117,473 research outputs found
Au/SBA-15 Based Robust and Convenient- to-Use Nanopowder Material for Surface Enhanced Raman Scattering (SERS) with High SERS Enhancement Factor
No full textPowdered nanocomposite materials composed of SBA-15 mesoporous silica and different types of Au nanoparticles within the mesoporous channel pores (Au/SBA-15) are shown to serve as robust and efficient substrates for surface-enhanced Raman spectroscopy (SERS). Using the Au/SBA-15 samples as SERS substrates and 4-mercaptopyridine (4-Mpy) as SERS reporter molecule, SERS enhancement factors as high as ∼105 are obtained. The degree of SERS enhancement is found to depend on the size of the Au nanoparticles as well as the synthetic procedures employed to synthesize the Au/SBA-15 materials. The high SERS enhancement given by the Au/SBA-15 as compared to any other powered SERS substrates appears to be the result of the formation of SERS “hot spots” due to the side-by-side alignment of Au nanoparticles within the cylindrical channel pores of the SBA-15 mesoporous silica host. Because of their powdered forms, longevity, simple sample preparation procedures, easily tunable surface, and high SERS enhancement factors, Au/SBA-15 can also be expected to serve as simple and convenient-to-use substrates for SERS-based analysis of various analytes, besides 4-Mpy. Furthermore, this work demonstrates the synthesis of supported “naked” Au nanoparticles and their use as SERS substrate directly and without any further chemical modification
Assessment of the Diuretic Effect of the Leaves of Cucumis Dipsaceus Ehrenb (Cucurbitaceae) in Rats: Using Aqueous and 80% Methanol Extracts
No full textLishan Asefa,1 Teshome Nedi2 1Department of Biomedical Science, College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia; 2Department of Pharmacology and Clinical Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, EthiopiaCorrespondence: Lishan Asefa, Email [email protected]; [email protected]: The diuretic activity of the Cucumis dipsaceus leaf, which is used in indigenous medicine, has been claimed but has not yet undergone scientific evaluation.Objective: The objective of this study was to assess the diuretic activity of the aqueous and 80% methanol extracts derived from the leaves of Cucumis dipsaceus in rats.Methods: For the extraction process, the maceration technique was employed to obtain the aqueous and 80% methanol extracts from the Cucumis dipsaceus leaves. Male rats were then divided randomly into eight groups, with six rats in each group. These groups consisted of a negative control group, a positive control group, and three different groups for each extract at varying doses. The urine output volumes, the concentrations of urinary electrolytes (sodium, potassium, and chloride) and urinary pH, were measured and analysed to compare the results among the different groups.Results: Both the aqueous and 80% methanol extracts of Cucumis dipsaceus leaves demonstrated a significant increase in urinary output at doses of 200mg/kg body weight (p< 0.01) and 400mg/kg body weight (p< 0.001). When comparing the urinary electrolyte excretion with the negative control group, the groups treated with the 400mg/kg body weight dose of the aqueous extract showed significant differences in the urinary excretion of sodium (p< 0.05), chloride (p< 0.01), and K+ (p< 0.01). Similarly, the urinary excretion of K+ and Cl- also exhibited significant differences at moderate doses (K+: p< 0.01, Cl-: p< 0.05) and the highest doses (both: p< 0.01) of the 80% methanol extract. Furthermore, the highest doses of both the aqueous (p< 0.01) and 80% methanol (p< 0.01) extracts demonstrated significant differences in saluretic effect.Conclusion: Both crude extracts of C. dipsaceus leaves have significant diuretic activity, providing support for the traditional use of the plant as a diuretic agent.Keywords: Cucumis dipsaceus, diuretic activity, electrolyte excretion, Na+/K+ rati
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
Lillian L. Lambert, Author, Speaker, and Entrepreneur
No full textLillian L. Lambert, Author, Speaker, and Entrepreneu
Letter to Alfred L. Shoemaker, February 10, 1948
No full textA handwritten letter from an unknown author addressed to Alfred L. Shoemaker, dated February 10, 1948. Within, the author discusses the Pennsylvania Dutch word for Ash Wednesday, along with traditions associated with this day.https://digitalcommons.ursinus.edu/shoemaker_documents/1118/thumbnail.jp
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