Necrotizing fasciitis(NF)is a rapidly progressing,life-threatening soft tissue infection,with upper limb NF posing a particularly serious threat to patient survival and quality of life.Negative pressure wound therapy(...Necrotizing fasciitis(NF)is a rapidly progressing,life-threatening soft tissue infection,with upper limb NF posing a particularly serious threat to patient survival and quality of life.Negative pressure wound therapy(NPWT)has shown considerable advantages in accelerating wound healing and mitigating functional impairment.A retrospective study by Lipatov et al.demonstrated that NPWT significantly reduced the time needed for wound closure preparation while enhancing the success rate of local repair.Despite its benefits,certain limitations highlight the need for further optimization.This paper investigates the potential for personalized dynamic regulation of NPWT,its integration with adjunctive therapies,and the role of multidisciplinary collaboration.Furthermore,it explores the incorporation of advanced technologies such as artificial intelligence,imaging modalities,and biomaterials,presenting novel pathways for the personalized management and global standardization of NF treatment.展开更多
BACKGROUND Diabetic foot ulcers(DFUs)are a significant challenge in diabetic care,and the efficacy of negative pressure wound therapy(NPWT)in treating them remains a subject of continuous investigation.AIM To provide ...BACKGROUND Diabetic foot ulcers(DFUs)are a significant challenge in diabetic care,and the efficacy of negative pressure wound therapy(NPWT)in treating them remains a subject of continuous investigation.AIM To provide a comprehensive meta-analysis of the role of NPWT in the manage-ment of DFUs.METHODS A systematic review was performed based on Preferred Reporting Items for Sys-tematic Reviews and Meta-Analyses guidelines,searching databases like PubMed,Embase,Web of Science,and the Cochrane Library.Randomized clinical trials(RCTs)were included to compare NPWT to other dressings for DFUs.Outcomes measured were wound healing time and rate,granulation tissue formation time,amputation rate,and adverse events.Study quality was evaluated using Coch-rane's risk of bias tool.Analyses utilizedχ2,I2,fixed or random-effects models via Stata v17.RESULTS Of the 1101 identified articles,9 RCTs were selected for meta-analysis.Studies spanned from 2005 to 2020 and originated from countries including the United States,Chile,Pakistan,Italy,India,and Germany.Meta-analysis demonstrated a significant improvement in wound healing rate[risk ratio(RR)=1.46,95%CI:1.22-1.76,P<0.01]and a reduction in amputation rate(RR=0.69,95%CI:0.50-0.96,P=0.006)with NPWT.Furthermore,the time for granulation tissue formation was significantly reduced by an average of 19.54 days.However,the incidence of adverse events did not significantly differ between NPWT and control treatments.CONCLUSION NPWT significantly improves wound healing rates and reduces amputation rates in DFUs.It also hastens the formation of granulation tissue.However,the therapy does not significantly alter the risk of adverse events compared to alternate treatments.展开更多
BACKGROUND Patients with paraplegia are vulnerable to ischial pressure ulcers.Surgical treatments often lead to complications such as seroma and infection,necessitating repeated interventions that increase surgical di...BACKGROUND Patients with paraplegia are vulnerable to ischial pressure ulcers.Surgical treatments often lead to complications such as seroma and infection,necessitating repeated interventions that increase surgical difficulty.This case report aimed to introduce a novel treatment strategy combining negative pressure wound therapy(NPWT)with a fenestrated Penrose drain to manage refractory seroma in patients with a history of ischial pressure ulcers.CASE SUMMARY A 63-year-old woman presented with soft tissue defects on the left ischium and right trochanter.After surgical debridement,an inferior gluteal artery perforator(IGAP)flap was used to reconstruct the left ischium.NPWT was applied at a setting of 75 mmHg on postoperative day 3 owing to the development of seroma,combined with a fenestrated Penrose drain to facilitate effective drainage of serous fluid.A 54-year-old man presented with a 4 cm×2 cm ulcer on the left ischium after previous excision and flap coverage.After thorough debridement,the IGAP flap was elevated,and NPWT with a fenestrated Penrose drain was implemented immediately postoperatively at 75 mmHg to promote drainage.Both patients achieved a stable recovery without complications.CONCLUSION NPWT combined with a fenestrated Penrose drain placement is a promising strategy for addressing refractory seromas in cases of complex pressure ulcers.展开更多
Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperativ...Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperative pain, hospital stay, and other factors between the negative pressure group and the control group. Methods: This study is a prospective controlled trial that selected patients undergoing two-port thoracoscopic valve surgery at a certain hospital from January 2019 to December 2024. Patients were randomly assigned to the control group and the negative pressure group using a random number table method. The control group consisted of 30 patients (20 males, 10 females, mean age 42.03 ± 12.89 years), and the negative pressure group consisted of 35 patients (26 males, 9 females, mean age 41.84 ± 11.83 years). The control group received traditional chest drainage, while the negative pressure group received negative pressure chest drainage. Postoperative pain scores, hospital stay, drainage time, number of tube blockages, and incidences of pneumothorax or subcutaneous emphysema were recorded and statistically analyzed. Results: The negative pressure group had a significantly shorter postoperative drainage time compared to the control group (49.09 ± 11.99 hours vs. 79.10 ± 7.32 hours, P < 0.001). The postoperative pain score was lower in the negative pressure group (4.49 ± 1.27 vs. 7.03 ± 0.85, P < 0.001), and the hospital stay was significantly shorter (9.83 ± 1.69 days vs. 14.73 ± 2.32 days, P < 0.001). The incidence of pneumothorax or subcutaneous emphysema was significantly lower in the negative pressure group than in the control group (14.29% vs. 56.67%, P = 0.0003). Conclusion: The application of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery can effectively reduce postoperative pain, shorten hospital stay, and lower the incidence of tube blockage and pneumothorax, demonstrating good clinical outcomes.展开更多
BACKGROUND Negative pressure wound therapy(NPWT)is a potential treatment for diabetic foot ulcers(DFUs),although the mechanisms underlying its effectiveness remain unclear.This study posits that NPWT may improve wound...BACKGROUND Negative pressure wound therapy(NPWT)is a potential treatment for diabetic foot ulcers(DFUs),although the mechanisms underlying its effectiveness remain unclear.This study posits that NPWT may improve wound healing by promoting angiogenesis and activating the nuclear factor erythroid 2-related factor 2(Nrf2)/Kelch-like epichlorohydrin-associated protein 1(Keap1)signaling pathway,which is crucial for the body’s defense against oxidative stress.The hypothesis indicates that enhancing antioxidant defenses through NPWT may positively affect the healing process.There are still limited data on the roles of Nrf2,its downstream signaling molecules,and angiogenesis markers in patients undergoing NPWT.AIM To study the mechanism of NPWT in DFUs.METHODS This study included a total of 40 hospitalized patients with DFUs from Xuzhou Central Hospital,who were divided into Control group(n=21)and NPWT group(n=19).The levels of Nrf2 and Keap1 were analyzed in the granulation tissue 7 days after treatment.The wound condition,erythrocyte sedimentation rate(ESR),procalcitonin(PCT),interleukin 6(IL-6),tumor necrosis factor alpha(TNF-α),vascular endothelial growth factor(VEGF),basic fibroblast growth factor(b-FGF),cluster of differentiation 31(CD31),and levels of oxidative stress[malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),and total antioxidant capacity(T-AOC)]were analyzed before and 7 days after treatment by the Mann-Whitney U test.RESULTS The NPWT group demonstrated significant improvements in wound healing compared to the control group after 7 days of treatment.The levels of ESR,PCT,IL-6,and TNF-αwere significantly reduced in the NPWT group compared to the control group(P<0.05),while the levels of CD31,VEGF,and b-FGF showed significant increases(P<0.05).The NPWT group exhibited notable elevations in the levels of Nrf2 and its downstream targets(SOD,CAT,and T-AOC),accompanied by decreases in the levels of Keap1 and MDA(P<0.05).CONCLUSION NPWT may contribute to the healing of DFUs by potentially reducing levels of oxidative stress.Its effects could possibly be enhanced through the action of Nrf2.展开更多
BACKGROUND Postoperative unobstructed drainage is an important measure for avoiding hematoma formation and preventing complications from anterior cervical surgery.AIM To discuss the characteristics and key points of c...BACKGROUND Postoperative unobstructed drainage is an important measure for avoiding hematoma formation and preventing complications from anterior cervical surgery.AIM To discuss the characteristics and key points of clinical management of two types of commonly used negative pressure drainage systems in clinical settings.METHODS Two types of commonly used silica gel negative pressure drainage balls and a type of gastrointestinal decompression apparatus were fully emptied and then injected with different amounts of water and air.Following this,the negative pressure values of the three devices were measured.Meanwhile,we undertook a retrospective analysis of the clinical data of 1328 patients who had been treated with different negative pressure drainage apparatuses during their anterior cervical surgery in our department between January 2007 and January 2018.RESULTS As the amount of injected air or water increased,the negative pressure of the silica gel negative pressure drainage ball decreased rapidly,dropping to zero when 150 mL of water or air was injected.In contrast,the negative pressure of gastrointestinal decompression apparatus decreased slowly,maintaining an ideal value even when 300 mL of water or air was injected.And statistical analysis demonstrated that patients who had been treated with the gastrointestinal decompression apparatus were less likely to develop severe complications than those who had been treated with the silica gel negative pressure drainage ball(P<0.05).CONCLUSION This study showed that the gastrointestinal decompression apparatus has the advantages of large suction capacity,long duration of continuous negative pressure,and good drainage effect,all of which are the favorable factors for the use of this apparatus for negative pressure drainage in anterior cervical surgery.展开更多
Objective： We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrowderived stroma cells （BMSCs） in vitro. Methods： BMSCs were isolated from adult marrow donated by a hip o...Objective： We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrowderived stroma cells （BMSCs） in vitro. Methods： BMSCs were isolated from adult marrow donated by a hip osteoarthritis patient with prosthetic replacement and cultured in vitro. The third passage cells were divided into negative pressure treatment group and control group. The treatment group was induced by negative pressure intermittently （pressure： 50 kPa, 30 min/times, and twice daily）. The control was cultured in conventional condition. The osteogenesis of BMSCs was examined by phase-contrast mi- croscopy, the determination of alkaline phosphatase （ALP） activities, and the immunohistochemistry of collagen type 1. The mRNA expressions of osteoprotegerin （OPG） and osteoprotegerin ligand （OPGL） in BMSCs were analyzed by real-time polymerase chain reaction （PCR）. Results： BMSCs showed a typical appearance of osteoblast after 2 weeks of induction by intermittent negative pressure, the activity of ALP increased significantly, and the expression of collagen type I was positive. In the treatment group, the mRNA expression of OPG increased significantly （P〈0.05） and the mRNA expression of OPGL decreased significantly （P〈0.05） after 2 weeks, compared with the control. Conclusion： Intermittent negative pressure could promote osteogenesis in human BMSCs in vitro.展开更多
Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with dif...Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.展开更多
Effects of continuous negative pressure water supply on water consumption, growth and development, as well as physiological mechanism and quality of Capsicum annuum L. were investigated in this paper. Meanwhile, the o...Effects of continuous negative pressure water supply on water consumption, growth and development, as well as physiological mechanism and quality of Capsicum annuum L. were investigated in this paper. Meanwhile, the optimal negative pressure water supply conditions for growth of C. annuum L. were screened out to achieve the goals of water conservation, high yield and high quality, thus providing theoretical foundation for its field production. The pot experiment within the greenhouse was utilized; the continuous negative pressure water supply was adopted; the four treatments, artificial watering（CK）, –5 k Pa（T1）, –10 k Pa（T2）, and –15 k Pa（T3） were set; and the daily water consumption, yield, as well as the biomass, nitrate reductase, root activity, vitamin C, capsaicin, and nutrient uptakes of nitrogen（N）, phosphorus（P） and potassium（K） during various stages of its growth were determined. Compared with CK, when the water supply pressure was controlled at –5 to –15 k Pa in the experiment, the total water consumption of C. annuum L. reduced by 53.42 to 67.75%, the total water consumption intensity reduced by 54.29 to 67.14%, and the water use efficiency increased by 12.66 to 124.67%. The N accumulation in a single strain of C. annuum L. from the color turning stage to the red ripe stage increased by 15.99 to 100.55%, respectively, compared with that of CK; the P accumulation increased by 20.47 to 154.00% relative to that of CK, and the K accumulation increased by 64.92 to 144.9% compared with that of CK. Compared with CK, C. annuum L. yield was remarkably improved by 13.79% at T1, and contents of vitamin C, capsaicin as well as carotenoids at all growth stages were enhanced by 13.42–147.01%, 11.54–71.01%, and 41.1–568.06%, respectively. Nitrate reductase activity, root activity and chlorophyll（a＋b） were markedly increased by 335.78–500%, 79.6–140.68% and 114.95–676.19%, respectively, from immature stage to full ripe stage. Adopting the continuous negative pressure water supply for C. annuum L. has a significant water-saving effect, and the water supply pressure being stable at –5 k Pa contributes to its growth and development, improves yield, enhances root activity, promotes nutrient uptake, and improves its quality, thus achieving the effects of water conservation, high yield, high quality and high efficiency.展开更多
Presented a new coal dust control program that was airtight negative pressure dust-control technology at the transpersite,combining with analysis with the movement of air currents and numerical simulation of gas-solid...Presented a new coal dust control program that was airtight negative pressure dust-control technology at the transpersite,combining with analysis with the movement of air currents and numerical simulation of gas-solid flow at the transpersite,and proved the mechanism of precipitation and proliferation for coal dust-controlt in theory.The technol- ogy has made good economic results at the Heidaigou Clean Plant,not only dust concen- tration control within 10 mg/m^3 to the work site,but also substantial energy savings and cost savings.展开更多
The negative pressure conical fluidized bed is widely used in the pharmaceutical industry.In this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass an...The negative pressure conical fluidized bed is widely used in the pharmaceutical industry.In this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle size.The pressure fluctuation signals are analyzed by the time and the frequency domain methods.A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed,where the calculation is to divide the original power spectrum by the average signal power.A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light,and the particle size is small.The standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime,and the variation rule of the kurtosis is independent of both the material mass and particle size.In the initial fluidization stage,the dominant pressure signal comes from the material movement;with the increase in the gas velocity,the power of a 2.5 Hz signal continues to increase.A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state,and a novel concept called stable fluidized zone proposed in this paper can be obtained.Controlling the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state.展开更多
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
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
A series of experiments on a solid feed system was performed to investigate the effect of negative pressure gradient on the gas-solid flow pattern and hydrodynamic characteristics.Based on the non-fluidized gas-solid ...A series of experiments on a solid feed system was performed to investigate the effect of negative pressure gradient on the gas-solid flow pattern and hydrodynamic characteristics.Based on the non-fluidized gas-solid two phase flow and particulate mechanics in the standpipe,a method for predicting the pressure of the air passing through the recycle chamber and the pressure drop through the loop seal slit in these systems is also presented.The predicted pressure profile along the negative pressure gradient from the proposed model exhibits a good agreement with the experimental data.The experimental data show that the gas flow in the standpipe is always upward in the negative pressure gradients,while the direction ofthe superficial gas velocity through the recycle chamber of the loop seal does not affect the pressure drop in standpipe.It increases with an increasing negative pressure gradient.展开更多
Cover-bearing-type bucket foundation for offshore wind turbines has been paid more and more attention due to its low cost and great bearing capacity. In order to ensure the cover-bearing mode, the muddy soil inside th...Cover-bearing-type bucket foundation for offshore wind turbines has been paid more and more attention due to its low cost and great bearing capacity. In order to ensure the cover-bearing mode, the muddy soil inside the bucket foundation should be reinforced by some soil consolidation methods, such as negative pressure and electro-osmosis. Firstly, tests were conducted to obtain the reasonable current density. Meanwhile, to improve the electro-osmotic speed and effectiveness, other factors such as intermittent power and layout of electrode, were also studied in the tests. Then, the soil reinforcing tests by negative pressure combined with electro-osmosis were performed for the muddy soil consolidation inside the bucket foundation. The results showed that soil reinforcement by negative pressure was quicker and more obvious during the early phase, and electro-osmotic method can affect more range of soil by rational arrangement of electrodes. Compared with negative pressure, the electro-osmotic method was a continuous and relatively slow process of reinforcement, which was complementary to the negative pressure method. The voltage value of electro-osmosis had little effect on the muddy soil reinforcement inside the bucket foundation, and 1.5 A was chosen as the most reasonable current value for scale model testing in the electro-osmotic method.展开更多
The introduction of negative pressure wound therapy has revolutionized the management of complicated wounds.However,the maintenance of an effective negative pressure environment is difficult in some instances,such as ...The introduction of negative pressure wound therapy has revolutionized the management of complicated wounds.However,the maintenance of an effective negative pressure environment is difficult in some instances,such as wounds in close proximity to an intestinal stoma or wounds surrounded by external fixations.We found that adhesive tape adheres more easily to itself than to wet skin or uneven surfaces.Therefore,we placed adhesive tape around surgical wounds prior to covering them with foam and sealing them with more tape.As a result of the strong adhesive force between pieces of tape,this method could provide a better environmental seal,even in situations where space is limited.Pre-placed adhesive tape around the wound site prior to foam placement could provide sufficient adhesion to maintain a continuous negative pressure environment during treatment.展开更多
Background: Septic open abdomens occur in trauma, burn and surgery. Currently, multiple concentrations of hypochlorous acid solutions have effectively decreased the microbiotic burden in wounds. We hypothesized that V...Background: Septic open abdomens occur in trauma, burn and surgery. Currently, multiple concentrations of hypochlorous acid solutions have effectively decreased the microbiotic burden in wounds. We hypothesized that Vashe?, a neutral hypochlorous acid solution (V-HOCL), would be safe as an intraperitoneal irrigation or washout disinfectant for septic open abdomens utilizing negative pressure wound therapy. Methods: This is a retrospective observational review of patients who required delayed abdominal closures after exploratory laparotomies. Group A (n = 8) had cyclical V-HOCL irrigation to their open abdomens combining AbtheraTM and V.A.C. Dressing System for negative pressure wound therapy with irrigation (NPWT-i) and Group B (n = 9) had intra-abdominal V-HOCL washouts. Results: Fifty percent of both groups had either septic or hemorrhagic shock on admission. Compared to Group B, Group A patients were older (median 50 vs 37 years), and had a median hospitalization of 28 vs 8 days, 4 times as many operations, more acute renal failure and co-morbidities. No statistically significant differences were detected be-tween the two treatment methods with the V-HOCL delivery and removal. Conclusion: There were no episodes of electrolyte imbalance, hypotension, hypertension, anaphylaxis, hemorrhage, visceral injury or systemic toxicity. V-HOCL with/without NPWT-i irrigation was a safe modality and tolerated well in this study.展开更多
In this paper we would like to give a brief review about the extensibility of the liquid-liquid locus into the negativepressure region. Negative pressure states are hardly explored; most researchers believe that the p...In this paper we would like to give a brief review about the extensibility of the liquid-liquid locus into the negativepressure region. Negative pressure states are hardly explored; most researchers believe that the pressure scale ends at p = 0.We would like to show that this is not true, the p = 0 point is not a special point for liquids, it can be 'easily' crossed. We aregoing to give a few example, where the extension of liquid-liquid locus for polymer blends and solutions below p = 0 givesus some interesting results, like the merging of UCST and LCST branches in weakly interacting polymer solutions or thereason why most UCST blends exhibit pressure induced immiscibility. Also, we will see what happens with the immiscibilityisland of aqueous polymer solutions when -- reaching the critical molar mass -- it 'disappears'.展开更多
Mechanical properties, such as the deformation and stress distributions for venous walls under the combined load of transmural pressure and axial stretch, are examined within the framework of nonlinear elasticity with...Mechanical properties, such as the deformation and stress distributions for venous walls under the combined load of transmural pressure and axial stretch, are examined within the framework of nonlinear elasticity with one kind of hyper-elastic strain energy functions. The negative pressure instability problem of the venous wall is explained through energy comparison. First, the deformation equation of the venous wall under the combined loads is obtained with a thin-walled circular cylindrical tube. The deformation curves and the stress distributions for the venous wall are given under the normal transmural pressure, and the regulations are discussed. Then, the deformation curves of the venous wall under the negative transmural pressure or the internal pressure less than the external pressure are given. Finally, the negative pressure instability problem is discussed through energy comparison.展开更多
BACKGROUND:Very good therapeutic effect has been obtained for limb negative pressure in treating limb ischemic diseases.But its mechanism in treating diabetic foot needs further investigation.OBJECTIVE:To observe the ...BACKGROUND:Very good therapeutic effect has been obtained for limb negative pressure in treating limb ischemic diseases.But its mechanism in treating diabetic foot needs further investigation.OBJECTIVE:To observe the changes of calcitonin gene related peptide(CGRP)in sensory nerve fiber of skin of dogs with diabetic foot before and after limb negative pressure treatment,and make a comparison with normal dogs,then analyze the mechanism of limb negative pressure in treating diabetic foot.DESIGN:A randomized controlled animal experiment.SETTING:Third Department of General Surgery,Xijing Hospital,Fourth Military Medical University of Chinese PLA.MATERIALS:Fifteen healthy hybrid dogs,of either gender,weighing 12-18 kg,were provided by Animal Room,Xijing Hospital of the Fourth Military Medical University of Chinese PLA.After being numbered,the involved dogs were randomly assigned into 3 groups:treatment group,model group and normal control group,5 dogs each.Limb negative pressure therapeutic machine(self-made);Anti-CGRP serum(primary antibody,Watpa Company,England);rabbit anti-BigG(second antibody),ABC compound solution,DAB reagent,glucose oxidase reagent,Trixon-X100 solution(Sigma company,USA),ammonium nickelous sulfate reagent(Xi'an Chemical Reagent Factory),neutral gum-solution(import,Shanghai Reagent Co.,Ltd.);Leitz1400 sliding freezing microtome(Leitz Company,Germany);Leica1800 cryostat microtome(Leica Company,Germany);Quantimet570 image analyzer(Leica Company,Germany).METHODS:This experiment was carried out in the Animal Room,Xijing Hospital,Fourth Military Medical University of Chinese PLA from October 2005 to June 2006.①After the dogs in the treatment and model groups were anesthetized,their pancreatic tissues were removed completely and animal models of typeⅠdiabetes mellitus were developed.All the femoral artery branches including deep femoral artery were ligated and cut off.A helical wire was inserted into the distal femoral artery cavity for narrowing femoral artery 1/2,then contributing to ischemic status of this limb,thus,dog models of diabetic foot of posterior limbs were developed.When the dogs in the treatment group were successfully modeled,negative pressure treatment was conducted on their affected limbs after 14 days.When the dogs were lightly anesthetized,depilation was performed on the base of left posterior limb in ring form.Then,their depilated limbs were placed in self-made negative pressure cabin for 15 minutes of-12 kPa negative pressure treatment every day within 10 days successively.Negative pressure treatment on affected limbs was omitted in the model group.The dogs in the normal control group were not modeled or given negative pressure treatment.②After 10 days of treatment,3 groups of animals all subjected to immunohistochemical staining of toe skin of affected limb for detecting CGRP-immunoreactive positive nerve fibers.Analysis of variance and LSD-t test were used for comparison of measurement data.MAIN OUTCOME MEASURES:Changes of CGRP in sensory nerve fibers of skin of 3 groups of animals.RESULTS:CGRP-immunoreactive positive nerve fibers in the skin of animals of model group were(53.24±5.6)μm/mm2,which were significantly more than those of control group[(11.73±2.3)μm/mm2,t=16.94,P<0.01].CGRP-immunoreactive positive nerve fibers in the skin of animals of treatment group were(32.49±2.9)μm/mm2,which were less than those of model group(t=8.47,P<0.01),but were still more than those of normal control group(t=8.47,P<0.01).CONCLUSION:①Following the onset of diabetic foot,CGRP-immunoreactive positive nerve fibers in the skin of distal limb are obviously increased,which may be a self-protective mechanism of body.②Limb negative pressure treatment can treat diabetic foot,which attributes to that the release of CGRP in the sensory nerve fibers can promote vasodilatation.展开更多
基金Supported by Henan Province Key Research and Development Program,No.231111311000Henan Provincial Science and Technology Research Project,No.232102310411+2 种基金Henan Province Medical Science and Technology Key Project,No.LHGJ20220566 and No.LHGJ20240365Henan Province Medical Education Research Project,No.WJLX2023079Zhengzhou Medical and Health Technology Innovation Guidance Program,No.2024YLZDJH022.
文摘Necrotizing fasciitis(NF)is a rapidly progressing,life-threatening soft tissue infection,with upper limb NF posing a particularly serious threat to patient survival and quality of life.Negative pressure wound therapy(NPWT)has shown considerable advantages in accelerating wound healing and mitigating functional impairment.A retrospective study by Lipatov et al.demonstrated that NPWT significantly reduced the time needed for wound closure preparation while enhancing the success rate of local repair.Despite its benefits,certain limitations highlight the need for further optimization.This paper investigates the potential for personalized dynamic regulation of NPWT,its integration with adjunctive therapies,and the role of multidisciplinary collaboration.Furthermore,it explores the incorporation of advanced technologies such as artificial intelligence,imaging modalities,and biomaterials,presenting novel pathways for the personalized management and global standardization of NF treatment.
基金Supported by the National Natural Science Foundation of China,No.82202454 and No.81873934the Wang Zhengguo Trauma Medicine Fund(Growth Factor Revival Plan)No.SZYZ-TR-09+1 种基金the Shandong Provincial Natural Science Foundation Youth Fund,No.ZR2020QH168the Jinan Science and Technology Plan Project,No.202225065。
文摘BACKGROUND Diabetic foot ulcers(DFUs)are a significant challenge in diabetic care,and the efficacy of negative pressure wound therapy(NPWT)in treating them remains a subject of continuous investigation.AIM To provide a comprehensive meta-analysis of the role of NPWT in the manage-ment of DFUs.METHODS A systematic review was performed based on Preferred Reporting Items for Sys-tematic Reviews and Meta-Analyses guidelines,searching databases like PubMed,Embase,Web of Science,and the Cochrane Library.Randomized clinical trials(RCTs)were included to compare NPWT to other dressings for DFUs.Outcomes measured were wound healing time and rate,granulation tissue formation time,amputation rate,and adverse events.Study quality was evaluated using Coch-rane's risk of bias tool.Analyses utilizedχ2,I2,fixed or random-effects models via Stata v17.RESULTS Of the 1101 identified articles,9 RCTs were selected for meta-analysis.Studies spanned from 2005 to 2020 and originated from countries including the United States,Chile,Pakistan,Italy,India,and Germany.Meta-analysis demonstrated a significant improvement in wound healing rate[risk ratio(RR)=1.46,95%CI:1.22-1.76,P<0.01]and a reduction in amputation rate(RR=0.69,95%CI:0.50-0.96,P=0.006)with NPWT.Furthermore,the time for granulation tissue formation was significantly reduced by an average of 19.54 days.However,the incidence of adverse events did not significantly differ between NPWT and control treatments.CONCLUSION NPWT significantly improves wound healing rates and reduces amputation rates in DFUs.It also hastens the formation of granulation tissue.However,the therapy does not significantly alter the risk of adverse events compared to alternate treatments.
基金Supported by Research fund of Dankook University in 2023,No.R202300627.
文摘BACKGROUND Patients with paraplegia are vulnerable to ischial pressure ulcers.Surgical treatments often lead to complications such as seroma and infection,necessitating repeated interventions that increase surgical difficulty.This case report aimed to introduce a novel treatment strategy combining negative pressure wound therapy(NPWT)with a fenestrated Penrose drain to manage refractory seroma in patients with a history of ischial pressure ulcers.CASE SUMMARY A 63-year-old woman presented with soft tissue defects on the left ischium and right trochanter.After surgical debridement,an inferior gluteal artery perforator(IGAP)flap was used to reconstruct the left ischium.NPWT was applied at a setting of 75 mmHg on postoperative day 3 owing to the development of seroma,combined with a fenestrated Penrose drain to facilitate effective drainage of serous fluid.A 54-year-old man presented with a 4 cm×2 cm ulcer on the left ischium after previous excision and flap coverage.After thorough debridement,the IGAP flap was elevated,and NPWT with a fenestrated Penrose drain was implemented immediately postoperatively at 75 mmHg to promote drainage.Both patients achieved a stable recovery without complications.CONCLUSION NPWT combined with a fenestrated Penrose drain placement is a promising strategy for addressing refractory seromas in cases of complex pressure ulcers.
文摘Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperative pain, hospital stay, and other factors between the negative pressure group and the control group. Methods: This study is a prospective controlled trial that selected patients undergoing two-port thoracoscopic valve surgery at a certain hospital from January 2019 to December 2024. Patients were randomly assigned to the control group and the negative pressure group using a random number table method. The control group consisted of 30 patients (20 males, 10 females, mean age 42.03 ± 12.89 years), and the negative pressure group consisted of 35 patients (26 males, 9 females, mean age 41.84 ± 11.83 years). The control group received traditional chest drainage, while the negative pressure group received negative pressure chest drainage. Postoperative pain scores, hospital stay, drainage time, number of tube blockages, and incidences of pneumothorax or subcutaneous emphysema were recorded and statistically analyzed. Results: The negative pressure group had a significantly shorter postoperative drainage time compared to the control group (49.09 ± 11.99 hours vs. 79.10 ± 7.32 hours, P < 0.001). The postoperative pain score was lower in the negative pressure group (4.49 ± 1.27 vs. 7.03 ± 0.85, P < 0.001), and the hospital stay was significantly shorter (9.83 ± 1.69 days vs. 14.73 ± 2.32 days, P < 0.001). The incidence of pneumothorax or subcutaneous emphysema was significantly lower in the negative pressure group than in the control group (14.29% vs. 56.67%, P = 0.0003). Conclusion: The application of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery can effectively reduce postoperative pain, shorten hospital stay, and lower the incidence of tube blockage and pneumothorax, demonstrating good clinical outcomes.
文摘BACKGROUND Negative pressure wound therapy(NPWT)is a potential treatment for diabetic foot ulcers(DFUs),although the mechanisms underlying its effectiveness remain unclear.This study posits that NPWT may improve wound healing by promoting angiogenesis and activating the nuclear factor erythroid 2-related factor 2(Nrf2)/Kelch-like epichlorohydrin-associated protein 1(Keap1)signaling pathway,which is crucial for the body’s defense against oxidative stress.The hypothesis indicates that enhancing antioxidant defenses through NPWT may positively affect the healing process.There are still limited data on the roles of Nrf2,its downstream signaling molecules,and angiogenesis markers in patients undergoing NPWT.AIM To study the mechanism of NPWT in DFUs.METHODS This study included a total of 40 hospitalized patients with DFUs from Xuzhou Central Hospital,who were divided into Control group(n=21)and NPWT group(n=19).The levels of Nrf2 and Keap1 were analyzed in the granulation tissue 7 days after treatment.The wound condition,erythrocyte sedimentation rate(ESR),procalcitonin(PCT),interleukin 6(IL-6),tumor necrosis factor alpha(TNF-α),vascular endothelial growth factor(VEGF),basic fibroblast growth factor(b-FGF),cluster of differentiation 31(CD31),and levels of oxidative stress[malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT),and total antioxidant capacity(T-AOC)]were analyzed before and 7 days after treatment by the Mann-Whitney U test.RESULTS The NPWT group demonstrated significant improvements in wound healing compared to the control group after 7 days of treatment.The levels of ESR,PCT,IL-6,and TNF-αwere significantly reduced in the NPWT group compared to the control group(P<0.05),while the levels of CD31,VEGF,and b-FGF showed significant increases(P<0.05).The NPWT group exhibited notable elevations in the levels of Nrf2 and its downstream targets(SOD,CAT,and T-AOC),accompanied by decreases in the levels of Keap1 and MDA(P<0.05).CONCLUSION NPWT may contribute to the healing of DFUs by potentially reducing levels of oxidative stress.Its effects could possibly be enhanced through the action of Nrf2.
基金Supported by the Multicenter Clinical Trial of hUC-MSCs in the Treatment of Late Chronic Spinal Cord Injury,No.2017YFA0105404the Key Discipline Construction Project of Pudong Health Bureau of Shanghai,No.PWZxk2017-08.
文摘BACKGROUND Postoperative unobstructed drainage is an important measure for avoiding hematoma formation and preventing complications from anterior cervical surgery.AIM To discuss the characteristics and key points of clinical management of two types of commonly used negative pressure drainage systems in clinical settings.METHODS Two types of commonly used silica gel negative pressure drainage balls and a type of gastrointestinal decompression apparatus were fully emptied and then injected with different amounts of water and air.Following this,the negative pressure values of the three devices were measured.Meanwhile,we undertook a retrospective analysis of the clinical data of 1328 patients who had been treated with different negative pressure drainage apparatuses during their anterior cervical surgery in our department between January 2007 and January 2018.RESULTS As the amount of injected air or water increased,the negative pressure of the silica gel negative pressure drainage ball decreased rapidly,dropping to zero when 150 mL of water or air was injected.In contrast,the negative pressure of gastrointestinal decompression apparatus decreased slowly,maintaining an ideal value even when 300 mL of water or air was injected.And statistical analysis demonstrated that patients who had been treated with the gastrointestinal decompression apparatus were less likely to develop severe complications than those who had been treated with the silica gel negative pressure drainage ball(P<0.05).CONCLUSION This study showed that the gastrointestinal decompression apparatus has the advantages of large suction capacity,long duration of continuous negative pressure,and good drainage effect,all of which are the favorable factors for the use of this apparatus for negative pressure drainage in anterior cervical surgery.
基金Project (No. 20070421123) supported by the Postdoctoral Science Foundation of China
文摘Objective： We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrowderived stroma cells （BMSCs） in vitro. Methods： BMSCs were isolated from adult marrow donated by a hip osteoarthritis patient with prosthetic replacement and cultured in vitro. The third passage cells were divided into negative pressure treatment group and control group. The treatment group was induced by negative pressure intermittently （pressure： 50 kPa, 30 min/times, and twice daily）. The control was cultured in conventional condition. The osteogenesis of BMSCs was examined by phase-contrast mi- croscopy, the determination of alkaline phosphatase （ALP） activities, and the immunohistochemistry of collagen type 1. The mRNA expressions of osteoprotegerin （OPG） and osteoprotegerin ligand （OPGL） in BMSCs were analyzed by real-time polymerase chain reaction （PCR）. Results： BMSCs showed a typical appearance of osteoblast after 2 weeks of induction by intermittent negative pressure, the activity of ALP increased significantly, and the expression of collagen type I was positive. In the treatment group, the mRNA expression of OPG increased significantly （P〈0.05） and the mRNA expression of OPGL decreased significantly （P〈0.05） after 2 weeks, compared with the control. Conclusion： Intermittent negative pressure could promote osteogenesis in human BMSCs in vitro.
基金The National Basic Research Program (973) of China (No. 2004CB418505)
文摘Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.
基金supported by the National High-Technology Research and Development Program of China (863 Program, 2013AA102900-3)
文摘Effects of continuous negative pressure water supply on water consumption, growth and development, as well as physiological mechanism and quality of Capsicum annuum L. were investigated in this paper. Meanwhile, the optimal negative pressure water supply conditions for growth of C. annuum L. were screened out to achieve the goals of water conservation, high yield and high quality, thus providing theoretical foundation for its field production. The pot experiment within the greenhouse was utilized; the continuous negative pressure water supply was adopted; the four treatments, artificial watering（CK）, –5 k Pa（T1）, –10 k Pa（T2）, and –15 k Pa（T3） were set; and the daily water consumption, yield, as well as the biomass, nitrate reductase, root activity, vitamin C, capsaicin, and nutrient uptakes of nitrogen（N）, phosphorus（P） and potassium（K） during various stages of its growth were determined. Compared with CK, when the water supply pressure was controlled at –5 to –15 k Pa in the experiment, the total water consumption of C. annuum L. reduced by 53.42 to 67.75%, the total water consumption intensity reduced by 54.29 to 67.14%, and the water use efficiency increased by 12.66 to 124.67%. The N accumulation in a single strain of C. annuum L. from the color turning stage to the red ripe stage increased by 15.99 to 100.55%, respectively, compared with that of CK; the P accumulation increased by 20.47 to 154.00% relative to that of CK, and the K accumulation increased by 64.92 to 144.9% compared with that of CK. Compared with CK, C. annuum L. yield was remarkably improved by 13.79% at T1, and contents of vitamin C, capsaicin as well as carotenoids at all growth stages were enhanced by 13.42–147.01%, 11.54–71.01%, and 41.1–568.06%, respectively. Nitrate reductase activity, root activity and chlorophyll（a＋b） were markedly increased by 335.78–500%, 79.6–140.68% and 114.95–676.19%, respectively, from immature stage to full ripe stage. Adopting the continuous negative pressure water supply for C. annuum L. has a significant water-saving effect, and the water supply pressure being stable at –5 k Pa contributes to its growth and development, improves yield, enhances root activity, promotes nutrient uptake, and improves its quality, thus achieving the effects of water conservation, high yield, high quality and high efficiency.
文摘Presented a new coal dust control program that was airtight negative pressure dust-control technology at the transpersite,combining with analysis with the movement of air currents and numerical simulation of gas-solid flow at the transpersite,and proved the mechanism of precipitation and proliferation for coal dust-controlt in theory.The technol- ogy has made good economic results at the Heidaigou Clean Plant,not only dust concen- tration control within 10 mg/m^3 to the work site,but also substantial energy savings and cost savings.
基金the National Standardization Project of TCM(ZYBZH-C-TJ-55)and National Science and Technology Major Project(2018ZX09201011-002).
文摘The negative pressure conical fluidized bed is widely used in the pharmaceutical industry.In this study,experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle size.The pressure fluctuation signals are analyzed by the time and the frequency domain methods.A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed,where the calculation is to divide the original power spectrum by the average signal power.A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light,and the particle size is small.The standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime,and the variation rule of the kurtosis is independent of both the material mass and particle size.In the initial fluidization stage,the dominant pressure signal comes from the material movement;with the increase in the gas velocity,the power of a 2.5 Hz signal continues to increase.A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state,and a novel concept called stable fluidized zone proposed in this paper can be obtained.Controlling the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state.
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.
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A series of experiments on a solid feed system was performed to investigate the effect of negative pressure gradient on the gas-solid flow pattern and hydrodynamic characteristics.Based on the non-fluidized gas-solid two phase flow and particulate mechanics in the standpipe,a method for predicting the pressure of the air passing through the recycle chamber and the pressure drop through the loop seal slit in these systems is also presented.The predicted pressure profile along the negative pressure gradient from the proposed model exhibits a good agreement with the experimental data.The experimental data show that the gas flow in the standpipe is always upward in the negative pressure gradients,while the direction ofthe superficial gas velocity through the recycle chamber of the loop seal does not affect the pressure drop in standpipe.It increases with an increasing negative pressure gradient.
基金Supported by National Natural Science Foundation of China(No. 51109160)National High Technology Research and Development Program of China ("863" Program, No. 2012AA051705)International Science and Technology Cooperation Program of China (No. 2012DFA70490)
文摘Cover-bearing-type bucket foundation for offshore wind turbines has been paid more and more attention due to its low cost and great bearing capacity. In order to ensure the cover-bearing mode, the muddy soil inside the bucket foundation should be reinforced by some soil consolidation methods, such as negative pressure and electro-osmosis. Firstly, tests were conducted to obtain the reasonable current density. Meanwhile, to improve the electro-osmotic speed and effectiveness, other factors such as intermittent power and layout of electrode, were also studied in the tests. Then, the soil reinforcing tests by negative pressure combined with electro-osmosis were performed for the muddy soil consolidation inside the bucket foundation. The results showed that soil reinforcement by negative pressure was quicker and more obvious during the early phase, and electro-osmotic method can affect more range of soil by rational arrangement of electrodes. Compared with negative pressure, the electro-osmotic method was a continuous and relatively slow process of reinforcement, which was complementary to the negative pressure method. The voltage value of electro-osmosis had little effect on the muddy soil reinforcement inside the bucket foundation, and 1.5 A was chosen as the most reasonable current value for scale model testing in the electro-osmotic method.
文摘The introduction of negative pressure wound therapy has revolutionized the management of complicated wounds.However,the maintenance of an effective negative pressure environment is difficult in some instances,such as wounds in close proximity to an intestinal stoma or wounds surrounded by external fixations.We found that adhesive tape adheres more easily to itself than to wet skin or uneven surfaces.Therefore,we placed adhesive tape around surgical wounds prior to covering them with foam and sealing them with more tape.As a result of the strong adhesive force between pieces of tape,this method could provide a better environmental seal,even in situations where space is limited.Pre-placed adhesive tape around the wound site prior to foam placement could provide sufficient adhesion to maintain a continuous negative pressure environment during treatment.
文摘Background: Septic open abdomens occur in trauma, burn and surgery. Currently, multiple concentrations of hypochlorous acid solutions have effectively decreased the microbiotic burden in wounds. We hypothesized that Vashe?, a neutral hypochlorous acid solution (V-HOCL), would be safe as an intraperitoneal irrigation or washout disinfectant for septic open abdomens utilizing negative pressure wound therapy. Methods: This is a retrospective observational review of patients who required delayed abdominal closures after exploratory laparotomies. Group A (n = 8) had cyclical V-HOCL irrigation to their open abdomens combining AbtheraTM and V.A.C. Dressing System for negative pressure wound therapy with irrigation (NPWT-i) and Group B (n = 9) had intra-abdominal V-HOCL washouts. Results: Fifty percent of both groups had either septic or hemorrhagic shock on admission. Compared to Group B, Group A patients were older (median 50 vs 37 years), and had a median hospitalization of 28 vs 8 days, 4 times as many operations, more acute renal failure and co-morbidities. No statistically significant differences were detected be-tween the two treatment methods with the V-HOCL delivery and removal. Conclusion: There were no episodes of electrolyte imbalance, hypotension, hypertension, anaphylaxis, hemorrhage, visceral injury or systemic toxicity. V-HOCL with/without NPWT-i irrigation was a safe modality and tolerated well in this study.
基金This work was partially supported by the Hungarian Science Foundation (OTKA F034333). The author was also supported by the Bolyai Research Fellowship.
文摘In this paper we would like to give a brief review about the extensibility of the liquid-liquid locus into the negativepressure region. Negative pressure states are hardly explored; most researchers believe that the pressure scale ends at p = 0.We would like to show that this is not true, the p = 0 point is not a special point for liquids, it can be 'easily' crossed. We aregoing to give a few example, where the extension of liquid-liquid locus for polymer blends and solutions below p = 0 givesus some interesting results, like the merging of UCST and LCST branches in weakly interacting polymer solutions or thereason why most UCST blends exhibit pressure induced immiscibility. Also, we will see what happens with the immiscibilityisland of aqueous polymer solutions when -- reaching the critical molar mass -- it 'disappears'.
基金Project supported by the National Natural Science Foundation of China (Nos. 10772104 and 10872045)the Innovation Project of Shanghai Municipal Education Commission (No. 09YZ12)the Shanghai Leading Academic Discipline Project (No. S30106)
文摘Mechanical properties, such as the deformation and stress distributions for venous walls under the combined load of transmural pressure and axial stretch, are examined within the framework of nonlinear elasticity with one kind of hyper-elastic strain energy functions. The negative pressure instability problem of the venous wall is explained through energy comparison. First, the deformation equation of the venous wall under the combined loads is obtained with a thin-walled circular cylindrical tube. The deformation curves and the stress distributions for the venous wall are given under the normal transmural pressure, and the regulations are discussed. Then, the deformation curves of the venous wall under the negative transmural pressure or the internal pressure less than the external pressure are given. Finally, the negative pressure instability problem is discussed through energy comparison.
文摘BACKGROUND:Very good therapeutic effect has been obtained for limb negative pressure in treating limb ischemic diseases.But its mechanism in treating diabetic foot needs further investigation.OBJECTIVE:To observe the changes of calcitonin gene related peptide(CGRP)in sensory nerve fiber of skin of dogs with diabetic foot before and after limb negative pressure treatment,and make a comparison with normal dogs,then analyze the mechanism of limb negative pressure in treating diabetic foot.DESIGN:A randomized controlled animal experiment.SETTING:Third Department of General Surgery,Xijing Hospital,Fourth Military Medical University of Chinese PLA.MATERIALS:Fifteen healthy hybrid dogs,of either gender,weighing 12-18 kg,were provided by Animal Room,Xijing Hospital of the Fourth Military Medical University of Chinese PLA.After being numbered,the involved dogs were randomly assigned into 3 groups:treatment group,model group and normal control group,5 dogs each.Limb negative pressure therapeutic machine(self-made);Anti-CGRP serum(primary antibody,Watpa Company,England);rabbit anti-BigG(second antibody),ABC compound solution,DAB reagent,glucose oxidase reagent,Trixon-X100 solution(Sigma company,USA),ammonium nickelous sulfate reagent(Xi'an Chemical Reagent Factory),neutral gum-solution(import,Shanghai Reagent Co.,Ltd.);Leitz1400 sliding freezing microtome(Leitz Company,Germany);Leica1800 cryostat microtome(Leica Company,Germany);Quantimet570 image analyzer(Leica Company,Germany).METHODS:This experiment was carried out in the Animal Room,Xijing Hospital,Fourth Military Medical University of Chinese PLA from October 2005 to June 2006.①After the dogs in the treatment and model groups were anesthetized,their pancreatic tissues were removed completely and animal models of typeⅠdiabetes mellitus were developed.All the femoral artery branches including deep femoral artery were ligated and cut off.A helical wire was inserted into the distal femoral artery cavity for narrowing femoral artery 1/2,then contributing to ischemic status of this limb,thus,dog models of diabetic foot of posterior limbs were developed.When the dogs in the treatment group were successfully modeled,negative pressure treatment was conducted on their affected limbs after 14 days.When the dogs were lightly anesthetized,depilation was performed on the base of left posterior limb in ring form.Then,their depilated limbs were placed in self-made negative pressure cabin for 15 minutes of-12 kPa negative pressure treatment every day within 10 days successively.Negative pressure treatment on affected limbs was omitted in the model group.The dogs in the normal control group were not modeled or given negative pressure treatment.②After 10 days of treatment,3 groups of animals all subjected to immunohistochemical staining of toe skin of affected limb for detecting CGRP-immunoreactive positive nerve fibers.Analysis of variance and LSD-t test were used for comparison of measurement data.MAIN OUTCOME MEASURES:Changes of CGRP in sensory nerve fibers of skin of 3 groups of animals.RESULTS:CGRP-immunoreactive positive nerve fibers in the skin of animals of model group were(53.24±5.6)μm/mm2,which were significantly more than those of control group[(11.73±2.3)μm/mm2,t=16.94,P<0.01].CGRP-immunoreactive positive nerve fibers in the skin of animals of treatment group were(32.49±2.9)μm/mm2,which were less than those of model group(t=8.47,P<0.01),but were still more than those of normal control group(t=8.47,P<0.01).CONCLUSION:①Following the onset of diabetic foot,CGRP-immunoreactive positive nerve fibers in the skin of distal limb are obviously increased,which may be a self-protective mechanism of body.②Limb negative pressure treatment can treat diabetic foot,which attributes to that the release of CGRP in the sensory nerve fibers can promote vasodilatation.
