Negative pressure device-assisted autologous fat grafting: A case report

This report describes a novel technique for improving depressed scars using negative pressure suction-assisted autologous fat grafting.A 35-year-old woman presented with a 20-year history of bilateral central buttock con-cavities,causing aesthetic concerns.To maximize fat graft survival and enhance tissue volume,we implemented intermittent negative pressure suction on the recipient area for one month preoperatively.The patient expressed satisfaction with the cosmetic outcome,and a three-month follow-up confirmed a significantly improved fat graft survival rate.This minimally invasive,cost-effective,and easily reproducible technique offers a promising clinical strategy for treating depressed scars.

Effectiveness of negative pressure wound therapy in complex surgical treatment of necrotizing fasciitis of the upper limb

BACKGROUND Necrotizing fasciitis(NF)of the upper extremities is a severe surgical pathology,and the incidence of this disease has been steadily increasing in recent decades.Surgical treatment is accompanied by the formation of extensive wounds,which can be treated with significant difficulties.In recent years,negative pressure wound therapy(NPWT)has proven to be highly effective.It is also promising for the treatment of NF.AIM To explore the effectiveness of NPWT in the treatment of NF of the upper extremities.METHODS The results of the treatment of 36 patients with NF of the upper extremities in two groups(NPWT group and control group;2022−2023)were retrospectively analyzed.In the NPWT group,the NPWT method(120 mmHg;constant mode)was used after surgical treatment.The number of vacuum-assisted dressings in patients ranged from 1 to 3,depending on the dynamics of the wound process.The duration of fixation of one bandage was up to 2−3 d.In the control group,conventional methods of local wound treatment were used.The following indicators were analyzed:The treatment delay,the prevalence of inflammation,the microbial landscape,the number of debridements,the duration of wound preparation for surgical closure,and the nature of skin plastic surgery.RESULTS Most patients experienced a significant treatment delay[4 d,interquartile range(IQR):2–7 d],which led to the spread of the pathological process to the forearm and shoulder.The most common pathogens were Staphylococcus aureus(14;38.9%)and Streptococcus pyogenes(22;61.1%).The average number of debridements per patient was 5(IQR:3–7),with no difference between groups.The average time to prepare wounds for surgical closure was 11±4 d in the NPWT group and 29±10 d(P=0.00001)in the control group.In the NPWT group,the wounds were more often closed with local tissues(15;83.3%),and in the control group,split-thickness skin grafts were more often used(4;50%).CONCLUSION The predominant isolation of Staphylococcus aureus and/or Streptococcus pyogenes from the lesions allowed us to classify these patients as NF type II.Multiple debridement procedures have become a feature of this disease treatment.The use of NPWT has significantly reduced the time required to prepare wounds for surgical closure.Early closure of wounds allows for more frequent use of local tissue repair,which ensures better results.NPWT is a highly effective way to prepare wounds for early surgical closure in patients with upper extremity NF.

Value of negative pressure sealing drainage on wound healing of Gustilo IIIB and IIIC open fractures

BACKGROUND Gustilo III fractures have a high incidence and are difficult to treat.Patients often experience difficulty in wound healing.Negative pressure drainage technology can help shorten wound healing time and has positive value in improving patient prognosis.AIM To explore the clinical value of the negative pressure sealing drainage technique in wound healing of Gustilo IIIB and IIIC open fractures.METHODS Eighty patients with Gustilo IIIB and IIIC open fractures with skin and soft tissue injuries who were treated in the Second People’s Hospital of Dalian from March 2019 to December 2021 were selected as the research subjects.They were divided into a study group(n=40,healed with negative pressure closed drainage)and a control group(n=40,healed with conventional dressing changes)according to the variation in the healing they received.The efficacy of the clinical interventions,the variations in the regression indicators(time to wound healing,time to fracture healing,time to hospitalization),and the conversion and healing of bacterial wounds were compared 1-3 mo after the intervention.RESULTS The total effective rate of patients among the study group was 95.00%(38/40),which was notably higher than 75.00%(30/40)among the control group(P<0.05).The wound healing time,fracture healing time,and hospital stay of the patients in the study group was shorter than the control group(P<0.05).After the intervention,the negative bacterial culture at the wound site rate and wound healing rate of the patients among the study group increased compared to the control group(P<0.05).CONCLUSION Negative pressure sealing and drainage technology has a good therapeutic effect on patients with Gustilo IIIB and IIIC open fracture wounds with skin and soft tissue injury.It can notably enhance the wound healing rate and the negative rate of bacteria on the wound surface and help to speed up the recovery process of patients.

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

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

Comparison Study of Different Drainage Tube Diameters with Negative Pressure Suction after Valve Replacement Surgery

Objective: This study aims to compare the effects of different drainage tube diameters (22F vs. 26F) combined with negative pressure suction on patients after valve replacement surgery, including postoperative indicators and complications. Methods: A total of 104 patients undergoing valve replacement surgery were included and divided into a 22F group (45 patients) and a 26F group (59 patients). The basic characteristics, postoperative ICU stay duration, drainage duration, postoperative complications, and pain scores were compared between the two groups. All data were analyzed using SPSS statistical software, with p Results: There were no significant differences between the two groups in terms of age, sex, and underlying diseases. The ICU stay duration and drainage duration showed no significant differences (p > 0.05). The total drainage volume in the 22F group was significantly lower than that in the 26F group (225 vs. 380 ml, p = 0.035), and the pain scores on the third postoperative day were also significantly lower in the 22F group (p Conclusion: Compared to the 26F group, patients in the 22F group exhibited less postoperative drainage volume and lower pain scores, suggesting that the 22F drainage tube may have better clinical outcomes after valve replacement surgery.

Spin logic devices based on negative differential resistance -enhanced anomalous Hall effect

Owing to rapid developments in spintronics,spin-based logic devices have emerged as promising tools for next-generation computing technologies.This paper provides a comprehensive review of recent advancements in spin logic devices,particularly focusing on fundamental device concepts rooted in nanomagnets,magnetoresistive random access memory,spin–orbit torques,electric-field modu-lation,and magnetic domain walls.The operation principles of these devices are comprehensively analyzed,and recent progress in spin logic devices based on negative differential resistance-enhanced anomalous Hall effect is summarized.These devices exhibit reconfigur-able logic capabilities and integrate nonvolatile data storage and computing functionalities.For current-driven spin logic devices,negative differential resistance elements are employed to nonlinearly enhance anomalous Hall effect signals from magnetic bits,enabling reconfig-urable Boolean logic operations.Besides,voltage-driven spin logic devices employ another type of negative differential resistance ele-ment to achieve logic functionalities with excellent cascading ability.By cascading several elementary logic gates,the logic circuit of a full adder can be obtained,and the potential of voltage-driven spin logic devices for implementing complex logic functions can be veri-fied.This review contributes to the understanding of the evolving landscape of spin logic devices and underscores the promising pro-spects they offer for the future of emerging computing schemes.

A triboelectric nanogenerator based on a spiral rotating shaft for efficient marine energy harvesting of the hydrostatic pressure differential

Equipment used in underwater sensing and exploration typically relies on cables or batteries for energy supply,resulting in a limited and inconvenient energy supply and marine environmental pollution that hinder the sustainable development of distributed ocean sensing networks.Here,we design a deep-sea differential-pressure triboelectric nanogenerator(DP-TENG)based on a spiral shaft drive using modified polymer materials to harness the hydrostatic pressure gradient energy at varying ocean depths to power underwater equipment.The spiral shaft structure converts a single compression into multiple rotations of the TENG rotor,achieving efficient conversion of differential pressure energy.The multi-pair electrode design enables the DP-TENG to generate a peak current of 61.7μA,the instantaneous current density can reach 0.69μA cm^(-2),and the output performance can be improved by optimizing the spiral angle of the shaft.The DP-TENG can charge a 33μF capacitor to 17.5 V within five working cycles.It can also power a digital calculator and light up 116 commercial power light-emitting diodes,demonstrating excellent output capability.With its simple structure,low production cost,and small form factor,the DP-TENG can be seamlessly integrated with underwater vehicles.The results hold broad prospects for underwater blue energy harvesting and are expected to contribute to the development of self-powered equipment toward emerging“smart ocean”and blue economy applications.

Differential pressure difference based altitude control of a stratospheric satellite

An autonomous altitude adjustment system for a stratospheric satellite(StratoSat)platform is proposed.This platform consists of a helium balloon,a ballonet,and a two-way blower.The helium balloon generates lift to balance the platform gravity.The two-way blower inflates and deflates the ballonet to regulate the buoyancy.Altitude adjustment is achieved by tracking the differential pressure difference(DPD),and a threshold switching strategy is used to achieve blower flow control.The vertical acceleration regulation ability is decided not only by the blower flow rate,but also by the designed margin of pressure difference(MPD).Pressure difference is a slow-varying variable compared with altitude,and it is adopted as the control variable.The response speed of the actuator to disturbance can be delayed,and the overshoot caused by the large inertia of the platform is inhibited.This method can maintain a high tracking accuracy and reduce the complexity of model calculation,thus improving the robustness of controller design.

Differential diagnosis of gastric submucosal masses and external pressure lesions

Lesions of the left triangular ligament of the liver are rare,and there are even fewer cases of vascular tumors misdiagnosed as gastrointestinal stromal tumors.We comment on the two cases reported in the article.The article did not include pictures of laparoscopic surgery,making it unconvincing.For gastric submucosal lesions,enhanced computed tomography venous phase imaging may be beneficial for differential diagnosis.Although endoscopic ultrasound is an effective tool for diagnosing submucosal lesions of the stomach,due to various factors,it cannot achieve an accurate diagnosis.During endoscopic examination,a more accurate diagnosis can be made depending on the personal experience of the operators.

Management of negative pressure wound therapy in the treatment of diabetic foot ulcers

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.

On the dissipation of negative excess porewater pressure induced by excavation in soft soil

Unloading induces negative excess porewater pressure in soil mass around a foundation pit during excavation. In this work, the dissipation rule of negative excess porewater pressure after excavation was studied. Analytical formulas for calculating the negative excess porewater pressures and the effective stresses were derived based on one-dimensional consolidation theory and Terzaghi’s effective stress principle. The influence of the dissipation of negative excess porewater pressure on earth pressure inside and outside a foundation pit and the stability of the retaining structure were analyzed through a numerical example. It was indicated that the dissipation of negative excess porewater pressure is harmful to the stability of the retaining structure and that rapid construction can make full use of the negative porewater pressure.

Asymmetric Fuzzy Control of a Positive and Negative Pneumatic Pressure Servo System

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 mecha- nisms employing the error and change in error of the controlled variable as input parameters, the current cham- ber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability. To verify the effectiveness and performance of the pro- posed 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 consis- tent 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.

Biosorption effects of copper ions on Candida utilis under negative pressure cavitation

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.

Water and salt movement in different soil textures under various negative irrigating pressures

supported by the National High-Tech R＆D Program of China （2013AA102901）

Airtight negative pressure dust-control technology and application of transpersite in the coal conveyer belt system

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.

Effect of continuous negative pressure water supply on the growth, development and physiological mechanism of Capsicum annuum L.

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.

Time-series analysis of the characteristic pressure fluctuations in a conical fluidized bed with negative pressure

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.

Negative Pressure Consolidation of Silt Inside Bucket Foundation

A series of model experiments of bucket foundations concerning suction installation and negative pressure consolidation in saturated silt were carried out in a cube steel bin at Tianjin University. The experimental results show that the silt inside the bucket has been strengthened by negative pressure, and the strengthening effect decreases with the increase of the distance from the bucket. A three-dimensional numerical model of the experiments was built by means of finite element software ABAQUS with fluid-solid coupling method. The results show that the bearing capacity of the silt inside the bucket foundation increases significantly at the former stage of negative pressure consolidation, while the increasing trend slows down over time. The rotation centers of the bucket foundation and the inner soil region tend to be closer to each other based on the consolidation. The bearing capacity of the bucket foundation is improved effectively with the increase of soil strength. The effects of negative pressure consolidation on the bearing capacity of bucket foundation were also illustrated by an actual offshore wind power project case.

The Relationship of Cavitation to the Negative Acoustic Pressure Amplitude in Ultrasonic Therapy

The relationship between the cavitation and acoustic peak negative pressure in the high-intensity focused ultrasound （HIFU） field is analyzed in water and tissue phantom. The peak negative pressure at the focus is determined by a hybrid approach combining the measurement with the simulation. The spheroidal beam equation is utilized to describe the nonlinear acoustic propagation. The waveform at the focus is measured by a fiber optic probe hydrophone in water. The relationship between the source pressure amplitude and the excitation voltage is determined by fitting the measured ratio of the second harmonic to the fundamental component at the focus, based on the model simulation. Then the focal negative pressure is calculated for arbitrary voltage excita- tion in water and tissue phantom. A portable B-mode ultrasound scanner is applied to monitor HIFU-indueed cavitation in real time, and a passive cavitation detection （PCD） system is used to acquire the bubble scattering signals in the HIFU focal volume for the cavitation quantification. The results show that： （1） unstable cavitation starts to appear in degassed water when the peak negative pressure of HIFU signals reaches 13.5 MPa; and （2） the cavitation activity can be detected in tissue phantom by B-mode images and in the PCD system with HIFU peak negative pressures of 9.0 MPa and 7.8 MPa, respectively, which suggests that real-time B-mode images could be used to monitor the cavitation activity in two dimensions, while PCD systems are more sensitive to detect scattering and emission signals from cavitation bubbles.

Application of Negative Pressure Manual Dressing Change Combined with Mupirocin Ointment in the Treatment of a Case of a Patient with Cirrhosis Complicated with Deep Thigh Abscess

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.