159 research outputs found

    Biocomposite films based on κ-carrageenan/locust bean gum blends and clays : physical and antimicrobial properties

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    The aims of this work were to evaluate the physical and antimicrobial properties of biodegradable films composed of mixtures of κ-carrageenan (κ-car) and locust bean gum (LBG) when organically modified clay Cloisite 30B (C30B) was dispersed in the biopolymer matrix. Film-forming solutions were prepared by adding C30B (ranging from 0 to 16 wt.%) into the κ-car/LBG solution (40/60 wt.%) with 0.3 % (w/v) of glycerol. Barrier properties (water vapour permeability, P vapour; CO2 and O2 permeabilities), mechanical properties (tensile strength, TS, and elongation-at-break, EB) and thermal stability of the resulting films were determined and related with the incorporation of C30B. Also, X-ray diffraction (XRD) was done in order to investigate the effect of C30B in film structure. Antimicrobial effects of these films against Listeria monocytogenes, Escherichia coli and Salmonella enterica were also evaluated. The increase of clay concentration causes a decrease of P vapour (from 5.34 × 10−11 to 3.19 × 10−11 g (m s Pa)−1) and an increase of the CO2 permeability (from 2.26 × 10−14 to 2.91 × 10−14 g (m s Pa)−1) and did not changed significantly the O2 permeability for films with 0 and 16 wt.% C30B, respectively. Films with 16 wt.% clay exhibited the highest values of TS (33.82 MPa) and EB (29.82 %). XRD patterns of the films indicated that a degree of exfoliation is attained depending on clay concentration. κ-car/LBG–C30B films exhibited an inhibitory effect only against L. monocytogenes. κ-car/LBG–C30B composite films are a promising alternative to synthetic films in order to improve the shelf life and safety of food products.J. T. Martins, A. I. Bourbon, A. C. Pinheiro and M. A. Cerqueira gratefully acknowledge the Fundacao para a Ciencia e Tecnologia (FCT, Portugal) for their fellowships (SFRH/BD/32566/2006, SFRH/BD/73178/2010, SFRH/BD/48120/2008 and SFRH/BPD/72753/2010, respectively), and B. W. S. Souza acknowledges the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES, Brazil)

    Exploring Subcellular Responses of Prostate Cancer Cells to X-Ray Exposure by Raman Mapping

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    Understanding the response of cancer cells to ionising radiation is a crucial step in modern radiotherapy. Raman microspectroscopy, together with Partial Least Squares Regression (PLSR) analysis has been shown to be a powerful tool for monitoring biochemical changes of irradiated cells on the subcellular level. However, to date, the majority of Raman studies have been performed using a single spectrum per cell, giving a limited view of the total biochemical response of the cell. In the current study, Raman mapping of the whole cell area was undertaken to ensure a more comprehensive understanding of the changes induced by X-ray radiation. On the basis of the collected Raman spectral maps, PLSR models were constructed to elucidate the time-dependent evolution of chemical changes induced in cells by irradiation, and the performance of PLSR models based on whole cell averages as compared to those based on average Raman spectra of cytoplasm and nuclear region. On the other hand, prediction of X-ray doses for individual cellular component showed that cytoplasmic and nuclear regions should be analysed separately. Finally, the advantage of the mapping technique over single point measurements was verified by a comparison of the corresponding PLSR models

    Infrared vibrational spectroscopy: a rapid and novel diagnostic and monitoring tool for cystinuria

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    Cystinuria is the commonest inherited cause of nephrolithiasis (~1% in adults; ~6% in children) and is the result of impaired cystine reabsorption in the renal proximal tubule. Cystine is poorly soluble in urine with a solubility of ~1 mM and can readily form microcrystals that lead to cystine stone formation, especially at low urine pH. Diagnosis of cystinuria is made typically by ion-exchange chromatography (IEC) detection and quantitation, which is slow, laboursome and costly. More rapid and frequent monitoring of urinary cystine concentration would significantly improve the diagnosis and clinical management of cystinuria. We used attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR) to detect and quantitate insoluble cystine in 22 cystinuric and 5 healthy control urine samples. Creatinine concentration was also determined by ATR-FTIR to adjust for urinary concentration/dilution. Urine was centrifuged, the insoluble fraction re-suspended in 5 μL water and dried on the ATR prism. Cystine was quantitated using its 1296 cm−1 absorption band and levels matched with parallel measurements made using IEC. ATR-FTIR afforded a rapid and inexpensive method of detecting and quantitating insoluble urinary cystine. This proof-of-concept study provides a basis for developing a high-throughput, cost-effective diagnostic method for cystinuria, and for point-of-care clinical monitoring

    Mesoscale Hydrographic Variability in the Vicinity of Points Conception and Arguello During April May 1983: The OPUS 1983 Experiment

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    In April and May 1983, interdisciplinary oceanographic observations were made of upwelling events in the Point Conception area off southern California. The principal objective was to observe the structure and time dependence of the upwelling system. To accomplish this, two ships, two aircraft, moorings, drogues, and satellite imagery were all included in the observational effort. During the intensive measurement period three main upwelling events and two intervening relaxation or downwelling intervals were sampled during what was a period of overall longer-term sea surface warming. Surface temperatures during upwelling were as low as 10.5°C in the upwelling center between Point Arguello and Point Conception, while during periods of nonupwelling winds, temperatures reached 14°–15°C in the same area. The upwelling center was also a source of higher-salinity water (33.7‰) relative to the offshore waters that were anomalously fresh (33.3‰). Upwelling was observed off Point Arguello, Point Conception, and the area between with a possible lag of up to a day at Point Conception relative to the other areas. The upwelling plume as observed by surface mapping and remote sensing tended to move in a variety of directions from SE to SW. Part of the movement was usually into the Santa Barbara Channel, but other parts of the plume occasionally moved southwestward. There was no obvious correlation of plume direction with the wind. During relaxation events the entire region was covered by a 10- to 20-m-thick warm (14°–16°C), fresh

    Kynurenic Acid Content in Selected Culinary Herbs and Spices

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    Previous studies demonstrated that kynurenic acid (KYNA) is present in various types of food in varying concentrations. Therefore, the aim of the study was to check whether KYNA is present in culinary herbs and spices. Achieved results indicate that KYNA is present in all 19 selected culinary herbs and spices. The highest concentration of KYNA was found in basil and thyme, 14.08 and 8.87 μg/g, respectively, while the lowest content of KYNA was found in cumin and black pepper, 0.64 and 0.10 μg/g, respectively. This is the first report on the concentration of KYNA in culinary herbs and spices. The need for more detailed investigation of dietary supplementation with culinary herbs and spices containing KYNA is suggested

    Boerhaave syndrome as a complication of colonoscopy preparation: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Colonoscopy is one of the most frequently performed elective and invasive diagnostic interventions. For every colonoscopy, complete colon preparation is mandatory to provide the best possible endoluminal visibility; for example, the patient has to drink a great volume of a non-resorbable solution to flush out all feces. Despite the known possible nauseating side effects of colonoscopy preparation and despite the knowledge that excessive vomiting can cause rupture of the distal esophagus (Boerhaave syndrome), which is a rare but severe complication with high morbidity and mortality, it is not yet a standard procedure to provide a patient with an anti-emetic medication during a colon preparation process. This is the first report of Boerhaave syndrome induced by colonoscopy preparation, and this case strongly suggests that the prospect of being at risk of a severe complication connected with an elective colonoscopy justifies a non-invasive, inexpensive yet effective precaution such as an anti-emetic co-medication during the colonoscopy preparation process.</p> <p>Case presentation</p> <p>A 73-year-old Caucasian woman was scheduled to undergo elective colonoscopy. For the colonoscopy preparation at home she received commercially available bags containing soluble polyethylene glycol powder. No anti-emetic medication was prescribed. After drinking the prepared solution she had to vomit excessively and experienced a sudden and intense pain in her back. An immediate computed tomography (CT) scan revealed a rupture of the distal esophagus (Boerhaave syndrome). After initial conservative treatment by endoluminal sponge vacuum therapy, she was taken to the operating theatre and the longitudinal esophageal rupture was closed by direct suture and gastric fundoplication (Nissen procedure). She recovered completely and was discharged three weeks after the initial event.</p> <p>Conclusions</p> <p>To the best of our knowledge, this is the first report of a case of Boerhaave syndrome as a complication of excessive vomiting caused by colonoscopy preparation. The case suggests that patients who are prepared for a colonoscopy by drinking large volumes of fluid should routinely receive an anti-emetic medication during the preparation process, especially when they have a tendency to nausea and vomiting.</p
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