首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
Objective: This study was to develop a strain analysis method to evaluate the left ventricular (LV) functions in type 2 diabetic patients with an asymptomatic LV diastolic dysfunction. Methods: Two groups (10 asymptomatic type 2 diabetic subjects and 10 control ones) were considered. All of the subjects had normal ejection fraction values but impaired diastolic functions assessed by the transmitral blood flow velocity. For each subject, based on cardiac MRI, global indexes including LV volume, LV myocardial mass, cardiac index (CI), and transmitral peak velocity, were measured, and regional indexes (i.e., LV deformation, strain and strain rate) were calculated through an image-registration technology. Results: Most of the global indexes did not differentiate between the two groups, except for the CI, LV myocardial mass and transmitral peak velocity. While for the regional indexes, the global LV diastolic dysfunction of the diabetic indicated an increased strain (0.08?±?0.044 vs. ?0.031?±?0.077, p?=?0.001) and a reduced strain rate (1.834?±?0.909 vs. 3.791?±?2.394, p?=?0.033) compared to the controls, moreover, the local LV diastolic dysfunction reflected by the strain and strain rate varied, and the degree of dysfunction gradually decreased from the basal level to the apical level. Conclusions: The results showed that the strain and strain rates are effective to capture the subtle alterations of the LV functions, and the proposed method can be used to estimate the LV myocardial function based on cardiac MRI.  相似文献   

2.
We report the loading efficacy of folic acid (FA) by polyamidoamine (PAMAM-G3 and PAMAM-G4) nanoparticles in aqueous solution at physiological pH. Thermodynamic parameters ΔH = ?47.57 (kJ Mol?1), ΔS = ?122.78 (J Mol?1, K?1) and ΔG = ?10.96 (kJ Mol?1) showed FA-PAMAM bindings occur via H-bonding and van der Waals contacts. The stability of acid-PAMAM conjugate increased as polymer size increased. The acid loading efficacy was 40 to 50%. TEM images exhibited major polymer morphological changes upon acid encapsulation. PAMAM dendrimers are capable of FA delivery in vitro.  相似文献   

3.
《Biomarkers》2013,18(3):281-287
Background: MRproADM and MRproANP can be used as diagnostic and prognostic markers in heart failure.

Aim: The objective was to identify confounding factors for the interpretation of plasma MRproADM and MRproANP concentrations.

Methods: A total of 518 healthy volunteers with a mean age of 60.84?±?7.41 years were analyzed. We evaluated the influence of demographic factors, renal function and echocardiographic indices on the candidate peptides.

Results: Multivariate analysis revealed that age (P?<?0.001), BMI (P?<?0.001) and eGFR (P?<?0.001) were independent predictors for MRproADM concentrations in healthy subjects. The independent predictors for MRproANP were age (P?<?0.001), female gender (P?<?0.001), heart rate (P?<?0.001) and eGFR (P?=?0.039).

Conclusion: The interpretation of both peptides is multifaceted due to confounders. Knowledge of these factors will further our understanding of how these peptides behave in health and in disease.  相似文献   

4.
Evaluation of protectant ability of Newbouldia laevis (Seem.) extracts against infestation by Callosobruchus maculatus in cowpea, Vigna unguiculata L. (Walp.) was carried out in the laboratory at ambient temperature of 28?±?2?°C and 70?±?5% relative humidity. Extracts from wood ash, leaf, stem and root bark were tested at different concentrations of 0, 1, 2, 3, 4 and 5%. One hundred per cent mortality of adult beetles was achieved at all concentrations within 72?h of treatment with extracts except in wood ash at 1% concentration, but they were significantly different (p?<?0.05) from the controls. All the extracts were still able to cause high beetle mortality after one, two and three months of cowpea storage at high concentrations (4 and 5%) except wood ash, although there was a slight decrease in mortality during the period of storage. All the extracts significantly (p?<?0.05) reduced oviposition and adult emergence of C. maculatus when compared with the controls although the reduction was higher at 5% concentration than others. Adult beetle emergence was completely prevented at higher concentrations (4 and 5%) except in wood ash. Both oviposition and adult emergence increased during the months of storage probably because of the slight reduction in the effectiveness of the extracts. The root bark extract was much more effective in reducing oviposition and adult emergence than others throughout the period of storage. The plant extracts of N. laevis was able to protect the cowpea seeds from damage and prevent weight loss. Cowpea seed damage and weight loss was significantly more (p?<?0.05) in the controls than other for the three-month duration probably because of the more adult emergence. The extracts from N. laevis did not adversely affect the germination of the protected seeds and seed germination ranged from 86.7 to 100%. It has been shown in this study that the extracts of N. laevis were effective against C. maculatus in cowpea although the root bark extract seemed to be the most effective while the wood ash extract was least effective. Their effectiveness, however, slightly decreased during the period of storage. N. laevis could be incorporated into pest management of stored cowpeas since the products are ecologically safe.  相似文献   

5.
《Chronobiology international》2013,30(10):1223-1230
The rhythms of activity across the 24-h sleep-wake cycle, determined in part by the circadian clock, change with aging. Few large-scale studies measured the activity rhythm objectively in the general population. The present population-based study in middle-aged and elderly persons evaluated how activity rhythms change with age, and additionally investigated sociodemographics, mental health, lifestyle, and sleep characteristics as determinants of rhythms of activity. Activity rhythms were measured objectively with actigraphy. Recordings of at least 96?h (138?±?14?h, mean?±?SD) were collected from 1734 people (age: 62?±?9.4?yrs) participating in the Rotterdam Study. Activity rhythms were quantified by calculating interdaily stability, i.e., the stability of the rhythm over days, and intradaily variability, i.e., the fragmentation of the rhythm relative to its 24-h amplitude. We assessed age, gender, presence of a partner, employment, cognitive functioning, depressive symptoms, body mass index (BMI), coffee use, alcohol use, and smoking as determinants. The results indicate that older age is associated with a more stable 24-h activity profile (β?=?0.07, p?=?0.02), but also with a more fragmented distribution of periods of activity and inactivity (β?=?0.20, p?<?0.001). Having more depressive symptoms was related to less stable (β?=??0.07, p?=?0.005) and more fragmented (β?=?0.10, p?<?0.001) rhythms. A high BMI and smoking were also associated with less stable rhythms (BMI: β?=??0.11, p?<?0.001; smoking: β?=??0.11, p?<?0.001) and more fragmented rhythms (BMI: β?=?0.09, p?<?0.001; smoking: β?=?0.11, p?<?0.001). We conclude that with older age the 24-h activity rhythm becomes more rigid, whereas the ability to maintain either an active or inactive state for a longer period of time is compromised. Both characteristics appear to be important for major health issues in old age.  相似文献   

6.
Objectives

Decaying wood samples were collected, and actinomycetes were isolated and screened for laccase production. The identity of the efficient laccase-producing isolate was confirmed by using a molecular approach. Fermentation conditions for laccase production were optimized, and laccase biochemical properties were studied.

Results

Based on the 16S rRNA gene sequencing and phylogenetic analysis, the isolate coded as HWP3 was identified as Streptomyces sp. LAO. The time-course study showed that the isolate optimally produced laccase at 84 h with 40.58?±?2.35 U/mL activity. The optimized physicochemical conditions consisted of pH 5.0, ferulic acid (0.04%; v/v), pine back (0.2 g/L), urea (1.0 g/L), and lactose (1 g/L). Streptomyces sp. LAO laccase was optimally active at pH and temperature of 8.0 and 90 °C, respectively, with remarkable pH and thermal stability. Furthermore, the enzyme had a sufficient tolerance for organic solvents after 16 h of preincubation, with laccase activity?>?70%. Additionally, the laccase maintained considerable residual activity after pretreatment with 100 mM of chemical agents, including sodium dodecyl sulphate (69.93?±?0.89%), ethylenediaminetetraacetic acid (93.1?±?7.85%), NaN3 (96.28?±?3.34%) and urea (106.03?±?10.72%).

Conclusion

The laccase's pH and thermal stability; and robust catalytic efficiency in the presence of organic solvents suggest its industrial and biotechnological application potentials for the sustainable development of green chemistry.

  相似文献   

7.
8.
We investigated the contribution of internal water storage and efficiency of water transport to the maintenance of water balance in six evergreen tree species in a Hawaiian dry forest. Wood‐saturated water content, a surrogate for relative water storage capacity, ranged from 70 to 105%, and was inversely related to its morphological correlate, wood density, which ranged between 0·51 and 0·65 g cm?3. Leaf‐specific conductivity (kL) measured in stem segments from terminal branches ranged from 3 to 18 mmol m?1 s?1 MPa?1, and whole‐plant hydraulic efficiency calculated as stomatal conductance (g) divided by the difference between predawn and midday leaf water potential (ΨL), ranged from 70 to 150 mmol m?2 s?1 MPa?1. Hydraulic efficiency was positively correlated with kL (r2 = 0·86). Minimum annual ΨL ranged from ? 1·5 to ? 4·1 MPa among the six species. Seasonal and diurnal variation in ΨL were associated with differences among species in wood‐saturated water content, wood density and kL. The species with higher wood‐saturated water content were more efficient in terms of long‐distance water transport, exhibited smaller diurnal variation in ΨL and higher maximum photosynthetic rates. Smaller diurnal variation in ΨL in species with higher wood‐saturated water content, kL and hydraulic efficiency was not associated with stomatal restriction of transpiration when soil water deficit was moderate, but avoidance of low minimum seasonal ΨL in these species was associated with a substantial seasonal decline in g. Low seasonal minimum ΨL in species with low kL, hydraulic efficiency, and wood‐saturated water content was associated with higher leaf solute content and corresponding lower leaf turgor loss point. Despite the species‐specific differences in leaf water relations characteristics, all six evergreen tree species shared a common functional relationship defined primarily by kL and stem water storage capacity.  相似文献   

9.
Compression wood is formed at the underside of conifer twigs to keep branches at their equilibrium position. It differs from opposite wood anatomically and subsequently in its mechanical and hydraulic properties. The specific hydraulic conductivity (ks) and vulnerability to drought‐induced embolism (loss of conductivity versus water potential ψ) in twigs of Norway spruce [Picea abies (L.) Karst.] were studied via cryo‐scanning electron microscope observations, dye experiments and a newly developed ‘Micro‐Sperry’ apparatus. This new technique enabled conductivity measurements in small xylem areas by insertion of syringe cannulas into twig samples. The hydraulic properties were related to anatomical parameters (tracheid diameter, wall thickness). Compression wood exhibited 79% lower ks than opposite wood corresponding to smaller tracheid diameters. Vulnerability was higher in compression wood despite its narrower tracheids and thicker cell walls. The P50 (ψ at 50% loss of conductivity) was ?3.6 MPa in opposite but only ?3.2 MPa in compression wood. Low hydraulic efficiency and low hydraulic safety indicate that compression wood has primarily a mechanical function.  相似文献   

10.
Purpose: Voriconazole has both low aqueous solubility and stability. We hypothesize that designing voriconazole in the form of a nano powder inhaler at a geometric diameter within 1–5?μm will enhance its stability and solubility. Therefore, we prepared nanoagglomerates of voriconazole which will collapse in the lungs to reform the nanoparticles.

Method: The nanoparticles were formulated using both stearic acid and sodium deoxycholate as edge activators. Osmogenic polycation polyethyleneimine (PEI) was used to form agglomerates of controllable size.

Results: Voriconazole nanoparticles and agglomerates showed a significant higher cumulative drug release than the pure powder (p?R2?=?0.95. Small-sized particles were formed (353?nm), while their zeta potential was ?30.7?mV. The agglomerates were 2.7?μm in size and their zeta potential was ?20.9?mV. The formation of porous agglomerates was confirmed using a transmission electron microscope. Cascade impactor was used to evaluate the aerodynamic properties of the nanoparticles and the agglomerates. The aerodynamic characterization of the nanoparticles and the agglomerates resulted in a significant smaller mass median aerodynamic diameter (MMAD) (p?p?p?p?Conclusion: The results suggest that using the combination of edge activators and diluted polycationic polymer solution provides porous voriconazole nanoagglomerates in a respirable range, which is proved successful in enhancing both the deposition and the dissolution of water insoluble-drugs in the lung.  相似文献   

11.
The current study was conducted to provide normative data on actigraphic dichotomy index (I?<?O) (the percentage of in bed activity counts that are less than the median of out of bed counts) in healthy population and to assess whether the I?<?O could be an effective index in discriminating the circadian motor activity of cancer patients from healthy controls. In this retrospective study, we recovered 408 actigraphic records from two databases: healthy controls (n?=?182; 79 males; mean age 38.7?±?12.6) and patients with metastatic colorectal cancer (n?=?226; 149 males; mean age 58.4?±?11.4). Beside the usual actigraphic sleep parameters (time in bed, sleep onset latency, total sleep time, wake after sleep onset, sleep efficiency, number of awakenings, and mean motor activity), we also computed the dichotomy index and number of actigraphic wake parameters, namely, diurnal motor activity, diurnal total sleep time, number of sleep episodes, and the mean duration of the longest diurnal sleep episode. Using the Youden index, we calculated the cut off value that performed the best for I?<?O and actigraphic wake parameters. Finally, we created Receiver Operator Characteristic curves to test the efficacy of each actigraphic parameter to discriminate cancer patient from healthy controls. Mean I?<?O was 99.5% (SD, 0.48%) in the healthy group, as compared to 96.6% (SD, 3.6%) in the cancer group (p?<?0.0001). Important age-related effects appeared unlikely after performing both the main analysis with age as a covariate, and a subset analysis in 104 subjects matched for age and sex. In the main analysis, all actigraphic parameters, except total sleep time, significantly differentiated the two groups of participants. However, the I?<?O was the one that clearly performed best. Here, we provide the first large dataset on I?<?O in healthy subjects, we confirm the relevance of this circadian index for discriminating advanced stage colorectal cancer patients from healthy subjects, and we lay the grounds for further investigations of this circadian index in patients with other chronic diseases.  相似文献   

12.
Abstract

In efforts to speed up the assessment of microorganisms, researchers have sought to use bacteriophages as a biosensing tool, due to their host-specificity, wide abundance, and safety. However, the lytic cycle of the phage has limited its efficacy as a biosensor. Here, we cloned a fragment of tail protein J from phage lambda and characterized its binding with the host, E. coli K-12, and other microorganism. The N-terminus of J was fused with a His-tag (6HN-J), overexpressed, purified, and characterized using anti-His monoclonal antibodies. The purified protein demonstrated a size of ~38?kDa upon SDS-PAGE and bound with the anti-His monoclonal antibodies. ELISA, dot blot, and TEM data revealed that it specifically bound to E. coli K-12, but not to Pseudomonas aeruginosa. The observed protein binding occurred over a concentration range of 0.01–5?μg/ml and was found to inhibit the in vivo adsorption of phage to host cells. This specific binding was exploited by surface plasmon resonance (SPR) to generate a novel 6HN-J-functionalized SPR biosensor. This biosensor showed rapid label-free detection of E. coli K-12 in the range of 2?×?104 ?2?×?109 CFU/ml, and exhibited a lower detection limit of 2?×?104 CFU/ml.  相似文献   

13.
Phytostabilization aims to reduce environmental and health risks arising from contaminated soil. To be economically attractive, plants used for phytostabilization should produce valuable biomass. This study investigated the biomass production and metal allocation to foliage and wood of willow (Salix viminalis L.), poplar (Populus monviso), birch (Betula pendula), and oak (Quercus robur) on five different soils contaminated with trace elements (TE), with varying high concentrations of Cu, Zn, Cd, and Pb as well as an uncontaminated control soil. In the treatment soils, the biomass was reduced in all species except oak. There was a significant negative correlation between biomass and foliar Cd and Zn concentrations, reaching up to 15 mg Cd kg?1 and 2000 mg Zn kg ?1 in willow leaves. Lead was the only TE with higher wood than foliage concentrations. The highest Pb accumulation occurred in birch with up to 135 mg kg ?1 in wood and 78 mg kg ?1 in foliage. Birch could be suitable for phytostabilization of soils with high Cd and Zn but low Pb concentrations, while poplars and willows could be used to stabilise soils with high Cu and Pb and low Zn and Cd concentrations.  相似文献   

14.
Highlights? Immunomodulatory properties of MSCs in vitro and in vivo are discussed. ? Safety and efficacy of treatments with allogeneic MSCs are discussed. ? Future directions to improve efficacy of MSC treatments are proposed.  相似文献   

15.
Background: Histopathological assessments approaches in bivalves have become an important tool in environmental toxicology. This study seeks to develop a quantitative histopathological index (Ih) and inflammation score as biomarkers in the aim to assess the health status of nanoparticles exposed mussels.

Methods: Digestive gland hematoxylin and eosin (H&;E) stained sections from Mytilus galloprovincialis were assessed after in vivo exposure (for 3, 6 and 12?h) to silver nanoparticles (Ag-NPs?Results: Silver nanoparticles clearly induced histopathological alterations in digestive gland (maximum inflammation 2.75 with AgNP?p?Ih with AgNP?p?Ih were recorded after uptake routes were blockade: AgNP?p?Conclusions: Histopathological assessments showed to be promising tool in nanotoxicity which seems to depend on nanoparticles size, exposure time and interestingly to uptake routes. It was not clear: is it the length of exposure or the size of particles is more impactful.  相似文献   

16.
    
Summary Results of four crosses are presented, which indicate that, in Schizosaccharomyces pombe, the plus segment of the mating-type locus is regulated from a central position, in between of the plus and the minus segment. This conclusion is based on the mapping of a plus-restraining entity r, which is revealed by recombination in certain crosses, or by mutation to unstable strains. To this end, a meiosis-defective mating-type mutation was used as a marker for the plus segment, by taking advantage of its suppressibility by a nonsense suppressor. This suppressibility was substantiated by an additional cross.  相似文献   

17.
The aim of this study was to analyze the effects of intensive management and forest landscape structure (in terms of age class distribution) on timber and energy wood production (m3?ha?1), net present value (NPV, ? ha?1) with implications on net CO2 emissions (kg CO2 MWh?1 per energy unit) from energy wood use of Norway spruce grown on medium to fertile sites. This study employed simulations using a forest ecosystem model and the Emission Calculation Tool, considering in its analyses: timber (saw logs, pulp) and energy wood (small-sized stem wood and/or logging residuals for top part of stem, branches, and needles) from the first thinning and harvesting residuals and stumps from the final felling. At the stand level, both fertilization and high pre-commercial stand density clearly increased timber production and the amount of energy wood. Short rotation length (40 and 60?years) outputted, on average, the highest annual stem wood production (most fertile and medium fertile sites), the 60?year rotation also outputted the highest average annual net present value (NPV with interest rates of 1?C4%). On the other hand, even longer rotation lengths, up to 80 and 100?years, were needed to output the lowest net CO2 emissions per year in energy wood use. At the landscape level, the largest productivity (both for timber and energy wood) was obtained using rotation lengths of 60 and 80?years with an initial forest landscape structure dominated by older mature stands (a right-skewed age-class distribution). If the rotation length was 120?years, the initial forest landscape dominated by young stands (a left-skewed age-class distribution) provided the highest productivity. However, the NPV with interest rate of 2% was, on average, the highest with a right-skewed distribution regardless of the rotation length. If the rotation length was 120?years, normal age class distribution provided, on average, the highest NPV. On the other hand, the lowest emissions (kg CO2 MWh?1a?1) were obtained with the left-skewed age-class distribution using the rotation lengths of 60 and 80?years, and with the normal age-class distribution using the rotation length of 120?years. Altogether, the management regimes integrating both timber and energy wood production and using fertilization provided, on average, the lowest emissions over all management alternatives considered.  相似文献   

18.

Poly-arginine peptides R18 and R18D have previously been demonstrated to be neuroprotective in ischaemic stroke models. Here we examined the proteolytic stability and efficacy of R18 and R18D in reducing infarct core growth and preserving the ischaemic penumbra following middle cerebral artery occlusion (MCAO) in the Sprague Dawley rat. R18 (300 or 1000 nmol/kg), R18D (300 nmol/kg) or saline were administered intravenously 10 min after MCAO induced using a filament. Serial perfusion and diffusion-weighted MRI imaging was performed to measure changes in the infarct core and penumbra from time points between 45- and 225-min post-occlusion. Repeated measures analyses of infarct growth and penumbral tissue size were evaluated using generalised linear mixed models (GLMMs). R18D (300 nmol/kg) was most effective in slowing infarct core growth (46.8 mm3 reduction; p?<?0.001) and preserving penumbral tissue (21.6% increase; p?<?0.001), followed by R18 at the 300 nmol/kg dose (core: 29.5 mm3 reduction; p?<?0.001, penumbra: 12.5% increase; p?<?0.001). R18 at the 1000 nmol/kg dose had a significant impact in slowing core growth (19.5 mm3 reduction; p?=?0.026), but only a modest impact on penumbral preservation (6.9% increase; p?=?0.062). The in vitro anti-excitotoxic neuroprotective efficacy of R18D was also demonstrated to be unaffected when preincubated for 1–3 h or overnight, in a cell lysate prepared from dying neurons or with the proteolytic enzyme, plasmin, whereas the neuroprotective efficacy of R18 was significantly reduced after a 2-h incubation. These findings highlight the capacity of poly-arginine peptides to reduce infarct growth and preserve the ischaemic penumbra, and confirm the superior efficacy and proteolytic stability of R18D, which indicates that this peptide is likely to retain its neuroprotective properties when co-administered with alteplase during thrombolysis for acute ischaemic stroke.

  相似文献   

19.
Metal pollution in water and soil is an environmental and public health issue. Cadmium (Cd) is included in the list of priority hazardous substances in the European Water Framework Directive. Phytoremediation system is a cost-effective, plant-based approach that takes advantage of the ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. We studied the presence and the importance of an invasive species, such as Lemna minuta, in the environment and the effects of Cd pollution on this species. Growth, removal, and tolerance were evaluated for different Cd concentrations and different times of plant exposure. Overall, the results show that L. minuta has a good capacity of growth, metal bioconcentration, and tolerance up to 3 days of exposure at 0.5 and 1.5 mg L?1 of Cd. In particular, L. minuta was able to accumulate Cd up to 3771 mg kg?1 on dry mass basis. We can conclude that L. minuta possesses a great capability of Cd absorption and accumulation, thus supporting a potential use of this species in designing a metal bioremediation system in phytoremediation field.  相似文献   

20.
Polygodial is a potent and selective inhibitor of ascidian metamorphosis that shows promise for controlling fouling by ascidians in bivalve aquaculture. The current study examined the potency of, and associated effects of seawater exposure on, a rosin-based soluble-matrix paint laced with 0.08–160?ng?polygodial?g?1 wet paint matrix. Paint-coated surfaces were soaked in seawater for 0, 2, 4 or 12?weeks prior to screening for antifouling activity using a bioassay based on the nuisance ascidian Ciona savignyi Herdman. Mortality was greater (mean 50% lethal concentration: 5?±?2?ng?g?1; mean 75% lethal concentration: 17?±?4?ng?g?1) and metamorphosis was inhibited (mean 50% anti-metamorphic concentration: 2?±?0.4?ng?g?1; mean 75% anti-metamorphic concentration: 15?±?10?ng?g?1) in C. savignyi larvae exposed to polygodial-laced soluble-matrix paints, relative to control paints without polygodial. Soaking in seawater prior to testing reduced the efficacy of the formulation up to nearly 12-fold, but even after soaking for 12?weeks paints laced with polygodial at 160?ng?g?1 wet paint matrix prevented ?90% of the larvae of C. savignyi from completing metamorphosis. The outcome of this experiment provides a positive first step in evaluating the suitability of polygodial-laced soluble-matrix paints for use in aquaculture.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号