Micro-power negative pressure wound technique reduces risk of incision infection following loop ileostomy closure

BACKGROUND Prophylactic loop ileostomy is an effective way to reduce the clinical severity of anastomotic leakage following radical resection of rectal cancer.Incisional surgical site infection(SSI)is a common complication after ileostomy closure.AIM To evaluate the efficacy and safety of the micro-power negative pressure wound technique(MPNPWT)in preventing incisional SSI.METHODS This was a prospective,randomized controlled clinical trial conducted at a single center.A total of 101 consecutive patients who underwent ileostomy closure after rectal cancer surgery with a prophylactic ileostomy were enrolled from January 2019 to December 2021.Patients were randomly allocated into an MPNPWT group and a control group.The MPNPWT group underwent intermittent suturing of the surgical incision with 2-0 Prolene and was covered with a micro-power negative pressure dressing.The surgical outcomes were compared between the MPNPWT(n=50)and control(n=51)groups.Risk factors for incisional SSI were identified using logistic regression.RESULTS There were no differences in baseline characteristics between the MPNPWT(n=50)and control groups(n=51).The incisional SSI rate was significantly higher in the control group than in the MPNPWT group(15.7%vs 2.0%,P=0.031).However,MPNPWT did not affect other surgical outcomes,including intra-abdominal complications,operative time,and blood loss.Postoperative hospital stay length and hospitalization costs did not differ significantly between the two groups(P=0.069 and 0.843,respectively).None of the patients experienced adverse effects of MPNPWT,including skin allergy,dermatitis,and pain.MPNPWT also helped heal the infected incision.Our study indicated that MPNPWT was an independent protective factor[odds ratio(OR)=0.005,P=0.025)]and diabetes was a risk factor(OR=26.575,P=0.029)for incisional SSI.CONCLUSION MPNPWT is an effective and safe way to prevent incisional SSI after loop ileostomy closure.

Pre-Drilling Prediction Techniques on the High-Temperature High-Pressure Hydrocarbon Reservoirs Offshore Hainan Island,China

Decreasing the risks and geohazards associated with drilling engineering in high-temperature high-pressure(HTHP) geologic settings begins with the implementation of pre-drilling prediction techniques(PPTs). To improve the accuracy of geopressure prediction in HTHP hydrocarbon reservoirs offshore Hainan Island, we made a comprehensive summary of current PPTs to identify existing problems and challenges by analyzing the global distribution of HTHP hydrocarbon reservoirs, the research status of PPTs, and the geologic setting and its HTHP formation mechanism. Our research results indicate that the HTHP formation mechanism in the study area is caused by multiple factors, including rapid loading, diapir intrusions, hydrocarbon generation, and the thermal expansion of pore fluids. Due to this multi-factor interaction, a cloud of HTHP hydrocarbon reservoirs has developed in the Ying-Qiong Basin, but only traditional PPTs have been implemented, based on the assumption of conditions that do not conform to the actual geologic environment, e.g., Bellotti's law and Eaton's law. In this paper, we focus on these issues, identify some challenges and solutions, and call for further PPT research to address the drawbacks of previous works and meet the challenges associated with the deepwater technology gap. In this way, we hope to contribute to the improved accuracy of geopressure prediction prior to drilling and provide support for future HTHP drilling offshore Hainan Island.

Estimation of active earth pressure based on pseudo-dynamic approach and discretization technique

A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduced to generate the potential failure surface,which is applicable to the case that soil strength parameters have spatial variability.For the purpose of analyzing the effect of earthquake,pseudo-dynamic approach is adopted to introduce the seismic forces,which can take into account the dynamic properties of seismic acceleration.A new type of micro-element is used to calculate the rate of work of external forces and the rate of internal energy dissipation.The analytical expression of seismic active earth pressure coefficient is deduced in the light of upper bound theorem and the corresponding upper bound solutions are obtained through numerical optimization.The method is validated by comparing the results of this paper with those reported in literatures.The parametric analysis is finally presented to further expound the effect of diverse parameters on active earth pressure under non-uniform soil.

Liquid Level Measurement in Oil Tanks Based on Double-differential Pressure Technique

The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.

Perfect Solvent- and Catalyst-Free Syntheses of Imine Derivatives Using the Pressure Reduction Technique

In the field of organic syntheses, the development of environmentally friendly methods based on the concept of green chemistry has been always required. In response to this requirement, we reported solvent- and catalyst-free syntheses of imines using the pressure reduction technique as a key technology. We found that this reaction proceeded very rapidly in the initial stage, but its rate decreased with the passage of time. It was also found that the reaction of benzaldehyde with aniline had a specificity that the phase transition occurred. In this method, the desired imines could be obtained in good to excellent yields, but target compounds had to be given by purifications using organic solvents. Therefore, we tried to develop the perfect synthetic method of imine derivatives without organic or inorganic solvents. We selected two methods and took them into this investigation. One was exactly mixing (1:1, substance ratio) aldehydes and amines and the other was employing lower pressure (>0.1 mmHg, previous method: 1.0 mmHg) at the pressure reducing technique. When this improved synthetic method was performed, it was revealed that pure target imines were obtained in excellent yields without any purification.

Environmentally Friendly Syntheses of Imines Applying the Pressure Reduction Technique: Reaction Cases of Less Reactive Amines and Studies by Computational Chemistry

Recently, the development of environmentally friendly syntheses of imine derivatives, which were attracting great attention for their reactivity and structure in various fields, progressed rapidly because the concept of green chemistry had deeply penetrated into society. In our previous work, we had reported new synthetic methods of imine derivatives using some active amines under solvent- and catalyst-free reaction conditions. This synthetic reaction proceeded smoothly and target compounds were obtained in excellent yields. In this system, when less reactive amines were used as substrates, the synthetic reaction was not finished in the short reaction time, and the corresponding compounds were given in moderate yields. In order to solve this point, we tried to improve the reaction conditions of this method. Through this improvement, it was found that pure target compounds could be obtained in excellent yields by using 1.1 equivalents of less reactive amines to aldehydes and extending the reaction time compared with our previous work. In this paper, we will introduce the detail of this study, and also report the result of the investigation of the reaction property by computational chemistry.

Efficient Solvent- and Catalyst-Free Syntheses of Imine Derivatives Applying the Pressure Reduction Technique: Remarkable Change of the Reaction Rate with the Phase Transition

Because imines could be used as convenient starting materials in various fields, the development of an easy synthetic method of imine was strongly desired. In response to this demand, we thought that it would be an effective synthesis method if an aldehyde and an amine could be reacted to give an imine in good yield under solvent- and catalyst-free conditions. In fact, we tried the reaction of benzaldehyde with various amines under solvent- and catalyst-free conditions followed by removal of water that was produced in the reaction system by a vacuum pump, and desired imines could be obtained in good yields. Observation of this reaction using a nuclear magnetic resonance spectrometer revealed that the reaction rate was extremely fast at the initial stage but slowed over time. However, the reaction of benzaldehyde with aniline differed greatly, and the reaction rate dramatically improved in 47 - 48 minutes after the start of the reaction. At this time, we found that the reaction system underwent a phase transition from the liquid phase to the solid phase.

Technique and experiment of active direct gas pressure measurement in coal roadway

An active measurement method and its principle was introduced consideringthe low success rate,special difficulty,and long measurement time of the direct gas pressuremeasurement currently used in coal roadways.The technology of drilling,boreholesealing depth,borehole sealing length,sealing control of the measuring process,compensatorycomputation of gas loss quantity and other key techniques were discussed.Finally,based on the latest instrument the authors developed,a series of experiments of directgas pressure measurement in the coal roadways of the Jincheng and Tongchuanmine district,were carried out.The experimental results show that active gas pressuremeasurement technique has advantages as follows:(1) the application scope of direct gaspressure measurement technique is wide and it does not have the restriction of coalhardness,coal seam fissure and other conditions;(2) the measured results are credible,which can be tested by the same gas pressure value acquired from a different borehole inthe same place;(3) the measurement process is convenient and quick,it takes about 2 to3 days to acquire the gas pressure value in a coal seam.

PROGRESS OF ACOUSTIC WAVE TECHNIQUE ANDITS APPLICATION IN UNDERGROUND PRESSURE MEASUREMENT

This paper carries out tbe experirnent study on the correlation between am stress-strain process of rock samples and the acoustie parameter change of rock by using the measurement system of KS acoustic wave data processing device. On the spot, the stability of surrounding rock is studied by means of experiments on the relationship between the change process (from elastie to plastic failure zone) in surrounding rock of roadway and the change law of acoustic parameters of rock. These acoustie parameters inelude wave amplitude, spectral amplitude, spectrum area, spectral density,wave veloeity and attenuation coefficient etc.

Lanthanum-doped Bi_4Ti_3O_(12) ceramics prepared by high-pressure technique

We present an effective way in this paper to increase the density of lanthanum doped bismuth titanate ceramics, Bi4-xLaxTi3O12 （BLT）, thereby significantly improving the performance of the BLT ceramics. Dense BLT ceramicses, Bi4-xLaxTi3O12 （x = 0.25, 0.5, 0.75, 1.0）, are prepared by using nanocrystalline powders fabricated by a -gel method and high-pressure technique. The microstructures of the BLT ceramicses prepared separately by conventional-pressure and high-pressure techniques are investigated by using x-ray diffraction and transmission electron microscope. The influence of La-doping on the densification of bismuth titanate ceramics is investigated. The experimental results indicate that the phase compositions of all samples with various lanthanum dopings sintered at 900℃ possess layer- structure of Bi4Ti3O12. The green compacts are pressed under 2.5 GPa, 3.0 GPa, 3.5 GPa and 4.0 GPa, separately. It is found that the density of BLT ceramics is significantly increased due to the decreasing of porosity in the green compacts by high-pressure process.

To investigate the clinical effect of modified closed negative pressure suction technique combined with flap transplantation on the treatment of deep chronic refractory wounds

Objective:To investigate the clinical effect of modified closed negative pressure suction technique combined with flap transplantation on the treatment of deep chronic refractory wounds.Methods:During March of 2015 to April of 2018,52 cases of patients with deep chronic refractory wounds were selected as research objects.They were divided into the control group and the treatment group by use of the random number table method,with 26 cases in each group.Among them,the control group was given conventional debridement combined with flap reconstruction,and the treatment group was treated with modified closed negative pressure suction technique combined with flap transplantation to observe the clinical effect.Results:(1)According to the analysis on the effect of flap transplantation,the excellent and good rate of the treatment group was 92.3%,and in the control group,it was 76.9%(p<0.05).(2)According to the statistics,the incidence of complications in the treatment group was lower than that in the control group(p<0.05).Conclusions:Modified closed negative pressure suction technique combined with flap transplantation has a good effect on the treatment of deep chronic refractory wounds with fewer complications.

Morphological Engineering of Sensing Materials for Flexible Pressure Sensors and Artificial Intelligence Applications

As an indispensable branch of wearable electronics,flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring,human-machine interaction,artificial intelligence,the internet of things,and other fields.In recent years,highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms.Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance.This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors.We discuss different architectures and morphological designs of sensing materials to achieve high performance,including high sensitivity,broad working range,stable sensing,low hysteresis,high transparency,and directional or selective sensing.Additionally,the general fabrication techniques are summarized,including self-assembly,patterning,and auxiliary synthesis methods.Furthermore,we present the emerging applications of high-performing microengineered pressure sensors in healthcare,smart homes,digital sports,security monitoring,and machine learning-enabled computational sensing platform.Finally,the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.

Upper bound solutions of stability factor of shallow tunnels in saturated soil based on strength reduction technique

Based on the upper bound theorem of limit analysis,the factor of safety for shallow tunnel in saturated soil is calculated in conjunction with the strength reduction technique.To analyze the influence of the pore pressure on the factor of safety for shallow tunnel,the power of pore pressure is regarded as a power of external force in the energy calculation.Using the rigid multiple-block failure mechanism,the objective function for the factor of safety is constructed and the optimal solutions are derived by employing the sequential quadratic programming.According to the results of optimization calculation,the factor of safety of shallow tunnel for different pore pressure coefficients and variational groundwater tables are obtained.The parameter analysis shows that the pore pressure coefficient and the location of the groundwater table have significant influence on the factor of safety for shallow tunnel.

Processing and analysis of transient pressure measurements from permanent down-hole gauges

With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.

Slow-pull and different conventional suction techniques in endoscopic ultrasound-guided fine-needle aspiration of pancreatic solid lesions using 22-gauge needles

AIM To evaluate the cytological diagnostic capacity and sample quality of the slow-pull technique and compare them with different suction techniques.METHODS From July 2010 to December 2015, 102 patients with pancreatic solid lesions who underwent endoscopic ultrasound-guided fine-needle aspiration(EUS-FNA) with 22-gauge needles were retrospectively evaluated. EUS-FNA diagnosis was based on a cytological examination, and final diagnosis was based on a comprehensive standard of cytological diagnosis, surgical pathology and clinical or imaging follow-up. Cytological specimens were characterized for cellularity and blood contamination. The cytological diagnostic capacity and sample quality of the slow-pull technique and suction techniques with 5-m L/10-m L/20-m L syringes were analyzed.RESULTS Of all of the EUS-FNA procedures, the slow-pull technique and suction techniques with 5-m L/10-m L/20-m L syringes were used in 31, 19, 34 and 18 procedures, respectively. There were significant differences between these four suction techniques in terms of cytological diagnostic accuracy(90.3% vs 63.2% vs 58.8% vs 55.6%, P = 0.019), sensitivity(88.2% vs 41.7% vs 40.0% vs 36.4%, P = 0.009) and blood contamination(score ≥ 2 for 29.0% vs 52.6% vs 70.6% vs 72.2%, P = 0.003). The accuracy and sensitivity of the slow-pull technique were significantly higher than those of the suction techniques using 5-m L(P = 0.03, P = 0.014), 10-m L(P = 0.005; P = 0.006) and 20-mL syringes(P = 0.01, P = 0.01). Blood contamination was significantly lower in the slow-pull technique than in the suction techniques with 10-m L(P = 0.001) and 20-mL syringes(P = 0.007).CONCLUSION The slow-pull technique may increase the cytological diagnostic accuracy and sensitivity with slight blood contamination during EUS-FNA when using 22-gauge needles for solid pancreatic masses.

Comparative Observation of Ar,Ar-H_2 and Ar-N_2 DC Arc Plasma Jets and Their Arc Root Behaviour at Reduced Pressure

Results observed experimentally are presented, about the DC arc plasma jets and their arc-root behaviour generated at reduced gas pressure without or with an applied magnetic field. Pure argon, argon-hydrogen or argon-nitrogen mixture was used as the plasma-forming gas. A specially designed copper mirror was used for a better observation of the arc-root behaviour on the anode surface of the DC non-transferred arc plasma torch. It was found that in the cases without an applied magnetic field, the laminar plasma jets were stable and approximately axisymmetrical. The arc-root attachment on the anode surface was completely diffusive when argon was used as the plasma-forming gas, while the arc-root attachment often became constrictive when hydrogen or nitrogen was added into the argon. As an external magnetic field was applied, the arc root tended to rotate along the anode surface of the non-transferred arc plasma torch.

Fiber Bragg Grating Based Sensing'Platform for Foot Plantar Pressure Measurement

presented an application of using 3 D printing technique for the design and fabrication of a novel fiber Bragg grating( FBG)based sensing platform for foot planar pressure measurement.Pressure sensing unit was fabricated using 3 D printing technique by layering of extruded polylactic acid( PLA) material and mounting FBG sensor at the center of each sensing unit for pressure measurement. Performance of the sensing system was validated by applying load step by step as well as cyclic load on FBG pressure sensors. A simulation study was carried out using the sensing platform to assess foot plantar pressure distribution arises from weight gaining and losing processes of pregnant woman. The monitored four different foot positions such as first metatarsus,second metatarsus,mid-foot and heel exhibited obvious differences during testing process. Foot plantar pressure of heel was 1. 7 times of the pressure occurred at the first and second metatarsus( fore-foot),while there was limited pressure occurred at the mid-foot position during weight gaining process of a female subject. The occurred pressures at the two metatarsus areas were around 90%( pressure ratio) of heel and decreased continuously as the increase of subject weight,but weight losing process had very limited influence on this pressure ratio. Center of gravity of pregnant woman was found to shift backward substantially during the weighting gaining process,leading to a significant rise of the heel pressure. Hence, the protection of the heel position for female is highly important during both pregnancy and after baby delivery.

A METHOD OF CALCULATING PRESSURE DISTRIBUTION OF PERIODIC PULSATION FLUID TRANSPORTED IN PIPING NETWORK

The pressure pulsation induced by the pumped periodic pulsation fluid is the main factor of causing fluid resonance and stimulating pipelines vibrations and noise. In order to reduce the faults caused by the vibrations of pipelines, two aspects have been researched: one is to develop high quality filters, weaken and restrain the crest of pulsation pressure; the other is to design structural parameters of the piping network and eliminate the fluid resonance. Both need calculating the pressure pulsations of different structural parameters and frequencies, and knowing the amplitude frequency. In this paper the stiffness matrix technique is used for treating the coupling of subsystems of pipelines and calculating the pressure distribution of the piping network and it is tested by simulation and experiments.

Effects of Voluntary Apnea on Haemodynamic Responses during Groundwork Techniques of Judo

Context: Several studies were conducted on physiology of apnea in scuba diving. No survey has been reported in fighting sports. Objective: To evaluate cardiovascular variations misled by voluntary apnea during groundwork techniques of judo training. Methods: The temporal evolution of heart rate and modifications of the blood pressure have been investigated during cross sectional and experimental study. A total of 28 Congolese judoists took part in the study. The voluntary apnea was achieved by a judoist to try to carry out two kinds of groundwork (hon-gesagatame and kamishiho-gatame). According to the case, Student t test and analysis of variance were used for comparing data. Multivariate analysis was used to evaluate the effect of “type of groundwork technique × category of weight”. Results: Between 0 and 3 seconds, tachycardia has been observed during the static groundwork techniques and then bradycardia occurred to 3 - 9 seconds for the dynamic groundwork techniques : +6.8% of the rest frequency versus -9.4% for hon-gesa;+4.9% versus -13.7% for kami-shiho. Thereafter, it followed a fluctuation of heart rate of 9 - 15 seconds. Beyond, a stagnation was noted for hongesa, whereas a minimal increase (<5%) for kami-shiho. In relation to the systolic arterial pressure, a meaningful rise was recovered: +46.5% (hon-gesa) versus +50.1% (kami-shiho) in static exercise;+43.4% (hon-gesa) versus +43.3% (kami-shiho) in dynamic exercise. The report was similar for the diastolic arterial pressure: +31.5% (hon-gesa) versus 30.0% (kami-shiho) in static exercise;+20.3% (hon-gesa) versus +23.8% (kami-shiho) in dynamic exercise. Conclusion: The apnea consecutive to the hindrance of an exit groundwork technique to judo drags bradycardia increased while exercise realized static posture, and a rise of the arterial pressure.

Contrast-enhanced ultrasound for quantitative assessment of portal pressure in canine liver fibrosis

AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound(CEUS) in a canine model.METHODS: Liver fibrosis was established in adult canines(Beagles; n = 14) by subcutaneous injection of carbon tetrachloride(CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases(Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures(FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Q p/Q a and I p/I a.RESULTS: Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0(n = 3), F1(n = 12), F2(n = 14), F3(n = 11), and F4(n = 2). There were significant differences in the measurements of Qp/Qa(19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia(1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively(all P < 0.001). There were statistically significant negative correlations between FPP and Q p/Q a(r =-0.707, P < 0.001), and between FPP and Ip/Ia(r =-0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Q p/Q a and I p/I a was highly sensitive, as assessed by the area under the receiveroperating curve(0.866 and 0.895, respectively).CONCLUSION: C E U S i s a p o t e n t i a l m e t h o d t o accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip/Ia parameters.