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 complic...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.展开更多
An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly desi...An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.展开更多
Neutral beam injection(NBI)systems based on negative hydrogen ion sources-rather than the positive ion sources that have typically been used to date-will be used in the future magnetically confined nuclear fusion expe...Neutral beam injection(NBI)systems based on negative hydrogen ion sources-rather than the positive ion sources that have typically been used to date-will be used in the future magnetically confined nuclear fusion experiments to heat the plasma.The collisions between the fast negative ions and neutral background gas result in a significant number of high-energy positive ions being produced in the acceleration area,and for the high-power long-pulse operation of NBI systems,this acceleration of positive ions back to the ion source creates heat load and material sputtering on the source backplate.This difficulty cannot be ignored,with the neutral gas density in the acceleration region having a significant impact on the flux density of the backstreaming positive ions.In the work reported here,the pressure gradient in the acceleration region was estimated using an ionization gauge and a straightforward 1D computation,and it was found that once gas traveled through the acceleration region,the pressure dropped by nearly one order of magnitude,with the largest pressure drop occurring at the plasma grid.The computation also revealed that the pressure drop in the grid gaps was substantially smaller than that in the grid apertures.展开更多
BACKGROUND Radicular cysts are one of the most common odontogenic cystic lesions found in the jaw.Nonsurgical treatment of large radicular cysts is a topic of ongoing debate,and there is still no clear consensus on th...BACKGROUND Radicular cysts are one of the most common odontogenic cystic lesions found in the jaw.Nonsurgical treatment of large radicular cysts is a topic of ongoing debate,and there is still no clear consensus on the most effective therapies.The apical negative pressure irrigation system aspirates the cystic fluid and releases the static pressure in the radicular cyst,representing a minimally invasive approach for decompression.In this case,the radicular cyst was in close proximity to the mandibular nerve canal.We used nonsurgical endodontic treatment with a homemade apical negative pressure irrigation system and the prognosis was good.CASE SUMMARY A 27-year-old male presented to our Department of General Dentistry with complaints of pain in the mandibular right molar when chewing.The patient had no history of drug allergies or systemic disease.A multidisciplinary management approach was designed and included root canal retreatment with a homemade apical negative pressure irrigation system,deep margin elevation and prosthodontic treatment.According to a 1-year follow-up period,the patient showed a favorable outcome.CONCLUSION This report reveals that nonsurgical treatment with an apical negative pressure irrigation system may provide new insights into the treatment of radicular cysts.展开更多
BACKGROUND Thermal injuries on free transferred or replanted tissues resulting from loss of sensibility are an infrequent occurrence.They require immediate and appropriate management before they progress to an irrever...BACKGROUND Thermal injuries on free transferred or replanted tissues resulting from loss of sensibility are an infrequent occurrence.They require immediate and appropriate management before they progress to an irreversible condition.Although negative pressure wound therapy(NPWT)can prevent wound progression by increasing microcirculation,the inappropriate application of NPWT on complicationthreatened transferred and replanted tissues can induce an adverse effect.CASE SUMMARY A 48-year-old woman who underwent immediate breast reconstruction with a deep inferior epigastric artery perforator free flap.While applying a heating pad directly to the flap site,she sustained a deep second to third-degree contact burn over 30%of the transferred flap on postoperative 7 d.As the necrotic changes had progressed,we applied an NPWT dressing over the burned area after en-bloc debridement of the transferred tissues on postoperative 21 d.After 4 d of NPWT application,the exposed fatty tissues of the flap changed to dry and browncolored necrotic tissues.Upon further debridement,we noted that the wound gradually reached total necrosis with a collapsed vascular pedicle of deep inferior epigastric artery.CONCLUSION Although NPWT has been shown to be successful for treating various wound types,the significant risk of NPWT application in short-lasting reconstructed flap wounds after thermal injury should be reminded.展开更多
BACKGROUND Skin cancer is a common malignant tumor in dermatology.A large area must be excised to ensure a negative incisal margin on huge frontotemporal skin cancer,and it is difficult to treat the wound.In the past,...BACKGROUND Skin cancer is a common malignant tumor in dermatology.A large area must be excised to ensure a negative incisal margin on huge frontotemporal skin cancer,and it is difficult to treat the wound.In the past,treatment with skin grafting and pressure dressing was easy to cause complications such as wound infections,subcutaneous effusion,skin necrosis,and contracture.Negative pressure wound therapy(NPWT)has been applied to treat huge frontotemporal skin cancer.CASE SUMMARY Herein,we report the case of a 92-year-old woman with huge frontotemporal skin cancer.The patient presented to the surgery department complaining of ruptured bleeding and pain in a right frontal mass.The tumor was pathologically diagnosed as highly differentiated squamous cell carcinoma.The patient underwent skin cancer surgery and skin grafting,after which NPWT was used.She did not experience a relapse during the three-year follow-up period.CONCLUSION NPWT is of great clinical value in the postoperative treatment of skin cancer.It is not only inexpensive but also can effectively reduce the risk of surgical effusion,infection,and flap necrosis.展开更多
Utilization of negative pressure wound therapy with instillation (NPWTi) for sternal dehiscence wounds secondary to sternal wound infection after surgery has become an accepted therapy. NPWTi accelerates wound healing...Utilization of negative pressure wound therapy with instillation (NPWTi) for sternal dehiscence wounds secondary to sternal wound infection after surgery has become an accepted therapy. NPWTi accelerates wound healing through macrostrain, microstrain, and cyclic fluid instillation. Wounds benefit from additional superficial infection control with the removal of microorganisms, the release of proinflammatory mediators, stimulation of angiogenesis, as well as mechanical debridement. However, very few cases of utilizing NPWTi in the treatment of sternal wound infections have been reported in the literature. This case study describes the use of NPWTi with hypochlorous acid for the treatment of a sternal wound infection.展开更多
Introduction: The standard treatment for complex wound care is autografting. The advent of dermal substitutes has provided a novel tool for the preparation of the bed to be grafted. However, most types of dermal matri...Introduction: The standard treatment for complex wound care is autografting. The advent of dermal substitutes has provided a novel tool for the preparation of the bed to be grafted. However, most types of dermal matrices require the application of a skin graft a second time. Currently, other strategies have been developed to improve the vascularization process, such as negative pressure wound therapy (NPWT), which has been reported to reduce the time required for vascular growth and dermal matrix integration and thus achieve a shorter waiting period for autologous graft application. The present study aims to evaluate the effectiveness and safety of dermal matrix management associated with NPWT in the treatment of complex wounds. Methods: Seven patients with a diagnosis of complex wounds were enrolled in this study between July 1, 2015, and June 31, 2016. After debridement and having an adequate wound bed, patients who met the criteria for the application of combined therapy were treated with dermal substitutes and a negative pressure system. The percentage of graft integration into the wound bed, complications, length of hospital stay, and duration of therapy were analyzed. Results: The mean age was 42.5 ± 16 (39 - 54) years old;three women and four men were included in the study. The approximate size of skin loss was 120.7 ± 75 cm<sup>2</sup> (25 - 250 cm<sup>2</sup>). The combined therapy of dermal matrix plus NPWT was instituted in all cases for a period of 14 days. There were no complications, with 100% graft integration in 6 of 7 cases. Patients were discharged after a mean hospital stay of 5.4 days. Conclusions: This study demonstrates that the utilization of combined dermal matrix plus NPWT therapy can be performed safely and effectively in patients with complex wounds with low complication rates and a short hospital stay.展开更多
Diabetic foot(DF) is a common complication of diabetes and the first cause of hospital admission in diabetic patients. In recent years several guidelines have been proposed to reinforce the the management of DF with a...Diabetic foot(DF) is a common complication of diabetes and the first cause of hospital admission in diabetic patients. In recent years several guidelines have been proposed to reinforce the the management of DF with a notable increase in diabetes knowledge and an overall reduction of amputations. Significant improvements have been reached in the treatment of diabetic foot ulcers(DFUs) and nowadays clinicians have several advanced medications to apply for the best local therapy. Among these, negative pressure wound therapy(NPWT) is a useful adjunct in the management of chronic and complex wounds to promote healing and wound bed preparation for surgical procedures such as skin grafts and flap surgery. NPWT has shown remarkable results although its mechanisms of action are not completely understood. In this paper, we offer a complete overview of this medication and its implication in the clinical setting. We have examined literature related to NPWT concerning human, animal and in vitro studies, and we have summarized why, when and how we can use NPWT to treat DFUs. Further we have associated our clinical experience to scientific evidence in the field of diabetic foot to identify a defined strategy that could guide clinician in the use of NPWT approaching to DFUs.展开更多
This study examined the effect of different negative pressures and soil textures on water and salt movement to improve the efficiency of negative pressure irrigation(NPI).Four soil textures of varying fineness(Loamy S...This study examined the effect of different negative pressures and soil textures on water and salt movement to improve the efficiency of negative pressure irrigation(NPI).Four soil textures of varying fineness(Loamy Sand,Loam,Silty Loam,and Sandy Loam) and three negative pressure values(0,-5,and-10 kPa) were used.As irrigation time increased,wetting front movement speeds decreased,and as negative pressure increased,wetting front size decreased.Coarse soils had the smallest wetting front under greater negative pressure.Next,water infiltration rate decreased as irrigation time increased,and coarse soils had the lowest average infiltration rate under greater negative pressure.Finally,salt content increased with distance from the irrigation emitter and with increased negative pressure.Further,coarse soils were found to have decreased desalination under greater negative pressure.Thus,soil texture has a strong effect on NPI efficiency.However,by adjusting pressure values in accordance with soil texture,soil water content can be controlled and maintained.These findings are important to the improvement of NPI systems,increasing their practicality for agricultural use.展开更多
A five steps pressure swing adsorption process was designed for acetone and toluene mixtures separation and recovery. Dynamic distributions of gas phase content and temperature were investigated. Based on the theory o...A five steps pressure swing adsorption process was designed for acetone and toluene mixtures separation and recovery. Dynamic distributions of gas phase content and temperature were investigated. Based on the theory of Soret and Dufour, a non-isothermal mathematical model was developed to simulate the PSA process. Effects of heat and mass transfer coefficients were studied. The coupled Soret and Dufour effects were also evaluated. It is found that the heat transfer coefficient has little effect on mass transfer in adsorption stage. However, it has some impacts in desorption stage. The maximum value of C/C0 increases by about 25% as heat transfer coefficient decreases. The temperature variation is less than 0.05 K with the change of mass transfer coefficient, so that the effect of mass transfer coefficient on heat transfer can be ignored. It is also concluded that the Soret and Dufour coupled effects are not obvious in pressure swing adsorption compared with fixed-bed adsorption.展开更多
The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonline...The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control. In order to meet the demand of generating dynamic pressure signal in the application of the hardware-in-the-loop simulation of aerospace engineering, a positive and negative pneumatic pressure servo system is provided to implement dynamic adjustment of sealed chamber pressure. A mathematical model is established with simulation and experiment being implemented afterwards to discuss the characteristics of the system, which shows serious asymmetry in the process of charging and discharging. Based on the analysis of the system dynamics, a fuzzy proportional integral derivative(PID) controller with asymmetric fuzzy compensator is proposed. Different from conventional adjusting mechanisms employing the error and change in error of the controlled variable as input parameters, the current chamber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability.To verify the effectiveness and performance of the proposed controller, the comparison experiments tracking sinusoidal and square wave commands are conducted.Experimental results show that the proposed controller can obtain better dynamic performance and relatively consistent control performance across the scope of work(2-140 kPa). The research proposes a fuzzy control method to overcome asymmetry and enhance adaptability for the positive and negative pneumatic pressure servo system.展开更多
In order to remove N_(2) from low quality natural gas,a mathematical model has been established by Aspen adsorption,using the CH_(4)-selective sorbent silicalite-1 pellets.The dynamic adsorption isotherm was first sim...In order to remove N_(2) from low quality natural gas,a mathematical model has been established by Aspen adsorption,using the CH_(4)-selective sorbent silicalite-1 pellets.The dynamic adsorption isotherm was first simulated by breakthrough simulation of a CH_(4)/N_(2) mixture at different adsorption pressures and feed flow rates based on breakthrough experiments.The resulting simulated CH_(4) dynamic adsorption amounts were very close to the experimental data at three different adsorption pressures(100,200,and 300 kPa).Moreover,a single-bed,three-step pressure swing adsorption(PSA)experiment was performed,and the results were in good agreement with the simulated data,further corroborating the accuracy of the gas dynamic adsorption isotherm obtained by the simulation method.Finally,based on the simulated dynamic adsorption isotherm of CH_(4) and N_(2),a four-bed,eight-step PSA process has been designed,which enriched 75%(vol)CH_(4) and 80%(vol)CH_(4) to 95%(vol)and 99%(vol),and provided 99%(vol)recovery.展开更多
A pressure swing adsorption (PSA) hydrogen purification model for the four-component gas (H_(2)/CO_(2)/CH_(4)/CO=73/16/8/3 mol%) in a layered bed packed with Cu-BTC and zeolite 5A was established to achieve better hyd...A pressure swing adsorption (PSA) hydrogen purification model for the four-component gas (H_(2)/CO_(2)/CH_(4)/CO=73/16/8/3 mol%) in a layered bed packed with Cu-BTC and zeolite 5A was established to achieve better hydrogen purification performance.By comparing its simulation results with the experimental data,the adsorption isotherm model was validated and could be used to accurately describe the adsorption process of the gas mixture on the two adsorbents.The breakthrough curves of the mixed gas on the layered bed were studied to verify the correctness of the established simulation models.Based on the validated model,the performance of the PSA system based on the layered bed was carried out,including the hydrogen purity and recovery.The simulation results show that the hydrogen purification system based on the layered bed model can achieve hydrogen purity of 95.469% and hydrogen recovery of 83.219%.Moreover,a parametric study was carried out and its results show that reductions in feed flow rate and adsorption time result in an increase in hydrogen purity and a decrease in hydrogen recovery.A longer equalization time between the two adsorption beds can simultaneously increase the hydrogen purity and recovery.展开更多
Objective: To explore the treatment and nursing characteristics for pressure injury on the inside of the thigh caused by forced posture in patients with cirrhosis and diabetes mellitus. Methods: A patient with cirrhos...Objective: To explore the treatment and nursing characteristics for pressure injury on the inside of the thigh caused by forced posture in patients with cirrhosis and diabetes mellitus. Methods: A patient with cirrhosis and diabetes mellitus complicated with abscess of right inner thigh pressure injury was selected as the study object, who was admitted to Xuzhou Medical University Hospital on June 29, 2019. The analysis of the clinical diagnosis, treatment and nursing process were applied to explore the prognosis of the patient with cirrhosis and diabetes mellitus complicated with deep abscess of the thigh. Results: The traditional treatment including incision and drainage was not allowed, as the general treatment was not effective for the patients with cirrhosis and diabetes mellitus complicated with deep abscess in the inner thigh. After 8 days of negative pressure manual dressing change combined with mupirocin ointment treatment, the local skin condition returned to normal. Conclusion: After literature search, it was found that the above-mentioned cirrhosis combined with diabetes and deep abscess cases in the inner thigh were rare clinically. When the traditional treatment of incision and drainage is limited, negative pressure manual dressing change combined with antibiotics is an effective method, which is worthy of clinical application and promotion.展开更多
The high pressure static adsorption curves of shale samples from Silurian Changning-Weiyuan Longmaxi Formation were tested by using high pressure isothermal adsorption equipment.The physical modeling of depletion prod...The high pressure static adsorption curves of shale samples from Silurian Changning-Weiyuan Longmaxi Formation were tested by using high pressure isothermal adsorption equipment.The physical modeling of depletion production was tested on single cores and multi-core series by using self-developed shale gas fluid-solid coupling experiment system.The adsorption and desorption laws were summarized and a high pressure isothermal adsorption model was established.The calculation formula of gas content was corrected,and the producing law of adsorption gas was determined.The study results show that the isothermal adsorption law of the shale reservoir under high pressure was different from the conventional low pressure.The high pressure isothermal adsorption curve had the maximum value in excess adsorption with pressure change,and the corresponding pressure was the critical desorption pressure.The high pressure isothermal curve can be used to evaluate the amount of adsorbed gas and the producing degree of adsorption gas.The high pressure isothermal adsorption model can fit and characterize the high pressure isothermal adsorption law of shale.The modified gas content calculation method can evaluate the gas content and the proportion of adsorbed gas more objectively,and is the theoretical basis of reserve assessment and production decline analysis.The producing degree of adsorption gas is closely related to the pressure,only when the reservoir pressure is lower than the critical desorption pressure,the adsorption gas can be produced effectively.In the process of gas well production,the pressure drop in the near-well area is large,the production of adsorption gas is high;away from the wellbore,the adsorption gas is low in production,or no production.展开更多
The pressure swing adsorption (PSA) models discussed here are divided into three categories: partialdifferential equation model, electrical analogue model and neural network model. The partial differential equationmod...The pressure swing adsorption (PSA) models discussed here are divided into three categories: partialdifferential equation model, electrical analogue model and neural network model. The partial differential equationmodel, including equilibrium and kinetic models, has provided an elementary viewpoint for PSA processes. Usingthe simplest equilibrium models, some influential factors, such as pressurization with product, incomplete purge,beds with dead volume and heat effects, are discussed respectively. With several approximate assumptions i.e.,concentration profile in adsorbent, 'frozen' column, symmetry and heat effects of bed wall, the more complexkinetic models can be simplified to a certain degree at the expense of a limited application. It has also been foundthat the electrical analogue model has great flexibility to handle more realistic PSA processes without any additionalhypothesis.展开更多
AIM To review negative pressure wound therapy(NPWT) as animportant addition to the conventional methods of wound management.METHODS A systematic review, performed by searching the PubM ed, EMBASE and Cochrane Library ...AIM To review negative pressure wound therapy(NPWT) as animportant addition to the conventional methods of wound management.METHODS A systematic review, performed by searching the PubM ed, EMBASE and Cochrane Library databases, showed 11 case reports comprising a total of 22 kidney transplantation(KT) patients(range, 1 to 9), who were treated with NPWT. Application of NPWT was associated with successful healing of wounds, leg ulcer, lymphocele and urine leak from ileal conduit.RESULTS No complications related to NPWT were reported. However, there was paucity of robust data on the effectiveness of NPWT in KT recipients; therefore, prospective studies assessing its safety and efficacy of NPWT and randomised trials comparing the effectiveness of NPWT with alternative modalities of wound management in KT recipients is recommended.CONCLUSION Negative pressure incision management system, NPWT with instillation and endoscopic vacuum-assisted closure system are in investigational stage.展开更多
Negative Pressure pulmonary oedema (NPPO) is a medical emergency. It occurs when there is a strong inspiratory effort in obstructed upper airway. Laryngospasm is the main cause of postextubation negative pressure pulm...Negative Pressure pulmonary oedema (NPPO) is a medical emergency. It occurs when there is a strong inspiratory effort in obstructed upper airway. Laryngospasm is the main cause of postextubation negative pressure pulmonary oedema. Though it is life-threatening, early diagnosis and prompt treatment lead to rapid resolution with no residual respiratory complications. The mainstay management is to provide respiratory support, mostly in the intensive care unit. The recommended mode of respiratory support is to provide an invasive or non-invasive positive airway pressure. This requires the use of a ventilator. Most surgery centres in sub-Saharan Africa do not have intensive care unit or ventilators in their recovery wards. We report two cases of postextubation NPPO which occurred in a typical African hospital with no ventilator. All these two cases were successfully managed with a non-rebreather mask. The periods of resolution, both clinical and radiological, were 24 - 48 hrs. This is not significantly different from the resolution periods quoted in literature from cases managed in well-resourced centres with means of positive pressure ventilation. We therefore conclude that early detection and prompt initiation of management are important keys which can lead to good outcomes, even in low-resource centres.展开更多
基金Supported by the Zhejiang Provincial Natural Science Foundation of China,No.LQ20H260002.
文摘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.
基金financially supported by the Renewable Energy and Hydrogen Projects in National Key Research & Development Program of China (2019YFB1505000)。
文摘An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC2202700).
文摘Neutral beam injection(NBI)systems based on negative hydrogen ion sources-rather than the positive ion sources that have typically been used to date-will be used in the future magnetically confined nuclear fusion experiments to heat the plasma.The collisions between the fast negative ions and neutral background gas result in a significant number of high-energy positive ions being produced in the acceleration area,and for the high-power long-pulse operation of NBI systems,this acceleration of positive ions back to the ion source creates heat load and material sputtering on the source backplate.This difficulty cannot be ignored,with the neutral gas density in the acceleration region having a significant impact on the flux density of the backstreaming positive ions.In the work reported here,the pressure gradient in the acceleration region was estimated using an ionization gauge and a straightforward 1D computation,and it was found that once gas traveled through the acceleration region,the pressure dropped by nearly one order of magnitude,with the largest pressure drop occurring at the plasma grid.The computation also revealed that the pressure drop in the grid gaps was substantially smaller than that in the grid apertures.
基金Supported by the Medical Health Science and Technology Project of Zhejiang Provincial Health Commission,No.2022RC158.
文摘BACKGROUND Radicular cysts are one of the most common odontogenic cystic lesions found in the jaw.Nonsurgical treatment of large radicular cysts is a topic of ongoing debate,and there is still no clear consensus on the most effective therapies.The apical negative pressure irrigation system aspirates the cystic fluid and releases the static pressure in the radicular cyst,representing a minimally invasive approach for decompression.In this case,the radicular cyst was in close proximity to the mandibular nerve canal.We used nonsurgical endodontic treatment with a homemade apical negative pressure irrigation system and the prognosis was good.CASE SUMMARY A 27-year-old male presented to our Department of General Dentistry with complaints of pain in the mandibular right molar when chewing.The patient had no history of drug allergies or systemic disease.A multidisciplinary management approach was designed and included root canal retreatment with a homemade apical negative pressure irrigation system,deep margin elevation and prosthodontic treatment.According to a 1-year follow-up period,the patient showed a favorable outcome.CONCLUSION This report reveals that nonsurgical treatment with an apical negative pressure irrigation system may provide new insights into the treatment of radicular cysts.
文摘BACKGROUND Thermal injuries on free transferred or replanted tissues resulting from loss of sensibility are an infrequent occurrence.They require immediate and appropriate management before they progress to an irreversible condition.Although negative pressure wound therapy(NPWT)can prevent wound progression by increasing microcirculation,the inappropriate application of NPWT on complicationthreatened transferred and replanted tissues can induce an adverse effect.CASE SUMMARY A 48-year-old woman who underwent immediate breast reconstruction with a deep inferior epigastric artery perforator free flap.While applying a heating pad directly to the flap site,she sustained a deep second to third-degree contact burn over 30%of the transferred flap on postoperative 7 d.As the necrotic changes had progressed,we applied an NPWT dressing over the burned area after en-bloc debridement of the transferred tissues on postoperative 21 d.After 4 d of NPWT application,the exposed fatty tissues of the flap changed to dry and browncolored necrotic tissues.Upon further debridement,we noted that the wound gradually reached total necrosis with a collapsed vascular pedicle of deep inferior epigastric artery.CONCLUSION Although NPWT has been shown to be successful for treating various wound types,the significant risk of NPWT application in short-lasting reconstructed flap wounds after thermal injury should be reminded.
文摘BACKGROUND Skin cancer is a common malignant tumor in dermatology.A large area must be excised to ensure a negative incisal margin on huge frontotemporal skin cancer,and it is difficult to treat the wound.In the past,treatment with skin grafting and pressure dressing was easy to cause complications such as wound infections,subcutaneous effusion,skin necrosis,and contracture.Negative pressure wound therapy(NPWT)has been applied to treat huge frontotemporal skin cancer.CASE SUMMARY Herein,we report the case of a 92-year-old woman with huge frontotemporal skin cancer.The patient presented to the surgery department complaining of ruptured bleeding and pain in a right frontal mass.The tumor was pathologically diagnosed as highly differentiated squamous cell carcinoma.The patient underwent skin cancer surgery and skin grafting,after which NPWT was used.She did not experience a relapse during the three-year follow-up period.CONCLUSION NPWT is of great clinical value in the postoperative treatment of skin cancer.It is not only inexpensive but also can effectively reduce the risk of surgical effusion,infection,and flap necrosis.
文摘Utilization of negative pressure wound therapy with instillation (NPWTi) for sternal dehiscence wounds secondary to sternal wound infection after surgery has become an accepted therapy. NPWTi accelerates wound healing through macrostrain, microstrain, and cyclic fluid instillation. Wounds benefit from additional superficial infection control with the removal of microorganisms, the release of proinflammatory mediators, stimulation of angiogenesis, as well as mechanical debridement. However, very few cases of utilizing NPWTi in the treatment of sternal wound infections have been reported in the literature. This case study describes the use of NPWTi with hypochlorous acid for the treatment of a sternal wound infection.
文摘Introduction: The standard treatment for complex wound care is autografting. The advent of dermal substitutes has provided a novel tool for the preparation of the bed to be grafted. However, most types of dermal matrices require the application of a skin graft a second time. Currently, other strategies have been developed to improve the vascularization process, such as negative pressure wound therapy (NPWT), which has been reported to reduce the time required for vascular growth and dermal matrix integration and thus achieve a shorter waiting period for autologous graft application. The present study aims to evaluate the effectiveness and safety of dermal matrix management associated with NPWT in the treatment of complex wounds. Methods: Seven patients with a diagnosis of complex wounds were enrolled in this study between July 1, 2015, and June 31, 2016. After debridement and having an adequate wound bed, patients who met the criteria for the application of combined therapy were treated with dermal substitutes and a negative pressure system. The percentage of graft integration into the wound bed, complications, length of hospital stay, and duration of therapy were analyzed. Results: The mean age was 42.5 ± 16 (39 - 54) years old;three women and four men were included in the study. The approximate size of skin loss was 120.7 ± 75 cm<sup>2</sup> (25 - 250 cm<sup>2</sup>). The combined therapy of dermal matrix plus NPWT was instituted in all cases for a period of 14 days. There were no complications, with 100% graft integration in 6 of 7 cases. Patients were discharged after a mean hospital stay of 5.4 days. Conclusions: This study demonstrates that the utilization of combined dermal matrix plus NPWT therapy can be performed safely and effectively in patients with complex wounds with low complication rates and a short hospital stay.
文摘Diabetic foot(DF) is a common complication of diabetes and the first cause of hospital admission in diabetic patients. In recent years several guidelines have been proposed to reinforce the the management of DF with a notable increase in diabetes knowledge and an overall reduction of amputations. Significant improvements have been reached in the treatment of diabetic foot ulcers(DFUs) and nowadays clinicians have several advanced medications to apply for the best local therapy. Among these, negative pressure wound therapy(NPWT) is a useful adjunct in the management of chronic and complex wounds to promote healing and wound bed preparation for surgical procedures such as skin grafts and flap surgery. NPWT has shown remarkable results although its mechanisms of action are not completely understood. In this paper, we offer a complete overview of this medication and its implication in the clinical setting. We have examined literature related to NPWT concerning human, animal and in vitro studies, and we have summarized why, when and how we can use NPWT to treat DFUs. Further we have associated our clinical experience to scientific evidence in the field of diabetic foot to identify a defined strategy that could guide clinician in the use of NPWT approaching to DFUs.
基金supported by the National High-Tech R&D Program of China (2013AA102901)
文摘This study examined the effect of different negative pressures and soil textures on water and salt movement to improve the efficiency of negative pressure irrigation(NPI).Four soil textures of varying fineness(Loamy Sand,Loam,Silty Loam,and Sandy Loam) and three negative pressure values(0,-5,and-10 kPa) were used.As irrigation time increased,wetting front movement speeds decreased,and as negative pressure increased,wetting front size decreased.Coarse soils had the smallest wetting front under greater negative pressure.Next,water infiltration rate decreased as irrigation time increased,and coarse soils had the lowest average infiltration rate under greater negative pressure.Finally,salt content increased with distance from the irrigation emitter and with increased negative pressure.Further,coarse soils were found to have decreased desalination under greater negative pressure.Thus,soil texture has a strong effect on NPI efficiency.However,by adjusting pressure values in accordance with soil texture,soil water content can be controlled and maintained.These findings are important to the improvement of NPI systems,increasing their practicality for agricultural use.
基金Projects(20976200,20676154) supported by the National Natural Science Foundation of China
文摘A five steps pressure swing adsorption process was designed for acetone and toluene mixtures separation and recovery. Dynamic distributions of gas phase content and temperature were investigated. Based on the theory of Soret and Dufour, a non-isothermal mathematical model was developed to simulate the PSA process. Effects of heat and mass transfer coefficients were studied. The coupled Soret and Dufour effects were also evaluated. It is found that the heat transfer coefficient has little effect on mass transfer in adsorption stage. However, it has some impacts in desorption stage. The maximum value of C/C0 increases by about 25% as heat transfer coefficient decreases. The temperature variation is less than 0.05 K with the change of mass transfer coefficient, so that the effect of mass transfer coefficient on heat transfer can be ignored. It is also concluded that the Soret and Dufour coupled effects are not obvious in pressure swing adsorption compared with fixed-bed adsorption.
基金Supported by National Natural Science Foundation of China(Grant No.51575199)
文摘The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control. In order to meet the demand of generating dynamic pressure signal in the application of the hardware-in-the-loop simulation of aerospace engineering, a positive and negative pneumatic pressure servo system is provided to implement dynamic adjustment of sealed chamber pressure. A mathematical model is established with simulation and experiment being implemented afterwards to discuss the characteristics of the system, which shows serious asymmetry in the process of charging and discharging. Based on the analysis of the system dynamics, a fuzzy proportional integral derivative(PID) controller with asymmetric fuzzy compensator is proposed. Different from conventional adjusting mechanisms employing the error and change in error of the controlled variable as input parameters, the current chamber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability.To verify the effectiveness and performance of the proposed controller, the comparison experiments tracking sinusoidal and square wave commands are conducted.Experimental results show that the proposed controller can obtain better dynamic performance and relatively consistent control performance across the scope of work(2-140 kPa). The research proposes a fuzzy control method to overcome asymmetry and enhance adaptability for the positive and negative pneumatic pressure servo system.
文摘In order to remove N_(2) from low quality natural gas,a mathematical model has been established by Aspen adsorption,using the CH_(4)-selective sorbent silicalite-1 pellets.The dynamic adsorption isotherm was first simulated by breakthrough simulation of a CH_(4)/N_(2) mixture at different adsorption pressures and feed flow rates based on breakthrough experiments.The resulting simulated CH_(4) dynamic adsorption amounts were very close to the experimental data at three different adsorption pressures(100,200,and 300 kPa).Moreover,a single-bed,three-step pressure swing adsorption(PSA)experiment was performed,and the results were in good agreement with the simulated data,further corroborating the accuracy of the gas dynamic adsorption isotherm obtained by the simulation method.Finally,based on the simulated dynamic adsorption isotherm of CH_(4) and N_(2),a four-bed,eight-step PSA process has been designed,which enriched 75%(vol)CH_(4) and 80%(vol)CH_(4) to 95%(vol)and 99%(vol),and provided 99%(vol)recovery.
基金Funded by the National Key R&D Program of China (No.2021YFB2601603)the National Natural Science Foundation of China (Nos. 52176191, 51476120)+2 种基金the Science and Technology Innovation Project of Jianghan University (No. 2021kjzx005)the 111 Project (No. B17034)the Innovative Research Team Development Program of the Ministry of Education of China (No. IRT_17R83)。
文摘A pressure swing adsorption (PSA) hydrogen purification model for the four-component gas (H_(2)/CO_(2)/CH_(4)/CO=73/16/8/3 mol%) in a layered bed packed with Cu-BTC and zeolite 5A was established to achieve better hydrogen purification performance.By comparing its simulation results with the experimental data,the adsorption isotherm model was validated and could be used to accurately describe the adsorption process of the gas mixture on the two adsorbents.The breakthrough curves of the mixed gas on the layered bed were studied to verify the correctness of the established simulation models.Based on the validated model,the performance of the PSA system based on the layered bed was carried out,including the hydrogen purity and recovery.The simulation results show that the hydrogen purification system based on the layered bed model can achieve hydrogen purity of 95.469% and hydrogen recovery of 83.219%.Moreover,a parametric study was carried out and its results show that reductions in feed flow rate and adsorption time result in an increase in hydrogen purity and a decrease in hydrogen recovery.A longer equalization time between the two adsorption beds can simultaneously increase the hydrogen purity and recovery.
文摘Objective: To explore the treatment and nursing characteristics for pressure injury on the inside of the thigh caused by forced posture in patients with cirrhosis and diabetes mellitus. Methods: A patient with cirrhosis and diabetes mellitus complicated with abscess of right inner thigh pressure injury was selected as the study object, who was admitted to Xuzhou Medical University Hospital on June 29, 2019. The analysis of the clinical diagnosis, treatment and nursing process were applied to explore the prognosis of the patient with cirrhosis and diabetes mellitus complicated with deep abscess of the thigh. Results: The traditional treatment including incision and drainage was not allowed, as the general treatment was not effective for the patients with cirrhosis and diabetes mellitus complicated with deep abscess in the inner thigh. After 8 days of negative pressure manual dressing change combined with mupirocin ointment treatment, the local skin condition returned to normal. Conclusion: After literature search, it was found that the above-mentioned cirrhosis combined with diabetes and deep abscess cases in the inner thigh were rare clinically. When the traditional treatment of incision and drainage is limited, negative pressure manual dressing change combined with antibiotics is an effective method, which is worthy of clinical application and promotion.
基金Supported by China National Science and Technology Major Project(2017ZX05037-001)the "13th Five-Year Plan" National Demonstration Project(2016ZX05062-002-001)
文摘The high pressure static adsorption curves of shale samples from Silurian Changning-Weiyuan Longmaxi Formation were tested by using high pressure isothermal adsorption equipment.The physical modeling of depletion production was tested on single cores and multi-core series by using self-developed shale gas fluid-solid coupling experiment system.The adsorption and desorption laws were summarized and a high pressure isothermal adsorption model was established.The calculation formula of gas content was corrected,and the producing law of adsorption gas was determined.The study results show that the isothermal adsorption law of the shale reservoir under high pressure was different from the conventional low pressure.The high pressure isothermal adsorption curve had the maximum value in excess adsorption with pressure change,and the corresponding pressure was the critical desorption pressure.The high pressure isothermal curve can be used to evaluate the amount of adsorbed gas and the producing degree of adsorption gas.The high pressure isothermal adsorption model can fit and characterize the high pressure isothermal adsorption law of shale.The modified gas content calculation method can evaluate the gas content and the proportion of adsorbed gas more objectively,and is the theoretical basis of reserve assessment and production decline analysis.The producing degree of adsorption gas is closely related to the pressure,only when the reservoir pressure is lower than the critical desorption pressure,the adsorption gas can be produced effectively.In the process of gas well production,the pressure drop in the near-well area is large,the production of adsorption gas is high;away from the wellbore,the adsorption gas is low in production,or no production.
基金Supported by the National Natural Science Foundation of China (No. 29876011).
文摘The pressure swing adsorption (PSA) models discussed here are divided into three categories: partialdifferential equation model, electrical analogue model and neural network model. The partial differential equationmodel, including equilibrium and kinetic models, has provided an elementary viewpoint for PSA processes. Usingthe simplest equilibrium models, some influential factors, such as pressurization with product, incomplete purge,beds with dead volume and heat effects, are discussed respectively. With several approximate assumptions i.e.,concentration profile in adsorbent, 'frozen' column, symmetry and heat effects of bed wall, the more complexkinetic models can be simplified to a certain degree at the expense of a limited application. It has also been foundthat the electrical analogue model has great flexibility to handle more realistic PSA processes without any additionalhypothesis.
文摘AIM To review negative pressure wound therapy(NPWT) as animportant addition to the conventional methods of wound management.METHODS A systematic review, performed by searching the PubM ed, EMBASE and Cochrane Library databases, showed 11 case reports comprising a total of 22 kidney transplantation(KT) patients(range, 1 to 9), who were treated with NPWT. Application of NPWT was associated with successful healing of wounds, leg ulcer, lymphocele and urine leak from ileal conduit.RESULTS No complications related to NPWT were reported. However, there was paucity of robust data on the effectiveness of NPWT in KT recipients; therefore, prospective studies assessing its safety and efficacy of NPWT and randomised trials comparing the effectiveness of NPWT with alternative modalities of wound management in KT recipients is recommended.CONCLUSION Negative pressure incision management system, NPWT with instillation and endoscopic vacuum-assisted closure system are in investigational stage.
文摘Negative Pressure pulmonary oedema (NPPO) is a medical emergency. It occurs when there is a strong inspiratory effort in obstructed upper airway. Laryngospasm is the main cause of postextubation negative pressure pulmonary oedema. Though it is life-threatening, early diagnosis and prompt treatment lead to rapid resolution with no residual respiratory complications. The mainstay management is to provide respiratory support, mostly in the intensive care unit. The recommended mode of respiratory support is to provide an invasive or non-invasive positive airway pressure. This requires the use of a ventilator. Most surgery centres in sub-Saharan Africa do not have intensive care unit or ventilators in their recovery wards. We report two cases of postextubation NPPO which occurred in a typical African hospital with no ventilator. All these two cases were successfully managed with a non-rebreather mask. The periods of resolution, both clinical and radiological, were 24 - 48 hrs. This is not significantly different from the resolution periods quoted in literature from cases managed in well-resourced centres with means of positive pressure ventilation. We therefore conclude that early detection and prompt initiation of management are important keys which can lead to good outcomes, even in low-resource centres.
