Characterization of a novel fluidic friction-reduction tool used in extended-reach well considering periodic particle-laden jet

Fluidic oscillators(FOs)can be used as an efficient fluidic vibration tool to solve high friction problems in extended-reach wells.However,the complex mechanism of FOs makes the design challenging,and the dynamic erosion behavior inside FOs is still unclear.In this paper,new FOs are proposed and the working characteristics under the influence of periodic particle-laden jets are investigated.Firstly,the results reveal the working mechanism of new FOs,showing that the generation of pressure pulses is closely connected with periodic jet switching and the development of vortices.Secondly,the important performance parameters,i.e.,pressure pulse and oscillation frequency,are extensively studied through numerical simulation and experimental verification.It is found that the performance can be optimized by adjusting the tool structure according to different engineering requirements.Finally,the oscillating solid-liquid two-phase flow inside FO is studied.It is demonstrated that the accumulation of particles leads to a significant reduction in performance.The results also reveal five locations that are susceptible to erosion and the erosion behavior of these locations are studied.It has been shown that the periodic jet causes fluctuations in the amount of erosion at the outlet and splitter.This research can provide valuable references for the design and optimization of vibration friction-reduction tools.

Endoscopic Surgery versus External Ventricular Drainage Surgery for Severe Intraventricular Hemorrhage

The efficacy and applied value of endoscopic hematoma evacuation vs. external ventricular drainage (EVD) in the treatment of severe ventficular hemorrhage (IVH) were explored and compared.From Jan.2015 to Dec.2016,the clinical data of 42 cases of IVH were retrospectively analyzed,including 18 patients undergoing endoscopic hematoma evacuation (group A),and 24patients receiving EVD (group B).The hematoma clearance rate was calculated by 3D Slicer software,and complications and outcomes were compared between the two groups.There were no significant differences in age,sex and Graeb score between groups A and B (P>0.05).The hematoma clearance rate was 70.81%±27.64% in group A and 48.72%±36.58% in group B with a statistically significant difference (P<0.05).The operative time in groups A and B was 72.45±25.26 min and 28.54±15.27min,respectively (P<0.05).The Glasgow Coma Scale (GCS) score increased from 9.28±2.72 at baseline to 11.83±2.91 at 1 week postoperatively in group A,and from 8.25±2.62 at baseline to 10.79±4.12 at 1 week postoperatively in group B (P<0.05).The length of hospital stay was 12.67±5.97 days in group A and 17.33±8.91 days in group B with a statistically significant difference (P<0.05).The GOS scores at 6 months after surgery were 3.83±1.12 in group A,and 2.75±1.23 in group B (P<0.05). These results suggested that endoscopic hematoma evacuation has an advantage of a higher hematoma clearance rate,fewer complications and better outcomes in the treatment of severe IVH,indicating it is a safe,effective and promising approach for severe IVH.

Isolation and identification of an isomer of β-sitosterol by HPLC and GC-MS

Phytosterols are a group of steroids alcohols which had been regarded as a functional factor. An unknown compound in phytosterol samples and phytosterol standard samples was detected by HPLC using symmetry C18 column. The quan- tity of the compound was increased with the enrichment of β-sitosterol. After being collected and analyzed by GC-MS and compared with standard diagram from Wiley and Nist standard chart library, it proved to be γ-sitosterol, a 24β epimer of β-sitosterol.

Accelerated Cutaneous Wound Healing Using an Injectable Teicoplanin-loaded PLGA-PEG-PLGA Thermogel Dressing

Bacterial infection is a very troublesome issue in wound treatment, which stimulates exudate formation and severely delays the healing process. Herein, a thermogelling dressing system composed of two triblock copolymers of poly(D,L-lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D,L-lactic acid-co-glycolic acid)(PLGA-PEG-PLGA) with different block lengths was developed to deliver teicoplanin(TPN), a glycopeptide antibiotic, for cutaneous wound repair. The TPN-loaded thermogel was a free-flowing sol at room temperature and formed a semi-solid gel at physiological temperature. In vitro studies demonstrated that the TPN-loaded thermogel system exhibited desired tissue adhesiveness and realized the sustained release of TPN in a fast-followed-slow manner for over three weeks. Furthermore, a full-thickness excision wound model in Sprague-Dawley(SD) rats was constructed to assess the efficacy of TPNloaded thermogel formulation. Gross and histopathologic observations implied that treatment with the thermogel formulation reduced inflammation response, promoted disposition of collagen, enhanced angiogenesis, and accelerated wound closure and maturity of SD rats.The combination of the bioactivity of TPN and the acidic nature of the thermogel matrix was responsible for such an enhanced wound healing process. Consequently, the TPN-loaded PLGA-PEG-PLGA thermogel is a good candidate of wound dressing for full-thickness excision wound healing.