinal P-glycoprotein (P-gp) is recognized as a significant biochemical barrier affecting oral absorption for a number of drugs apart from the cytochrome P450 3A enzyme. Various ...conflicting reports have been published regarding the effects of grapefruit juice (GFJ)
on P-gp mediated drug efflux, in which GFJ has been shown to have no effect, as an inhibitor effect or activation of the enzyme. Therefore the present study's objective was to provide clarification of previous findings, adopting a two-way approach, involving both single dose and multiple
dosage regimens. Diltiazem (DTZ) 15 mg/kg was administered concomitantly with 5 ml/kg of GFJ to one group (n = 6) of male Wistar rats and another group (n = 6) of animals were provided distilled water with DTZ (the control). A third group of rats was administered GFJ orally for
six days and on seventh day GFJ and DTZ were administered concomitantly. The Cmax and AUC of DTZ were decreased significantly in the presence of multiple dose treatment of GFJ. These data were also decreased in presence of simultaneous treatment of single dose GFJ. In vitro
metabolism studies and gut sac experiments were conducted in order to understand the mechanism involved. In the liver S9 fraction prepared from the rats treated with multiple doses of GFJ, DTZ metabolism was significantly increased compared to the control. Furthermore, the amount of drug transported
from the duodenum was reduced in GFJ treated rats compared to that of the control (1581.0 ± 7.8 nM vs 1084.81 ± 6.1 nM, respectively). Grapefruit juice was also reported to inhibit the organic anion transporting polypeptide (OATP), an influx transporter thus reducing the blood
levels of OATP substrates which was evident from the in vitro studies. The amount of drug transported from the duodenum was reduced in the presence of pravastatin, a specific OATP inhibitor (1581.0 ± 7.8 nM to 1265.0 ± 5.5 nM). Oral single dose exposure to GFJ showed no
effect on P-gp, whereas multiple dose administration of GFJ resulted in increased levels of P-gp expression and decreased levels of OATP, thus showing a varied effect on intestinal absorption, and therefore overcoming the inhibition of DTZ metabolism in rats.
Hazardous wastes disposed of in engineered landfills interact with rainwater, generate harmful leachate and may contaminate groundwater. To minimize this, a suitable multi-layered cover system (MLCS) ...is constructed over the buried waste. Field assessment of complex moisture dynamics in unsaturated MLCS and its long-term hydraulic efficiency has not been investigated in detail for extremely humid conditions (annual rainfall >1000 mm). Therefore, the overarching purpose of this study was to investigate the long-term hydraulic performance of a three-layered hydraulic barrier cover system under humid Indian conditions. The field cover setup was exposed to natural weather condition in the Northeast Indian state of Assam, for 800 days. The MLCS was instrumented to measure continuous variation of volumetric water content and matric suction as function of time and depth. The field measurements were used to determine the appropriate input hydraulic parameters and evapotranspiration model that can be used for numerical modeling. The results showed that simulation using drying van Genuchten soil-water characteristic curve parameters and Penman-Monteith evapotranspiration model matched the field observations. Events of the highest precipitation and extreme drought (cause for desiccation) did not lead to percolation in the drainage layer (60 cm) and barrier layer (100 cm). Numerical analyses performed for 87 years by considering the climate data of two different humid locations (Eastern and Western part) of India revealed that the progressive saturation of barrier layer occurred within 18 to 20 years. However, when geosynthetic clay liner was incorporated as additional barrier material, the saturation time increased by two-fold (42 to 44 years).
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•Long-term monitoring of hazardous waste cover system was evaluated.•Numerical simulation of the field measurements was performed.•Identified the soil hydraulic parameters and evapotranspiration model.•Climate change impact on hazardous cover system simulated for two humid regions.•Geo-synthetic clay liner enhanced cover saturation time by two fold.
Abstract
Objective
Clinical research data warehouses (RDWs) linked to genomic pipelines and open data archives are being created to support innovative, complex data-driven discoveries. The computing ...and storage needs of these research environments may quickly exceed the capacity of on-premises systems. New RDWs are migrating to cloud platforms for the scalability and flexibility needed to meet these challenges. We describe our experience in migrating a multi-institutional RDW to a public cloud.
Materials and Methods
This study is descriptive. Primary materials included internal and public presentations before and after the transition, analysis documents, and actual billing records. Findings were aggregated into topical categories.
Results
Eight categories of migration issues were identified. Unanticipated challenges included legacy system limitations; network, computing, and storage architectures that realize performance and cost benefits in the face of hyper-innovation, complex security reviews and approvals, and limited cloud consulting expertise.
Discussion
Cloud architectures enable previously unavailable capabilities, but numerous pitfalls can impede realizing the full benefits of a cloud environment. Rapid changes in cloud capabilities can quickly obsolete existing architectures and associated institutional policies. Touchpoints with on-premise networks and systems can add unforeseen complexity. Governance, resource management, and cost oversight are critical to allow rapid innovation while minimizing wasted resources and unnecessary costs.
Conclusions
Migrating our RDW to the cloud has enabled capabilities and innovations that would not have been possible with an on-premises environment. Notwithstanding the challenges of managing cloud resources, the resulting RDW capabilities have been highly positive to our institution, research community, and partners.
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