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A high resolution depth attenuation product (Kdhires) was developed using MODIS 500 m and 250 m spectral bands. The Kdhires was compared with Wang’s operational Kd for the Chesapeake Bay. Minimal differences were observed between the two methods, with greatest deviation occurring in areas of high turbidity in the tributaries. After tuning the new Kdhires, the mean absolute error and bias between the two algorithms was 0.22 m?1 and 0.026 m?1, indicating good agreement. Higher spatial resolution provides for improved retrievals along the coast and into the narrow sections of the tributaries, coinciding with areas of concern to estuarine health and coastal management applications. 相似文献
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Gene delivery systems are designed to control the location of administered therapeutic genes within a patient's body. Successful in vivo gene transfer may require (i) the condensation of plasmid and its protection from nuclease degradation, (ii) cellular interaction and internalization of condensed plasmid, (iii) escape of plasmid from endosomes (if endocytosis is involved), and (iv) plasmid entry into cell nuclei. Expression plasmids encoding a therapeutic protein can be, for instance, complexed with cationic liposomes or micelles in order to achieve effective in vivo gene transfer. A thorough knowledge of pharmaceutics and drug delivery, bio-engineering, as well as cell and molecular biology is required to design optimal systems for gene therapy. This mini-review provides a critical discussion on cationic lipid-based gene delivery systems and their possible uses as pharmaceuticals. 相似文献
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The transport of L- and D-lactate into rat pancreatic islets and HIT-T15 insulinoma cells was studied by measuring uptake of 14C-labelled substrate at room temperature and by following changes in intracellular pH (pHi) in islets and HIT-T15 cells loaded with 2',7'-bis(carboxyethyl)-5'(6')-carboxyfluorescein (BCECF). Uptake of L-lactate into HIT-T15 cells was rapid, reaching equilibrium after 5 min with an apparent Km value of 4.8 mM. Transport was markedly inhibited by alpha-cyano-4-hydroxycinnamate, alpha-fluorocinnamate, quercetin and p-chloromercuribenzenesulphonate (pCMBS), and was enhanced in citrate medium. Uptake of D-lactate was less rapid, apparent equilibrium not being reached within 10 min. In contrast to HIT-T15 cells, rat pancreatic islets showed greatly reduced rates of transport of L- and D-lactate together with a correspondingly lower degree of inhibition by alpha-cyano-4-hydroxycinnamate. The addition of L- or D-lactate to HIT-T15 cells, but not dispersed islet cells, resulted in a marked and rapid intracellular acidification followed by a gradual recovery. In both HIT-T15 cells and isolated islets, the rates of transport of both L- and D-lactate in the presence of alpha-cyano-4-hydroxycinnamate were significantly greater in a depolarising K+ medium compared to the normal Na+ medium. These observations suggest that native rat islet cells have considerably reduced activity of the lactate-/H+ transport system compared to HIT-T15 insulinoma cells. There is evidence in both cell types of an additional electrogenic pathway for lactate which might play a role in coupling lactate efflux to beta-cell depolarisation. 相似文献
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M J Harrison P A Tomlinson C S Ubhi J Wright J D Hardcastle 《Annals of the Royal College of Surgeons of England》1988,70(2):61-63
Changes in anal pressure have been monitored during the induction of anaesthesia. Falls in pressure accompany loss of consciousness following bolus doses of commonly used intravenous and inhalational anaesthetic agents. Subsequent rises in pressure towards pre-anaesthetic levels are usually associated with the time taken to correct responses and initial recovery. Premedication, including anticholinergic drugs in conventional dosage, does not affect anal pressure. 相似文献
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Christina Djokoto George Tomlinson Stephen Waldman Marc Grynpas Angela M. Cheung 《Journal of clinical densitometry》2004,7(4):448-456
Dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) are the accepted modalities for the evaluation of fracture risk in the clinical setting. However, neither method provides a direct measurement of bone mechanics. In this study, we investigated a prototype device, known as a mechanical response tissue analyzer (MRTA), which provides direct mechanical measurements of mechanical properties of bone. A total of 56 healthy volunteers (20 men and 36 women) between the ages of 18 and 83 were recruited. The MRTA was used to measure the cross-sectional bending stiffness (EI) of the ulna bone. Axial speed of sound (SOS) at the ulna bone was determined by QUS; bone mineral content (BMC) and bone mineral density (BMD) were determined by DXA. Correlations, regression analysis, and analyses of variance (ANOVAs) were used to compare the three modalities. These analyses revealed that although there are strong linear relationships among the data collected by the various technologies, the bone properties reflected by MRTA are not fully explained by DXA and QUS. We conclude that the total information conveyed by MRTA measurements is unique. Further research is needed to delineate the different qualities of bone strength that are captured by MRTA, but not by DXA or QUS. 相似文献
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S Gunasti† SS Marakli† I Tuncer‡ N Ozpoyraz§ VL Aksungur† 《Journal of the European Academy of Dermatology and Venereology》2007,21(6):811-817
BACKGROUND: We have seen several patients with itchy lichenified plaques located bilaterally on the elbows and/or knees and have named this condition 'psoriatic neurodermatitis' (PN). OBJECTIVE: The purpose of this study was to compare clinical and histopathological characteristics of these patients to those of patients with typical lichen simplex chronicus (LSC). METHODS: Nineteen patients with PN and 34 patients with typical LSC were included. Besides clinical dermatological evaluation, the prick test was carried out on 49 patients; the Phadiatop test on 40 patients; the patch test with European standard series on 47 patients; histopathological evaluation on 39 patients; and clinical psychiatric examination on 38 patients. RESULTS: Almost exclusively, PN was seen in females and was located on the extremities. It caused more plaques than typical LSC did. In PN, the plaques were smaller, sharper, more keratotic and less excoriated, and had fewer lichenoid papules around them. Itching was usually more severe in the evening, while resting and in a hot environment in typical LSC, but not in PN. In plaques of PN, microabscesses in the horny layer, hypogranulosis, regular acanthosis and thinning of the suprapapillary plates were more frequent, and hyperpigmentation in the basal layer was less. In patients with PN, depressive disorder was found more frequently; and generalized anxiety disorder or psychosomatic characteristics, less. There were no significant differences in the results of prick, Phadiatop and patch tests between patients with PN and those with typical LSC. CONCLUSION: In our opinion, it is most likely that the so-called PN is itchy psoriasis superimposed by LSC. 相似文献