Effect of temperature and pH on the encapsulation and release of ß-carotene from octenylsuccinated oat ß-glucan micelles.

Effect and working mechanism of temperature and pH on encapsulation and release of ß-carotene from octenylsuccinated-oat-ß-glucan-micelles (OSßG-Ms) were investigated. The stability and solubility of ß-carotene, and changes in surface hydrophilicity, core hydrophobicity, and size of ß-carotene-loaded-OSßG-Ms were determined. When exposed to temperature (25-45 °C) and pH (4.5-8.5), ß-carotene solubilization changed in parabolic manners. Size and absolute zeta-potential of ß-carotene-loaded-OSßG-Ms decreased with temperature, while they gave parabolic changing patterns with pH. Those results were ascribed to their hydrophilicity, hydrophobicity, and core/shell compactness via regulating molecule mobility, orientation, and interactions by temperature/pH. The higher temperature concluded with higher ß-carotene release, while a U-shaped release profile was observed with pH. Besides its diffusion, erosion-induced shrinking and collapsing of OSßG-Ms favored ß-carotene release at pH 1.2-4.5, which was replaced by swelling-induced structural-relaxation at pH 6.8-8.5. The results were favourable in controlling the behavior of ß-carotene-loaded-OSßG-Ms by selectively applying environmental parameters.

Molecular mechanism underlying the effects of temperature and pH on the size and surface charge of octenylsuccinated oat ß-glucan aggregates.

Environmental temperature and pH induced significant changes in the size and surface charge (ζ) of octenylsuccinated oat ß-glucan aggregates. The underlying mechanisms were explored by using 1H-NMR, fluorescence spectra, thermodynamic analysis, and SAXS. At pH 6.5, the size decreased with temperature while ζ continuously increased. With increasing pH at 293 K, parabolic and U-shaped trends were observed in the size and ζ, peaking at pH 8.5 and 6.5, respectively. At any tested pH, the size decreased with temperature. Overall, ζ significantly increased with temperature at each pH. As temperature increased, the compactness of hydrophobic-domains increased while the compactness of hydrophilic-domains decreased. In an acidic environment, both the compactness increased with decreasing pH, but in an alkaline environment, they decreased with pH. The compactness changes were co-driven by enthalpy and entropy and corresponded to changes in the hydrophobic interactions in hydrophobic-domains, hydrogen bonds in hydrophilic-domains and electrostatic repulsions among octenylsuccinate molecules.

Free ammonia aids ultrasound pretreatment to enhance short-chain fatty acids production from waste activated sludge.

Ultrasound pretreatment was proved to be effective in accelerating waste activated sludge (WAS) disintegration and promoting anaerobic fermentative short-chain fatty acids (SCFA) production. However, due to the high activities of SCFA consumers, SCFA yield is limited. Herein we reported an efficient strategy, i.e., using free ammonia (FA) to aid ultrasound pretreatment, to enhance SCFA accumulation. Experimental results showed that the greatest SCFA yield of 316.7 ±â€¯14.9 mg COD/g VSS was obtained at 2 w/mL ultrasound pretreatment for 15 min followed by initial 60 mg/L FA pretreatment for 2 d, which was 2.2 times (1.7 times) of that from sole ultrasound (FA) pretreatment. The mechanism study revealed that this combination method accelerated sludge solubilization, enhanced the release of biodegradable organics, and caused severe inhibitions to SCFA consumption. Moreover, this method has inhibitory effects on specific activities of hydrolytic microorganisms, SCFA-producing bacteria and methanogens, but the inhibitions to methanogens were severe.

STARD-rapid screening for the 6 most common G6PD gene mutations in the Chinese population using the amplification refractory mutation system combined with melting curve analysis.

Dot-blot hybridization and high-resolution melting curve methods are used to detect G6PD gene mutations; however, the performance and throughput limitations of these methods hinder their use for screening large populations. For simple screening, we developed a novel approach called "Amplification Refractory Mutation System combined with Melting Curve Analysis (ARMS-MC)," which enables rapid and batch-based detection of the 6 most common G6PD mutations.In this method, we established 4 PCR reaction systems that can be used to detect the 6 most common G6PD mutations (c.95A>G, c.392G>T, c.871G>A, c.1024C>T, c.1376G>T, and c.1388G>A) in the Chinese population.The ARMS-MC method was evaluated with 174 cases of clinical G6PD-deficient samples, and the results were verified by direct sequencing at G6PD gene exons. The results showed that 170 samples had ≥1 of the 6 mutations, which accounted for 97.70% of all mutations. These results were consistent with the results of direct sequencing with 100% accuracy and specificity. Sequencing validation revealed other mutations in the 4 samples in which no mutation was detected by the ARMS-MC method.ARMS-MC provides a rapid, simple, inexpensive, and accurate screening method for detecting the most common G6PD mutations in Chinese people.

Neuroprotective Mechanisms of Lycium barbarum Polysaccharides Against Ischemic Insults by Regulating NR2B and NR2A Containing NMDA Receptor Signaling Pathways.

Glutamate excitotoxicity plays an important role in neuronal death after ischemia. However, all clinical trials using glutamate receptor inhibitors have failed. This may be related to the evidence that activation of different subunit of NMDA receptor will induce different effects. Many studies have shown that activation of the intrasynaptic NR2A subunit will stimulate survival signaling pathways, whereas upregulation of extrasynaptic NR2B will trigger apoptotic pathways. A Lycium barbarum polysaccharide (LBP) is a mixed compound extracted from Lycium barbarum fruit. Recent studies have shown that LBP protects neurons against ischemic injury by anti-oxidative effects. Here we first reported that the effect of LBP against ischemic injury can be achieved by regulating NR2B and NR2A signaling pathways. By in vivo study, we found LBP substantially reduced CA1 neurons from death after transient global ischemia and ameliorated memory deficit in ischemic rats. By in vitro study, we further confirmed that LBP increased the viability of primary cultured cortical neurons when exposed to oxygen-glucose deprivation (OGD) for 4 h. Importantly, we found that LBP antagonized increase in expression of major proteins in the NR2B signal pathway including NR2B, nNOS, Bcl-2-associated death promoter (BAD), cytochrome C (cytC) and cleaved caspase-3, and also reduced ROS level, calcium influx and mitochondrial permeability after 4 h OGD. In addition, LBP prevented the downregulation in the expression of NR2A, pAkt and pCREB, which are important cell survival pathway components. Furthermore, LBP attenuated the effects of a NR2B co-agonist and NR2A inhibitor on cell mortality under OGD conditions. Taken together, our results demonstrated that LBP is neuroprotective against ischemic injury by its dual roles in activation of NR2A and inhibition of NR2B signaling pathways, which suggests that LBP may be a superior therapeutic candidate for targeting glutamate excitotoxicity for the treatment of ischemic stroke.

Bioinspired patterning with extreme wettability contrast on TiO2 nanotube array surface: a versatile platform for biomedical applications.

Binary wettability patterned surfaces with extremely high wetting contrasts can be found in nature on living creatures. They offer a versatile platform for microfluidic management. In this work, a facile approach to fabricating erasable and rewritable surface patterns with extreme wettability contrasts (superhydrophilic/superhydrophobic) on a TiO2 nanotube array (TNA) surface through self-assembly and photocatalytic lithography is reported. The multifunctional micropatterned superhydrophobic TNA surface can act as a 2D scaffold for site-selective cell immobilization and reversible protein absorption. Most importantly, such a high-contrast wettability template can be used to construct various well-defined 3D functional patterns, such as calcium phosphate, silver nanoparticles, drugs, and biomolecules in a highly selective manner. The 3D functional patterns would be a versatile platform in a wide range of applications, especially for biomedical devices (e.g., high-throughput molecular sensing, targeted antibacterials, and drug delivery). In a proof-of-concept study, the surface-enhanced Raman scattering and antibacterial performance of the fabricated 3D AgNP@TNA pattern, and the targeted drug delivery for site-specific and high-sensitivity cancer cell assays was investigated.

Compromised white matter microstructural integrity after mountain climbing: evidence from diffusion tensor imaging.

The aim of the present study was to investigate cerebral microstructural alterations after single short-term mountain climbing. Voxel-based morphometry (VBM) analysis of gray matter (GM) and white matter (WM) volumes and Tract-Based Spatial Statistics (TBSS) analysis of WM fractional anisotropy (FA) based on MRI images were carried out on 14 mountaineers before and after mountain climbing (6206 m). In addition, verbal and spatial 'two-back' tasks and serial reaction time task were also tested. No significant changes were detected in total and regional volumes of GM, WM, and cerebral spinal fluid after mountain climbing. Significant decreased FA values were found in the bilateral corticospinal tract, corpus callosum (anterior and posterior body, splenium), reticular formation of dorsal midbrain, left superior longitudinal fasciculus, right posterior cingulum bundles, and left middle cerebellar peduncle. In all the above regions, the radial diffusivity values tended to increase, except in the left superior longitudinal fasciculus the change was statistically significant. There were no significant changes in the two cognitive tests after mountain climbing. These findings indicate that short-term high-altitude exposure leads to disturbances mainly in cerebral WM, showing compromised fiber microstructural integrity, which may clarify the mechanisms underlining some cognitive and motor deficits tested previously.

Grey and white matter abnormalities in chronic obstructive pulmonary disease: a case-control study.

OBJECTIVES: The irreversible airflow limitation characterised by chronic obstructive pulmonary disease (COPD) causes a decrease in the oxygen supply to the brain. The aim of the present study was to investigate brain structural damage in COPD. DESIGN: Retrospective case-control study. Patients with COPD and healthy volunteers were recruited. The two groups were matched in age, gender and educational background. SETTING: A hospital and a number of communities: they are all located in southern Fujian province, China. PARTICIPANTS: 25 stable patients and 25 controls were enrolled from December 2009 to May 2011. METHODS: Using voxel-based morphometry and tract-based spatial statistics based on MRI to analyse grey matter (GM) density and white matter fractional anisotropy (FA), respectively, and a battery of neuropsychological tests were performed. RESULTS: Patients with COPD (vs controls) showed decreased GM density in the limbic and paralimbic structures, including right gyrus rectus, left precentral gyrus, bilateral anterior and middle cingulate gyri, bilateral superior temporal gyri, bilateral anterior insula extending to Rolandic operculum, bilateral thalamus/pulvinars and left caudate nucleus. Patients with COPD (vs controls) had decreased FA values in the bilateral superior corona radiata, bilateral superior and inferior longitudinal fasciculus, bilateral optic radiation, bilateral lingual gyri, left parahippocampal gyrus and fornix. Lower FA values in these regions were associated with increased radial diffusivity and no changes of longitudinal diffusivity. Patients with COPD had poor performances in the Mini-Mental State Examination, figure memory and visual reproduction. GM density in some decreased regions in COPD had positive correlations with arterial blood Po(2), negative correlations with disease duration and also positive correlations with visual tasks. CONCLUSION: The authors demonstrated that COPD exhibited loss of regional GM accompanied by impairment of white matter microstructural integrity, which was associated with disease severity and may underlie the pathophysiological and psychological changes of COPD.

Selective formation of ordered arrays of octacalcium phosphate ribbons on TiO(2) nanotube surface by template-assisted electrodeposition.

Using a patterned superhydrophobicity/superhydrophilicity template, micropatterned octacalcium phosphate (OCP) has been successfully fabricated on TiO(2) nanotube array surface. The resultant OCP micropattern has been characterized with scanning electron microscopy, optical microscopy, X-ray diffraction and electron probe microanalyzer. It is shown that the ribbon-like OCP crystals possess a highly ordered and hierarchically porous structure at nano-micro-scales. They can be selectively grown at superhydrophilic areas which are confined by the hydrophobic regions. The high wetting contrast template proves to be useful for constructing well-defined dual scale OCP film with porous structure biomimic to natural bone. A mechanism has been proposed to explain the formation of the OCP patterned film with hierarchically porous structure and distinct selectivity.