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排序方式: 共有227条查询结果,搜索用时 15 毫秒
1.
Three experiments were conducted in hens to determine the effects of high levels of dietary phosphorus (P, 1-1.5%), chloride (Cl, 0.8%) or both on acid-base balance and eggshell quality and to consider whether any adverse effects on eggshell quality can be attributed to alteration of blood acid-base balance. Eggshell quality and values for a blood indicator of acid-base balance were reduced by high levels of dietary P or Cl in all of the experiments. Eggshell quality and values for the blood acid-base indicator were further reduced by high dietary levels of the combination of minerals. The adverse effects associated with high levels of the combination were greater than the sum of adverse effects associated with high levels of each mineral. The effects of P and Cl on plasma levels of these minerals were inconsistent and varied among experiments. The use of pair-fed controls revealed that the adverse effects of combined P and Cl on eggshell quality and acid-base balance were independent of their effects on feed and calcium intake. Calcium excretion was increased by consumption of the high P, high Cl diet. The information obtained from these experiments suggests that the adverse effects of high levels of dietary P and/or Cl on eggshell quality may be due, at least in part, to increased Ca excretion. This, in turn, may be mediated by acidemia resulting from the dietary manipulations, although the present data were insufficient to provide a direct link between acidemia and Ca excretion. 相似文献
2.
Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface _lasmon). These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on) perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented. 相似文献
3.
Behrang Keshavarz Lawrence J. Hettinger Daniel Vena Jennifer L. Campos 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2014,232(3):827-836
Vection is the illusion of self-motion in the absence of real physical movement. The aim of the present study was to analyze how multisensory inputs (visual and auditory) contribute to the perception of vection. Participants were seated in a stationary position in front of a large, curved projection display and were exposed to a virtual scene that constantly rotated around the yaw-axis, simulating a 360° rotation. The virtual scene contained either only visual, only auditory, or a combination of visual and auditory cues. Additionally, simulated rotation speed (90°/s vs. 60°/s) and the number of sound sources (1 vs. 3) were varied for all three stimulus conditions. All participants were exposed to every condition in a randomized order. Data specific to vection latency, vection strength, the severity of motion sickness (MS), and postural steadiness were collected. Results revealed reduced vection onset latencies and increased vection strength when auditory cues were added to the visual stimuli, whereas MS and postural steadiness were not affected by the presence of auditory cues. Half of the participants reported experiencing auditorily induced vection, although the sensation was rather weak and less robust than visually induced vection. Results demonstrate that the combination of visual and auditory cues can enhance the sensation of vection. 相似文献
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Reza Heidari Akram Jamshidzadeh Nahid Keshavarz Negar Azarpira 《Scientia pharmaceutica》2015,83(1):143-158
Methimazole is the most widely prescribed antithyroid medication in humans. However, hepatotoxicity is a deleterious adverse effect associated with methimazole administration. No specific protective agent has been developed against this complication yet. This study was designed to investigate the role of taurine as a hepatoprotective agent against methimazole-induced liver injury in mice. Different reactive metabolites were proposed to be responsible for methimazole hepatotoxicity. Hence, methimazole-induced liver injury was investigated in intact and/or enzyme-induced animals in the current investigation. Animals were treated with methimazole (200 mg/kg, by gavage), and hepatic injury induced by this drug was investigated in intact and/or enzyme-induced groups. Markers such as lipid peroxidation, hepatic glutathione content, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in plasma, and histopathological changes in the liver of animals were monitored after drug administration. Methimazole caused liver injury as revealed by increased plasma ALT. Furthermore, a significant amount of lipid peroxidation was detected in the drug-treated animals, and hepatic glutathione reservoirs were depleted. Methimazole-induced hepatotoxicity was more severe in enzyme-induced mice. The above-mentioned alterations in hepatotoxicity markers were endorsed by significant histopathological changes in the liver. Taurine administration (1 g/kg, i.p.) effectively alleviated methimazole-induced liver injury in both intact and/or enzyme-induced animals. 相似文献
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Developments in the fields of lab-on-a-chip and microfluidic technology have benefited nanomaterial production processes due to fluid miniaturization. The ability to acquire, manage, create, and modify structures on a nanoscale is of great interest in scientific and technological fields. Recently, more attention has been paid to the production of core–shell nanomaterials because of their use in various fields, such as drug delivery. Heterostructured nanomaterials have more reliable performance than the individual core or shell materials. Nanoparticle synthesis is a complex process; therefore, various techniques exist for the production of different types of nanoparticles. Among these techniques, microfluidic methods are unique and reliable routes, which can be used to produce nanoparticles for drug delivery applications.Developments in the fields of lab-on-a-chip and microfluidic technology have benefited nanomaterial production processes due to fluid miniaturization. 相似文献
8.
Aghil Igder Scott Pye Ahmed Hussein Mohammed Al-Antaki Alireza Keshavarz Colin L. Raston Ata Nosrati 《RSC advances》2020,10(25):14761
Polysulfone (PSF) was prepared under high shear in a vortex fluidic device (VFD) operating in confined mode, and its properties compared with that prepared using batch processing. This involved reacting the pre-prepared disodium salt of bisphenol A (BPA) with a 4,4′-dihalodiphenylsulfone under anhydrous conditions. Scanning electron microscopy (SEM) established that in the thin film microfluidic platform, the PSF particles are sheet-like, for short reaction times, and fibrous for long reaction times, in contrast to spherical like particles for the polymer prepared using the conventional batch synthesis. The operating parameters of the VFD (rotational speed of the glass tube, its tilt angle and temperature) were systematically varied for establishing their effect on the molecular weight (Mw), glass transition temperature (Tg) and decomposition temperature, featuring gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) respectively. The optimal VFD prepared PSF was obtained at 6000 rpm rotational speed, 45° tilt angle and 160 °C, for 1 h of processing with Mw ∼10 000 g mol−1, Tg ∼158 °C and decomposition temperature ∼530 °C, which is comparable to the conventionally prepared PSF.Polysulfone (PSF) was prepared under high shear in a vortex fluidic device (VFD) operating in confined mode. This involved reacting the pre-prepared disodium salt of bisphenol A (BPA) with a 4,4′-dihalodiphenylsulfone under anhydrous conditions. 相似文献
9.
Mercede Erfanian Christiana Kartsonaki Azita Keshavarz 《Nordic journal of psychiatry》2013,67(4-5):219-228
AbstractObjective: Misophonia is a neurophysiological disorder, phenotypically characterized by heightened autonomic nervous system arousal which is accompanied by a high magnitude of emotional reactivity to repetitive and pattern-based auditory stimuli. This study identifies the prevalence of psychiatric symptoms in misophonia sufferers, the association between severity of misophonia and psychiatric symptoms, and the association between misophonia severity and gender. Methods: Fifty-two misophonia sufferers, 30 females (mean age?=?40.93 ± 15.29) and 22 males (mean age?=?51.18 ± 15.91) were recruited in our study and they were diagnosed according the criteria proposed by Schröder et al. The participants were evaluated by the A-MISO-S for the severity of misophonia and the MINI to assess the presence of psychiatric symptoms. Results: The most common comorbid symptoms reported by the misophonia patients were respectively PTSD (N?=?8, 15.38%), OCD (N?=?6, 11.53%), MDD (N?=?5, 9.61%), and anorexia (N?=?5, 9.61%). Misophonia severity was associated with the symptoms of MDD, OCD, and PTSD as well as anorexia. There was an indication of a significant difference between men and women in the severity of misophonic symptoms. Conclusion: Our findings highlight the importance of recognizing psychiatric comorbidity among misophonia sufferers. The presence of these varying psychiatric disorders’ features in individuals with misophonia suggests that while misophonia has unique clinical characteristics with an underlying neurophysiological mechanism, may be associated with psychiatric symptoms. Therefore, when assessing individuals with misophonia symptoms, it is important to screen for psychiatric symptoms. This will assist researchers and clinicians to better understand the nature of the symptoms and how they may be interacting and ultimately allocating the most effective therapeutic strategies. 相似文献