Differences in the effects and action modes of gut commensals against dextran sulfate sodium-induced intestinal inflammation

Inflammatory bowel disease(IBD)is a complex relapsing inflammatory disease in the gut and is driven by complicated host-gut microbiome interactions.Gut commensals have shown different functions in IBD prevention and treatment.To gain a mechanistic understanding of how different commensals affect intestinal inflammation,we compared the protective effects of 6 probiotics(belonging to the genera Akkermansia,Bifidobacterium,Clostridium,and Enterococcus)on dextran sulfate sodium(DSS)-induced colitis in mice with or without gut microbiota.Anti-inflammatory properties(ratio of interleukin(IL)-10 and IL-12)of these strains were also evaluated in an in vitro mesenteric lymph nodes(MLN)co-culture system.Results showed that 4 probiotics(belonging to the species Bifidobacterium breve,Bifidobacterium bifidum,and Enterococcus faecalis)can alleviate colitis in normal mice.The probiotic strains differed in regulating the intestinal microbiota,cytokines(IL-10,IL-1βand interferon(IFN)-γ),and tight junction function(Zonulin-1 and Occludin).By constrast,Akkermansia muciniphila AH39 and Clostridium butyricum FHuNHHMY49T1 were not protective.Interestingly,B.breve JSNJJNM2 with high anti-inflammatory potential in the MLN model could relieve colitis symptoms in antibiotic cocktail(Abx)-treated mice.Meanwhile,E.faecalis FJSWX25M1induced low levels of cytokines in vitro and showed no beneficial effects.Therefore,we provided insight into the clinical application of probiotics in IBD treatment.

Whole-process optimization for industrial production of glucosamine sulfate sodium chloride based on QbD concept

The double salt of glucosamine sulfate sodium chloride(glucosamine-SP) is an important pharmaceuticals ingredient for healing osteoarthritis. However, the study about its industrial production is rarely documented, let alone the optimization over the whole process to produce glucosamine-SP using glucosamine hydrochloride and anhydrous sodium sulfate as synthetic raw materials. In order to improve the production efficiency, this study screened the process parameters based on the concept of quality by design(QbD), optimized 13 operational parameters related to reaction and separation in the process, and finally proposed the mixed dropping process. The reaction conditions for the preparation of glucosamineSP were found as follows: the molar ratio of anhydrous sodium sulfate to glucosamine hydrochloride is 0.42, the mass ratio of water to glucosamine hydrochloride is is 2.0, the reaction temperature is 50 ℃ and the reaction time is 1 h. Through step-by-step scaling up following QbD, the mixed dropping process was successfully applied to achieve a trial production of 200 kg products satisfying national quality standards.In all, the results of this study have high technical value and guiding significance for the industrial mass production of glucosamine-SP.

Sodium selenite ameliorates dextran sulfate sodiuminduced chronic colitis in mice by decreasing Th1, Th17, and γδT and increasing CD4(+)CD25(+) regulatory T-cell responses

AIM To assess the effect of sodium selenite on the severity of dextran sulfate sodium(DSS)-induced colitis in C57BL/6 mice.METHODS Mice were randomly divided into four groups(n = 10/group): normal group, selenium(Se) group, chronic colitis group, and Se + chronic colitis group. The mice were sacrificed on day 26. Survival rates, clinical symptoms, colon length, and histological changes were determined. The percentages and absolute numbers of immune system cells in the lamina propria lymphocytes(LPL) of the colon, the expression of m RNA in colon tissue, and the concentrations of Th1, Th17, and Treg cytokines in LPL from the large intestine, were measured.RESULTS Se significantly ameliorated the symptoms of colitis and histological injury(P < 0.05 each), increasing the proportions of neutrophils and CD4+ CD25+ T cells(P < 0.05 each) and decreasing the proportions of γδT cells, CD4+, CD4+CD44+, and CD4+ CD69+ T cells in LPL(P < 0.05 each). Moreover, Se reduced the expression of IL-6, IFN-γ, IL-17 A, IL-21, T-bet, and RORγt(P < 0.05 each), but enhanced the expression of IL-10 and Foxp3(P < 0.05 each). CONCLUSION These results suggest that Se protects against DSSinduced chronic colitis perhaps by increasing the number of CD4(+)CD25(+) Tregs that suppress the secretion of proinflammatory cytokines and populations of Th1, Th17, and γδT cells.

Differential analysis of intestinal microbiota and metabolites in mice with dextran sulfate sodium-induced colitis

BACKGROUND Intestinal micro-ecological imbalances impair the intestinal barrier and induce intestinal inflammation,for example,ulcerative colitis(UC).According to the latest research,abnormalities in intestinal microbiota structure and their metabolites play a dominant role in UC progression;in addition,they could affect the mucus barrier based on different factors.Although numerous studies have confirmed the important role of intestinal microbiota in UC pathogenesis,the intricate connection between microbiota and metabolites and mucus barrier in UC occurrence remains unclear,and correlation analyses of differential microbiota and their metabolites under UC are relatively scarce.AIM To reveal the differential intestinal microbiota and metabolites in UC pathogenesis and explore more sensitive biomarker compositions.METHODS We used the antibiotic combination method to establish intestinal pseudo-aseptic mice;afterward,dextran sulfate sodium(DSS)was applied to establish an acute experimental colitis mice model.Colitis severity,assessed based on disease activity index,colorectal length,colorectal wet weight,and histological lesions,and mucus-related staining(mucopolysaccharide alcian blue and immunofluorescence of mucin),was compared between the pseudo-aseptic and bacterial colitis mice.Finally,differential intestinal microbiota,metabolites,and their association and correlations,were analyzed by 16s rDNA sequencing in combination with non-targeted metabolomics,through gas chromatography-mass spectrometry.RESULTS Compared with the pseudo-aseptic mice,intestinal bacteria positive mice were more severely ill and their intestinal mucus loss was more pronounced in DSS-induced colitis(P<0.05),suggesting that different microbiota and metabolites could cause the different degrees of colitis.Subsequently,we observed that in addition to Klebsiella,and Bacteroides,which were widely associated with colitis,Candidatus Stoquefichus,Anaerobiospirillum,Muribaculum,and Negativibacillus may be involved in protection against colitis.Furthermore,differential metabolites of the microbiota were mainly enriched in the synthesis-related pathways of key structural sequences of mucin.In combination with the mucin-related staining and immunofluorescence results,the findings indicate that the differential microbiota and their metabolites potentially regulate the composition and function of mucus under colitis.CONCLUSION Microbiota and their metabolites are major factors regulating the composition and function of mucus,in turn influencing the function and structure of intestinal mucus barrier under colitis.The different microbiota and metabolites identified in the present study could be novel biomarkers for colitis.

Dramatic Changes of Matrix Metalloproteinases-7 and Lysozyme in the Ulcerative Colitis of Mice Induced by Dextran Sulfate Sodium

Ulcerative colitis （UC） is a lifelong illness with profound emotional and social impacts, and could cause serious damage to large intestine, especially in colon. However, the pathogenesis of UC remained unclear. The present study attempts to find out the role of matrix metalloproteinases-7 （MMP-7） and lysozyme in the pathogenesis of UC through a mice model induced by dextran sulfate sodium （DSS）. The UC model was evaluated both by disease activity index （DAI） and the intestinal histopathology. The results show that there is a high correlation between the DAI score and the pathological changes of colon. Interleukin-6 （IL-6） serum levels and large intestinal fluids levels in UC mice are always higher than that of the control groups, which might be associated with the degree of the inflammation damage in the colon. The change tendency of the MMP-7 mRNA and protein expressions are both up-regulated firstly and then down-regulated from 1 to 5 d in the colon, but only the MMP-7 protein is up-regulated at 7 d again. The up-regulated MMP-7 levels in the early stage of UC may play a protective role through the activated defensins, while the down-regulated levels in the mid-later stage of UC may be connected with the severe lesions in the colon. However, the up-regulated MMP-7 levels in the later stage of UC in the colon may also contribute to the tissue repair or be served as a marker to CRC （colorectal cancer）. The distribution of lysozyme protein indicates that there may be Paneth-like cells in the colon. Both the changes of MMP-7 and lysozyme in the small intestine may play a protective role for the safe environment of the whole gut, especially to the colon of UC.

Experimental investigation of the effects of oil asphaltene content on CO_(2) foam stability in the presence of nanoparticles and sodium dodecyl sulfate

Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope(SEM),UV adsorption spectrophotometric concentration measurement and Zeta potential measurement.When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 751 s to 239 s,and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s.When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 526 s to 171 s,and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s.In addition,due to asphaltene-SDS/silica interaction in the aqueous phase,the absolute value of Zeta potential decreases,and the surface charges of particles reduce,leading to the reduction of repulsive forces between two interfaces of thin liquid film,which in turn,damages the foam stability.

Sodium dodecyl sulfate (SDS) as an effective corrosion inhibitor for Mg-8Li-3Al alloy in aqueous NaCl: A combined experimental and theoretical investigation

The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.

The Involvement of Ca^2＋ Signal Pathways in Distal Colonic Myocytes in a Rat Model of Dextran Sulfate Sodium-induced Colitis

Background： Disrupted Ca2＋ homeostasis contributes to the development of colonic dysmotility in ulcerative colitis （UC）, but the underlying mechanisms are unknown. This study aimed to examine the alteration of colonic smooth muscle （SM） Ca2＋ signaling and Ca2＋ handling proteins in a rat model of dextran sulfate sodium （DSS）-induced UC. Methods： Male Sprague-Dawley rats were randomly divided into control （n = 18） and DSS （n = 17） groups. Acute colitis was induced by 5% DSS in the drinking water for 7 days. Contractility of colonic SM strips （controls, n = 8 and DSS, n = 7） was measured in an organ bath. Cytosolic resting Ca2＋ levels （n = 3 in each group） and Ca2＋ transients （n = 3 in each group） were measured in single colonic SM cells. Ca2＋ handling protein expression was determined by Western blotting （n = 4 in each group）. Differences between control and DSS groups were analyzed by a two-sample independent t-test. Results： Average tension and amplitude of spontaneous contractions of colonic muscle strips were significantly enhanced in DSS-treated rats compared with controls （1.25 ± 0.08 g vs. 0.96 - 0.05 g, P = 0.007; and 2.67 - 0.62 g vs. 0.52 ±0.10 g, P= 0.013）. Average tensions of carbachol-evoked contractions were much weaker in the DSS group （1.08 ±0.10 g vs. 1.80 ±0.19 g, P = 0.006）. Spontaneous Ca2＋ transients were observed in more SM cells from DSS-treated rats （15/30 cells） than from controls （5/36 cells）. Peak caffeine-induced intracellular Ca2＋ release was lower in SM cells of DSS-treated rats than controls （0.413 ±0.046 vs. 0.548 ±0.041, P = 0.033）. Finally, several Ca2＋ handling proteins in colonic SM were altered by DSS treatment, including sarcoplasmic reticulum calcium-transporting ATPase 2a downregulation and phospholamban and inositol 1,4,5-trisphosphate receptor 1 upregulation. Conclusions： Impaired intracellular Ca2＋ signaling of colonic SM, caused by alteration of Ca2＋ handing proteins, contribute to colonic dysmotility in DSS-induced UC.

New approach of medicinal herbs and sulfasalazine mixture on ulcerative colitis induced by dextran sodium sulfate

BACKGROUND Sulfasalazine has been used as a standard-of-care in ulcerative colitis for decades,however,it results in severe adverse symptoms,such as hepatotoxicity,blood disorders,male infertility,and hypospermia.Accordingly,the new treatment strategy has to enhance pharmacological efficacy and stimultaneously minimize side effects.AIM To compare the anti-inflammatory action of sulfasalazine alone or in combination with herbal medicine for ulcerative colitis in a dextran sodium sulfate(DSS)-induced colitis mouse model.METHODS To induce ulcerative colitis,mice received 5%DSS in drinking water for 7 d.Animals were divided into five groups(n=9 each)for use as normal(non-DSS),DSS controls,DSS+sulfasalazine(30 mg/kg)-treatment experimentals,DSS+sulfasalazine(60 mg/kg)-treatment experimentals,DSS+sulfasalazine(30 mg/kg)+Citrus unshiu peel and Bupleuri radix mixture(30 mg/kg)(SCPB)-treatment experimentals.RESULTS The SCPB treatment showed an outstanding effectiveness in counteracting the ulcerative colitis,as evidenced by reduction in body weight,improvement in crypt morphology,increase in antioxidant defenses,down-regulation of proinflammatory proteins and cytokines,and inhibition of proteins related to apoptosis.CONCLUSIONSCPB may represent a promising alternative therapeutic against ulcerative colitis,without inducing adverse effects.

Protective Effect of Total Alkaloids of Sophora Alopecuroides on Dextran Sulfate Sodium-Induced Chronic Colitis

Objective：To investigate the effect of total alkaloids of Sophora alopecuroides（TASA） on dextran sulfate sodium（DSS）-induced colitis in mice.Methods：Chronic experimental colitis was induced by administration of 4 cycles of 4%DSS.Fifty mice were randomly distributed into 4 groups（normal,DSS,DSS/high-dose TASA, and DSS/low-dose TASA groups） by a random number table with body weight stratification.Mice in the normal group（n=11） and DSS-induced colitis control group（n=15） received control treatment of 20 mL/kg distilled water; DSS plus TASA high- and low-dose groups（n=12 each） were treated with TASA solution（20 mL/kg） at the doses of 60 mg/kg and 30 mg/kg,respectively.The severity of colitis was assessed on the basis of clinical signs, colon length,and histology scores.Moreover,secretory immunoglobulin A（slgA） and haptoglobin（HP） were analyzed by enzyme linked immunosorbent assay;intercellular adhesion molecule 1（ICAM-1） and macrophage-migration inhibitory factor（MIF） gene expressions were analyzed by quantitative reverse transcriptase realtime polymerase chain reaction（qRT-PCR） using SYBA greenⅠ;and nuclear factorκB（NF-κB） expression and activation and p65 interaction with the promoter of ICAM-1 gene were assessed by Western blotting and chromatin immunoprecipitation assay.Results：TASA administration significantly attenuated the damage and substantially reduced HP elevation and maintained the level of cecum slgA.TASA inhibited the ICAM-1 gene expression and had no effect on MIF gene expression.Also,TASA was able to reduce phospho-lκBα（p-lκBα） protein expression;however,it had no effect on the activation of IκB kinaseα（IKKα） and inhibitor of NF-κBα（IκBα）.Moreover,TASA inhibited the p65 recruitment to the ICAM-1 gene promoter.Conclusions：TASA had a protective effect on DSS-induced colitis.Such effect may be associated with its inhibition of NF-κB activation and blockade of NF-κB-regulated transcription activation of proinflammatory mediator gene.

Inhibitory Effect of Recombinant IL-25 on the Development of Dextran Sulfate Sodium-Induced Experimental Colitis in Mice

The role of interleukin 25 （IL-25） in a number of human diseases still has not been extensively studied, here we attempt to evaluate the role of recombinant IL-25 （rIL-25） in the development of dextran sulfate sodium （DSS）- induced experimental colitis. Acute colitis was induced in female C57BL/6 mice by oral administration of 2.5% DSS in drinking water ad libitum. At the same time as the start of DSS exposure, mice were injected intraperitoneally with 0.4 ＋tg of rIL-25 or PBS. Then disease activity index （DAI）, histological changes and survival rate were observed. The levels of IL-17, IL-23, and TGF-β1 in colon tissues were determined by ELISA, and the production of IL-17 by CD4＋/CD8＋ T cells was detected by intracellular flow cytometry. In contrast to the DSS treated mice, DSS ＋ rIL-25 treated mice displayed a lower DAI, limited histological changes and prolonged survival. The levels of IL-23 and TGF-β1 were significantly elevated in the DSS ＋ rIL-25 treated mice compared to the DSS treated mice. There was no significant difference in the production of IL-17 in colon tissues and CD4＋/CD8＋ T cells between the DSS ＋ rIL-25 treated mice and DSS treated mice. Our findings suggest the role of IL-25 in inhibiting development and progression of acute colitis in DSS-induced mouse colitis model. Cellular ＆ Molecular Immunology. 2008;5（6）：425-431.

Changes of CD8＋ T cells in dextran sulfate sodium-induced colitis mice pretreated with oral immune regulation

Background It has been reported that CD8＋ regulatory cells could be induced upon oral tolerance. The purpose of this study was to investigate the changes of CD8a＋ T cells in dextran sulfate sodium （DSS）-induced colitis mice pretreated by oral immune regulation. Methods The effects of five low oral doses of colitis-extracted proteins （CEP） on colitis were evaluated by clinical manifestation and histological lesions. The percentages of CD8a＋ T cells gating on CD3＋ T cells were evaluated in the gut-associated lymphoid tissues （GALT） and the spleens by flow cytometry. Differences between the two groups were compared by Student＇s t test or Mann-Whitney U test. Results Compared to bovine serum albumin （BSA）-fed control mice, administration of CEP resulted in marked alleviation of colitis. The proportion of CDSa＋ T ceils, not only in intraepithelial lymphocytes （IELs） and lamina propria lymphocytes （LPLs） of the large intestine （LI） but also in spleen from CEP-fed colitis mice, was significantly higher than that from BSA-fed colitis mice （LI-IELs： （71.5±5.4）% vs. （60.1±4.3）%, P 〈0.01; LI-LPLs： （60.7±5.2）% vs. （51.9±4.7）%, P 〈0.01; spleen： （24.1±3.6）% vs. （20.3±4.1）%, P 〈0.05; n=8）. Mucosal repair in repair-period mice five days after termination of DSS treatment was also accompanied by an increase of CD8a＋ T cells in large intestinal mucosal lymphocytes （LI-IELs： （72.1±3.7）% vs. （61.5±4.5）%, P 〈0.01; LI-LPLs： （62.1±5.7）% vs. （52.7±3.6）%, P 〈0.01; n=8）. The proportion of CD3＋ T cells increased in Peyer＇s patches （PPs） and decreased in mesenteric lymph nodes （MLNs） from colitis mice compared to untreated mice, whereas the change pattern of CD3＋T cells in PPs and MLNs from CEP-fed colitis mice was just on the contrary. Conclusion Improvement of DSS-induced colitis resulted from oral immune regulation is associated with an increase in CD8a＋T cells in spleen and large intestinal mucosa.

Dextran sodium sulfate colitis murine model: An indispensable tool for advancing our understanding of inflammatory bowel diseases pathogenesis

Inflammatory bowel diseases(IBD),including Crohn's disease and ulcerative colitis,are complex diseases that result from the chronic dysregulated immune response in the gastrointestinal tract. The exact etiology is not fully understood,but it is accepted that it occurs when an inappropriate aggressive inflammatory respon-se in a genetically susceptible host due to inciting environmental factors occurs. To investigate the path-ogenesis and etiology of human IBD,various animal models of IBD have been developed that provided indispensable insights into the histopathological and morphological changes as well as factors associated with the pathogenesis of IBD and evaluation of therapeutic options in the last few decades. The most widely used experimental model employs dextran sodium sulfate(DSS) to induce epithelial damage. The DSS colitis model in IBD research has advantages over other various chemically induced experimental models due to its rapidity,simplicity,reproducibility and controllability. In this manuscript,we review the newer publicized advances of research in murine colitis models that focus upon the disruption of the barrier function of the intestine,effects of mucin on the development of colitis,alterations found in microbial balance and resultant changes in the metabolome specifically in the DSS colitis murine model and its relation to the pathogenesis of IBD.

Enhancing the leaching effect of an ion-absorbed rare earth ore by ameliorating the seepage effect with sodium dodecyl sulfate surfactant

Ameliorating the problem of low leaching efficiency,long leaching period,and high agent consumption should be studied to efficiently exploit ion-absorbed rare earth ore resources.In this study,the surfactant sodium dodecyl sulfate(SDS) is used to enhance the leaching effect of an ion-absorbed rare earth ore by ameliorating the seepage effect for the first time.The effects of surfactant concentration,leaching agent dosage,solution flow velocity,and solution pH on the leaching rate were explored,and the mechanism of SDS was discussed.Under the optimum conditions,the addition of a small amount of SDS(mass fraction0.04%) can increase the leaching rate by about 5%,shorten the leaching period,and reduce the consumption of the leaching agent.SDS significantly ameliorates the seepage effect of the ore body by reducing the surface tension of the leaching agent and ameliorating the wettability of the mineral surface.This effect is the main factor that improves the leaching efficiency.DFT(density functional theory) calculation results show that SDS can react with rare earth ions,which reduces the adsorption strength on clay mineral surfaces.Hence,rare earth ions are easily exchanged by ammonium ions,and mass transfer is enhanced.

Silica supported sodium hydrogen sulfate(NaHSO_4/SiO_2):A mild and efficient reusable catalyst for the synthesis of aryl-14-H-dibenzo[a,j]xanthenes under solvent-free conditions

A simple and efficient procedure for the preparation of aryl- 14-H-dibenzo [aj]xanthenes by a one-pot condensation reaction of 2-naphthol and aryl aldehydes, in the presence of silica supported sodium hydrogen sulfate （NaHSO4/SiO2） as a catalyst and in the absence of solvent has been developed. The present method offers several advantages such as excellent yields, short reaction time （10-30min）, mild condition, simple work-up, and the use of a cheap and environmentally friendly catalyst with remarkable reusability.

Hydration Characteristics of Sodium Sulfate Slag Cement System

The hydration characteristics by thermal analysis (DTA) were determined, and an isothermal calorimeter (IC) was used to study the pastes. The experimental results indicate: (1) The main hydration products of SSC are C-S-H (I) gel with a low Ca/Si ratio, crystalline Thomsonite-type and AFt-type phases containing certain alkali cations; (2) No phases of the AFm-type and high alkaline Ca (OH)(2) in SSC system could benefit the hydrated cements to improve its strength and durability; (3) Crystalline Thomsonite-type and AFt-type phases containing Na+ will greatly reduce free alkali and alleviate the harmness of alkali aggregate reaction (AAR) in SSC system; (4) Similar to ordinary Portland cement (OPC), the hydration process of SSC could be classified into five stage: initial, induction, acceleration, deceleration and decay; (5) Regardless of the activator used, the apparent activation energy is higher with the increased slag in cement system, and the rising temperature could promote the hydration of SSC.

Efficient and Eco-friendly Process for the Synthesis of Bi(indolyl)methanes Catalyzed by Sodium Hydrogensulfate Monohydrate in Ionic Liquid n-Butylpyridinium Tetrafluoroborate

Efficient electrophilic substitution reaction of indoles with various aromatic aldehydes were carried out with a catalytic amount of sodium hydrogensulfate monohydrate （NaHSO4·H20） in ionic liquid n-butylpyridinium tetrafluoroborate （[Bpy]BF4） to afford the corresponding bi（indolyl）methanes in excellent yields. The notable advantages of this protocol in terms of low cost of catalyst and ionic liquid, mild conditions, simple operation, short reaction time, high yields and recycling of the ionic liquid.

Hollow calcium carbonate microspheres prepared in the presence of polyoxyethylene(20) sorbitan monolaurate and sodium dodecyl sulfate

Hollow calcium carbonate （ CaCO3 ） microspheres were prepared in aqueous solution with the presence of polyoxyethylene （20） sorbitan monolaurate （ Tween20 ） and sodium dodecyl sulfate （SDS）. The microspheres were characterized with X-ray diffraction （XRD） , scanning electron microscopy （SEM） and transmission electron microscope （TEM）. The X-ray diffraction data showed that the hollow CaCO3 microsphere consisted of calcite crystals. The influence of Tween20 and SDS concentrations on the morphology of CaCO3 crystals was investigated. The results suggested that the ＂core-shell model＂ of Tween20/SDS micelle aggregated as templates, which could control the growth of hollow CaCO3 microspheres. The interaction between mixed surfactants and calcium ions played a critical role in organizing calcium carbonate in microscopic level.

The Electrooxidation of Tetracycline at Acetylene Black Electrode in the Presence of Sodium Dodecyl Sulfate

The electrooxidation of tetracycline (TC) at acetylene black electrode has been studied in the presence of sodium dodecyl sulfate (SDS). Tetracycline (TC) exhibited very sensitive oxidation peak in this system. The peak current was proportional to TC concentration, and the detection limit was 1.2×10-8 mol/L. The system was used to the determination of TC in Pharmaceuticals.

Molecular dynamics simulations of the effects of sodium dodecyl sulfate on lipid bilayer

Molecular dynamics simulations have been performed on the fully hydrated lipid bilayer with different concentrations of sodium dodecyl sulfate （SDS）. SDS can readily penetrate into the membrane. The insertion of SDS causes a decrease in the bilayer area and increases in the bilayer thickness and lipid tail order, when the fraction of SDS is less than 28%. Through calculating the binding energy, we confirm that the presence of SDS strengthens the interactions among the DPPC lipids, while SDS molecules act as intermedia. Both the strong hydrophilic interactions between sulfate and phosphocholine groups and the hydrophobic interactions between SDS and DPPC hydrocarbon chains contribute to the tight packing and ordered alignment of the lipids. These results are in good agreement with the experimental observations and provide atomic level information that complements the experiments.