169,855 research outputs found
Synthesis of novel derivatives of resveratrol and screening for potential cancer chemopreventive activities
No full textResveratrol (trans-3,4’,5-trihydroxystilbene) has attracted the attention of the biomedical researchers because of its beneficial physiological effects it produces. Positive effects of resveratrol has been observed in the field of cardiovascular diseases and neurodegenerative disorders. It has been also identified as a potent cancer chemopreventive agent in assays representing the three major stages of carcinogenesis (i.e. tumor initiation, promotion and progression). We have synthesized a variety of Resveratrol analogues by chemical modification of the parent trihydroxy stilbene skeleton. The compounds were screened for cancer chemopreventive potential using a series of bioassays relevant for the prevention of carcinogenesis in humans (inhibition of cytochrome P450 1A; determination of NAD(P)H:quinone reductase activity; scavenging of radicals; inhibition of cyclooxygenase activity; inhibition of NO synthase; antiestrogenic and estrogenic activity)
Synthesis of resveratrol derivatives and in vitro screening for potential cancer chemopreventive activities
No full textNew resveratrol (trans-3,4’,5-trihydroxystilbene) analogs were synthesized and screened for their in vitro cancer chemopreventive potential using various bioassays relevant for the prevention of carcinogenesis in humans: Two assays to detect modulators of carcinogen metabolism (Cyp1A inhibition; determination of NAD(P)H/quinone reductase (QR) activity), three assays to identify radical scavenging and antioxidant properties (DPPH, ORAC, superoxide anion radicals in differentiated HL-60 cells), four assays to determine anti-inflammatory and anti-hormonal effects (iNOS, Cox-1 and aromatase inhibition, anti-estrogenic potential). 3,40,5-Tri-O-methyl resveratrol 1a was about seven-fold more active than resveratrol in inhibiting Cyp1A activity, it was a potent inducer of QR activity, and it showed pure anti-estrogenic activity (whereas resveratrol is a known mixed estrogen (ant)agonist with both estrogenic and anti-estrogenic properties). Dual estrogen ant-/agonist activity was restored in the mono-O-benzyl-substituted derivatives 4b (40-O-benzyl resveratrol) and 5b (3-O-benzylresveratrol). With respect to aromatase inhibition (Cyp19), which provided the highest number of actives, the benzyl-substituted series was more potent than the methyl-substituted derivatives of resveratrol, and 3-O-benzyl resveratrol 5b was about eightfold more active than resveratrol. Overall,
21 3,40,5-tri-O-pivaloyl resveratrol oxide 7c was identified as a potent inducer of phase 2 enzymes
22 concomitant with inhibition of LPS-mediated iNOS induction
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
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Brown seaweed polyphenols as novel antioxidants for better health and food quality
No full textIn the Far East and Pacific, there is a long tradition of consuming seaweeds as sea vegetables, while in western countries the principal use of seaweeds is as source of phycocolloids (eg. thickening and gelling agents for agro-food industry). In Asia, recent epidemiological studies have demonstrated that regular consumption of seaweeds might be related to a reduction of prostate, colorectal and breast cancer risk. Researches carried out on natural products from seaweeds lead to the identification of a variety of antioxidant compounds, among which polyphenolic compounds. Brown seaweeds are particularly rich in polyphenols: from 5 to 15 % of the dry weight. These compounds are made from phloroglucinol units, connected by aryl/aryl bonds (fucols), by aryl ether bonds (phlorethols) or both (fucophlorethols). Some of them contain one additional hydroxyl group at each second ring and a regular sequence of para- and ortho- positioned ether links (fuhalols and pseudofuhalols). In comparison with terrestrial plants, little is known about the antioxidant activity of seaweed polyphenols.
The main objectives of the SEAHEALTH project carried out with financial support from the Commission of the European Communities (“Quality of Life and Management of Living Resources” RTD programme) is to demonstrate benefits of seaweeds antioxidant substances on human health (prevention of atherosclerosis and cancer) and food quality.
This paper presents the results obtained during the first half of the SEAHEALTH project. In a first step, extraction/purification process of seaweed antioxidants was optimised. For comparative reasons and to establish a superior method for polyhenols determination, two quantitative methods were evaluated: Folin Ciocalteu’s and DMBA (2,4-dimethoxybenzaldehyde). Qualitative analysis were performed by 1H NMR and HPLC-MS. Size exclusion chromatography (SEC) was evaluated as a method to separate polyhenols according to their molecular weight. An important antioxidant and scavenging activity of some of the extracts was observed in vitro (DPPH and ORAC tests). The capacity of seaweed extracts to scavenge superoxide anion radical generated during the oxidation of xanthine to uric acid in the presence of xanthine oxidase was measured. The influence of the extracts on carcinogen metabolism was assessed by measuring inhibition of phase I enzyme (cytochrome P450 Cp1A) activity. The anti-inflammatory and the anti-hormonal effects of the extracts were evaluated by measuring inhibition of cyclooxygenase and aromatase activity, respectively. Acute toxicological studies were performed on mice and rats by oral and intraperitoneal routes with two different oral doses of seaweed extracts. Finally, some food products (fruit juices and yoghourts) were formulated from seaweed extracts. Results showed that antioxidant activity was still detectable in formulated products
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration
No full textAccurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post
Get PDFAn article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp
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