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Abstract Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids suffer from poor tolerance to high temperature and high salinity. Thermoviscosifying polymers (TVP) whose aqueous solution shows viscosity increase upon increasing temperature and salt concentration have received considerable attention recently, which is promising for utilization in fracturing fluids to overcome these problems. In this work, both the salt-induced viscosifying property and mechanism of a TVP solution were investigated and the performance of TVP used as fracturing fluid based on the conditions of the Jianghan inter-salt shale oil reservoir in China was evaluated. It is found that the salt-induced viscosifying property of the TVP solution decreases with temperature and shear rate, but increases with polymer concentration. The number of intermolecular hydrophobic domains increases with the salt concentration contributing to the strengthening of a 3D network structure, which results in an increase in viscosity. In addition, the TVP fracturing fluid formulated with saturated brine exhibits excellent temperature and shear resistance, sand-suspending performance, and gel-breaking performance. Its viscosity remains above 50 mPa s after being sheared for 1 h even at a high temperature of 140 °C and the sand-suspending stability can be maintained for more than 1 week at 100 °C. Furthermore, the fracturing fluid can be easily broken down within 12 h using 0.2 wt%–0.3 wt% potassium persulfate without residue.

Viscoelastic surfactants (VES) are often used as viscous diverters in acidizing stimulation to prolong the acid consumption time and maximize zonal coverage of the acid for improving well productivity. However, the ceiling temperature of commercial VES cannot exceed 120 °C in practical use because of the poor thermal stability and fragile molecular structure, hindering their implementation in hightemperature oil reservoirs, i.e., ≥150 °C. Here we synthesized a novel C22-tailed diamine, N-erucaminopropyl-N,N-dimethylamine (EDPA), and examined comparatively its rheological behavior, assemblies morphology and molecular stability in 20 wt% HCl with a commercial VES, erucyl dimethyl amidopropyl betaine (EDAB). The feasibility of EDPA for acidizing stimulation was assessed by acid etching of carbonate rock with its HCl solution at 150 °C. Rheological results showed that the 2.5 wt% EDPAe20 wt% HCl solution maintains stable viscosity of 90 mPa s at 150 °C for 60 min, while that of 2.0 wt% EDAB HCl solution is just 1 mPa s under identical conditions. 1H NMR spectra and cryo-TEM observations revealed that the chemical structure and self-assembled architectures of EDPA remained intact in such context, but the EDAB suffered from degradation due to the hydrolysis of the amide group, accounting for the poor heat-resistance and acid-tolerance. The reaction rate of 2.5 wt% EDPA HCl solution with carbonate rock was one order of magnitude lower than that of 20 wt% HCl solution at 150 °C, underpinning the potential of EDPA to be used in the high-temperature reservoirs acidizing. This work improved the thermal tolerance of VES in highly concentrated HCl solution, paving a feasible way for the acidization of high-temperature reservoir environments (~150°C). [ABSTRACT FROM AUTHOR]

Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO2 (WAG) flooding, and conventional polymer gels used for blocking the “channeling” paths usually suffer from either low injectivity or poor gelation control. Herein, we for the first time developed an in-situ high-pressure CO2-triggered gel system based on a smart surfactant, N-erucamidopropyl-N,N-dimethylamine (UC22AMPM), which was introduced into the aqueous slugs to control gas channeling in WAG processes. The water-like, low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO2 owing to the formation of wormlike micelles (WLMs), as well as their growth and shear-induced structure buildup under shear flow. The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating, and can be impaired via pressurization above the critical pressure of CO2 because of its soaring solvent power. Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre- or post-injected CO2 slugs under shear flow, thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode. This smart surfactant enabled high injectivity and satisfactory gelation control, attributable to low initial viscosity and the combined properties of one component and CO2-triggered gelation, respectively. This work could provide a guide towards designing gels for reducing CO2 spillover and reinforcing the CO2 sequestration effect during CO2 enhanced oil recovery processes. [ABSTRACT FROM AUTHOR]

The metal-dielectric-vacuum junction is defined as the triple junction owned enhanced electric field, thus this special region is regarded as the location where primary electrons emission is favored. For electron emission, triple junction could affect both the flashover breakdown of insulators and the electron emission property of ferroelectric cathodes. In this study, we theoretically investigate the electric field enhancement in the triple-junction region. It is found that the key parameter to determine the field enhancement is the taper angle of the electrode and the relative permittivity of the dielectric. In addition, we first deduce the accurate expression of the electric field in this special region. The controlling parameters for determining the field enhancement are discussed in detail. We also discover the way to reduce the electric field of this region through simulation. The current analysis would be useful for both the electron emission enhancement and the issue of flashover breakdown. [ABSTRACT FROM AUTHOR]

By employing a chiral bifunctional thiourea-tertiary amine as catalyst, domino Michael-type Friedel-Crafts alkylation/cyclization of β-naphthols with akylidene Meldrum's acids was realized. The reactions afforded various enantioenriched β-arylsplitomicins with good yields (up to 99%) in moderate enantioselectivities (up to 79%). [ABSTRACT FROM AUTHOR]

By employing a chiral bifunctional thiourea-tertiary amine as catalyst, domino Michael-type Friedel-Crafts alkyla-tion/cyclization of ß-naphthols with akylidene Meldrum's acids was realized. The reactions afforded various enantioenriched ß-aryl-splitomicins with good yields (up to 99%) in moderate enantio-selectivities (up to 79%). [ABSTRACT FROM AUTHOR]

The electric fatigue of the antiferroelectric ceramics was investigated. Samples were polycrystalline ceramics prepared by conventional sintering method. The electric fields of different frequencies with rectangular shape were applied in fatigue procedure. At cycle numbers lower than 104, the switched (P*), non-switched (Pr⁁) polarization and the switched (Pr*), non-switched (Pr⁁) remanent polarization were almost the same as their value at first cycle. However from 104 up to 107, there were a 14% decrease in P⁁ and a 260% increase in Pr*. It was found that lower frequency yielded a faster fatigue than higher frequency. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is known to induce allergic contact dermatitis and subsequent occupational medicamentosa-like dermatitis (OMLD) with multi-system injuries, including liver, kidney, and skin injuries. However, the mechanisms underlying immune system dysfunction that result in organ injury have not yet been clearly elucidated. In the present study, we measured the levels of secreted cytokines by effect or T cells in TCE-treated guinea pigs to better understand the contribution of allergic disorders in renal injuries. We immunized guinea pigs with trichloroethylene using the Guinea Pig Maximization Test (GPMT) and scored the inflammation on the guinea pigs' skin. The kidney function and ultra-structural changes in the kidneys were detected using biochemical methods and electron microscopy. The deposition of cytokines was determined using immunohistochemistry. The sensitization rate was 63.16% in the TCE-sensitized groups. The electron microscopy results showed tubular epithelial cell mitochondrial swelling, vacuolar degeneration, and atrophy of the microvillus in the sensitized groups. A high degree of cytokine deposition was observed in the renal tubular proximal epithelial cells in the TCE-sensitized groups. As observed in this study, the variation in the level of immune system activation not only indicates that TCE can largely magnify the immune reaction but also suggests a potential role of immune dysfunction in renal impairment., Competing Interests: Authors declare no conflict of interest.

Background: High anatomic location, fragility, and generous blood supply of the spleen makes laparoscopic splenectomy (LS) difficult to master, and few patients need splenectomy for benign disorders. The aim of this research was to assess operative outcomes and hematological results of a large series of patients treated with LS for chronic immune thrombocytopenic purpura (ITP) and to determine which clinical variables predict favorable hematological outcome., Methods: LS was successfully performed for 154 patients with chronic ITP from September 1999 to April 2009 at the First Affiliated Hospital of Sun Yat-sen University. Operative outcomes were assessed retrospectively. Long-term follow-up data were obtained from outpatient medical records and phone interviews. Clinical and laboratory variables (including gender, age, disease duration before surgery, previous response to steroids, preoperative platelet count, and postoperative peak platelet count) were evaluated by univariate analysis to identify potential predictors of hematological outcome. Multivariate Logistic regression model was used to determine independent predictors of hematological outcome., Results: One patient died from subphrenic abscess and postoperative sepsis. The overall major morbidity rate was 8.4%. None of the patients required a second surgery for complications. Of the 127 patients available for a mean follow-up of 43.6 months (range 9 - 114 months), the overall initial response (i.e., at two months after LS) and long-term response to LS were achieved in 89.0% and 80.3%, respectively. Five patients (3.9%) developed pneumonia 3 - 35 months after LS. Univariate analysis showed a significant difference in mean age between responders (29.1 years) and nonresponders (38.8 years; P < 0.05). Patients who responded to steroid therapy had better hematological outcome than those who did not respond (P < 0.05). Compared to nonresponders, responders to LS had a significantly higher postoperative peak platelet count (404 × 10(9)/L versus 213 × 10(9)/L, P < 0.001). Multivariate Logistic regression analysis identified postoperative peak platelet count as the only independent predictor of favorable response to LS (P < 0.001)., Conclusions: LS is a safe and effective treatment for chronic ITP. Postoperative peak platelet count may serve as a major predictor of long-term response.

Objective: To study the changes of nitric oxide (NO) in the BALB/c hairless mice skin after trichloroethylene (TCE) irritation and the protection of ginkgo biloba extract (GbE) and vitamin E (VE)., Methods: 132 BALB/c hairless mice were randomly divided into blank control group, solvent group (olive oil), TCE groups (20%TCE, 40%TCE, 80%TCE and 100%TCE), GbE groups (0.1%GbE, 1%GbE and 10%GbE) and VE groups (5%VE, 10% VE and 20% VE), with 11 animals in each group, 5 for acute irritation test and 6 for the cumulative irritation test. The skin irritation was observed, and the levels of NO in the dorsal skin of BALB/C hairless mice were detected. The kit of NO was used to detect the levels of NO in the dorsal skin of BALB/c hairless mice., Results: (1) The skin presented erythema and edema after TCE irritation both in acute irritation and cumulative irritation test and the skin inflammation showed time-dose effect relationship; the mice skin was protected in GbE or VE groups. (2) In the acute stimulation test, the levels of NO in 80%TCE group (69.895 +/- 9.605 micromol/mg pro) and 100%TCE group (77.273 +/- 9.290 micromol/mg pro) were significantly different compared with blank control group and solvent control group (P < 0.05 or P < 0.01). In the protection group, the NO level were reduced, with the statistically significant differences. (3) In acute irritation test, the levels of NO in 80%TCE group (60.362 +/- 9.817 micromol/mg pro) and 100%TCE group (68.027 +/- 9.354 micromol/mg pro) were significantly different compared with blank control group and solvent control group, (P < 0.05 or P < 0.01); In the protection group, 1% GbE, 10% GbE, 10% VE and 20%VE could reduce the levels of NO, with statistically significant differences., Conclusion: TCE can produce the irritation on the dorsal skin of BALB/c hairless mice and induce the significant increase of the NO levels. GbE and VE can protect the skin from TCE irritation damage.

Objective: To investigate the expression of apoptosis and caspase-8, cyt c in the skin of the BALB/c mice exposed to trichloroethylene (TCE)., Methods: 30 BALB/c mice were divided in random into the solvent control group, 10% TCE group, 20% TCE group, 40% TCE group, 80% TCE group and 100% TCE group. Apoptotic cells were detected by TUNEL and EM. The expressions of caspase-8 and cyt c were detected with immunohistochemical method., Results: EM showed that the apoptosis of cells was found in the high dosage groups. The immunohistochemical results showed that there were significant differences in the apoptosis rate and the activity of cyt c between the different dosage groups. There was the significant difference in the apoptosis rate between the 40%, 80%, 100% TCE groups the control group (P < 0.01). There was the significant difference in the expression of cyt c between the 20%, 40%, 80%, 100% TCE groups [(2.60 +/- 0.54), (3.42 +/- 0.56), (5.81 +/- 1.30) and (6.00 +/- 0.70), respectively] and the control group (P < 0.01). The expressions of caspase-8 had no significant differences (P > 0.05)., Conclusion: Apoptosis plays an important role in trichloroethylene induced irritant injury in skin and the apoptosis may be related with the mitochondrial injury.

Objective: To explore mechanism of dermal toxicity of trichloroethylene(TCE)., Methods: Normal human keratinocytes (KC) were isolated from foreskins of healthy donors undergoing circumcision by two-step trypsin digestion and cultured in serum-free medium. Cells were treated with medium, 1% acetone (volume fraction) 0.125, 0.500 or 2.000 mmol/L TCE for different time (4, 8, 12 or 24) hours. After treatment, MTT assay and ATPase activity detected, inhibition ratio of mitochondrial enzyme was calculated according to optical density (A) value of MTT assay. Mitochondrial membrane potential (MMP) was detected by flow cytometry FCM after being stained with Rhodamine123 (Rh123). Morphological changes were also observed through transmission electron microscope (TEM)., Results: Cellular viability and ATPase activity declined with dose of TCE, while inhibition ratio of mitochondrial enzyme increased with dose of TCE. FCM results showed that after treatment with 2.000 mmol/L TCE, fluorescence density of Rh123 decreased quickly from 18.73 +/- 0.45(0 h) to 8.20 +/- 0.66(8 h) (P < 0.01). After 8 h, fluorescence density maintained at the level equal to that of 8 h (fluorescence density of Rh123 were 8.20 +/- 0.36 and 8.20 +/- 0.40 for 12 and 24 h respectively, compared with that for 8 h group, P > 0.05). The results also showed that MMP diminished with dose of TCE. Under TEM, mitochondria in TCE-treated group appeared extensive swelling and vacuolar degeneration with less matrix and obscure or vanished mitochondria cristae but in control group, mitochondrial structure was integrated, with uniform matrix and visible mitochondria cristae., Conclusions: TCE could inhibit mitochondrial metabolic enzyme, reduce ATP production, diminish MMP, and destroy ultrastructure of mitochondria in KC, all these contributing to the cytotoxicity of TCE.