Fracturing fluids are being increasingly used for viscosity development and proppant transport during hydraulic fracturing operations. Furthermore, the breaker is an important additive in fracturing fluid to extensively degrade the polymer mass after fracturing operations, thereby maximizing fracture conductivity and minimizing residual damaging materials. In this study, the efficacy of different enzyme breakers was examined in alkaline and medium-temperature reservoirs. The parameters considered were the effect of the breaker on shear resistance performance and sand-suspending performance of the fracturing fluid, its damage to the reservoir after gel breaking, and its gel-breaking efficiency. The experimental results verified that mannanase II is an enzyme breaker with excellent gel-breaking performance at medium temperatures and alkaline conditions. In addition, mannanase II did not adversely affect the shear resistance performance and sand-suspending performance of the fracturing fluid during hydraulic fracturing. For the same gel-breaking result, the concentration of mannanase II used was only one fifth of other enzyme breakers (e.g., mannanase I, galactosidase, and amylase). Moreover, the amount of residue and the particle size of the residues generated were also significantly lower than those of the ammonium persulfate breaker. Finally, we also examined the viscosity-reducing capability of mannanase II under a wide range of temperatures (104–158 °F) and pH values (7–8.5) to recommend its best-use concentrations under different fracturing conditions. The mannanase has potential for applications in low-permeability oilfield development and to maximize long-term productivity from unconventional oilwells.

Sepsis is characterized by persistent systemic inflammation, which can cause multi-organ dysfunction. The poly polymerase-1 inhibitor olaparib possesses anti-inflammatory properties. This study aimed to assess the effects of olaparib (pre- and post-treatments) on sepsis, and to investigate whether it could suppress CD14 expression via the ERK pathway in polymicrobial sepsis and peritoneal macrophages models. Sepsis was induced by cecal ligation and puncture in C57BL/6 male mice. Fifty mice were randomly divided into five groups: The sham group was treated with vehicle or olaparib, the cecal ligation and puncture group with vehicle or with olaparib (5 mg/kg i.p.) 1 h before or 2 h after surgery. Olaparib pretreatment significantly improved the survival of septic mice ( P <  0.001). Pre- and post-treatment of mice with olaparib partly alleviated cecal ligation and puncture-induced organ injury by decreasing the amounts of the pro-inflammatory mediators TNF-α and IL-6 as well as bacterial burden in the serum, peritoneal lavage fluid, and organs ( P <  0.05). The protective effect of olaparib was associated with CD14 suppression via inhibition of ERK activation. Olaparib facilitated negative regulation of ERK-mediated CD14 expression, which may contribute to multi-organ injury in sepsis.

Objective. To evaluate a new haemostasis method using an ultrasound probe to compress the radial artery and haemostasis under direct vision to replace traditional manual compression of the radial artery. Methods. According to a random number table, 240 patients with gastrointestinal tumours who had undergone arterial puncture were divided into Group A (120 cases) and Group B (120 cases). In Group A, patients were under the guidance of ultrasound to confirm the vascular port, determine the compression position of the ultrasound probe, observe the degree of vascular deformation, and press the radial artery puncture port with pressure to stop bleeding under direct vision. In Group B, traditional manual compression was used. All patients received 5 min of compression for haemostasis, and haemostasis conditions were recorded after compression and 24 hours postoperatively. Results. The incidence of bleeding, haematoma, and skin ecchymosis at the puncture site after 5 minutes of compression in Group A was lower than that in Group B ( P < 0.05 ). No significant difference was found between the two groups at 24 hours after the operation ( P > 0.05 ). Conclusion. The method using an ultrasound probe to guide radial artery compression to haemostasis is better than traditional manual compression when applied for compression haemostasis after removing the radial artery catheter.

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