Study of eye drops dispensing and dose variability by using plastic dropper tips

The application of eye drops from flexible dropper bottles fitted with different types of dropper tips is associated with the high variability of eye drop weights. The aim of this report was to investigate the simultaneous effect of three factors influencing the mean weight of drops dispensing from two plastic dropper tips. Using a designed experiment (Box-Behnken), the effect of the concentration of benzalkonium chloride solutions (BAC) in the range of 0-0.02%, the dispensing angle from 90° to 30° from horizontal, and the residual volume of liquid in the dropper bottle from 4 to 10 mL on the mean drop weights were examined. The significant effect of the increase in BAC concentration resulted in a linear decrease in drop weights for both of the dropper tips investigated. The significant effect of the dispensing angle was influenced by the dropper tip design. For the dropper tip A, the effect of the dropper tip tilt was described by the quadratic equation with a minimum, which corresponded to the dispensing angle equal to that of 48° from horizontal. Below this angle, the increase in drop weights occurred due to the drop formation from the wetted external surface of the tip orifice. The linear decrease in drop weights in response to the decrease in dispensing angle was detected for the dropper tip B. The regression equations and the contour line plots obtained allowed the drop weights to be estimated for the actual combinations of both the BAC concentration and the dispensing angle. The effect of the residual volume was found to be non-significant. Based on the formula of Tate's law, the direct proportion between surface tension of a solution and the radius of the effective perimeter of a dropper tip can be used to estimate the theoretical maximal weight of drops at the dispensing angle of 90°. Using the stalagmometric values of surface tension of the BAC solutions, the maximal drop weights were estimated for both of the dropper tips investigated. A comparison between the theoretical and the experimentally measured drop weights enabled the dropper tips behavior to be discussed by using Harkins and Brown correction factor F. The F-value of 0.74 noted for the dropper tip A differed from that of stalagmometer F-value (0.61) indicating a deviation from the simple drop formation process in answer to more complicated design of the dropper tip A. On the other hand, the F-value of 0.6 observed for the dropper tip B demonstrated the better consistency with stalagmometry. As a result, the dropper tip B with the linear decrease of drop weights in response to the increased concentration of BAC and the decreased dispensing angle without the adverse external drop formation could be recommended in real drop dispensing.     

差分拉曼光谱对眼药水塑料瓶的分类研究

目的 建立一种便捷精准无损检验眼药水塑料瓶的方法。方法 使用便携式差分拉曼光谱仪检测33个塑料眼药水瓶,根据获得的各样品数据,包括差分拉曼光谱图的峰位、峰数等对样品进行成分分析,并通过统计分析软件“统计产品与服务解决方案”(SPSS 26.0)对样品进行K均值聚类,利用轮廓系数优选K值。对分类结果中样品数目较多的一类样品进行填料分析,利用皮尔逊相关系数验证分析结果的准确性。结果 样品主要成分为聚乙烯和聚对苯二甲酸乙二醇酯,利用轮廓系数优选K值为2,K均值聚类算法对样品的分类结果与成分分析结果能够相互印证。以聚乙烯类样品为例,根据填料不同可将其分为7组。皮尔逊相关系数计算结果能够证明上述分类分组结果可靠。结论 利用该方法能够准确无损地检测眼药水塑料瓶,并对其进行分类研究。     

荧光剂–示踪液体法检查滴眼剂包装密封完整性

目的 建立一种荧光剂–示踪液体法检查利巴韦林滴眼液包装系统的密封完整性,为滴眼剂产品包装密封完整性验证提供通用廉价的方案。方法 以罗丹明B为示踪剂,采用高效液相色谱–荧光检测器法进行检测,评价利巴韦林滴眼液货架期的密封性,以及模拟临床开启后的密封性。结果 此方法可准确检测包装材料中发生的5 μm孔径泄漏,检测限级别达到《化学药品注射剂包装系统密封性研究技术指南》(试行)中的3级,能有效评价利巴韦林滴眼液包装系统的密封完整性。结论 该方法的通用性强、灵敏度高,可为滴眼剂产品包装系统密封完整性检查提供技术支持。     

非职业投资者利用综合收益信息的眼动研究

目的通过眼动研究深入考察非职业投资者利用综合收益信息的过程,以及列报方式对估值决策的影响。方法采用眼动技术追踪了综合收益列报的"一表法"和"两表法"下86名MBA学生信息获得、认知和利用的过程。结果 (1)非职业投资者按照呈报的顺序阅读财务报告,证实了"顺序搜寻"信息策略。(2)列报方式不影响信息的获得,但显著影响综合收益信息区域的注视点时长、注视点个数和观察时长。(3)"一表法"下非职业投资者能更好地识别综合收益增长与公司投资价值之间的关系。结论列报方式通过信息认知来影响信息利用,"一表法"有利于非职业投资者改善估值决策。     

塑性变形诱发表面自纳米化的研究及其应用

详细介绍了强烈塑性变形诱发表面自纳米化的研究进展,即形变诱发表面自纳米化的方法与设备、表面自纳米化层的结构及其表征、形变诱发表面自纳米化的机理及其相关应用,并展望了形变诱发表面自纳米化的研究与应用.     

大视场自由曲面复眼设计研究

在大视场小体积的人造复眼结构中,倾斜的边缘子眼成像时存在较大的轴外像差。提出一种复眼结构,利用光线在子眼中的折转与自由曲面矫正像差,提高了边缘子眼的成像质量,进而增大了复眼结构的视场角。设计出5组子眼对180°视场成像,每组对应特定的视场范围。利用光学仿真软件CodeV对5组子眼分别做了光学仿真,得到了各组子眼的像差曲线,光学传递函数MTF曲线。结果表明,在整个180°视场范围内,频率为100 lp/mm时,MTF值均大于0.2,畸变在30%以内,复眼具有良好的成像质量。     

Using response surface methodology to assess the effects of iron and spent mushroom substrate on arsenic phytotoxicity in lettuce (Lactuca sativa L.)

The effects of iron (Fe) and spent mushroom substrate (SMS) arsenic (As) phytotoxicity towards lettuce in artificial soils were investigated to separate the adverse soil parameters relating to As toxicity using a response surface methodology. SMS induced the root elongation of lettuce in both control and As-treated soils. However, in phytotoxicity test using a median effective concentration (EC₅₀) of As, Fe and the interaction between both parameters (Fe*SMS) significantly affected EC₅₀, which explained 71% and 23% of the response, respectively. The refined model was as follows: EC₅₀ of As (mg kg⁻¹) = 10.99 + 60.03 × Fe − 10.50 × Fe*SMS. The results confirmed that the soil parameters relating to the As mobility in soils were important factors affecting its toxicity. In conclusion, Fe significantly reduced the As phytotoxicity. However, although SMS enhanced the root elongation, SMS in As-treated soils decreased EC₅₀ of As on the root growth via its interaction with Fe. Despite the limitations of the artificial soils and range of parameters studied, the application of this statistical tool can be considered a powerful and efficient technique for interpretation and prediction of the complicated results caused by the interactions between many factors within the soil environments.     

基于响应面分析的结构参数对蒸汽喷射泵性能的影响

为了更准确地优化蒸汽喷射泵的结构参数, 提高喷射泵的性能, 选取A (喉径比) 、B (扩散器锥度) 、C (喉管长度与直径的比值) 、D (喷嘴距) 为优化变量, R (引射系数) 为目标响应, 将数值模拟法与响应面法相结合, 建立了能够较好反映各优化变量对引射系数的响应回归模型。通过方差分析和分析建立的响应面3D图, 得出:喉径比、扩散器锥度以及喷嘴距对喷射泵性能有显著影响, 且喉径比与扩散器锥度都与喷嘴距有较显著的交互作用, 借助Design Expert软件优化后得到在考虑这些交互作用下的最优结构参数组合为:A=0.11, B=8.75°, C=3, D=36 mm。研究结果为准确的选取蒸汽喷射泵的结构参数, 提高喷射泵的性能提供了新方法。     

Optimization,Kinetics, and Equilibrium Studies on the Removal of Lead(II) from an Aqueous Solution Using Banana Pseudostem as an Adsorbent

Natural adsorbents such as banana pseudostem can play a vital role in the removal of heavy metal elements from wastewater. Major water resources and chemical industries have been encountering difficulties in removing heavy metal elements using available conventional methods. This work demonstrates the potential to treat various effluents utilizing natural materials. A characterization of banana pseudostem powder was performed using environmental scanning electron microscopy (ESEM) and Fourier-transform infrared (FTIR) spectroscopy before and after the adsorption of lead(II). Experiments were carried out using a batch process for the removal of lead(II) from an aqueous solution. The effects of the adsorption kinetics were studied by altering various parameters such as initial pH, adsorbent dosage, initial lead ion concentration, and contact time. The results show that the point of zero charge (PZC) for the banana pseudostem powder was achieved at a pH of 5.5. The experimental data were analyzed using isotherm and kinetic models. The adsorption of lead(II) onto banana pseudostem powder was fitted using the Langmuir adsorption isotherm. The adsorption capacity was found to be 34.21 mg·g^–1, and the pseudo second-order kinetic model showed the best fit. The optimum conditions were found using response surface methodology. The maximum removal was found to be 89%.     

Prediction and Minimization of Delamination in Drilling of Medium-Density Fiberboard (MDF) Using Response Surface Methodology and Taguchi Design

In this article, an attempt has been made to predict and minimize the delamination in drilling of medium density fiberboard (MDF). The experiments are carried out on LAMIPAN PB panel based on orthogonal array with feed rate and cutting speed as process parameters. The second order delamination factor models at entry and exit of the holes have been developed using response surface methodology. The parametric analysis has been carried out to study the interaction effects of the machining parameters. Taguchi's quality loss function approach has been employed to simultaneously minimize the delamination factor at entry and exit of the holes. From the analysis of means and analysis of variance, the optimal combination level and the significant parameters on delamination factor are obtained. The optimization results showed that the combination of low feed rate with high cutting speed is necessary to minimize delamination in drilling of MDF.     

Modelling the Effect of Initial Grain Size on Dynamic Recrystallization Using a Modified Cellular Automata and a Adaptive Response Surface Method

A modified cellular automata (CA) model of dynamic recrystallization (DRX) and a flow stress-based nucleation parameter identification method have been developed.In the method,the modified CA model,which takes the role of deformation degree on nucleation behavior into consideration,is coupled with an adaptive response surface model (ARSM) to search for the optimum nucleation parameter.The DRX behavior of an oxygen free high conductivity (OFHC) copper with different initial grain sizes has been taken as an e...     

Using response surface design to determine the optimal parameters of genetic algorithm and a case study

Genetic algorithms (GAs) are efficient stochastic search techniques for approximating optimal solutions within complex search spaces and used widely to solve NP-hard problems. Genetic algorithm includes a number of parameters whose different levels strictly affect the performance of the algorithm. The general approach to determine the appropriate parameter combination of GA depends on too many trials of different combinations, and the best one of them that produces good results is selected for the programme, which would be used for problem solving. A few researchers studied on the parameter optimisation of GA. In this paper, response surface-dependent parameter optimisation is proposed to determine the optimal parameters of GA. Results are tested for benchmark problems that are most common in mixed-model assembly line balancing problems of type-I.     

AZ31镁合金表面气相沉积不锈钢薄膜的实验研究

利用真空蒸发镀膜技术在镁合金表面沉积不锈钢薄膜是提高镁合金防腐性能的新尝试.本研究利用该技术在AZ31上成功制备了不锈钢薄膜.通过在5%NaCl溶液中的浸入实验和极化实验考察了腐蚀性能,发现镀膜后耐蚀性显著降低.另外,镀膜后的显微硬度也未有明显提高.利用AFM,SEM,EDX等分析手段对薄膜进行了观察和检测,发现耐蚀性变差的原因主要是薄膜表面存在贯穿性的微米级孔洞和Cr元素分布不均匀造成的.     

Biosorption of copper ions from aqueous solution by Codium vermilara: Optimization,kinetic, isotherm and thermodynamic studies

In this investigation, the efficiency of Codium vermilara for copper ions removal from aqueous solution was studied. Central Composite Design has been used for the Response Surface Methodology and has been found to be an effective method for investigating the influences of various variables and their interactions on the efficiency of Cu²⁺ ions removal. The interactive impacts of four variables: algal dose, pH, initial concentrations of copper and contact time on the copper removal efficiency were assessed. Algal dose 0.75 g/L, pH 5.28, contact time 70.51 min, and copper concentration 48.75 mg/L were found to be the conditions of optimum biosorption. The efficiency of copper removal was found to be 85.5% under these optimum conditions. Copper removal on the biomass of C. vermilara followed well the kinetics of pseudo-first-order, Elvoish and Intraparticle diffusion. Compared to the other models, Dubinin-Radushkevich isotherm best suited the experimental data revealing that the adsorption mechanism was physical adsorption. Thermodynamic parameters exhibited non-spontaneous, randomness and endothermic biosorption of Cu²⁺ ions. Additionally, the biosorbent characterization was estimated by scanning electron microscopy and Fourier transform infrared analysis. Thus, C. vermilara could be used as possible biosorbent for removing heavy metals and other pollutants from the environment.     

Optimized preparation of nitrogen-doped carbon dots by response surface methodology and application in Cd2+ detection

The technical parameters of synthesizing N-doped carbon quantum dots (N-CQDs) from citric acid and tris(hydroxymethyl)aminomethane (Tris) were optimized using a Box-Behnken model of response surface methodology. Statistical analysis showed the quantum yield was significantly affected by reaction time and Tris weight. The optimal synthesis conditions were reaction temperature at 170?°C, reaction time of 4.50?h and Tris weight of 0.70?g, with the quantum yield up to 82.4%. The N-CQDs probe was further applied for Cd²⁺ detection. The fluorescence intensity and Cd²⁺ concentration were linearly related in the range of 20-300?µg·L^?1 with a relation coefficient of 0.9956 and a detection limit of 20.69?µg·L^?1.     

Design and Analysis of Storing Experiments: A Case Study

In order to achieve robust and stable food products of desired quality and characteristics, all stages of the food production process, including storage conditions, should be considered during product development projects. This article describes a multistage production development project on low-fat mayonnaise, where experimental design was used to set up a pilot plant study involving ingredient factors, processing factors, and storage factors and their effect on mayonnaise viscosity. The article discusses three alternative empirical modeling approaches to analyze the data—namely, a simple graphics approach, a robustness approach, and a mixed models approach—considering their multistratum (split-plot) structure and repeated measurements of each subsample. In the case study, all information relevant for business decisions was obtained through the combination of graphical analysis and the robustness approach. This information could also be extracted by a practitioner, while the mixed model analysis clearly requires a graduate statistician. In order to obtain valid and useful information for the practitioner in an efficient way, the authors believe that, usually, the first two approaches would be sufficient. The more complex mixed model strategy might be advisable if a deeper understanding is required or desired.     

Investigating the effects of feeding properties on rock breakage by jaw crusher using response surface method and gene expression programming

The present study investigates the effects of feeding properties on rock comminution by a laboratory-scale jaw crusher. For this purpose, detailed crushability tests were carried out on four different rock types to assess their degree of rock crushability (DRC). Various feeding sizes (9.5 – 19 mm) and quantities (500 – 1500 g) were adopted to reveal the choke feeding intensity during crushing actions. The efficiency of feeding properties was investigated through the response surface methodology (RSM). The RSM results demonstrated that the characterized feeding size (F₈₀, mm) dominates the general size reduction, whereas the feeding quantity (m_f, g) is associated with the crushing energy consumption and product flakiness. Therefore, the choke feeding intensity has a direct relation to the m_f and F₈₀. In addition, novel gene expression programming (GEP) models were employed to generate empirical formulations to predict the DRC parameters. The established GEP models have a satisfactory estimation capability. Therefore, the DRC of the investigated rocks can be optimized through the proposed GEP models based on the coupling variables of m_f and F₈₀.     

剧烈塑性变形法制备纳米晶材料Ni和Ni／SiO2

剧烈塑性变形法是制备纳米材料的一种新方法。报道由此法制备的纳米晶Ｎｉ和纳米晶复合材料Ｎｉ／ＳｉＯ２的热稳定性和力学性能的研究结果。     

Co2+、C共掺杂纳米TiO2光催化降解苯酚的研究

以钛酸丁酯、硝酸钴和葡萄糖为原料,采用溶胶凝胶法制备钴、碳共掺杂的纳米Co-C/TiO_2催化剂,通过X射线衍射(XRD)和紫外可见漫反射光谱(UV-vis)表征分析,鉴定样品的晶型,估算晶粒大小以及测定样品的光学性能,并计算带隙能。结果表明,Co-C/TiO_2催化剂仍然以锐钛矿型存在,晶粒尺寸约为12.08nm;催化剂的带隙能降低,吸收带边发生红移。在紫外光照下,考察光照时间、催化剂用量、苯酚初始浓度和pH值等因素对Co-C/TiO_2光催化降解苯酚的影响。利用响应面优化设计及降解模型拟合,得到降解苯酚的最佳条件为:加入0.05g催化剂,初始浓度为17.44μg/mL,pH=5.68,此时苯酚降解量最大可达15.67mg/g。     

超微马达实用化技术及在医用内窥镜中的应用研究

介绍和总结了超微马达 (直径 12mm)的实用化关键技术 ,并应用超微马达研制了一种新型医用内窥镜系统。通过在目前临床应用的内窥镜前端装上一个超微马达 ,驱动一可用形状记忆合金调整角度的光学反射镜作低速 36 0°旋转 ,扩大了传统内窥镜的侧向观察视野 ,并减少了内窥镜对人体组织造成的意外损伤和给病人带来的痛苦 ,实现了内窥镜前端操作的自动化。超微马达在医用内窥镜中的应用表明了超微马达已从研究阶段步入实用化阶段