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Summary The property development of drilling fluids strongly relies on the emergence of novelty additives and the formulation design of drilling fluids. Few studies focus on the influences of preparation technology on various properties of drilling fluids. At present, high-speed mechanical agitation is still the only method of formulating drilling fluids in the industrial community. In the paper, two kinds of sulfonated drilling fluids that were used frequently in China were prepared by the combination of high-power ultrasound and high-speed mechanical agitation. After the mechanical agitation, we exerted ultrasonic oscillations on the sulfonated drilling fluids and intensified the input of ultrasonic energy by increasing ultrasonic time or power. In addition, the superposition of mechanical agitation during ultrasonic oscillations could further help the sulfonated drilling fluids to absorb more ultrasonic energy when the time and power of ultrasonic oscillations remained unchanged. The effects of ultrasonic oscillations on the colloidal properties of sulfonated drilling fluids were investigated. The results show that the introduction of ultrasonic energy into sulfonated drilling fluids is able to cause the formation of thinner and denser mudcakes on borehole walls and further reduce the low temperature and low pressure (LTLP) and high temperature and high pressure (HTHP) filtrate volume. The HTHP accumulative filtrate volume within 30 minutes can be decreased by a maximum of 24.7%. Simultaneously, various Bingham-type rheological values, particularly yield point, get decreased. The ultrasonic improvement of filtration and rheological properties benefits from the formation of the stable colloidal structure of drilling fluids under acoustic cavitation. According to the total organic carbon (TOC) measurements, it is found that ultrasonic oscillations promote the adsorption of sulfonated additives on bentonite clays. The analysis of particle size and zeta potential also confirms that ultrasonic oscillations not only decrease the average clay particle size but also enhance the zeta potential absolute value. In our experimental range, all the colloidal properties acquire the continuing improvement with the increase in ultrasonic energy input, which cannot be achieved only through the high-speed mechanical agitation. Compared with our previous research works, the subject investigated in the paper is the given drilling fluid system, but not the bentonite suspension containing one single additive. It indicates that we take a step forward in the field application of ultrasound-assisted mud preparation technique.

During drilling fluid preparation, ultrasonic oscillations were introduced into water-bentonite suspension incorporating sulfonated wood coal (SMC) by a specially designed device. The influences of ultrasonic oscillations on fluid loss and rheological performances of the drilling fluid as well as mechanism of ultrasonic action were investigated. The experimental results showed that the filtrate volume decreased with the increase of ultrasonic time till a certain extent and then leveled off. In the presence of ultrasound, shorter time of 15 min and mild intensity of 250 W could lead to a satisfactory result in fluid loss properties, including the reasonable filtrate volume and thin and compact filter cakes. With increasing ultrasonic intensity, the fluid loss properties changed relatively little but various rheological data of the drilling fluids always increased. Adsorption tests through total organic carbon, infrared spectrum and thermogravimetic analyses as well as clay particle size analysis confirmed that as compared with the conventional agitation, ultrasound-assisted mud preparation could not only increase adsorbed amount of SMC on bentonite but also decrease average clay particle diameter attributed to acoustic cavitation. A plausible mechanism based on sonochemical thermodynamics is proposed to explain the improvement of the colloidal structure and performances of drilling fluid.

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O} n or {[Cd(Pim)(bbimb)]·4H2O} n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2] n or [Cd(Seb)(bbimb)0.5(H2O)] n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2−, heptanedioate) or sebacate (Seb2−, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2− ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O—H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2− ligands to form binuclear Cd2 units which are linked by bbimb and Seb2− ligands into a 2D hxl layer. The 2D layers are further connected by O—H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV–Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.

Two Cd(II) coordination polymers, [Cd(L)(NO3)2] (1) and [Cd2.5(L)(BDC)1.5Cl2]2·3H2O (2) have been synthesized based on a novel tetra-imidazole ligand under hydrothermal conditions. (L = bis(3,5-bis((1H-imidazol-1-yl)methyl)-2,4,6-trimethylphenyl)methane, H2BDC = 1,4-benzenedicarboxylate acid). Polymer 1 displays a 1D chain connected by the L ligand, and extends to a 3D supramolecular structure via C H⋯O hydrogen bonds. When added the auxiliary H2BDC ligand, a 2D trilayer structure for 2 was constructed, which shows a trinodal (3,4,6)-connected net with unprecedented symbol of (3·4·5)2(32·42·52)(3·44·5·68·7)2. 1 and 2 display photoluminescence at 462 nm and 490 nm, respectively. Thermogravimetric properties of both coordination polymers have also been investigated.

Two new Cd

Two entangled MOFs based on rigid 1,6-naphthalenedisulfonate (1,6-NDS) mixed with flexible 1,4-bis(benzoimidazol-1-yl)butane (bbimb) ligands, [Zn(1,6-NDS)(bbimb)1.5]·2H2O (1) and [Cd2(1,6-NDS)2(bbimb)3(H2O)4]·2H2O (2), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric and photoluminescent analyses. In 1, the Zn(II) ions are connected by bbimb ligands into a 2D (6,3) brick wall structure with the 1,6-NDS2- as dangling arms threaded into the voids of two adjacent layers up and down, and finally generates a 2D→3D polythreading framework. While the Cd(II) centers in 2 are connected by bbimb ligands into a 3D (10,3)-b network, and four (10,3)-b networks interweave to generate a 4-fold interpenetrating structure. 1 and 2 dispay similar photoluminescence at 343 nm (λex = 302 nm) and 342 nm (λex = 293 nm), respectively. And both MOFs display selective sensing of Fe3+ through the luminescent quenching experiments.

The influences of structure parameters of polyetheramines as clay-swelling inhibitors in water-based drilling fluids on the application performances were studied. Interactions of polyetheramines with clays were investigated through elemental analysis (EA), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that lower molecular weight, hydrophobic oxypropylene segment, and plentiful amino group of polyetheramines favored improvement of inhibitive properties, enhancement of adsorption abilities, and expelling interlayer bound waters of clays (as confirmed by cutting rolling test, bentonite inhibition test, EA, XRD, and TGA studies). Simultaneously, the polyetheramines did not produce adverse effect to filtration control of the drilling fluids. In addition, XRD patterns revealed that these polyetheramines could intercalate into interlayer spaces of clays and display a monolayer arrangement. The corresponding basal spacing of clays was correlated only with molecular weight of polyetheramines. The dense loading of polyetheramines in the interlayer of clays was beneficial in improving inhibitive properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Some starch-graft-polyacrylamide copolymers were prepared by the polymerization of corn starch with acrylamide in aqueous medium using a complex initiation system consisting of ceric ammonium sulphate and ammonium persulphate. The copolymers were applied to water-based drilling fluid as filtration control agents. Their grafting parameters such as percentage of grafting, grafting efficiency, and solution viscosity (η) were investigated by using elemental analyzer and rotational viscometer. The results showed that increases in initiator concentration and reaction temperature first favored and then impeded the grafting reaction. Grafting of acrylamide onto starch increased with the increase of monomer concentration. It also increased with increasing reaction time up to a certain degree and then leveled off. For the graft copolymers, a higher percentage of grafting and higher η were beneficial in decreasing the filtrate volume of water-based drilling fluid, even under an operating environments of 147°C and saturated salinity. A possible mechanism is proposed to interpret the improvement of fluid loss properties. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers

Background Abnormal activation of STAT3 and miR-21 plays a vital role in progression and invasion of solid tumors. The cyclin-dependent kinase 5 (CDK5) is reported to contribute to cancer metastasis by regulating epithelial-mesenchymal transition (EMT). However, the role of STAT3/miR-21 axis and CDK5 in head and neck squamous cell carcinoma remains unclear. Methods We measured the expression of miR-21, CDK5 and EMT markers in 60 HNSCC tumor samples. We used Immunohistochemistry and in situ hybridization assay to examine the role of STAT3/miR-21 axis and CDK5 activation in the invasiveness of HNSCC. The clinical survival relevance was analyzed by Kaplan-Meier analysis and univariate/multivariate COX regression model. Multiple approaches including scratch, transwell chamber assay and other molecular biology techniques were used to validate the anti-invasion effect of targeting miR-21 in Tca8113 and Hep-2 cell lines in vitro. Furthermore, whether miR-21 depletion inhibits HNSCC invasion in vivo was confirmed in Tca8113 xenograft tumor model. Results The expression of miR-21 and CDK5 were significantly correlated with lymph node metastasis in HNSCC. Hep-2 and Tca8113 cell lines showed co-overexpression of miR-21 and CDK5. WP1066 or asON-miR-21 treatment depleted miR-21 and CDK5 expression and significantly inhibited migration or invasion in Hep-2 and Tca8113 cells. The expression levels of CDK5/p35, N-cadherin, vimentin, β-catenin were inhibited while E-cadherin level was increased by miR-21 depletion in vitro and in vivo. Conversely, ectopic CDK5 overexpression significantly induced tumor cell motility and EMT. Moreover, ectopic CDK5 overexpression in Hep-2 and Tca8113 cells rescued the observed phenotype after miR-21 silencing or WP1066 treatment. Conclusions miR-21 cooperates with CDK5 to promote EMT and invasion in HNSCC. This finding suggests that CDK5 may be an important cofactor for targeting when designing metastasis-blocking therapy by targeting STAT3/miR-21 axis with STAT3 inhibitor or miR-21 antisense oligonucleotide. This is the first demonstration of the novel role of STAT3/miR-21 axis and CDK5/CDK5R1 (p35) in metastasis of HNSCC. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0487-x) contains supplementary material, which is available to authorized users.

A terpolymer of acrylamide (AM), acrylic acid (AA), and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) was synthesized by a free-radical solution polymerization technique, characterized by FTIR methods, and applied together with aluminum citrate in oilfield drilling as a high-temperature-resistant filtration control agent. Before and after thermal aging for 16 h at 180°C, the combined effect of the terpolymer and aluminum citrate on the Bingham-type rheological and fluid-loss properties of the corresponding fresh-water and salt-water muds was further investigated. The results showed that before the thermal aging, there was a similar changing trend in the rheological and fluid-loss properties of the muds with terpolymer concentration, regardless of the presence of aluminum citrate. After the thermal aging, some hydrophilic polycomplexes of AM-AA-AMPS terpolymer with aluminum citrate may have been formed and consequently inhibited viscosity loss of the muds, thereby improving the fluid-loss properties. A possible mechanism is proposed to explain the improvement. J. VINYL ADDIT. TECHNOL, 2010. © 2009 Society of Plastics Engineers

The effects of ultrasonic oscillations on extrusion processing, phase morphology, and compatibility as well as mechanical properties for blends of propylene based plastomer (DP) and ethylene/1-octene copolymer (EOC) were examined. The results show that introduction of ultrasonic oscillations into polymer melts in extrusion can in situ improve their processability, including the reduction of die pressure and shear viscosity under a constant shear rate (flow rate) and the increase of throughput under the same shear stress (die pressure). Scanning electron microscopy observation reveals that with ultrasonic oscillations, morphology of reduced disperse phase (EOC) size and good interfacial adhesion between EOC and DP matrix are formed in DP/EOC blends. The interfacial tension between DP and EOC melts obtained from the Palierne emulsion model decreases with applying ultrasonic oscillations. FTIR and GPC analysis indicate that in situ copolymer formation between DP and EOC happens with ultrasonic oscillations and copolymer consequently acts as compatibilizer for the blends. Accordingly, it leads to an elevation of stress at break and elongation at break of the blends.

Blends of propylene based plastomer (DP) and ethylene/1-octene copolymer (EOC) of various concentrations are prepared by a melt-blending process at 160°C, using a corotating twin-screw extruder. The rheology, phase morphology, and mechanical and thermal properties of DP/EOC blends are investigated. The results show that addition of DP in EOC can lead to significant improvement of mechanical properties, including yield strength, strength at break, and Young's modulus, concomitant with the reduction of melt viscosity. The experimental data for melt viscosity and elongation at break respectively display a positive deviation from additivity, indicating the enhancement of the component interaction and superior interface properties between DP and EOC phases. The transition from plastic to elastomeric properties coincides with phase inversion. At this 85/15 DP/EOC composition, the decrease in the viscosity of DP matrix enhances EOC dispersed phase size, due to the increase in their viscosity mismatch. DSC analysis shows that the melting temperature of DP and EOC phases in blends remains constant irrespective of the composition, respectively. The nucleation effect of EOC on DP tends to increase the crystallization temperature of DP phase. It is also verified that the EOC phase can be prevented from crystallizing with increasing DP content in the blends.

In this article, the ultrasonic degradation of polypropylene (PP) melt was conducted in a specially designed reactor. Dynamic stress rheometer and gel permeation chromatography (GPC) were used to study the degradation behavior of PP melt. Thermal properties of ultrasonically treated PP were further discussed. The results showed the decrease of complex viscosity, zero shear viscosity, representative relaxation time, viscoelastic moduli as well as cross-over modulus, but an increase of cross-over frequency with introduction of ultrasonic irradiation, due to reduction of weight average molecular weight and increase of molecular weight distribution index of the polymer. The ultrasonic chain scissions of PP melt mainly occurred at the initial 3 min of irradiation and subsequently tended to terminate under our experimental conditions. In addition, the crystallization temperature and melting temperature of PP together got decreased in the presence of ultrasonic irradiation due to the occurrence of lower molecula...

The copper chaperone for superoxide dismutase (CCS) has been identified as a key factor integrating copper into copper/zinc superoxide dismutase (CuZnSOD) in yeast (Saccharomyces cerevisiae) and mammals. In Arabidopsis (Arabidopsis thaliana), only one putative CCS gene (AtCCS, At1g12520) has been identified. The predicted AtCCS polypeptide contains three distinct domains: a central domain, flanked by an ATX1-like domain, and a C-terminal domain. The ATX1-like and C-terminal domains contain putative copper-binding motifs. We have investigated the function of this putative AtCCS gene and shown that a cDNA encoding the open reading frame predicted by The Arabidopsis Information Resource complemented only the cytosolic and peroxisomal CuZnSOD activities in the Atccs knockout mutant, which has lost all CuZnSOD activities. However, a longer AtCCS cDNA, as predicted by the Munich Information Centre for Protein Sequences and encoding an extra 66 amino acids at the N terminus, could restore all three, including the chloroplastic CuZnSOD activities in the Atccs mutant. The extra 66 amino acids were shown to direct the import of AtCCS into chloroplasts. Our results indicated that one AtCCS gene was responsible for the activation of all three types of CuZnSOD activity. In addition, a truncated AtCCS, containing only the central and C-terminal domains without the ATX1-like domain failed to restore any CuZnSOD activity in the Atccs mutant. This result indicates that the ATX1-like domain is essential for the copper chaperone function of AtCCS in planta.

To study a family with Bw subtype of ABO blood group system, and to review safety issues in relation with clinical transfusion.The molecular basis for the blood type was studied with serological assay, polymerase chain reaction-sequence specific primer (PCR-SSP) and DNA sequencing, TA clone and haplotype analysis in one blood donor whose ABO blood group were difficulty typed and her family. The bioinformatics analysis was carried out by biological analysis software to investigate the change of structure and function of enzymes influenced by the change amino acid. A retrospective survey was carried out to investigate what is the actual position that the donor blood was used in the clinical transfusion.Three members from the family were found to have a Bw subtype. A substitution of nucleotide C by T at position 721 in exon 7 was discovered, which resulted in replacement of amino acid Arg to Trp. Review of clinical record suggested that there has been no significant abnormality association with past three blood transfusions.A 721CT mutation of the ABO gene probably underlies the Bw subtype. Further research is needed for understanding the clinical significance of this subtype in the blood transfusion.