Phosphonate coating of SiO<Subscript>2</Subscript> nanoparticles abrogates inflammatory effects and local changes of the lipid composition in the rat lung: a complementary bioimaging study

Background

The well-known inflammatory and fibrogenic changes of the lung upon crystalline silica are accompanied by early changes of the phospholipid composition (PLC) as detected in broncho-alveolar lavage fluid (BALF). Amorphous silica nanoparticles (NPs) evoke transient lung inflammation, but their effect on PLC is unknown. Here, we compared effects of unmodified and phosphonated amorphous silica NP and describe, for the first time, local changes of the PLC with innovative bioimaging tools.

Methods

Unmodified (SiO₂-n), 3-(trihydroxysilyl) propyl methylphosphonate coated SiO₂-n (SiO₂-p) as well as a fluorescent surrogate of SiO₂-n (SiO₂-FITC) nanoparticles were used in this study. In vitro toxicity was tested with NR8383 alveolar macrophages. Rats were intratracheally instilled with SiO₂-n, SiO₂-p, or SiO₂-FITC, and effects on lungs were analyzed after 3 days. BALF from the right lung was analyzed for inflammatory markers. Cryo-sections of the left lung were subjected to fluorescence microscopy and PLC analyses by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MS), Fourier transform infrared microspectroscopy (FT-IR), and tandem mass spectrometry (MS/MS) experiments.

Results

Compared to SiO₂-p, SiO₂-n NPs were more cytotoxic to macrophages in vitro and more inflammatory in the rat lung, as reflected by increased concentration of neutrophils and protein in BALF. Fluorescence microscopy revealed a typical patchy distribution of SiO₂-FITC located within the lung parenchyma and alveolar macrophages. Superimposable to this particle distribution, SiO₂-FITC elicited local increases of phosphatidylglycerol (PG) and phosphatidylinositol (PI), whereas phoshatidylserine (PS) and signals from triacylgyceride (TAG) were decreased in the same areas. No such changes were found in lungs treated with SiO₂-p or particle-free instillation fluid.

Conclusions

Phosphonate coating mitigates effects of silica NP in the lung and abolishes their locally induced changes in PLC pattern. Bioimaging methods based on MALDI-MS may become a useful tool to investigate the mode of action of NPs in tissues.

     

Synthesized Hollow TiO<Subscript>2</Subscript>@g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> Composites for Carbon dioxide Reduction Under Visible Light

The hollow TiO₂@g-C₃N₄ composites were synthesized by a facile stirring method. The phase compositions, optical properties, and morphologies of the samples were characterized via X-ray diffraction, scanning electron microscope, transmission electron microscopy, high resolution transmission electron microscopy, fourier transform infrared spectroscopy, N₂ adsorption–desorption, UV–Vis diffuse reflectance spectroscopy and Photoluminescence. The photocatalyitc performance was evaluated by reduction carbon dioxide under visible light irradiation. The results indicated that TiO₂@g-C₃N₄ nanocomposites displayed higher photocatalytic activity compared with pure g-C₃N₄. The increased photocatalytic activity of TiO₂@g-C₃N₄ nanocomposites can be attributed to facilitating the photo-induced electron–hole separation efficiency and enhancing the photo-induced electron migration.

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Metabolomic effects of CeO<Subscript>2</Subscript>, SiO<Subscript>2</Subscript> and CuO metal oxide nanomaterials on HepG2 cells

Background

To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for 3 days to five different CeO₂ (either 30 or 100 μg/ml), 3 SiO₂ based (30 μg/ml) or 1 CuO (3 μg/ml) nanomaterials with dry primary particle sizes ranging from 15 to 213 nm. Metabolomic assessment of exposed cells was then performed using four mass spectroscopy dependent platforms (LC and GC), finding 344 biochemicals.

Results

Four CeO₂, 1 SiO₂ and 1 CuO nanomaterials increased hepatocyte concentrations of many lipids, particularly free fatty acids and monoacylglycerols but only CuO elevated lysolipids and sphingolipids. In respect to structure-activity, we now know that five out of six tested CeO₂, and both SiO₂ and CuO, but zero out of four TiO₂ nanomaterials have caused this elevated lipids effect in HepG2 cells. Observed decreases in UDP-glucuronate (by CeO₂) and S-adenosylmethionine (by CeO₂ and CuO) and increased S-adenosylhomocysteine (by CuO and some CeO₂) suggest that a nanomaterial exposure increases transmethylation reactions and depletes hepatic methylation and glucuronidation capacity. Our metabolomics data suggests increased free radical attack on nucleotides. There was a clear pattern of nanomaterial-induced decreased nucleotide concentrations coupled with increased concentrations of nucleic acid degradation products. Purine and pyrimidine alterations included concentration increases for hypoxanthine, xanthine, allantoin, urate, inosine, adenosine 3′,5′-diphosphate, cytidine and thymidine while decreases were seen for uridine 5′-diphosphate, UDP-glucuronate, uridine 5′-monophosphate, adenosine 5′-diphosphate, adenosine 5′-monophophate, cytidine 5′-monophosphate and cytidine 3′-monophosphate. Observed depletions of both 6-phosphogluconate, NADPH and NADH (all by CeO₂) suggest that the HepG2 cells may be deficient in reducing equivalents and thus in a state of oxidative stress.

Conclusions

Metal oxide nanomaterial exposure may compromise the methylation, glucuronidation and reduced glutathione conjugation systems; thus Phase II conjugational capacity of hepatocytes may be decreased. This metabolomics study of the effects of nine different nanomaterials has not only confirmed some observations of the prior 2014 study (lipid elevations caused by one CeO₂ nanomaterial) but also found some entirely new effects (both SiO₂ and CuO nanomaterials also increased the concentrations of several lipid classes, nanomaterial induced decreases in S-adenosylmethionine, UDP-glucuronate, dipeptides, 6-phosphogluconate, NADPH and NADH).

     

Effect of Potassium on the Physiochemical and Catalytic Characteristics of V<Subscript>2</Subscript>O<Subscript>5</Subscript>/TiO<Subscript>2</Subscript> Catalysts in <Emphasis Type="Italic">o</Emphasis>-Xylene Partial Oxidation to Phthalic Anhydride

Abstract

Vanadia species formed on the surface depend on the K/V atomic ratio. At small K/V ratios, Raman spectra show the formation of the K-doped and K-perturbed monomeric species. At K/V?=?1, kristalline KVO₃ is mainly present on the surface. In situ high temperature XRD-results exhibit a promoting effect on the anatase to rutile phase transformation in the presence of 0.03 and 0.21 wt% potassium. Large amount of K (3 wt%) provides thermal stability of V/Ti/O catalyst and no transformation is found up to 600?°C. Reduction of vanadia K-doped vanadia catalysts is moved to higher temperatures than for the catalyst without potassium. The catalyst having 0.21 wt% K possesses the highest activity in o-xylene oxidation. Furthermore, the K-doped monomeric vanadia species in this catalyst leads to a promoted adsorption or a prevented desorption of phthalide, resulting in a decreased selectivity towards phthalide and CO_x and a increased PA selecticity.

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Improving the efficiency of dye-sensitized solar cell via tuning the Au plasmons inlaid TiO<Subscript>2</Subscript> nanotube array photoanode

Plasmonic enhancement is an effective method to improve the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). The size and amount of plasmon play key roles in plasmonic effect; however, the report on the relationship between morphology and processing of plasmon is rare. In this work, a series of Au nanoparticles (NPs) inlaid into TiO₂ nanotube (NT) based photoanodes have been synthesized through tuning HAuCl₄ solution concentration and irradiation time during the photoreduction process. Meanwhile, the optical and photoelectrical properties of these plasmonic DSSCs have also been verified. The results demonstrate that the optimized plasmonic DSSC (irradiation time: 5 min, solution concentration: 0.5 mM) showed a 19.0% improvement of PCE, compared to the reference DSSC without Au NPs. The improved PCE is mainly attributed to the enhanced photocurrent generated by surface plasmon resonance (SPR) effect of small sized Au NPs as well as light scattering effect of large sized particles.

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Influence of Tetraalkylammonium Compounds on Photocatalytic and Physical Properties of TiO<Subscript>2</Subscript>

A wide range of experimental data are reported for the first time on the TiO₂ prepared by hydrolysis of highly concentrated Ti(OⁱPr)₄ in water solutions of quaternary ammonium compounds (QACs). These TiO₂ materials have been shown to be photocatalytically active under visible light irradiation (LED, 450 nm) using acetone as a model substrate oxidized in the gas phase. Five-fold increase in activity in comparison with the commercial photocatalyst KRONOClean 7000 is achieved. Colloidal solutions of hydrolyzed Ti(OⁱPr)₄ have been studied by SAXS method suggesting the way in which QACs solutions may influence the final composition of TiO₂. Phase composition, morphology, texture and surface properties of the modified TiO₂ have been studied using XRD, BET, SEM and low-temperature FTIR with CO probe. The surface elemental composition has been investigated by XPS method. Additional low-energy levels and high concentration of acid surface sites originated from N/C-doping, are likely to be the main reasons for exceptional photocatalytic performance of these samples.

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[Zn(<Emphasis Type="SmallCaps">l</Emphasis>-proline)<Subscript>2</Subscript>] Catalyzed One-Pot Synthesis of Propargylamines Under Solvent-Free Conditions

A simple, one-pot, three-component, green synthesis of a wide range of propargylamines is reported by A³-coupling (aldehyde, alkyne and amine) via C–H activation of alkynes using [Zn(l-proline)₂] as an efficient and reusable heterogeneous catalyst. High catalytic activity was achieved in comparatively low temperature under solvent-free conditions. All reactions were carried out in an open atmosphere without the use of any co-catalyst/additive.

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Embedding Noble-Metal-Free Ni<Subscript>2</Subscript>P Cocatalyst on g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> for Enhanced Photocatalytic H<Subscript>2</Subscript> Evolution in Water Under Visible Light

Photocatalytic hydrogen evolution is considered as one of the promising pathways to settle the energy crises and environmental issues by utilizing solar energy. In this paper, noble-metal-free Ni₂P was used as cocatalyst to enhance g-C₃N₄ for photocatalytic hydrogen production under visible light irradiation (λ?>?420 nm). Characterization results indicated that Ni₂P nanoparticles were successfully loaded onto g-C₃N₄, which can significantly contribute to accelerate the separation and transfer of photogenerated electron. The hydrogen evolution rate reached ～?270 µmol h^?1 g^?1 and the apparent quantum yield (AQY) was ～?2.85% at 420 nm. Meanwhile, there is no obviously decrease of the hydrogen production rate even after 36 h under visible light illumination. In addition, the mechanism of photocatalytic hydrogen evolution was also elaborated in detail.

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Removal of atrazine by photoelectrocatalytic process under sunlight using WN-codoped TiO<Subscript>2</Subscript> photoanode

The present study was focused on the degradation of Atrazine (ATZ) and major by-products (DEA, DIA, DEDIA and ATZ-OH) from water by photoelectrocatalytic (PEC) oxidation process under solar light. The undoped TiO₂, sub-stoichiometric TiO₂ (TiO_2?x) and codoped TiO₂ (TiO₂:WN) photoanodes were prepared by means of a radio frequency magnetron sputtering (RF-MS) deposition process. The X-ray photoelectron spectra (XPS) analysis shows that the N and W atoms were incorporated into the O and Ti lattice sites of TiO₂ respectively (case of TiO₂:WN film), while the XPS measurements of the TiO_2?x films composition was determined to be TiO_1.9. The UV–Vis transmittance spectra shows that in the case of the TiO₂:WN films, the presence of nitrogen and tungsten improve the optical response of TiO₂ under visible range compare to the presence of oxygen vacancies in to the TiO_2?x films. The experimental results under solar light with an initial concentration of ATZ (100 µg L^?1) show that after 180 min of treatment, the degradation of ATZ were 34.98%, 68.57% and 94.33% using TiO₂, TiO_2?x and TiO₂:WN photoanodes, respectively. These results of ATZ degradation proved that TiO₂:WN photoanode was more photoactive under solar light. The evolution by-products of ATZ under sunlight show that the principal mechanism of ATZ degradation was the oxidation of alkyl side chain and dealkylation.

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A Comparative Study of the Photoconduction,Photocatalytic and Electrocatalytic Performance of g-C<Subscript>3</Subscript>N<Subscript>4</Subscript>/ZnS/CuS Heterojunctions with Different Morphologies

Ternary heterojunctions g-C₃N₄/ZnS/CuS with different morphologies were constructed. The g-C₃N₄/ZnS/CuS (hexagonal-nanosheets) exhibited the largest photocurrent, the best photocatalytic and electrochemical activity, which revealed the influence discipline of different morphologies on photoconductivity, photo/electro-catalytic activity. It indicated that this heterojunction can be used as an excellent photoconductor device, a high-efficiency photo/electro-catalyst.

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Product Selectivity as a Function of ZrO<Subscript>2</Subscript> Phase in Cu/ZrO<Subscript>2</Subscript> Catalysts in the Conversion of Cyclohexanol

The influence of ZrO₂ phase on the product selectivity arising from the preparation method of Cu/ZrO₂ is studied in the gas phase conversion of cyclohexanol. This study results are supported by NH₃-TPD, XRD, pyridine-FTIR and N₂O pulse chemisorptions measurements. However, N₂O pulse chemisorptions studies did not reveal significant differences between the two catalysts. The product selectivity is completely dependent on the ZrO₂ phase which ultimately led to the differences in the acidic properties observed through NH₃-TPD and pyridine-FTIR experiments. Catalyst poisoning experiments using NH₃ co-feeding brought a reversal in the product selectivity.

Graphical Abstract

Cu/ZrO₂ catalyst prepared by impregnation method containing monoclinic ZrO₂ yields cyclohexanone and Cu/ZrO₂ catalyst prepared by coprecipitation method with tetragonal ZrO₂ phase possessing strong acidic sites yields benzene when cyclohexanol is contacted in vapour phase conditions

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Neuroinflammation is induced by tongue-instilled ZnO nanoparticles via the Ca<Superscript>2+</Superscript>-dependent NF-κB and MAPK pathways

Background

The extensive biological applications of zinc oxide nanoparticles (ZnO NPs) in stomatology have created serious concerns about their biotoxicity. In our previous study, ZnO NPs were confirmed to transfer to the central nervous system (CNS) via the taste nerve pathway and cause neurodegeneration after 30 days of tongue instillation. However, the potential adverse effects on the brain caused by tongue-instilled ZnO NPs are not fully known.

Methods

In this study, the biodistribution of Zn, cerebral histopathology and inflammatory responses were analysed after 30 days of ZnO NPs tongue instillation. Moreover, the molecular mechanisms underlying neuroinflammation in vivo were further elucidated by treating BV2 and PC12 cells with ZnO NPs in vitro.

Results

This analysis indicated that ZnO NPs can transfer into the CNS, activate glial cells and cause neuroinflammation after tongue instillation. Furthermore, exposure to ZnO NPs led to a reduction in cell viability and induction of inflammatory response and calcium influx in BV2 and PC12 cells. The mechanism underlying how ZnO NPs induce neuroinflammation via the Ca²⁺-dependent NF-κB, ERK and p38 activation pathways was verified at the cytological level.

Conclusion

This study provided a new way how NPs, such as ZnO NPs, induce neuroinflammation via the taste nerve translocation pathway, a new mechanism for ZnO NPs-induced neuroinflammation and a new direction for nanomaterial toxicity analysis.

     

Replication of SMSI via ALD: TiO<Subscript>2</Subscript> Overcoats Increase Pt-Catalyzed Acrolein Hydrogenation Selectivity

The effects of sub-nanometer atomic layer deposition films of titania and alumina are compared for the acrolein hydrogenation selectivity of Pt/SrTiO₃ catalysts. The titania-overcoated catalyst is similar to strong metal-support interaction catalysts formed by high temperature reduction, with a thin titania film on top of the supported Pt nanoparticles and an increase in allyl alcohol selectivity, neither of which are observed for the alumina-overcoated catalyst.

Graphical Abstract

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Protein corona: implications for nanoparticle interactions with pulmonary cells

Background

We previously showed that cerium oxide (CeO₂), barium sulfate (BaSO₄) and zinc oxide (ZnO) nanoparticles (NPs) exhibited different lung toxicity and pulmonary clearance in rats. We hypothesize that these NPs acquire coronas with different protein compositions that may influence their clearance from the lungs.

Methods

CeO₂, silica-coated CeO₂, BaSO₄, and ZnO NPs were incubated in rat lung lining fluid in vitro. Then, gel electrophoresis followed by quantitative mass spectrometry was used to characterize the adsorbed proteins stripped from these NPs. We also measured uptake of instilled NPs by alveolar macrophages (AMs) in rat lungs using electron microscopy. Finally, we tested whether coating of gold NPs with albumin would alter their lung clearance in rats.

Results

We found that the amounts of nine proteins in the coronas formed on the four NPs varied significantly. The amounts of albumin, transferrin and α-1 antitrypsin were greater in the coronas of BaSO₄ and ZnO than that of the two CeO₂ NPs. The uptake of BaSO₄ in AMs was less than CeO₂ and silica-coated CeO₂ NPs. No identifiable ZnO NPs were observed in AMs. Gold NPs coated with albumin or citrate instilled into the lungs of rats acquired the similar protein coronas and were cleared from the lungs to the same extent.

Conclusions

We show that different NPs variably adsorb proteins from the lung lining fluid. The amount of albumin in the NP corona varies as does NP uptake by AMs. However, albumin coating does not affect the translocation of gold NPs across the air-blood barrier. A more extensive database of corona composition of a diverse NP library will develop a platform to help predict the effects and biokinetics of inhaled NPs.

     

Suppression of PTPN6 exacerbates aluminum oxide nanoparticle-induced COPD-like lesions in mice through activation of STAT pathway

Background

Inhaled nanoparticles can deposit in the deep lung where they interact with pulmonary cells. Despite numerous studies on pulmonary nanotoxicity, detailed molecular mechanisms of specific nanomaterial-induced lung injury have yet to be identified.

Results

Using whole-body dynamic inhalation model, we studied the interactions between aluminum oxide nanoparticles (Al₂O₃ NPs) and the pulmonary system in vivo. We found that seven-day-exposure to Al₂O₃ NPs resulted in emphysema and small airway remodeling in murine lungs, accompanied by enhanced inflammation and apoptosis. Al₂O₃ NPs exposure led to suppression of PTPN6 and phosphorylation of STAT3, culminating in increased expression of the apoptotic marker PDCD4. Rescue of PTPN6 expression or application of a STAT3 inhibitor, effectively protected murine lungs from inflammation and apoptosis, as well as, in part, from the induction of chronic obstructive pulmonary disease (COPD)-like effects.

Conclusion

In summary, our studies show that inhibition of PTPN6 plays a critical role in Al₂O₃ NPs-induced COPD-like lesions.

     

Calcium-dependent cyto- and genotoxicity of nickel metal and nickel oxide nanoparticles in human lung cells

Background

Genotoxicity is an important toxicological endpoint due to the link to diseases such as cancer. Therefore, an increased understanding regarding genotoxicity and underlying mechanisms is needed for assessing the risk with exposure to nanoparticles (NPs). The aim of this study was to perform an in-depth investigation regarding the genotoxicity of well-characterized Ni and NiO NPs in human bronchial epithelial BEAS-2B cells and to discern possible mechanisms. Comparisons were made with NiCl₂ in order to elucidate effects of ionic Ni.

Methods

BEAS-2B cells were exposed to Ni and NiO NPs, as well as NiCl₂, and uptake and cellular dose were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS). The NPs were characterized in terms of surface composition (X-ray photoelectron spectroscopy), agglomeration (photon cross correlation spectroscopy) and nickel release in cell medium (ICP-MS). Cell death (necrosis/apoptosis) was investigated by Annexin V-FITC/PI staining and genotoxicity by cytokinesis-block micronucleus (cytome) assay (OECD 487), chromosomal aberration (OECD 473) and comet assay. The involvement of intracellular reactive oxygen species (ROS) and calcium was explored using the fluorescent probes, DCFH-DA and Fluo-4.

Results

NPs were efficiently taken up by the BEAS-2B cells. In contrast, no or minor uptake was observed for ionic Ni from NiCl₂. Despite differences in uptake, all exposures (NiO, Ni NPs and NiCl₂) caused chromosomal damage. Furthermore, NiO NPs were most potent in causing DNA strand breaks and generating intracellular ROS. An increase in intracellular calcium was observed and modulation of intracellular calcium by using inhibitors and chelators clearly prevented the chromosomal damage. Chelation of iron also protected against induced damage, particularly for NiO and NiCl₂.

Conclusions

This study has revealed chromosomal damage by Ni and NiO NPs as well as Ni ionic species and provides novel evidence for a calcium-dependent mechanism of cyto- and genotoxicity.

     

Electrocatalytic H<Subscript>2</Subscript> Evolution of Bis(3,5-di-methylpyrazol-1-yl)acetate Anchored Hexa-coordinated Co(II) Derivative

A mononuclear Co(II) derivative, (1) is afforded by employing a ‘scorpionate’ type precursor, bdtbpza [bdtbpza?=?bis(3,5-di-t-butylpyrazol-1-yl)acetate]. Single crystal X-ray structure reveals that the Co^II ion exhibits an octahedral geometry possessing on a O₆ coordination environment. Detailed EPR interpretation and electrocatalytic hydrogen evolution study are reported. Electrochemical and catalytic study of 1 in DMSO with the presence of acetic acid as weak proton source shows an observed rate constant of 3.7?×?10³ s^?1 and hydrogen evolution Faradaic efficiency of 74.7%. The catalytic process requires two-electron reduction of the catalyst and formation of a cobalt(II)-hydride species as reactive intermediate.

Graphical Abstract

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Preparation and Characterization of an Efficient Nano-Inorganic Composite of CuO/ZnO/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> for the Catalytic Amination of Aryl Halides in Aqueous Conditions

In this research, an efficient recyclable nano-inorganic composite of CuO/ZnO/Al₂O₃ (CuO/ZnO/Al₂O₃ nanocatalyst) is prepared, characterized and used for the amination of aryl halides with aqueous ammonia in water. The catalyst was prepared by co-precipitation method and characterized by various techniques such as the X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, and brunauer–Emmett–Teller surface area analysis. Various aryl halides reacted with aqueous ammonia and corresponding products were obtained in high yields. CuO/ZnO/Al₂O₃ nanocatalyst as an efficient stable catalyst is recyclable up to five consecutive runs by simple filtration.

Graphical Abstract

An efficient recyclable nano-inorganic composite of CuO/ZnO/Al₂O₃ (CuO/ZnO-Al₂O₃ nanocatalyst) is prepared, characterized and used for the amination of aryl halides with aqueous ammonia in water.

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Comparison of two modes of vitamin B<Subscript>12</Subscript>supplementation on neuroconduction and cognitive function among older people living in Santiago,Chile: a cluster randomized controlled trial. a study protocol [ISRCTN 02694183]

Background

Older people have a high risk of vitamin B₁₂ deficiency; this can lead to varying degrees of cognitive and neurological impairment. CBL deficiency may present as macrocytic anemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. Less is known about subclinical vitamin B12 deficiency and concurrent neuroconduction and cognitive impairment. A Programme of Complementary Feeding for the Older Population (PACAM) in Chile delivers 2 complementary fortified foods that provide approximately 1.4 μg/day of vitamin B12 (2.4 μg/day elderly RDA). The aim of the present study is to assess whether supplementation with vitamin B12 will improve neuroconduction and cognitive function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of clinical deficiency.

Methods

We designed a cluster double-blind placebo-controlled trial involving community dwelling people aged 70-79 living in Santiago, Chile. We randomized 15 clusters (health centers) involving 300 people (20 per cluster). Each cluster will be randomly assigned to one of three arms: a) a 1 mg vitamin B12 pill taken daily and a routine PACAM food; b) a placebo pill and the milk-PACAM food fortified to provide 1 mg of vitamin B12; c) the routine PACAM food and a placebo pill.The study has been designed as an 18 month follow up period. The primary outcomes assessed at baseline, 4, 9 and 18 months will be: serum levels of vitamin B12, neuroconduction and cognitive function.

Conclusions

In view of the high prevalence of vitamin B12 deficiency in later life, the present study has potential public health interest because since it will measure the impact of the existing program of complementary feeding as compared to two options that provide higher vitamin B12 intakes that might potentially may contribute in preserving neurophysiologic and cognitive function and thus improve quality of life for older people in Chile.

Trial registration

ISRCTN: ISRCTN02694183

     

Effect of electrolyte additives on high-temperature cycling performance of spinel LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> cathode

Lithium difluoroborate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFBOP) and lithium difluorophosphate (LiPF₂O₂) are investigated as electrolyte additives to alleviate the severe cycle capacity fading of spinel LiMn₂O₄ cathode of lithium-ion batteries, especially at elevated temperatures. Compared with that of the routine electrolyte, the capacity retention is significantly improved at both room temperature and 55 °C by adding LiBOB and LiDFOB as electrolyte additives. Moreover, surface layer formation processes on the LiMn₂O₄ electrode in the presence of the LiBOB, LiDFOB, LiDFBOP and LiPF₂O₂ are investigated by photoelectron spectroscopy (XPS) and X-ray diffraction. According to the analysis results, BOB^? anions from LiBOB or LiDFOB bond with the dissolved Mn²⁺ to form an insoluble and stable surface layer on the LiMn₂O₄ surface, which is beneficial to the suppression of the LiMn₂O₄ dissolution and electrolyte decomposition, and eventually to the improvement of the cycling performance at elevated temperatures.

Graphical abstract

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