Amount Of Sodium Dodecyl Sulfate Research Articles

Inhibition of Polyphenol Oxidase Activity by Mesoporous Silica Nanoparticles and Multiwalled Carbon Nanotubes Modified with Surfactants.

Polyphenol oxidase (PPO) is the culprit behind the browning of fruits and vegetables. Therefore, how to reduce the thermal deactivation temperature of PPO or use as few safe reagents as possible to inhibit enzymatic browning has practical significance. Mesoporous silica nanoparticles (MSNs) and multiwalled carbon nanotubes (MWCNTs) are stable and have high biosafety. In the present study, efficient PPO inhibitors were developed based on MSNs and MWCNTs. It is found that after modification with a very small amount of dodecyl trimethylammonium bromide (DTAB, ≥60 μg/mL), MSNs can significantly inhibit the activity of PPO although single MSNs and single DTAB show very limited effect on PPO activity. After modification with a very small amount of sodium dodecyl sulfate (SDS, 5.7-9.5 μg/mL), MWCNTs almost completely inactivate PPO. However, SDS@MSN and DTAB@MWCNT cannot decrease PPO activity significantly.

Fabrication of an In‐situ Synthesized Porous Silica‐Ruthenium‐Nickel Composite Catalyst for Hydrolysis of Ammonia Borane

AbstractThis work investigated in‐situ synthesis of porous silica‐nickel‐ruthenium composite catalysts for hydrolysis of ammonia borane. The precursors were prepared with an anionic surfactant, sodium dodecyl sulfate (SDS), to form porous structure in the precursor particles, and the precursors was treated in aqueous solution including sodium borohydride and ammonia borane for in‐situ process to parallelly activate and use the catalysts for hydrolysis of ammonia borane. The result of TEM and nitrogen sorption measurements suggested that the primary particle size of the in‐situ synthesized catalysts decrease with increasing the amount of SDS and sodium chloride as the additive for controlling the primary particle size probably because of the effect of sodium ions to inhibit nuclei growth of the primary particles. From the EDS analyses, the composition of active nickel and ruthenium contents increased with increasing the amount of SDS and sodium chloride except for the highest amount of SDS probably because of adsorption of the metal cations with the excess amount of the surfactant anion to decrease the amount of the metal cations including the catalyst. The in‐situ synthesized catalyst including small size primary particles and high nickel and ruthenium content tended to exhibit high activity for hydrolysis of ammonia borane.

Human ferritin nanocarriers for drug-delivery: A molecular view of the disassembly process

Ferritins are natural proteins which spontaneously self-assemble forming hollow nanocages physiologically deputed to iron storage and homeostasis. Thanks to their high stability and easy production in vitro, ferritins represent an intriguing system for nanobiotechnology. Here we investigated the mechanism of disassembly and reassembly of a human recombinant ferritin constituted by the heavy chain (hHFt) exploiting a new procedure which involves the use of minimal amounts of sodium dodecyl sulfate (SDS) and assessed its effectiveness in comparison with two commonly used protocols based on pH shift at highly acidic and alkaline values. The interest in this ferritin as drug nanocarrier is related to the strong affinity of the human H-chain for the transferrin receptor TfR-1, overexpressed in several tumoral cell lines. Using different techniques, like NMR, TEM and DLS, we demonstrated that the small concentrations of SDS can eliminate the nanocage architecture without detaching the monomers from each other, which instead remain strongly associated. Following this procedure, we encapsulated into the nanocage a small ruthenium complex with a remarkable improvement with respect to previous protocols in terms of yield, structural integrity of the recovered protein and encapsulation efficiency. In our opinion, the extensive network of interchain interactions preserved during the SDS-based disassembly procedure represents the key for a complete and correct hHFt reassembly.

Polyvinyl alcohol: Starch based membrane scaffolds for tissue transparency requirements: Fabrication, characterization and cytotoxicity studies

In this study, the characterization and cytocompatibility of polyvinyl alcohol:starch (PVA:ST) based membrane tissue scaffolds developed for tissue transparency requirements in tissue engineering applications were evaluated in the presence of sodium dodecyl sulphate (SDS). In this context, two different amounts of SDS were added to the polymer structure of transparent membrane scaffolds to roughen the surfaces of PVA:ST membranes and to promote cell adhesion. In the light of this aim, three different types of membranes were created: A constant PVA:ST ratio of 9:1 (wt:wt) was used as a control and varying amounts of SDS (2 and 4 wt% of the total polymer amount) were added to the polymer solutions. Membrane tissue scaffolds were formed by freeze-drying method. Scaffold properties such as morphology, transparency, water absorption, chemical structure and cytocompatibility were investigated. In terms of physicochemical properties, it was observed that with the addition of SDS, the membranes had a rougher surface while retaining water retention and transparency. In cytotoxicity studies, the membranes were found to be non-cytotoxic and promoted cell proliferation as assessed by MTT assay. Furthermore, the PVA:ST membrane scaffold with 4% SDS added was able to promote the attachment, migration and proliferation of Mouse Embryonic Fibroblasts (MEFs) more than the control group. Overall, the results indicate that SDS-added PVA:ST scaffold membranes are suitable for human corneal stromal regeneration, wound dressing material and neural tissue engineering applications.

Robust cooperative of cadmium sulfide with highly ordered hollow microstructure coordination polymers for regulating the photocatalytic performance

Accurately controlling and achieving selective reactivity at difficult-to-access reaction sites in organic molecules is challenging owing to the similar local and electronic environments of multiple reaction sites. In this work, we regulated multiple reaction sites in a highly selective and active manner using cobalt coordination polymers (Co-CP) 1 and 1a with various particle sizes and morphologies ranging from large granular to ordered hollow hemispheres by introducing sodium dodecyl sulfate (SDS) as a surfactant. The size and morphology of the catalysts could be tuned by controlling the amount of SDS. An SDS concentration of 0.03 mmol generated 1a having a highly ordered hollow hemispherical microstructure with a well-defined platform as a pre-made building unit. Cadmium sulfide (CdS), as a typical photocatalyst, was subsequently uniformly anchored in-situ on the premade building unit 1a to produce CdS@1a composites, that inherited the originally ordered hollow hemispherical microstructure while integrating CdS as well-dispersed catalytic active sites. Furthermore, the well-established CdS@1a composites were used as photocatalysts in selective oxidation reactions under air atmosphere with blue irradiation. The CdS0.109@1a composite with unique structural characteristics, including uniformly distributed and easily accessible catalytic sites and excellent photoelectrochemical performance, served as a highly efficient heterogeneous photocatalyst for promoting the selective oxidation of sulfides to sulfoxides as the sole products. This work presents an approach for fabricating CPs as premade building units that function as well-defined platforms for integration with photocatalysts, enabling tuning of the structure-selectivity-activity relationships.

Reconstruction of the human nipple-areolar complex: a tissue engineering approach.

Introduction: Nipple-areolar complex (NAC) reconstruction after breast cancer surgery is challenging and does not always provide optimal long-term esthetic results. Therefore, generating a NAC using tissue engineering techniques, such as a decellularization-recellularization process, is an alternative option to recreate a specific 3D NAC morphological unit, which is then covered with an in vitro regenerated epidermis and, thereafter, skin-grafted on the reconstructed breast. Materials and methods: Human NACs were harvested from cadaveric donors and decellularized using sequential detergent baths. Cellular clearance and extracellular matrix (ECM) preservation were analyzed by histology, as well as by DNA, ECM proteins, growth factors, and residual sodium dodecyl sulfate (SDS) quantification. In vivo biocompatibility was evaluated 30days after the subcutaneous implantation of native and decellularized human NACs in rats. In vitro scaffold cytocompatibility was assessed by static seeding of human fibroblasts on their hypodermal side for 7days, while human keratinocytes were seeded on the scaffold epidermal side for 10days by using the reconstructed human epidermis (RHE) technique to investigate the regeneration of a new epidermis. Results: The decellularized NAC showed a preserved 3D morphology and appeared white. After decellularization, a DNA reduction of 98.3% and the absence of nuclear and HLA staining in histological sections confirmed complete cellular clearance. The ECM architecture and main ECM proteins were preserved, associated with the detection and decrease in growth factors, while a very low amount of residual SDS was detected after decellularization. The decellularized scaffolds were in vivo biocompatible, fully revascularized, and did not induce the production of rat anti-human antibodies after 30days of subcutaneous implantation. Scaffold in vitro cytocompatibility was confirmed by the increasing proliferation of seeded human fibroblasts during 7days of culture, associated with a high number of living cells and a similar viability compared to the control cells after 7days of static culture. Moreover, the RHE technique allowed us to recreate a keratinized pluristratified epithelium after 10days of culture. Conclusion: Tissue engineering allowed us to create an acellular and biocompatible NAC with a preserved morphology, microarchitecture, and matrix proteins while maintaining their cell growth potential and ability to regenerate the skin epidermis. Thus, tissue engineering could provide a novel alternative to personalized and natural NAC reconstruction.

Sodium Dodecyl Sulfate-Adjusted Phase Composition of Hydrated Tungsten Oxides as Stable Self-Supporting Electrodes for Supercapacitors with High Volumetric Specific Capacitance.

High pseudocapacitive activity of hydrated tungsten oxides (WO3·xH2O, x = 1 or 2) makes them promising materials for supercapacitors (SCs). During their synthesis, additives such as complexing agents and surfactants generally can only affect the morphology and/or size of the products. Here, we demonstrate that not only morphology and size of WO3·xH2O were affected, its phase composition could also change from WO3·2H2O to WO3·H2O simply by increasing the amount of sodium dodecyl sulfate (SDS) during its anodization synthesis. To the best of our knowledge, such a phenomenon has not been reported before. In addition, SDS introduced a special structure to the products, i.e., WO3·xH2O nanoplatelets constructed from nanoparticle multilayers with abundant nanogaps between the multilayers, which further arranged into nanoflowers with increased amounts of SDS. Benefiting from such a structure, low internal resistance, enhanced stability, and fast redox kinetics, the as-obtained WO3·xH2O/W-3 self-supporting electrode showed a high volumetric specific capacitance of 1402.92 F cm-3 and good cycling stability (a capacity retention of 106% after 10 000 cycles). In addition, an all-solid-state asymmetric SC device based on WO3·xH2O/W-3 delivered high a volumetric energy density of 44.0 mW h cm-3 at 0.5 W cm-3. Our method demonstrates a potential way to fabricate excellent self-supporting electrodes for SCs.

Electrode Imbibition and Surfactant Interactions with Vanadium Flow Battery Electrolytes

Redox flow batteries (RFB) are a critical technology for stationary grid-scale energy storage, with potential usage with intermittent power sources, such as wind and solar. RFBs are attractive for long-duration energy storage because the anolyte and catholyte are stored separately external to the electrochemical reactor. Separating the electrolytes and the electrochemical cell decouples energy and power densities, unlike batteries that store charge in the solid-state, such as Li-ion, Pb-acid, or Ni-Cd. A standard RFB chemistry is the all-vanadium redox flow battery (VRFB), which utilizes the four oxidation states of vanadium, with V2+, V3+, V4+, and V5+. Recently our group found that adding small amounts of sodium dodecyl sulfate (SDS) to a VFRB increased the kinetics of the V2+ to V3+oxidation.Furthermore, surfactants play essential roles in battery manufacturing and operation. Surfactants can change metal oxide crystal structure, inhibit dendrite growth, limit corrosion, and prevent nanoparticle agglomeration. Surfactants are never wholly removed during manufacturing and can be present during battery operation. Therefore, it is crucial to understand how surfactants impact battery performance and their effect on the materials.This talk describes SDS's equilibrium surface properties and adsorption characteristics at the liquid−air and liquid-solid interfaces, thus providing insights into the interactions of SDS with a VFRB electrolyte. Experiments focusing on the effects of sulfuric acid and vanadium ions on SDS's equilibrium surface tension and critical micelle concentration (CMC) were completed. The Szyszkowski equation is used to calculate SDS's adsorption parameters, such as interfacial surface excess, Γsz [mol/m2], the surface excess at the saturated interface, Γ∞ [mol/m2], the minimum molecular area in the adsorption layer at the saturated interface, Amin [nm2], and the Gibbs free energy of adsorption, ΔGads [kJ/mol]. Furthermore, an examination of the spontaneous imbibition of the VFRB electrolyte with SDS into a porous carbon electrode is presented. The microstructure of porous systems, interfacial tension, and fluid−solid interactions controls the capillary-driven flow and is vital in multiphase flow in porous media. Therefore, understanding SDS's effects on the VFRB electrolyte in an electrode is critical to understanding the electrochemical reactions and molecular interactions occurring.This work was supported as part of the Breakthrough Electrolytes for Energy Storage and Systems (BEES2), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0019409.

Understanding the effect of moderate concentration SDS on CO2 hydrates growth in the presence of THF

HypothesisAdditives like Tetrahydrofuran (THF) and Sodium Dodecylsulfate (SDS) improve Carbon Dioxide (CO2) hydrates thermal stability and growth rate when used separately. It has been hypothesised that combining them could improve the kinetics of growth and the thermodynamic stability of CO2 hydrates.Simulations and ExperimentsWe exploit atomistic molecular dynamics simulations to investigate the combined impact of THF and SDS under different temperatures and concentrations. The simulation insights are verified experimentally using pendant drop tensiometry conducted at ambient pressures and high-pressure differential scanning calorimetry.FindingsOur simulations revealed that the combination of both additives is synergistic at low temperatures but antagonistic at temperatures above 274.1 K due to the aggregation of SDS molecules induced by THF molecules. These aggregates effectively remove THF and CO2 from the hydrate-liquid interface, thereby reducing the driving force for hydrates growth. Experiments revealed that the critical micelle concentration of SDS in water decreases by 20% upon the addition of THF. Further experiments in the presence of THF showed that only small amounts of SDS are sufficient to increase the CO2 storage efficiency by over 40% compared to results obtained without promoters. Overall, our results provide microscopic insights into the mechanisms of THF and SDS promoters on CO2 hydrates, useful for determining the optimal conditions for hydrate growth.

Cork granules for remediation of soils contaminated with lindane

This work aims to assess the effectiveness of an integrated approach combining surfactant-assisted soil washing (SASW) and cork granules for removing lindane from contaminated soil. It focuses on the evaluation of cork granules (raw and regranulated) as natural sorbents for lindane and on the feasibility of the combination of this physical treatment with surfactant-enhanced soil washing to face the remediation of soil polluted with this hazardous pesticide. The results demonstrate that cork can efficiently retain lindane contained in aqueous solutions and dispersions consisting of mixtures of lindane and sodium dodecylsulfate (SDS) surfactant. Performance improves when using regranulated cork because of its higher affinity for nonpolar species. For lower concentrations of lindane and without surfactant, the raw cork granules presented a sorption capacity of 3.02 mg g− 1, while the regranulated cork presented 6.52 mg g−1. When using a much higher concentration of lindane and SDS, the capacities were 1.90 and 8.21 mg g−1 for raw and regranulated cork, respectively. As well, soil washing with SDS can separate efficiently lindane from spiked soil. It was also observed that the integration of both treatments was feasible, but not as efficient as initially expected. It exhibited a non-expected antagonistic effect caused by the entrapping of the lindane into SDS micelles, which makes it not readily available for sorption. Hence, the higher the amount of SDS the lower the lindane retained by the cork. If the aim is to eliminate lindane with cork specifically, the use of low concentrations of SDS in the combined treatment is encouraged, resulting in an uptake capacity for lindane of 80% from the soil. However, better overall results are achieved when higher concentrations of SDS are used where about 91% of lindane was removed from the soil remaining mainly in the liquid phase. Dichlorination caused by interaction with hydroxyl ions is also observed, being less important in the case of using cork because it attains operation at mild conditions. The results demonstrate that the integration of processes in soil remediation does not always yield expected outcomes and they enhance the knowledge about environmental technologies and their interactions.

Synthesis and optical properties of Y3Al5O12:Ce3+,Cr3+ nano-phosphor for white LED

In this paper, Y3Al5O12:Ce3+,Cr3+ (YAG:Ce3+,Cr3+) nano-phosphors are prepared by the co-precipitation method, the average particle size of the phosphor is ∼100 nm. In addition, two surface treatments are introduced to improve the homogeneity of the nanoparticles. One is the addition of an appropriate amount of sodium dodecyl sulfate, and the other is coating a carbon layer on the surface of the nanoparticles by a solvothermal method using glucose as the carbon source. The optical properties and mechanisms of the synthesized YAG:Ce3+,Cr3+ nano-phosphors are detailed analyzed in the text. The CIE color coordinates (0.30, 0.36) of the nanoscale YAG:Ce3+,Cr3+ phosphor combined with the 450 nm blue chip is close to standard white light, which has potential application in white LED.

SDS-induced hexameric oligomerization of myotoxin-II from Bothrops asper assessed by sedimentation velocity and nuclear magnetic resonance.

We report the solution behavior, oligomerization state, and structural details of myotoxin-II purified from the venom of Bothrops asper in the presence and absence of sodium dodecyl sulfate (SDS) and multiple lipids, as examined by analytical ultracentrifugation and nuclear magnetic resonance. Molecular functional and structural details of the myotoxic mechanism of group II Lys-49 phospholipase A2 homologues have been only partially elucidated so far, and conflicting observations have been reported in the literature regarding the monomeric vs. oligomeric state of these toxins in solution. We observed the formation of a stable and discrete, hexameric form of myotoxin-II, but only in the presence of small amounts of SDS. In SDS-free medium, myotoxin-II was insensitive to mass action and remained monomeric at all concentrations examined (up to 3mg/ml, 218.2μM). At SDS concentrations above the critical micelle concentration, only dimers and trimers were observed, and at intermediate SDS concentrations, aggregates larger than hexamers were observed. We found that the amount of SDS required to form a stable hexamer varies with protein concentration, suggesting the need for a precise stoichiometry of free SDS molecules. The discovery of a stable hexameric species in the presence of a phospholipid mimetic suggests a possible physiological role for this oligomeric form, and may shed light on the poorly understood membrane-disrupting mechanism of this myotoxic protein class.

Apple-derived 3D scaffold for improving gastrointestinal viability and in-situ growth of probiotics

This study develops a novel low-cost microbial delivery system by transforming common food materials such as apple tissue into a 3D scaffold. Apple tissue scaffold was constructed by decellularization of intact tissue using a minimal amount of sodium dodecyl sulfate (0.5 % w/v). Vacuum-assisted infusion of model probiotic Lactobacillus cells led to a high encapsulation yield of probiotic cells (1010 CFU/g of scaffold) in 3D scaffolds on a wet basis. The bio-polymer coated 3D scaffolds with infused cells significantly enhanced the survivability of infused probiotic cells during simulated gastric and intestinal digestions. In addition, imaging and plate counting results validate the growth of the infused cells in the 3D scaffold after 1–2 days of fermentation in MRS media, while cells without infusion in the scaffold had limited attachment with the intact apple tissue. Overall, these results highlight the potential of the apple tissue-derived 3D scaffold to deliver probiotic cells and include the biochemical compositions to support the growth of delivered microbial cells in the colon.

A new and efficient procedure to load bioactive molecules within the human heavy-chain ferritin nanocage.

For their easy and high-yield recombinant production, their high stability in a wide range of physico-chemical conditions and their characteristic hollow structure, ferritins (Fts) are considered useful scaffolds to encapsulate bioactive molecules. Notably, for the absence of immunogenicity and the selective interaction with tumor cells, the nanocages constituted by the heavy chain of the human variant of ferritin (hHFt) are optimal candidates for the delivery of anti-cancer drugs. hHFt nanocages can be disassembled and reassembled in vitro to allow the loading of cargo molecules, however the currently available protocols present some relevant drawbacks. Indeed, protein disassembly is achieved by exposure to extreme pH (either acidic or alkaline), followed by incubation at neutral pH to allow reassembly, but the final protein recovery and homogeneity are not satisfactory. Moreover, the exposure to extreme pH may affect the structure of the molecule to be loaded. In this paper, we report an alternative, efficient and reproducible procedure to reversibly disassemble hHFt under mild pH conditions. We demonstrate that a small amount of sodium dodecyl sulfate (SDS) is sufficient to disassemble the nanocage, which quantitatively reassembles upon SDS removal. Electron microscopy and X-ray crystallography show that the reassembled protein is identical to the untreated one. The newly developed procedure was used to encapsulate two small molecules. When compared to the existing disassembly/reassembly procedures, our approach can be applied in a wide range of pH values and temperatures, is compatible with a larger number of cargos and allows a higher protein recovery.

Rapid formation of methane hydrate in environment-friendly leucine-based complex systems

Given the growing demand for natural gas (NG) in energy supply systems worldwide, solidified natural gas (SNG) is viewed as a potential NG storage and transportation method owing to its numerous advantages. However, using significant amounts of sodium dodecyl sulfate (SDS) to improve its slow formation kinetics has a negative influence on the environment, and severe foaming hinders the system's recovery. To overcome the associated issues, the main promoter has been chosen to be the ecologically safe and non-foaming L-leucine, with low concentrations of SDS and NaCl, as well as glass beads of various particle sizes, added to achieve synergistic effects. The hydrophobic micro-regions created by the leucine molecules, as well as the porous hydrate characteristics, considerably enhanced hydrate formation in the leucine-based complex system. At the effective promotion concentration, the SDS dosage is reduced by 60–90%. Owing to their strong promotion effect and non-foaming feature, yielding almost non-toxic properties, the LS1 and LN4 systems may be employed commercially. With a target of advancing SNG technology, this study serves as a reference for future developments of SNG technology based on the idea of environmental friendliness.

Influence of surfactants and organic polymers on monolithic shape-stabilized phase change materials synthesized via sol-gel route

Shape-stabilized phase change materials (ss-PCMs) can store up to five times more thermal energy than commercially available composite PCM boards based on core-shell PCMs, but have low mechanical stabilities. Therefore, we have recently synthesized ss-PCMs with high mechanical stability via a novel porogen-assisted sol-gel process. Here, we track the ss-PCM formation in situ and analyze the influence of the porogens sodium dodecyl sulfate (SDS) and poly(vinyl alcohol) (PVA) on ss-PCM properties. During gelation the silica scaffold is built around PCM droplets covered with SDS in an O/W emulsion. All ss-PCMs exhibit a high shape-stability (∼100%), a high long-term performance (> 2000 thermal cycles) and a high chemical stability, regardless of the amount of porogen used in the synthesis. Higher PVA amounts separate the emulsion in large hydrophilic and small hydrophobic regions and increase the silica macropore width in ss-PCMs from 1007 nm to 8801 nm due to silica fragmentation during drying. The silica fragmentation lowers the compressive strength (1.2 MPa) and thermal conductivity (0.37 W/mK) of the ss-PCMs by 50% and by 17% (10 °C), respectively. In contrast, low SDS amounts can not stabilize all PCM droplets in the emulsion from phase-separation, resulting in a partially fragmented silica phase. Too high SDS concentrations decrease the viscosity and hence, stability of the emulsion. Consequentially, the silica macropores collapse during drying, which lower the compressive strength (1.02 MPa) and thermal conductivity (0.37 W/mK) of ss-PCMs by 63% and 25% (10 °C), respectively.

Simultaneous determination of three allergic proteins in rice and products by high performance liquid chromatography-tandem mass spectrometry combined with stable isotope-labeled peptides

基于稳定同位素标记特征肽段和液相色谱-质谱联用仪建立稻米及制品中3种过敏蛋白质的同时定量方法。稻米及制品样品经盐溶液提取,赖氨酰基内切酶(Lys-C)和胰蛋白酶依次水解,C18-SD柱净化后,采用纳升高效液相色谱-线性离子阱-静电场轨道阱(NanoLC-LTQ-Orbitrap)采集和Protein Discovery软件鉴定,NCBI和Uniprot数据库的基本局部搜索比对工具(BLAST)筛选验证,最终获得表征稻米及制品中α-淀粉酶/胰蛋白酶抑制剂类蛋白质(seed allergenic protein RAG2, RAG2)、乙二醛酶Ⅰ活性蛋白(glyoxalase Ⅰ)和α-球蛋白(19 kDa globulin)3种过敏蛋白质的特异性肽段。3个特异性肽段经液相色谱梯度洗脱,在Poroshell色谱柱上实现完全分离,由三重四极杆质谱仪分析。实验通过优化多反应监测(MRM)质谱参数,比较不同溶剂体系、水解酶种类和酶量等酶解条件,结合内标法定量,实现对稻米及制品中3种蛋白质的绝对定量。实验结果表明,当酶解溶剂中含1 g/L十二烷基硫酸钠,采用Lys-C和胰蛋白酶组合消化策略,可有效提高3种蛋白质的酶切效率至65.7%~97.3%。该方法在1~200 nmol/L范围内线性关系良好,相关系数均大于0.9972, 3种蛋白质的检出限和定量限分别为3 mg/kg和10 mg/kg。3种蛋白质在空白稻米制品基质中3个水平下的加标回收率为80.6%~103.7%,日间和日内精密度均小于11.5%。该方法稳定性好,检测灵敏度高,操作简便,在分析各类稻米及制品中3种过敏蛋白质含量具有广泛的应用前景。

Dosing metric in cellular experiments: The mol/cell metric has its limitations

It has been argued that the mol/cell metric is more universal than concentration of the toxic agent since in many cases the effect of dose expressed as mol/cell is independent of ex-perimental setup. We confirmed it for hemolysis of erythrocytes in phosphate-buffered saline induced by hypochlorite where the amount of femtomoles/cell of hypochlorite needed for 50% hemolysis was independent of erythrocyte concentration. However, in the presence of blood plasma this metric became dependent on cell concentration. Similarly, the effect of 3-bromopyruvic acid (3-BP) on PEO1 cells as a function of mol/cell ratio depended on the volume of the 3-BP containing medium, due to the reaction of 3-BP with components of the medium. Hemolytic amounts of sodium dodecyl sulfate and Triton X-100 expressed as mol/cell decreased with increasing cell concentration while the effect of DMSO on the viability of a constant number of fibroblasts was independent of the volume of DMSO-containing medium. These results demonstrate that the mol/cell metric is still dependent on experimental conditions when the toxic agent interacts with components of the medium or when its physical state is modified by the target cells, and the effect is independent of the mol/per cell ratio for high excess of a cell damaging agent.

Boosting high-rate-partial-state-of-charge performance of lead-acid batteries by incorporating trace amount of sodium dodecyl sulfate modified multi-walled carbon nanotubes into negative active materials

In this work, trace amount of sodium dodecyl sulfate modified multi-walled carbon nanotubes acid-treated multi-walled carbon nanotubes (SDS-MWCNTs) is incorporated into the negative active materials (NAMs) of lead acid battery by simply blending the SDS-MWCNTs aqueous dispersion with the dry mixture of lead oxide powder, expanders and carbon black for lead paste preparation. As the sulfate groups on SDS can combine with Pb2+ ions to make PbSO4 to generate 3PbO·PbSO4·H2O (3BS), the cured NAMs incorporated with SDS-MWCNTs exhibit an improved 3BS percentage as well as an increased 3BS crystal size. The 3BS percentage reaches 22.47% in the cured NAMs with 100 ppm SDS-MWCNTs, more than 5.4% higher than that in the NAMs without SDS-MWCNTs. After formation, the NAMs containing SDS-MWCNTs presents a morphology of the interconnected Pb rods, which accelerates the kinetics for the electrochemical reactions between Pb and PbSO4 and thus retards PbSO4 accumulation. Simulated cells are assembled, and the cell constructed by the negative plate containing 100 ppm SDS-MWCNTs can achieve a high-rate partial-state-of-charge (HRPSoC) cycle-life of 45,692 cycles, more than 2.1 times as long as that of the cell assembled with the negative plate without SDS-MWCNTs. Our method is of great convenience and low-cost, it is supposed to have a great feasibility in lead-acid battery industry.

Surfactant-Assisted Synthesis of Pt Nanocubes Using Poly(N-isopropylacrylamide) Nanogels.

Poly(N-isopropylacrylamide) (PNIPAM) nanogels were prepared by emulsion polymerization using sodium dodecyl sulfate (SDS) and employed as a capping agent in platinum nanoparticle (Pt NP) synthesis by liquid-phase reduction with hydrogen gas. When the PNIPAM nanogels were used without removing SDS, that is, a slight amount of SDS was included in the reaction solution, Pt nanocubes (NCs) were predominantly produced (>80%). The proportion of the resultant Pt NCs was much higher than that obtained using the PNIPAM linear polymer (∼60%). To clarify the effects of the three-dimensional polymer network and SDS, we synthesized Pt NPs using the PNIPAM nanogel without SDS (SDS-free PNIPAM nanogel) and found that Pt NCs are rarely formed, and most NPs obtained have an irregular shape. When only SDS was used as a capping agent, NCs were hardly obtained, but other polyhedral NPs were formed. Furthermore, the use of SDS together with the PNIPAM polymer led to the decrease in the proportion of the Pt NCs compared with that obtained using only the linear polymer. These results indicate that the enhancement of the Pt NC proportion using the PNIPAM nanogel with SDS is attributable to not only the three-dimensional polymer network of the PNIPAM nanogel but also the assist of SDS as a capping agent.