Emptying Process Research Articles

Simulation method of heat-mass transfer between hot wind and wet coating in the manufacturing process of pole piece

In order to improve the complex numerical calculation process for wet coating of pole piece, a three-dimensional numerical model of heat-mass transfer characteristics is established between hot wind and wet coating based on multi-field coupling theory of porous media and meshless parallel method, and its reliability is verified through literature data. Meanwhile, the difference calculation method and evaluation process are proposed for heat-mass transfer characteristics to solve this numerical model. The results show that the maximum errors are less than 14.7 % for this model. In addition, a scale modeling method is proposed to improve computational efficiency based on similarity theory. Meanwhile, the influences of different scale factors on temperature and humidity parameters are analyzed for wet coating. The results show that this method is accurate and reliable because the determination coefficient R2 of all parameters is more than 0.99. Meanwhile, compared with the calculation time of original model, the calculation efficiency increases by 44.6 % for the model with scale factor selected as 800. Finally, the variation and distribution of internal parameters are analyzed for wet coating during pore emptying process based on above simulation method. The results show that the variation trends of liquid film thickness, pore emptying rate, water saturation, gas saturation and effective gas diffusion coefficient are corresponding with the accelerated, uniform and decelerated drying processes of porous media. Meanwhile, the location of four-corner edges for wet coating is the weak link in heat-mass transfer process. Therefore, the heat-mass transfer characteristics for wet coating can be improved by increasing its initial thickness or adjust reasonable drying position in engineering.

Predicting gastric emptying of drug substances taken under postprandial conditions by combination of biorelevant dissolution and mechanistic in silico modeling

Physiologically based pharmacokinetic (PBPK) models can help to understand the effects of gastric emptying on pharmacokinetics and in particular also provide a platform for understanding mechanisms of food effects, as well as extrapolation between different postprandial conditions, whether standardized clinical or patient-oriented, non-clinical conditions. By integrating biorelevant dissolution data from the GastroDuo dissolution model into a previously described mechanistic model of fed-state gastric emptying, we simulated the effects of a high-calorie high-fat meal on the pharmacokinetics of sildenafil, febuxostat, acetylsalicylic acid, theobromine and caffeine. The model was able to simulate the variability in Cmax and tmax caused by the presence of the stomach road. The main influences investigated to affect the gastric emptying process were drug solubility (theobromine and caffeine), tablet dissolution rate (acetylsalicylic acid) and sensitivity to gastric motility (sildenafil and febuxostat). Finally, we showed how PBPK models can be used to extrapolate pharmacokinetics between different prandial states using theobromine as an example with results from a clinical study being presented.

Feasibility analysis of technical and environmental aspects of establishing an oil palm empty fruit bunch waste processing business unit

The purpose of this study was to analyze the feasibility of the plan to establish a business unit for processing OPEFB waste into briquettes and liquid smoke products based on technical and environmental aspects. The establishment of an OPEFB processing business unit will be established in the Sei Galuh PKS area, with a production capacity of 3000 kg/day and capable of producing charcoal briquette products of 644.25 kg/day and liquid smoke products of 314.11 kg/day. The business unit will be built on an area of ±767.5911 m² and consists of 12 facilities. The environmental impact caused by the establishment of this business unit can be reviewed from the physical development period of the project including land acquisition and the project operation period including waste and pollution that can be handled properly and does not cause adverse impacts on the environment around the business unit area. So that based on the technical and environmental aspects of this OPEFB processing business unit is feasible to establish.

An Experimental Assessment of Inconsistencies in Memory Forensics

Memory forensics is concerned with the acquisition and analysis of copies of volatile memory (memory dumps). Based on an empirical assessment of observable inconsistencies in 360 memory dumps of a running Linux system, we confirm a state of overwhelming inconsistency in memory forensics: almost a third of these dumps had an empty process list and was therefore obviously incomplete. Out of those dumps that were analyzable, almost every second dump showed some form of inconsistency that potentially impacts the interpretation of the dump in a forensic investigation. These results are based on a new way to estimate the level of causal consistency of a memory dump. The factors influencing these inconsistencies are less clear but in general correlate with the level of concurrency (system load and number of threads).

Bouncing Regimes of Supercooled Water Droplets Impacting Superhydrophobic Surfaces with Controlled Temperature and Humidity.

Superhydrophobic surfaces have shown significant potential for the passive anti-icing application due to their unique water repellency. Reducing the contact time between the impacting droplets and the underlying surfaces with certain textures, especially applying the pancake bouncing mechanism, is expected to eliminate droplet icing upon impingement. However, the anti-icing performance of such superhydrophobic surfaces against the impact of supercooled water droplets has not yet been examined. Therefore, we fabricated a typical post-array superhydrophobic surface (PSHS) and a flat superhydrophobic surface (FSHS), to study the droplet impact dynamics on them with controlled temperature and humidity. The contact time and the bouncing behavior on these surfaces and their dependence on the surface temperature, Weber number, and surface frost were systematically investigated. The conventional rebound and full adhesion were observed on the FSHS, and the adhesion is mainly induced by the penetration of the droplet into the surface micro/nanostructures and the consequent Cassie-to-Wenzel transition. On the PSHS, four distinct regimes including pancake rebound, conventional rebound, partial rebound, and full adhesion were observed, where the contact time increases correspondingly. Over a certain Weber number range, the pancake rebound regime where the droplet bounces off the surface with a dramatically shortened contact time benefits the anti-icing performance. By further decreasing the surface temperature, the pancake rebound turns into the conventional rebound, where the droplet is not levitated after the capillary emptying process. Our scale analysis indicates that the frost between the posts reduces the capillary energy stored during the downward penetration, resulting in the failure of the pancake bouncing. A droplet adheres onto the frosted surface at sufficiently low temperature, especially at larger Weber numbers, on account of the coupling influence of droplet nucleation and wetting transition.

Development of Combine Bio-adhesive – Floating Drug Delivery System by using Different Polymer

The goal of designing sustained release drug delivery systems of tablets is to reduce the frequency of dosing or to increase the effectiveness of the drug by localization at the site of action, reducing the dose required, or providing controlled drug delivery. The oral route is considered as the most promising route of drug delivery. Effective oral drug delivery may depend upon the factor such as gastric emptying process, gastrointestinal transit time of dosage form. Most of the oral dosage forms possess several physiological limitations such as variable gastrointestinal transit, because of variable gastric emptying leading to non-uniform absorption profiles, incomplete drug release and shorter residence time of the dosage form in the stomach. This lead to incomplete absorption of drug having absorption window especially upper part of small intestine, as once the drug passes down the absorption site the remaining quantity goes down unabsorbed.

The intestinal microbiota of a Risso's dolphin (Grampus griseus): possible relationships with starvation raised by macro-plastic ingestion.

Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we profiled the intestinal bacterial communities of a stranded Risso's dolphin (Grampus griseus) which died because of the ingestion of rubber gloves. In this study, we explored the potential relationships between starvation raised by plastic ingestion with the dolphin gut microbiota. Our results showed significant differences in bacterial diversity and composition among the different anatomical areas along the intestinal tract, which may be related to the intestinal emptying process under starvation. In addition, the intestinal bacterial composition of the Risso's dolphin showed both similarity and divergence to that of other toothed whales, suggesting potential roles of both host phylogeny and habitat shaping of the cetacean intestinal microbiome. Perhaps, the microbiota is reflecting a potentially disordered intestinal microbial profile caused by the ingestion of macro-plastics which led to starvation. Moreover, two operational taxonomic units (0.17% of the total reads) affiliated with Actinobacillus and Acinetobacter lwoffii were detected along the intestinal tract. These bacterial species may cause infections in immunocompromised dolphins which are malnourished. This preliminary study profiles the intestinal microbiota of a Risso's dolphin, and provides an additional understanding of the potential relationships between starvation raised by ingesting macro-plastics with cetacean gut microbiota.

The Use of Natural and Synthetic Polymers in the Formulation of Gastro retentive Drug Delivery System

The gastric emptying process drastically reduces the bioavailability of drugs that target the stomach for their action. A gastro retentive drug delivery system (GRDDS) becomes a solution to retain drugs in the stomach and release drugs from the formulation system within a certain period. The polymer used in the GRDDS formulation is the essential excipient that can retain the drugs in the stomach. Several ways for GRDDS to maintain its existence in the stomach are using some systems, such as mucoadhesive, low-density, high-density, swellable, eff ervescent, and expandable systems. A polymer is a macromolecular substance with a long repeating chain consisting of natural and synthetic polymers, each with diff erent potentials. It is considered for its ability to regulate drug release, good fl ow properties, can improve drug dissolution to improve bioavailability and stability during processing in the body. Combining natural and synthetic polymers is often carried out to obtain advantages and cover the existing polymer’s disadvantages. Polymers can release drugs using three diff erent mechanisms, i.e., diff usion, degradation, and expansion. These techniques are often chosen for the formulation of GRDDS because of their more fl exible system and fi t for almost all types of GRDDS. The polymer used in the GRDDS system is chosen from its physicochemical properties and the number of fl oating times, drug release rate, viscosity, fl oating lag times, bioavailability, and solubility.

In Situ Generation of Red-to-NIR Emissive Radical Cations in the Stomach for Gastrointestinal Imaging.

Red-to-near-infrared (NIR) fluorescent probes, with advantages such as high spatiotemporal resolution and in situ sensing abilities,are highly attractive for diagnosis of gastrointestinal diseases and targeted drug development. However, conventional red-to-NIR fluorophores with electron closed-shell structures require tedious synthetic procedures for preparation, and it is difficult to further decorate them with sensing groups. In this study, a series of easily prepared pyrroles with simple structures that can quickly be transformed into red-to-NIR emissive radical cations in acidic buffer solution and in vivo stomachs is developed. The in-situ-generated red-to-NIR emissive pyrrole radical cations in the stomach have excellent biocompatibility and stability and can be used not only for intravital gastrointestinal imaging with high spatiotemporal resolution, but also for dynamic monitoring of the gastric emptying process and assessment of anti-gastric-acid therapy. The acidity-induced generation of pyrrole radical cations is believed to provide a facile strategy for developing red-to-NIR fluorophores and studying gastrointestinal diseases.

In vivo evaluation of floating tablet clarithromycin 500mg

Floating drug delivery system (FDDS) containing Clarithromycin 500mg (CLA) designed to prolong the retention time in the stomach is also an approach to optimize the plasma CLA concentration in the gastric. However, the development of FDDS meets many obstacles about physiology such as cannot control and locate FDDS in gastrointestinal because of the process of stomach emptying. CLA is rapidly absorbed from the gastrointestinal tract, bioavailability in intact form is only about 55% with a relatively short half-life, about 5-7 hours when taking a 500mg dose. Therefore, this research approaching a dosage form CLA to prolong the gastric retention time by in vivo in living body is local dog because the test subject is a dog beagle because anatomically it is quite similar in size to the gastrointestinal tract with the human model. The technical to show CLA image in vivo by X - ray method each time before and after oral administration of a pill and finished until there is no more pill images in the stomach. In addition, plasma drug concentrations were also calculated at each time point using the HPLC with LCMS IT-TOF method and compared with tablets without buoyancy properties. Results of research FDDS containing CLA has been the floating tablet time is 3,5 to 4,5 hours. And plasma concentration between testing group reached at 6 and 8 hours (1964,00 ± 104,25 ng/ml and 1203,00 ± 191,68 ng/ml); and the drud’s peak group reached at 2,5 -3 hours (1169,88 ± 109,42 ng/ml and 1982,63 ± 266,48 ng/ml), respectivety.

Bridging the Gap between Food Effects under Clinical Trial Conditions and Real Life: Modeling Delayed Gastric Emptying of Drug Substances and Gastric Content Volume Based on Meal Characteristics

Delayed gastric emptying is known to have a major impact on drug absorption. While the test meal recommended by the FDA and EMA to study food effects represents a worst-case scenario, it does not reflect the reality of the patients. Physiologically based pharmacokinetic (PBPK) models could bridge the gap between clinical settings of food effect studies and the diverse nonclinical situations by simulating the effect of meals with different compositions and volumes. A mathematical equation based on a stretched exponential function was reparameterized to describe the gastric emptying process of mixed solid meals. The model was fitted to literature data including the gastric emptying data of 23 meals from 15 studies. Using a multiple linear regression model, we were able to predict the two function parameters from the meal characteristics caloric content and the percentage of calories derived from fat. After implementation into the PBPK software PK-Sim, the model, together with a separate compartment for liquid gastric contents, was compared to commercially available software. The model is able to simulate the gastric emptying of mixed solid meals containing drugs based on specific meal characteristics. A second compartment allows for distribution between liquid and solid components and rapid gastric emptying along the Magenstrasse.

IRun: Horizontal and Vertical Shape of a Region-Based Graph Compression.

Graph data are pervasive worldwide, e.g., social networks, citation networks, and web graphs. A real-world graph can be huge and requires heavy computational and storage resources for processing. Various graph compression techniques have been presented to accelerate the processing time and utilize memory efficiently. SOTA approaches decompose a graph into fixed-size submatrices and compress it by applying the existing graph compression algorithm. This approach is promising if the input graph is dense. Otherwise, an optimal graph compression ratio cannot be achieved. Graphs such as those used by social networks exhibit a power-law distribution. Thus, applying compression to the fixed-size block of a matrix could lead to the empty cell processing of that matrix. In this paper, we solve the problem of ordered matrix compression on a deep level, dividing the block into sub-blocks to achieve the best compression ratio. We observe that the ordered matrix compression ratio could be improved by adopting variable-shape regions, considering both horizontal- and vertical-shaped regions. In our empirical evaluation, the proposed approach achieved a 93.8% compression ratio on average, compared with existing SOTA graph compression techniques.

Design, Development and Evaluation of Gastroretentive Drug Delivery System of Antacids

Magaldrate is an antacid have been widely used in the treatment of various gastric and duodenal disorders such as heartburn, reflux esophagitis, acid indigestion, gastritis, sour stomach, upset stomach, irritable stomach, gastric and duodenal ulcers. The conventional antacids dosage forms have a short duration of action which is about 2-3 hours due to gastric emptying process. A gastroretentive dosage form of antacid is needed since the healing of gastric ulcers occurs when gastric pH is kept above 3-4 during 24 hours. The present study was aimed at developing Gastro retentive bilayer drug delivery systems containing Magaldrate to minimize the side effect, improve the prolongation of action, to reduce the frequency of drug administration. A wet granulation technique was used to formulate 9 batches. Superdisintegrants like Polyplasdone XL-10, Ac-Di-Sol, and sodium starch glycolate was used for immediate release layer and HPMC K4 M, Ac-Di-Sol and lactose like polymers were used in floating layer. Preformulation studies were carried out to optimize the ratios required for various grades of polymers. The prepared floating tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, buoyancy lag time, total floating time, water uptake (swelling index), and in vitro dissolution studies. Successful formulation was developed having floating lag time as low as 30 sec and drug release was sustained up to 12 hrs. A biphasic drug release can be obtained by using bilayer tableting technology which involved compression of immediate and sustained release layer together. Bilayered floating tablets with release characteristics offer critical advantages such as, site specificity with improved absorption and efficacy. This technology can be inculcated to various medicaments which have stomach as the major site of absorption.
 Keywords: Magaldrate, Antacid, Gastroretentive dosage form, Bilayer floating tab, Superdisintegrant

Impact of food viscosity on in vitro gastric emptying using dynamic and semi-dynamic models

Viscosity has been shown to affect food breakdown and nutrient release in the gastrointestinal tract, and the subsequent postprandial glycaemic response and satiety. However, the correlation between food viscosity and gastric emptying is not fully understood. This study investigated the in vitro gastric emptying behavior of peanut butter with different viscosities using semi-dynamic and the artificial gastric digestive system (AGDS) models. Results from both digestion models showed that high viscosity peanut butter had a slower pH decrease, higher buffering capacity, slower phase separation of gastric chyme and less protein hydrolysis and lipid digestion than the control and low viscosity groups. However, the AGDS displayed slower gastric emptying rate, smaller chyme particle size and less proteolysis than the semi-dynamic model, particularly in the high-viscosity group (e.g. ∼60% of gastric emptying rate for AGDS and ∼20% for semi-dynamic model at 120 min), due to the different mechanical shearing forces and gastric emptying patterns in these two models. This study demonstrated the role of food viscosity on the gastric emptying process, and it also suggested that viscosity should be taken into account when designing future functional foods with particular structure.

A Review on Techniques and Applications of Gastroretentive Drug Delivery System

A Controlled release dose forms have been widely utilized to enhance treatment with a number of significant medications. However, a number of physiological challenges, including the inability to control and localize the system within the target region of the gastrointestinal tract and the extremely changeable nature of the gastric emptying process, pose challenges to the development processes. The bioavailability and periods needed to reach peak plasma levels may be unpredictable as a result of this diversity. The goal of this review on gastro retentive drug delivery systems was to gather the most recent research with a special emphasis on the numerous gastro retentive technologies that have lately emerged as leading approaches in the area of site-specific oral controlled release drug delivery. We have included crucial elements in order to comprehend numerous physiological challenges to achieve stomach retention.

Formulation and Evaluation of Sustained Release Microcapsule of Metronidazole

The oral conventional metronidazole dosage forms have a short duration of action due to gastric emptying process, hence the treatment of ulcus pepticum using metronidazole become less effective. Due to retaining the dosage form in the stomach, a preparation form of sustained released drug delivery systems has been developed. The aim of this study was to developed a sustained released drug delivery systems of metronidazole using alginate and chitosan as polymers that could last longer in stomach. The formulation consisted of variatons in chitosan 0.5%, 0.75% and 1%. The drug released test was carried out using paddle method in simulated gastric medium pH 1.2 at 37°C. The dissolution test results showed that formula with 0.75% of chitosan giving the best sustained released effect and the kinetics drug realeased of microcapsule followed Higuchi order. Based on the results of the study, it can be concluded that microcapsules of metronidazole with a combination of alginate and chitosan can be prepared as sustained released formulation.

Preparation, optimization and in vivo study of gastric floating tablets of constunolide and dehydrocostus lactone with ideal therapeutic effect on gastric diseases

Costunolide (COS) and dehydrocostus lactone (DEH), as natural phytochemical components, mainly originated from Aucklandiae radix (AR) and Vladimiriae radix (VR) used in the treatment of gastric diseases in traditional Chinese medicine. The α-methylene-γ-butyrolactone ring structure is the same active part of COS and DEH, and shows good curative effects, such as breast cancer, leukemia and gastric related diseases. Furthermore, the previous research of the lab team found that the combination of COS and DEH promoted the repair of gastric ulcer and effectively alleviated intestinal metaplasia of gastric mucosa. Nevertheless, the rapid gastric emptying process and inefficient gastrointestinal absorption resulted in low oral bioavailability of COS and DEH. Based on floating and swelling technology, this study developed a gastric floating drug delivery system for prolonging gastric residence time to delay the drug release in the stomach and enhance the bioavailability of COS and DEH. The gastric floating tablets of COS and DEH were prepared by the direct powder compression method, and the optimized formulation contained 30% HPMC K15 M and 10% NaHCO3. The results of response variable showed that the floating lag time was 13.50 ± 1.87 s, total floating time was 11.83 ± 0.41 h, 2 h and 12 h cumulative drug release was 29.87 ± 2.22%, 70.89 ± 4.27%, respectively. Additionally, the physicochemical properties of the floating tablets were characterized by friability, hardness, weight variation, Fourier transform infrared spectrum (FT-IR), differential scanning calorimeter (DSC) and X-ray diffraction (X-RD). The study on release kinetics showed that the drug release mechanism of gastric floating tablets of COS and DEH was both diffusion and matrix erosion. Moreover, scanning electron microscope (SEM), swelling and erosion indexes studies further explained the release mechanism. Furthermore, in vivo X-ray imaging of male New Zealand rabbits proved the gastric retention effect of the gastric floating tablets in the stomach (10 ± 3.46 h). The results of these experiments demonstrated that the gastric floating tablets of COS and DEH had the potential for a good gastric residence time and sustained release effect.

A multi-trip electric bus routing model considering equity during short-notice evacuations

Widespread use of electric vehicles (EVs) and electric buses (EBs) adds new challenges to short-notice evacuations. Studies modeling EV behavior suggest that the power grid in most cases cannot handle EV demand during the evacuation preparation stage, but ignore the potential efficiencies of coordinated EBs. To overcome this shortcoming, a generalized framework based on three multi-trip EB routing models is developed to a) estimate the feasibility of using EBs during short-notice evacuations by examining evacuation efficiency, b) analyze EB charging behavior considering evacuation efficiency and path assignment equity, and c) explore the economic advantages of using EBs by comparing EBs with conventional liquefied natural gas (LNG) buses in terms of efficiency and operational cost. A genetic algorithm with an improved recombination strategy (GA-IR) is developed to solve these models. Computational results show that GA-IR outperforms GA in terms of convergence speed and solution quality, as GA-IR takes into account the empty trip removal process and the charging station re-insertion process, which is an innovation of GA-IR. Sensitivity analysis shows that using k-means clustering to position charging stations, and increasing the number of charging stations and EBs can improve evacuation efficiency.

Sustainable Livelihoods of Boarding House (Indekos) Entrepreneurs in Sleman Regency During the Covid-19 Pandemic

Sleman Regency, known as the Student City, is greatly affected by the mobility restriction policy which results in a gradual emptying process of boarding houses, so there is an urgency for regional studies regarding the impact of the pandemic on the livelihoods of boarding house business actors in Sleman Regency. In addition, there is no latest policy from the regency government to overcome the said impact other than the policy of implementing health protocols. Hence, the study focuses on the living conditions and livelihood strategies of boarding house entrepreneurs who are heavily affected by the Covid-19 pandemic. The paper aimed to look at two points of view, namely the bottom-up approach to see the affected objects related to changes in the livelihood strategies of boarding house entrepreneurs during the Covid-19 pandemic and the response of business actors in dealing with shock due to the pandemic; and the top-down approach to see the parties who have legal authority by conducting a critical study of the policies at the regency level related to boarding house business actors before and during the Covid-19 pandemic. This research found that there were changes in the assets and livelihood strategies of entrepreneurs which varied following the capacity of the boarding house entrepreneur. Whereas based on a top-down point of view; despite the change in social assistance policies in terms of the type of assistance, targets, and the amount of assistance provided before and during the Covid-19 pandemic; there is no social assistance that is directed specifically to boarding house business actors.

Recent Advance in Gastroretantive Drug Delivery System (GRDDS)

The drug delivery system is most important and preferable drug delivery system. This route has high patient acceptability, primarily due to easy of administration. Effective oral drug delivery depends upon the factors such as gastric emptying process, the gastrointestinal transit time of the dosage form drug release from the dosage form, and site of absorption of drug. In recent years, scientific and technological advancements have been made in the research and development of gastro retentive drug delivery systems. Hence forth a wide spectrum of dosage forms has been developed for the drugs which have narrow absorption window, unstable at intestinal pH, are soluble in acidic pH, and have a site of action specific to stomach. The purpose of writing this review was to investigate, compile and present the recent as well as past literature in a more concise way with a special focus on approaches that are currently utilized in the prolongation of gastric residence time. These include floating system, swelling and expanding system, bio/mucoadhesive system, high-density system, and other delayed gastric emptying devices. The present review addresses briefly the classification, formulation consideration for Gastroretantive drug delivery system (GRDDS), factors controlling gastric retention, merits, demerits, and applications of gastro retentive drug delivery systems.