1,721,217 research outputs found
Letter to Editor “Exploring the association between esophageal mucosal inflammation, impaired motility and GERD”: Author’s reply
No full textEvidence of macromolecular structure of humic acids from compost
No full textHumic acids (HA) from compost of domestic-waste origin were characterized by IR and UV-Vis spectra and by elemental analysis. The molecular structure was investigated by treatment with the monocarboxylic acid HCOOH and CH3COOH, dialysis experiments and size-exclusion chromatography (SEC). In contrast to former reports, HCOOH and CH3COOH caused the simple precipitation of HA. SEC experiments gave chromatograms with a broad peak, with an elution volume at the maximum height of the peak very close to that of the globular protein bovine serum albumin, a value slightly above the fractional range of the gel used for SEC tests. The chromatogram profile was found to be independent on HA concentration. The eluted fractions exhibited sharper peaks than the pristine HA sample. It can be concluded that the HA extracted from compost do not consist of relatively small molecules held together by weak intermolecular interactions (as reported in the literature), but rather have a canonical macromolecular structure. The simple approach employed here is proposed as a reference procedure for testing the chemical structure of humic acids of any origin
Diagnosis of Ineffective Esophageal Motility According to Chicago Classification Version 4.0: More Stringent Criteria, but Also New Difficulties
No full textNovel impedance-pH parameters, Mean Nocturnal Baseline Impedance (MNBI) and
Post-Reflux Swallow-Induced Peristaltic Wave (PSPW) index, have been proposed to improve the
gastro-esophageal reflux disease (GERD) diagnostic yield. This study aims to determine the integrity
of the esophageal epithelial barrier and chemical clearance using these novel parameters and to
correlate them with acid exposure time (AET) and acid clearance time (ACT) in obese patients who
are candidates for bariatric surgery (BS). Twenty impedance-pHmetry tracings of patients prior to BS
were reviewed. Nine (45%) patients with a conclusive diagnosis of GERD had significantly higher
ACT, lower MNBI in the distal esophagus and lower PSPW indexes compared to obese patients
without GERD. Moreover, 100% of obese patients with GERD had a pathological ACT compared
to obese patients without GERD (p = 0.003). However, the percentage of pathological MNBI and
PSPW index did not differ between obese patients with and without GERD. The PSPW index and
MNBI of the distal channel significantly correlated with ACT and AET. Further studies are needed
to assess the role of time-consuming novel parameters in the routine evaluation of morbidly obese
patients candidates for BS. The value of acid clearance time is confirmed as a relevant impedance-pH
parameter in these patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Trimethoprim removal from wastewater: Adsorption and electro-oxidation comparative case study
No full textTrimethoprim (TMP) is among the emerging pollutants that cause harmful effects on the aquatic environment and human health if not accurately controlled. This antibiotic is one of the most regularly administered drugs, thus, its contamination of water bodies has received much concern in recent years. In this case study, a comparison between adsorption and electrochemical oxidation was carefully performed to identify the best treatment for removing TMP from impacted water. Adsorption with commercial activated carbon F400 as an adsorbent showed higher TMP removal efficiencies (70.6%) than natural zeolites (17.6%). The experimental data for TMP adsorption onto F400 were well-fitted by the linear form of the Langmuir isotherm (R2 = 0.986). The values of qmax and KL were 18.40 mg g−1 and 1.40 L mg−1, respectively. The pseudo-second order model provided the best correlation with the experimental data. Electrochemical oxidation over two platinum-coated titanium electrodes led to 70.1% TMP removal after 330 min of treatment. The optimal operative conditions were achieved at a concentration of NaCl of 0.04 M and an applied current density of 120 A m−2. Cost estimates for both technologies indicated that electrochemical oxidation of TMP is comparable to adsorption if operating at low current density. Each process presents several advantages and limitations, and the choice of the right approach needs to consider different factors, including the composition of the wastewater and the cost and availability of resources
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