A Coupled FEM-BEM Approach for the Solution of the Free-Boundary Axi-Symmetric Plasma Equilibrium Problem

In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.     

Conversion of a renewable bio-resource to a functional composite material: Product design,comprehensive characterization and adsorption of 2,4-D herbicide

Based on the opinion of “utilizing waste resources to treat waste”, a sustainable resource waste was transformed into a useful and functional material by a comprehensive experimental setup. A high surface area lentil processing waste-based activated carbon was synthesized by microwave-assisted K₂CO₃ chemical activation and then successfully converted into a ferrospinel composite. The ferrospinel composite was characterized with BET, FTIR, XRD, XPS, FE-SEM, EDX mapping, Raman and VSM techniques and the detailed characterization analysis confirmed the successful formation of the ferrospinel composite. It was also applied as an effective adsorbent material in the treatment of 2,4-dichlorphenoxyacetic acid herbicide bearing wastewater. The pseudo-second order model better defined the kinetic pathway of the adsorption while the isothermal data indicated the best suitability to Langmuir model. The maximum adsorption capacity of the ferrospinel composite towards 2,4-dichlorophenoxyacetic acid was 400 mg/g at 45 °C. Thermodynamic studies showed the favorability and spontaneity of the adsorption process.     

A novel fMRI paradigm to dissociate the behavioral and neural components of mixed‐strategy decision making from non‐strategic decisions in humans

During competitive interactions, such as predator–prey or team sports, the outcome of one's actions is dependent on both their own choices and those of their opponents. Success in these rivalries requires that individuals choose dynamically and unpredictably, often adopting a mixed strategy. Understanding the neural basis of strategic decision making is complicated by the fact that it recruits various cognitive processes that are often shared with non‐strategic forms of decision making, such as value estimation, working memory, response inhibition, response selection, and reward processes. Although researchers have explored neural activity within key brain regions during mixed‐strategy games, how brain activity differs in the context of strategic interactions versus non‐strategic choices is not well understood. We developed a novel behavioral paradigm to dissociate choice behavior during mixed‐strategy interactions from non‐strategic choices, and we used task‐based functional magnetic resonance imaging (fMRI) to contrast brain activation. In a block design, participants competed in the classic mixed‐strategy game, “matching pennies,” against a dynamic computer opponent designed to exploit predictability in players’ response patterns. Results were contrasted with a non‐strategic task that had comparable sensory input, motor output, and reward rate; thus, differences in behavior and brain activation reflect strategic processes. The mixed‐strategy game was associated with activation of a distributed cortico‐striatal network compared to the non‐strategic task. We propose that choosing in mixed‐strategy contexts requires additional cognitive demands present to a lesser degree during the control task, illustrating the strength of this design in probing function of cognitive systems beyond core sensory, motor, and reward processes.     

Adsorptive removal of lead from aqueous solutions by amine–functionalized magMCM-41 as a low–cost nanocomposite prepared from rice husk: Modeling and optimization by response surface methodology

Amorphous silica that was extracted from rice husk was used to synthesize the magMCM-41 mesoporous silica. This was then functionalized by the APTMS group in order to produce NH₂-magMCM-41 as a novel and low–cost adsorbent. The XRD, VSM, N₂ adsorption–desorption, FT–IR, TGA, SEM and TEM analyses were utilized to characterize the produced materials. In order to optimize the adsorption of the Pb(II) ions, the RSM (response surface methodology) was applied by using the synthesized adsorbent in aqueous solutions. A rotatable CCD (central composite design) was adopted to carry out the experiments and RSM was used to analyze them. Three independent factors namely, initial solution pH (3–7), adsorbent dosage (0.1–2 g L^?1), and initial Pb(II) concentration (15–150 mg L^?1) were used to investigate the removal procedure. According to the obtained results, the initial solution pH of 5.22, adsorbent dosage of 0.1 g L^?1, and initial Pb(II) concentration of 150 mg L^?1 were considered as the optimum conditions with 64.32% removal of Pb(II) and an adsorption capacity of 540.64 mg g^?1. The maximum removal efficiency of Pb(II) ions was found to be 96.76%. The Sips isotherm model represents a better correlation with equilibrium data. It was reported by the kinetic study that data taken from the experiments fitted better to the pseudo–second–order model compared to the pseudo–first–order and intraparticle diffusion models. Finally, according to the thermodynamic study, the removal process strongly depends on temperature, which indicates an exothermic behavior and spontaneous nature of the adsorption.     

高纯度庆大霉素C1a游离碱制备工艺研究

目的 探索用大孔吸附树脂层析法及盐析结晶法精制纯化硫酸依替米星起始物料-庆大霉素C1a成品(HPLC纯度91%~93%)，从而减少由起始物料引入依替米星杂质的水平。方法 以庆大霉素C1a吸附量和庆大霉素C1a纯度为指标，考察大孔吸附树脂纯化庆大霉素C1a的吸附性能和洗脱参数；以盐析后庆大霉素C1a样品纯度和盐析收率为指标，考察盐析工艺最佳温度、溶剂、酸的添加量及酸的种类。结果 获得较优的树脂NM200，获得较优的解析液pH值为2.0和流速0.5BV/h。经过优化后，纯化收率从65%提高至74%。通过盐析结晶条件筛选和优化，确定室温先加溶剂后加硫酸(pH6.5)和甲醇与乙醇1:2的条件较优，优化后获得的庆大霉素C1a纯度达到98.2%，收率大于93%。研究了多种无机酸盐析结晶的情况，发现磷酸、硫酸和碳酸条件下能析出白色固体。结论 通过比较大孔吸附树脂和盐析结晶的纯化连接，组合纯化后获得的庆大霉素C1a游离碱纯度大于99.0%，比纯化前样品提高6%以上，收率大于70%。     

The Selection of a Pharmaceutical Salt—The Effect of the Acidity of the Counterion on Its Solubility and Potential Biopharmaceutical Performance

A roadmap for the selection of a pharmaceutical salt form for a development candidate is presented. The free base of the candidate did not have sufficient chemical stability for development. The initially selected salt form turned out to be undevelopable because it was unstable during scale-up synthesis and storage. The rationale for the new solid form screening and the criteria for selection are discussed. Before the final selection, the pH solubility profiles of the 2 new salts, a benzoate and a besylate, were compared. Atypical solubility behavior was observed for the benzoate salt in hydrochloric acid with and without normal saline. A scheme is proposed illustrating how the pKas of the counterion and active pharmaceutical ingredient, the medium composition, and final pH affect the solubility and solution equilibria of the 2 selected salt forms. This scheme also includes the equilibria between solution and solid phases in different pH ranges. The pharmaceutical importance of this research is that it sheds light on how the acidity of the counterion can affect the solubility of the selected salt form in the gastric environment. With a well-designed formulation strategy, this property potentially can be translated to optimal biopharmaceutical performance of the drug product.     

Drug Solubilization by Means of a Surface-Modified Edible Biopolymer Enabled by Hot Melt Extrusion

A coprocessing/formulation approach for increasing the solubility of poorly soluble drugs using solid dispersions is presented, whereby the active pharmaceutical ingredients (API) retains its crystalline state. The approach uses a biopolymer naturally produced as dendrimeric nanoparticles that has been surface-modified to act as a solubilizing agent. The solubilizing agent is enabled by hot melt extrusion to produce the solid dispersions. Four APIs, phenytoin (PHT), griseofulvin, ibuprofen, and loratadine were used as model compounds to evaluate solubility enhancement. The rank order in solubility enhancement follows that of the hydrophobicity of the APIs. The APIs remained predominantly crystalline after hot melt extrusion processing. However, APIs with weak crystal structure (ibuprofen and loratadine) underwent measurable crystallinity loss. The solubilizing power of the modified biopolymer increases with increasing hydrophobicity and strength of the crystal structure. The solubility is described in terms of a parallel liquid-phase partition-association. For one API (PHT), solubility enhancement was minimal. The dissimilar behavior of PHT is discussed in terms of the polarity match between the API and the hydrophobic microenvironment in the solubilizing agent. This approach is expected to apply to a large number of poorly soluble drugs, offering a complementary approach to existing processing and formulation drug solubilization methods.     

Thermodynamic Estimate of the Number of Solvent Molecules Displaced by a Solute Molecule for Enthalpy-Driven Adsorption: Phenobarbital and Activated Carbons as the Model System

A Modified Crisp Equation, describing the differential Gibbs free energy of the adsorption process, is being proposed, which considers multiple sites available on the surface for adsorption and their relative fractions. The differential Gibbs free energy can be calculated by the van't Hoff Equation, which depends on the affinity constant in the Langmuir-like equation. To consider the number of solvent molecules displaced by a solute molecule in the adsorption process, a new derivative of the Langmuir-like equation is being proposed as well. By comparing the differential Gibbs free energies obtained from the 2 thermodynamic relationships, it can be determined that a phenobarbital molecule displaces 5 water molecules on the activated carbon surface for site-specific adsorption from solution. For the series of experimental conditions studied, including 4 activated carbons, pH effects, temperature effects, and solvent effects, the corrected differential Gibbs free energies using n₁ = 5 for site-specific adsorption are quite consistent between the 2 thermodynamic relationships. The difference between the estimates of the differential Gibbs free energies by the Modified Crisp Equation and the van't Hoff Equation provides a new experimental method to calculate the number of solvent molecules displaced by an adsorbing solute molecule.     

Enmein的平衡溶解度、油水分配系数及环糊精包合作用的研究

目的 测定Enmein的平衡溶解度、油水分配系数,考察环糊精对其包合作用,为制剂研究奠定基础。方法 采用HPLC测定Enmein在不同溶剂中的平衡溶解度;采用摇瓶法测定Enmein在不同条件下的油水分配系数;以羟丙基-β-环糊精（HP-β-CD）、羟丙基-γ-环糊精（HP-γ-CD）2种材料制备Enmein包合物,经溶解度试验,比较溶解性能的变化。结果 （25±0.5）℃振摇24 h,Enmein在纯水中溶解度为（239.32±4.99）μg·mL^-1,在多种常见的有机溶剂中微溶,在常用的药用油溶剂中不溶;正辛醇-水体系中,测得Enmein油水分配系数P为4.64,不同生理pH环境及环糊精材料,对其lgP影响不大;经过2种材料包合后,Enmein的溶解度有所提高,其中以HP-γ-CD的增溶效果最好。结论 Enmein在水、常见的药用油溶剂中溶解性均不好;消化道生理pH变化及包合材料对Enmein的吸收影响不大;用Enmein的HP-γ-CD包合物为原料制备制剂,有利于提高其生物利用度。     

基于博弈论的我国分级诊疗制度分析与政策建议

目的研究我国建立分级诊疗制度的困境以及相关解决政策建议。方法利用博弈论和帕累托改进理论分析促进分级诊疗制度的实施方法。结果分级诊疗的难点在于未能实现帕累托改进,即患者和政府可以在分级诊疗制度中节约成本,但医生并未得到相应的激励,因此,缺乏下沉积极性。结论若能够让政府和患者节省的一部分费用补贴给大医院医生,则这些医生就会下沉到基层医疗机构,即可以实现帕累托改进,建立分级诊疗就医秩序。