Surface Characterization of Mixed-mode Adsorbents using BET C-Constant Energy Scale

Mixed-mode chromatography is a chromatographic method in which solutes interact with stationary phase through more than one interaction mode or mechanism. It is because of these multiple complex interactions, which makes it difficult to predict chromatographic behavior of analytes on Mixed-mode columns. In order to fully understand the retention mechanisms on Mixed-mode columns, the packing material properties must be well characterized since each characteristic may contribute to the overall chromatographic performance of the column. Many non-chromatographic and chromatographic techniques are available to characterize and compare Mixed-mode columns in terms of their interaction abilities, retentivity, surface chemistry, chemical properties and geometry. Characterization of different Mixed-mode columns on the basis of interaction energy characteristics has not been explored. In this study, different ratios of porous silica (Axia Luna Silica) and C18 (Axia Luna C18), which are commonly used single mode adsorbents were blended in various ratios to simulate Mixed-mode materials and analyzed by Low Temperature Nitrogen Adsorption (LTNA). Adsorption isotherms, surface area, and BET C-Constants were obtained for all the blended materials and a linear relationship between the BET C-Constant and the blend ratio of silica has been observed. A new BET C-Constant energy scale was created from a plot of non-specified average interaction energy vs. percent silica surface. A variety of commercially available Mixed-mode columns were unpacked and the materials were analyzed by LTNA in order to explore the use of the BET C-Constant energy scale as a universal indexation system to characterize Mixed-mode materials. Adsorption isotherms, surface area, and BET C-Constants were obtained for all the commercial Mixed-mode materials. The non-specified average interaction energy and the equivalent percent silica surface was calculated from the BET C-Constant and plotted on the BET C-Constant energy scale to enable Mixed-mode column comparison based on average interaction energy. The data in this research project suggests that the BET C-Constant may be a viable parameter that can be used to characterize commercial Mixed-mode columns on the basis of average interaction energy. Utilizing this BET C-Constant energy scale in conjunction with the study of retention behaviors on Mixed-mode material could lead to improvements in the understanding of method development on Mixed-mode columns, allow the comparison and selection of commercialized Mixed-mode columns, and even predict retention behavior of analytes in Mixed-mode columns

The staining pattern of brilliant blue G during macular hole surgery: a clinicopathologic study

Purpose.: To describe the intraoperative staining pattern of the internal limiting membrane (ILM)-specific dye Brilliant Blue G (BBG) in a cohort of patients with idiopathic macular holes; to analyze the associations of the staining pattern with pre- and postoperative variables and to correlate the staining pattern with transmission electron microscopy (TEM) of the excised ILM. Methods.: Fifty-five consecutive patients were studied. The staining pattern was divided into three subtypes based on the intraoperative appearance. The presence of a narrow rim of nonstaining around the macular hole (MH) edge was noted and measured. In the final 21 patients, the excised ILM was examined with TEM. Results.: The pattern of staining observed was categorized as uniform in 33 patients (60%), patchy nonstaining in 17 (31%), and no visible staining in 5 (9%). The staining pattern correlated with the MH stage. In the patients with uniform or patchy staining, a nonstaining rim was observed in 26 (52%) of the 50. The presence of a rim was associated with a greater hole diameter and lower postoperative visual acuity. The stain pattern correlated significantly with the amount of cellular tissue on the vitreous side of the ILM on TEM, with a greater proportion of multicellular layer membranes and new collagen in the incomplete staining groups. Conclusions.: A variety of nonstaining patterns around macular holes can be observed using BBG, and these patterns correlate to the amount of cellular tissue on the vitreous side of the ILM seen histologically. These patterns could be used to guide the ILM peeling requirement or extent in future studies

Improving Students’ Acquisition of Science Process Skills in Biology Subject: Moving Towards a Learner-Centred Classroom

The purpose of this study was to investigate the effect of inquiry-based learning (IBL) on students’ level of acquisition of integrated science process skills (ISPS) in Biology subject. The objective of the study was to determine the difference between students’ level of acquisition of ISPS when taught using IBL approach and Traditional Learning approach (TL) in Biology. The Non-equivalent Control Group Post- test only Design was employed in the study as a quasi experiment. The study was carried out in Kesses Sub County of Uasin-Gishu County, Kenya where there has been persistent low achievement in Biology subject at KCSE level. The study sample comprised of 116 students selected from form three students from two mixed day secondary schools. The sampling techniques used were stratified, systematic and simple random sampling. The experimental groups received instructions through use of IBL approach and control groups using the TL approach. Biology Integrated Science Process Skills Questionnaire (BISPSQ) was used for data collection. The results of the study indicated that students in the experimental groups outperformed the control groups in the acquisition of selected science process skills. It was concluded that IBL had a positive output on students’ acquisition of integrated science process skills than the TL method. Teachers and students of Biology in Kenya should be encouraged to incorporate IBL in teaching and learning so as to enhance the acquisition of integrated science process skills. Keywords: Inquiry-Based Learning (IBL); Acquisition of Biology Integrated Science Process Skills and Biology subject

Motivating Factors, Barriers, and Success Factors among Agri-based Micro- and Small-scale Women Entrepreneurs in Isabela, Philippines

In recent years, a number of women have started agribusiness enterprises in Isabela, Philippines, such as the production and retailing of dominant agricultural products like rice and corn, livestock and poultry raising, and the processing of root crops into native delicacies. This study aims to examine the motivating factors, start-up barriers, and success factors among micro- and small-scale women entrepreneurs in selected areas in Isabela, Philippines. A survey was conducted among 46 women entrepreneurs whose businesses were based in the cities of Ilagan and Cauayan and the town of Roxas. Descriptive statistics, factor analysis, and chi-square analysis were employed to analyze the data. In terms of their personal entrepreneurial competency (PEC) profile, the women entrepreneurs were found to be moderate (i.e., scoring 16–18 out of a possible 25) in terms of opportunity-seeking, demand for quality and efficiency, systematic planning and monitoring, persuasion and networking and self-confidence and weak in the area of goal-setting. Women entrepreneurs were motivated to establish a business by the following factors: achievement, competence, affiliation factor, and job/financial security. On the other hand, the women entrepreneurs faced common start-up problems like lack of training education, unavailability of low-interest loans for capital, and career-family conflict. Meanwhile, two success factors were found to be associated to performance (i.e., micro vs. small-scale): if the entrepreneur had finished a business degree and if their business was the only source of family income. The study recommended that organizations should conduct action-oriented trainings to develop the PECs of Isabela women entrepreneurs. Future studies should consider having a larger sample size

Model of the W3(OH) environment based on data for both maser and 'quasi-thermal' methanol lines

In studies of the environment of massive young stellar objects, recent progress in both observations and theory allows a unified treatment of data for maser and 'quasi-thermal' lines. Interferometric maser images provide information on the distribution and kinematics of masing gas on small spatial scales. Observations of multiple masing transitions provide constraints on the physical parameters. Interferometric data on 'quasi-thermal' molecular lines permits an investigation of the overall distribution and kinematics of the molecular gas in the vicinity of young stellar objects, including those which are deeply embedded. Using multiple transitions of different molecules, one can obtain good constraints on the physical and chemical parameters. Combining these data enables the construction of unified models, which take into account spatial scales differing by orders of magnitude. Here we present such a combined analysis of the environment around the ultracompact HII region in W3(OH). This includes the structure of the methanol masing region, physical structure of the near vicinity of W3(OH), detection of new masers in the large-scale shock front and embedded sources in the vicinity of the TW young stellar object.Comment: To appear in the Proceedings of the 2004 European Workshop: "Dense Molecular Gas around Protostars and in Galactic Nuclei", Eds. Y.Hagiwara, W.A.Baan, H.J. van Langevelde, 2004, a special issue of ApSS, Kluwe

PRIMH – PRI Mathématiques et histoire

Éric Brian, directeur d’étudesGiovanna C. Cifoletti, directrice d’étudesDinah Ribard, maître de conférences Qui a peur des chiffres ? Mathématiques et histoire : lectures de sources Nous avons consacré les premières séances à la discussion des travaux de trois étudiantes : Marie Chauvier et Francesca Aceto inscrites en master et Christelle Serra inscrite en diplôme. Marie Chauvier a présenté le grand ouvrage de Maryvonne Spiesser Une arithmétique commerciale du XVe siècle : le Compendy de la ..

Analysis of the Production and Marketing Operations of Swine Enterprises in the City of San Jose del Monte and Santa Maria, Bulacan, Philippines

Analysis of the production and marketing operations of swine enterprises in two major hog-producing towns in Bulacan was done to assess their status and performance. Seventy-one respondents from the City of San Jose del Monte (CSJDM) and 74 respondents from Sta. Maria, Bulacan, were personally interviewed using a structured questionnaire. Descriptive research design and integrated analysis were employed. Profitability and value chain analyses were also done. Sow-herd and growing-finishing production systems were prevalent in CSJDM and Santa Maria, respectively. Most enterprises in CSJDM were small backyard while those in Santa Maria were small commercial. However, CSJDM swine farms had better production performance though the values in both towns were a little behind the national standard. Santa Maria farms had generally wider market reach than CSJDM farms. The intermediaries were narrowed to wholesalers and processors as production level advanced. Profitability analysis revealed increasing profit with increasing scale of operation. Medium commercial enterprises mostly prevalent in Santa Maria showed the highest average net income. Value addition increased from farm to primary intermediary with increasing scale of operation. Sow-herd farrow to finish enterprises were more profitable than growing-finishing farms. Recommendations to further improve the swine enterprises were formulated. For swine raisers, we recommend clustering municipal hog raisers and traders into a cooperative, increasing production volume, adopting a community-based approach in herd-health improvement, encouraging joint production of commercial and backyard swine farms, and increasing efforts to promote social awareness regarding environmental impact of swine production. For the government, we recommend providing low interest loans, regulating meat importation, increasing campaign against pork meat smuggling, and promoting consumption of locally produced pork

Development and Survivorship of Scirtothrips Dorsalis Hood (Thysanoptera: Thripidae) in Different Growth Stages of Mango and Selected Weeds

The research objective was to quantify the development and survivorship rate of S. dorsalis in different phenological stages of mango and selected weeds. The research was conducted in the laboratory of PT. Trigatra Rajasa, Mango plantation in Ketowan, Arjasa, Situbondo, East Java, Indonesia from February to September 2015. The development and survivorship rate were done through observation of life span of S. dorsalis from egg to pupa. Analysis of Variance and Duncan Multiple Range Test (p = 0.05) with 5 replications were applied to ensure the significant differences among the treatments. The result showed that development and survivorship of Scirtothrips dorsalis were supported by mango flushes and flower as well as some weeds such as Leucania leucochepala, Ipomoea triloba, Achalypha indica, Desmanthus leptophyllus and Azadirachta indica as source of food. Achalypha indica was the most suitable host with development time (12.82 ± 0.21 days) and survivorship (33 %). Weed Tridax procumbent, Momordica charantia and Mimosa pudica were unable to provide the living requirement for immature developmental stage of S. dorsalis