Biphasic Drug Release from Rolled-Up Gelatin Capsules with a Cylindrical Cavity

Biphasic drug delivery systems are used for quick release of a specific amount of drug for immediate amelioration of a patient’s state, followed by sustained release, to avoid repeated administration. This type of delivery is often necessary for pain management and the treatment of many pathologies, such as migraines, hypertension, and insomnia. In this work, we propose a novel architecture of a biphasic release media that does not need the rapidly disintegrating layer and that allows for easily setting the sustained release rate. A drug-containing capsule is made by rolling up a thermally crosslinked gelatin strip on which drug reservoirs are formed by casting. The quick-release reservoir (QRR) is placed at the strip’s extremity, from which the rolling starts, while the sustained-release reservoir (SRR) is formed in the middle part of the strip. The strip is rolled around a cylinder that is a few millimeters wide, which is removed after rolling. The roll is stabilized by transglutaminase-catalyzed crosslinking of the consecutive shells. A biphasic release is successfully demonstrated with the use of model fluorescent drugs for single-dye and double-dye systems in phosphate-buffered saline (PBS) solution with pH = 7.4. In vitro, the drug from the QRR, placed at the walls of the cavity of the roll, is released immediately upon the capsule’s contact with the PBS solution. The drug from the SRR, embedded between the roll’s layers, diffuses steadily, with the lag time defined by the radial position of the reservoir.

The Design Of A Quick Release Attachment Mechanism For A Hydrofoil Board

<div>The primary objective of this project was to design a quick attach and detach system for use with a surfing foilboard. Foilboards are comprised of a board, mast, and fuselage, onto which wings are attached. These components are generally held together by long bolts, which makes the overall board tedious to assemble and disassemble. Research was conducted on the general concept of attaching components rigidly as well as on the market of current foilboard quick attach mechanisms, and a series of conceptual designs were created from it. All design concepts were rated using metrics generated from both the project objectives and market research, and the top-rated concept was then drawn up in Solidworks. Several design iterations were developed in order to meet both the minimum 300g weight, tensile and compressive strength, and attachment/detachment speed requirements. The design iterations were first validated using a series of Solidworks simulation analyses. Subsequently the final design candidate was analysed using a series of ANSYS Static Structural simulations. The final design can withstand the loads and torques during regular usage as well as cases of the rider standing on the side of the mast while the board is at rest. The design can be attached or detached within one second. It can survive up to 8.769x105 cycles of maximum cyclical loading and is easy to clean.</div>

The Design Of A Quick Release Attachment Mechanism For A Hydrofoil Board

<div>The primary objective of this project was to design a quick attach and detach system for use with a surfing foilboard. Foilboards are comprised of a board, mast, and fuselage, onto which wings are attached. These components are generally held together by long bolts, which makes the overall board tedious to assemble and disassemble. Research was conducted on the general concept of attaching components rigidly as well as on the market of current foilboard quick attach mechanisms, and a series of conceptual designs were created from it. All design concepts were rated using metrics generated from both the project objectives and market research, and the top-rated concept was then drawn up in Solidworks. Several design iterations were developed in order to meet both the minimum 300g weight, tensile and compressive strength, and attachment/detachment speed requirements. The design iterations were first validated using a series of Solidworks simulation analyses. Subsequently the final design candidate was analysed using a series of ANSYS Static Structural simulations. The final design can withstand the loads and torques during regular usage as well as cases of the rider standing on the side of the mast while the board is at rest. The design can be attached or detached within one second. It can survive up to 8.769x105 cycles of maximum cyclical loading and is easy to clean.</div>

Insights Gained from an Approximate Analytical Solution of the Evaporation Model Used by ConsExpo Web

Evaporation of chemicals is an important source of inhalative exposure. We analyzed here the ConsExpo evaporation model, which is characterized by a set of nonlinear differential equations only solvable by numerical means. It shows qualitatively different behavior for different parameters, but the exact conditions remain unclear. This article presents an approximate analytical solution of the ConsExpo evaporation model, derived by using a specific linearization of the nonlinear equations valid for small concentrations. From this solution, three different boundary cases or regimes are found: quick release, near equilibrium, and ventilation driven regime. Depending on the evaporation regime, different parameters influence peak substance air concentration: Quick release regime: total substance amount and room volume; near equilibrium regime: vapor pressure, substance concentration in the product, and molecular weight of the product matrix; ventilation driven regime: vapor pressure, substance concentration in the product, room volume, surface area, mass transfer coefficient, ventilation rate, and molecular weight of the product matrix. A graphical method is developed to display the position of a given scenario in relation to the three regimes. Thus, the approximate analytical solution allows for a given situation to prioritize research for reducing uncertainty of the most sensitive parameters and helps to identify promising risk management measures.

The nitrogen topdressing mode of indica-japonica and indica hybrid rice are different after side-deep fertilization with machine transplanting

Determination of the optimal fertilization method is crucial to maximize nitrogen use efficiency and yield of different rice cultivars. Side-deep fertilization with controlled-release nitrogen, in conjunction with machine transplanting and subsequent topdressing, was applied to Indica–japonica hybrid rice ‘Yongyou1540’ (YY1540) and indica hybrid rice ‘Tianyouhuazhan’ (TYHZ). Four nitrogen treatments were applied in 2018 and 2019: traditional nitrogen application with quick-release nitrogen (T1), single-dose deep fertilization at transplanting with 100% controlled-release nitrogen (T2), and deep fertilization of 70% controlled-release nitrogen and topdressing of 30% quick nitrogen at tillering (T3), or at panicle initiation (T4). Side-deep fertilization reduced the fertilizer application frequency without causing yield loss, T4 enhanced the yield of YY1540 by increasing the number of productive tillers and number of spikelets per panicle compared with T1, T2 and T3. The yield of TYHZ showed no significant difference among treatments. The T4 treatment decreased the number of tillers at the tilling peak stage and increased the percentage productive tillers and number of differentiated spikelets. Compared with the other treatments, T4 increased dry matter accumulation and leaf area index during panicle initiation and grain ripening, and contributed to enhanced nitrogen uptake and nitrogen utilization in YY1540. On average, nitrogen uptake and utilization in YY1540 were highest in T4, but no significant differences among treatments were observed in TYHZ. Dry matter accumulation and nitrogen uptake from panicle initiation to heading of YY1540 were correlated with number of spikelets per panicle, but no significant correlations were observed for TYHZ. Supplementary topdressing with quick-release nitrogen at the panicle initiation stage was required to increase yield of indica–japonica hybrid rice, whereas single-dose deep fertilization with controlled-release nitrogen is satisfactory for the indica hybrid cultivar.

Application of conical profile spindle-mandrel joints in multi-purpose machines

The article deals with the solution of the problem of improving the quality of torque transmission connections of spindle units of multi-purpose machines. The aim of the work is to determine the contact stiffness of the spindle-mandrel joints of various types, based on the conducted simulation experiments of the assembly and disassembly process of auxiliary tools of various structural forms, in conditions of reusable replacements. A comparative analysis of the mathematical expectations of contact stiffness of traditional and non-traditional conical profile split joints based on an equiaxial contour with a number of faces equal to three under external loading conditions is performed. The results obtained allow us to predict the quality indicators of multi-purpose machines in the design of quick-release connections