BACKGROUND Motorcycle accidents often result in abdominal trauma in patients seeking emergency care.Injuries to the hollow viscera,including the duodenum,jejunum,urinary bladder,and colorectum,are relatively common.In...BACKGROUND Motorcycle accidents often result in abdominal trauma in patients seeking emergency care.Injuries to the hollow viscera,including the duodenum,jejunum,urinary bladder,and colorectum,are relatively common.In contrast,owing to the protective function of the anterior rib cage,gastric rupture is exceptionally rare,with an incidence of<1.7%.Gastric rupture typically occurs in the anterior wall and rarely presents as multiple ruptures.This report describes an unusual case of multiple gastric ruptures resulting from blunt trauma.CASE SUMMARY A 21-year-old man,who was involved in a motorcycle collision at 70 km/hour after consuming a large meal,presented with hypotension.Physical examination revealed abdominal tenderness.Laboratory test results indicated elevated amylase,lipase,and liver enzyme levels.Computed tomography showed pneumoperitoneum,hemoperitoneum,and gastric wall discontinuation,suggesting gastric perforation alongside pancreatic,splenic,and hepatic injuries.Angiographic embolization was performed because of active contrast leakage in the left gastric and right gastroepiploic arteries.Emergency laparotomy revealed substantial blood loss,hematoma,and gastric contents scattered throughout the abdominal cavity.Two 10 cm gastric perforations in the anterior and posterior walls were identified,as well as severe liver damage,splenic injury,and pancreatic contusion.Surgical interventions included primary closure of the gastric wall,splenectomy,and partial hepatectomy.After temporary abdominal closure,the patient underwent a second surgery without further bleeding.The gastric repair site was resected and reinforced for optimal tissue healing.CONCLUSION Gastric rupture following blunt trauma is fatal.However,patients without severe complications can recover through surgical interventions and postoperative care.展开更多
Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,mo...Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,modifying current collectors with perforations,to address these issues.Lithium ion batteries with mechanically perforated current collectors are prepared and tested with charge/discharge cycles,revealing superior capacity as well as enhanced electrochemical stability over cycles.Impedance spectroscopy,scanning electron microscopy,and peeling tests are conducted to investigate the underlying mechanisms.Higher peel resistance,minimized interface cracking,and reduced electrical impedance are found in the perforated electrodes after cycles.Investigations indicate that the perforation holes on current collectors allow the active materials coating on the two sides of the current collector to bind together and,thus,lead to enhanced adhesion between the current collector and active layer.Mechanical simulation illustrates the role of perforated current collectors in curbing interface cracking during lithiation,while electrochemical simulation shows that the interfacial cracking hinders the diffusion of lithium ions,thereby increasing battery impedance and reducing the cyclic performance.This investigation reveals the potential of designing non-active battery components to enhance battery performance,advocating a nuanced approach to battery design emphasizing structural integrity and interface optimization.展开更多
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex...The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.展开更多
Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal diseases.During the last few years,the incidence rate of perforations in colonoscopi...Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal diseases.During the last few years,the incidence rate of perforations in colonoscopic procedures has increased,especially in therapeutic colonoscopies.The recent advancements in endoscopic techniques and gastrointestinal tumoral resection procedures such as endoscopic mucosal resection,endoscopic full-thickness resection,and endoscopic submucosal dissection(ESD)could be a risk factor for this increased risk.The incidence rate of mortality of serious colonoscopic perforations is 7.1%.The management plan for these perforations starts with conservative treatment in mild cases,endoscopic closure,and surgical management in severe cases.Recently,endoluminal vacuum therapy was found to be effective in the management of colorectal perforations and this has been reported in multiple case reports.This editorial provides an overview of the current guidelines for the management of iatrogenic colorectal perforations.These insights are from the perspectives of endoscopists and gastroenterologists.We also present a management algorithm based on the guidelines of the European Society of Gastrointestinal Endoscopy,the American Gastroenterological Association,and the World Society of Emergency Surgery.We also discussed in brief the use of endoluminal vacuum therapy in colorectal perforations.展开更多
A theoretical analysis on the perforation of Weldox 460E steel plates struck by flat-nosed projectiles is presented using a previously developed model within a unified framework.This model contains a dimensionless emp...A theoretical analysis on the perforation of Weldox 460E steel plates struck by flat-nosed projectiles is presented using a previously developed model within a unified framework.This model contains a dimensionless empirical equation to describe the variation of energy absorbed through global deformation as a function of impact velocity.The study further investigates the energy absorption mechanisms of Weldox 460E steel plates,with particular focus on the“plateau”phenomenon,i.e.,limited increase in ballistic limit with increasing plate thickness.This phenomenon is explained and compared with results from previously studied 2024-T351 aluminium plates.The model predictions agree well with experimental data for Weldox 460E steel plates impacted by flat-nosed projectiles,including:relationship between global deformation and impact velocity,ballistic limit,residual velocity,and critical conditions for the transition of failure modes.Moreover,the model effectively predicts the“plateau”phenomenon observed in intermediate plate thickness range.It is also found that the indentation absorption energy contributes a significantly larger fraction of the total absorption energy in Weldox 460E steel plates perforated by flat-nosed projectiles than in 2024-T351 aluminium plates,due to the differences in material properties.展开更多
BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and ...BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and an ideal postoperative antiinfective approach for PPA management has yet to be established.AIM To examine the spectrum of pathogenic bacteria in pediatric PPA and to summarize the postoperative experience with carbapenem(CBP)and cephalosporin(CPS)antibiotics.METHODS We retrospectively analyzed medical records of 65 children(43 boys,22 girls;mean age 6.92±3.41 years)with PPA who underwent surgery at our hospital between December 2019 and August 2022.Data were collected in September 2023.Based on postoperative antibiotic selection,patients were divided into CBP(32 cases)and CPS(33 cases)groups.Chi-square and T-tests compared recovery outcomes,while univariate and multivariate regression models identified independent factors affecting postoperative recovery.RESULTS There were no significant differences between the two groups in gender,age,weight,height,body mass index,baseline ear temperature,or heart rate(P>0.05).Escherichia coli(40.00%)and Pseudomonas aeruginosa(24.62%)were the most common pathogens in PPA.Postoperative analysis showed significantly shorter C-reactive protein(CRP)recovery times in the CPS group than in the CBP group[(6.18±1.84)vs(8.12±3.48)days,P=0.009].Univariate logistic regression indicated CPS selection(OR=0.32,95%CI:0.10-0.97,P=0.044)was significantly associated with a higher CRP recovery rate within 7 days.Multivariate analysis confirmed CPS selection(OR=3.49,95%CI:1.19-10.24,P=0.023)as an independent factor affecting CRP recovery within 7 days postoperatively.CONCLUSION The choice of CBP or CPS independently affects CRP recovery within 7 days.CBP offers no advantage over CPS in treating PPA,with CPS also demonstrating favorable clinical outcomes.展开更多
BACKGROUND Intestinal obstruction(IO)in pregnancy,though rare(1:1500-1:66000),carries high maternal(6%-10%)and fetal mortality(26%).Adhesions from prior surgery are the leading cause.Diagnosis is often delayed due to ...BACKGROUND Intestinal obstruction(IO)in pregnancy,though rare(1:1500-1:66000),carries high maternal(6%-10%)and fetal mortality(26%).Adhesions from prior surgery are the leading cause.Diagnosis is often delayed due to symptom overlap with nor-mal pregnancy,increasing risks of perforation and sepsis.CASE SUMMARY A 25-year-old gravida 2 para 1 woman at 28 weeks of gestation presented with 1-week constipation,feculent vomiting,and abdominal distension.She had a history of exploratory laparotomy in 2015 for blunt abdominal trauma.The diagnosis of IO in pregnancy was confirmed via abdominopelvic ultrasound and clinical findings.Interventions included conservative measures(nasogastric tube decompression,enemas)followed by emergency laparotomy with bowel resec-tion/anastomosis.Despite surgical management,the patient succumbed to septic shock.CONCLUSION High clinical suspicion,expedited cross-sectional imaging(computed tomogra-phy/Magnetic resonance imaging),and emergent surgery are critical to reduce mortality.展开更多
Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the ...Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.展开更多
It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,whi...It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,which is related to a change in the mode of failure.No theoretical model has so far explained this phenomenon satisfactorily.This paper presents a combined numerical and theoretical study on the perforation of 2024-T351 aluminum plates struck by flat-nosed projectiles.First,numerical simulations are performed to investigate the failure mechanisms/deformation modes of the aluminum plates.Then,a theoretical model is proposed based on the numerical results and the experimental observations within a unified framework.The model takes into account the main energy absorbing mechanisms and the corresponding energies absorbed are determined analytically.In particular,a dimensionless equation is suggested to describe the relationship between global deformations and impact velocity.It transpires that the model predictions are in good agreement with the test data and the numerical results for the perforation of 2024-T351 aluminum plates struck by rigid flat-nosed projectiles in terms of residual velocity,ballistic limit,relationship between global deformations and impact velocity,and transition of failure modes.It also transpires that the present model can predict the“plateau”phenomenon,which shows a slight increase in ballistic limit as plate thickness increases.Furthermore,the energy absorption mechanisms are discussed on the basis of the theoretical analysis.展开更多
Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperati...Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperative preparation,especially concerning computed tomography(CT) and magnetic resonance imaging of the donor site.The objective of this study was to aid the surgical approach to the LAP flap in female patients by precisely determining the characteristics of the lumbar perforators.Methods: We retrospectively reviewed the computed tomographic angiography images of 20 patients who underwent evaluation of the perforator positions from the four lumbar arteries.Four characteristics were studied:length,diameter,path of the lumbar pedicle,and thickness of the tissues available for transfer.Results: We analyzed 20 CT images,identifying 149 perforating vessels of the lumbar artery.The most suitable perforator for flap harvesting was the L4 perforator,which exhibited a larger diameter,a greater number of perforasomes,and a higher percentage of the cutaneous-septal tract.Conclusion: The LAP flap is a viable option for breast reconstruction and as a free flap in women.The L4 perforator artery is the most suitable for harvesting,owing to its superior perfusion capacity,diameter,and course;however,an interposition graft may be required to lengthen the vascular pedicle.展开更多
BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the d...BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the diagnosis of preoperative PPU during pregnancy and puerperium challenging.AIM To identify predictive factors for early diagnosis and treatment,and the association between the diagnosis and maternal/neonatal outcomes.METHODS We searched PubMed,PubMed Central,and Google Scholar.Articles were analyzed following preferred reporting items for systematic reviews and metaanalysis.The search items included:‘ulcer’,‘PUD’,‘pregnancy’,‘puerperium’,‘postpartum’,‘gravid’,‘labor’,‘perforated ulcer’,‘stomach ulcer’,‘duodenal ulcer’,‘peptic ulcer’.Additional studies were extracted by reviewing reference lists of retrieved studies.We included all available full-text cases and case series.Demographic,clinical,obstetric,diagnostic and treatment parameters,and outcomes were collected.RESULTS Forty-three cases were collected.The mean maternal age was 30.9 years;36.6%were multiparous,and 63.4%were nulliparous or primiparous,with multiparas being older than primiparas.Peptic ulcer perforated in 44.2%of postpartum and 55.8%of antepartum patients.Antepartum PPU incidence increased with advancing gestation 2.3%in the first,7%in the second,and 46.5%in the third trimester.The most common clinical findings were abdominal tenderness(72.1%),rigidity(34.9%),and distension(48.8%).Duodenal ulcer predominated(76.7%).In 79.5%,the time from delivery to surgery or vice versa was>24 hours.The maternal mortality during the third trimester and postpartum was 10%and 31.6%,respectively.The trimester of presentation did not influence maternal mortality.The fetal mortality was 34.8%,with all deaths in gestational weeks 24-32.CONCLUSION Almost all patients with PPU in pregnancy or puerperium presented during the third trimester or the first 8 days postpartum.Early intervention reduced fetal mortality but without influence on maternal mortality.Maternal mortality did not depend on the use of X-ray imaging,perforation location,delivery type,trimester of presentation,and maternal age.Explorative laparoscopy was never performed during pregnancy,only postpartum.展开更多
BACKGROUND Acute abdominal pain is one of the most common gastrointestinal symptoms.The etiology of acute abdomen can be challenging for gastroenterologists to establish.Cecal foreign body is a rare cause of cecal per...BACKGROUND Acute abdominal pain is one of the most common gastrointestinal symptoms.The etiology of acute abdomen can be challenging for gastroenterologists to establish.Cecal foreign body is a rare cause of cecal perforation.CASE SUMMARY We report a 35-year-old male from China who initially exhibited symptoms suggestive of acute appendicitis.However,during a minimally invasive colonoscopy procedure,the authors found that a wooden toothpick caused the perforation.The patient presented to our emergency department with a 2 days history of right lower abdominal pain and low grade fever.The patient was in good health and had eaten fish 2 days earlier.Physical examination revealed mild pain with positive rebound tenderness in the right lower abdomen.However,computed tomography of the abdomen confirmed a strip of high-density shadows protruding beyond the intestinal cavity outline,with a small amount of peritoneal seepage in the ileocecal area.Combined with the medical history,the possibility of foreign body perforation by a fishbone and peripheral peritonitis were considered.However,the high-density shadow was identified as a wooden toothpick,which was removed via a minimally invasive procedure using a foreign body forceps under colonoscopy.The patient's condition improved significantly within 5 days after treatment.CONCLUSION We emphasize the importance of a detailed patient history,accurate diagnosis and proper treatment in patients with acute abdomen.展开更多
In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool...In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.展开更多
AIM:To investigate the clinical signs of blepharokeratoconjunctivitis(BKC)and evaluate the efficacy of penetrating keratoplasty(PKP)for the disease.METHODS:Sixteen patients(16 eyes)with BKC complicated by corneal perf...AIM:To investigate the clinical signs of blepharokeratoconjunctivitis(BKC)and evaluate the efficacy of penetrating keratoplasty(PKP)for the disease.METHODS:Sixteen patients(16 eyes)with BKC complicated by corneal perforation hospitalised at Shandong Eye Hospital were retrospectively analyzed.All patients received PKP.Participants were assessed for symptoms,clinical manifestations,the activity and damage grading of BKC.A paired t-test was used to compare the uncorrected visual acuity(UCVA)before and after surgery for the perforated eye.RESULTS:The mean age of the patients was 16.3y.Blurred vision is the most common discomfort,followed by redness,and then photophobia.The duration of ocular discomfort lasted for 3.2y,on average.Three(18.8%)participants were associated with rosacea,while 11(68.8%)patients had recurrent chalazion or hordeolum.Demodex in eyelash follicles was positive in 11(68.8%)cases.All corneal perforations were≤3.0 mm in diameter.The perforation was located mainly in the inferior cornea(68.8%).The mean area of corneal vascularisation was 3.0 quadrants.All patients manifested bilateral BKC,with the perforated eyes ranked as severely damaged and presenting with severe inflammation.Most contralateral eyes manifested mild damage with no active inflammation.Majority(68.8%)of the perforated eyes were treated with PKP using a minimal graft.The UCVA increased significantly at the final follow-up(mean,21mo;P<0.001),with the manifestation of BKC alleviated greatly.None of the patients developed immune rejection or other serious complications.CONCLUSION:BKC combined with corneal perforation occurs mainly among young people with a long history of ocular discomfort.PKP,especially using a minimal graft,is an effective and safe option for treating the disease.展开更多
Hydraulic sandblasting perforation plays a crucial role in the fracturing and reconstruction of unconventional oil and gas reservoirs.The jet nozzle is an essential part of the hydraulic perforation tool.Insufficient ...Hydraulic sandblasting perforation plays a crucial role in the fracturing and reconstruction of unconventional oil and gas reservoirs.The jet nozzle is an essential part of the hydraulic perforation tool.Insufficient penetration depth,caused by excessive jet distances,presents challenges during the perforation process.To overcome this,an optimization design of the nozzle structure is required to enhance the perforation efficiency.In this paper,a computational fluid-dynamic model for conical-cylindrical nozzles has been elaborated.To further improve the rock-breaking efficiency of the jet nozzle,a fillet design is introduced at the nozzle inlet section.The SST k-ωmodel is employed to account for turbulent flow effects in submerged conditions.The results indicate that the nozzle’s geometric parameters greatly influence the flow characteristics.The orthogonal experimental method is employed to optimize the flow channel structure of the nozzle,taking the length of constant velocity core as the evaluation index.The following optimized geometric parameters for the conical-cylindrical nozzle have been determined accordingly:a cylindrical segment diameter of 3.2 mm,a contraction angle of 12°,a contraction segment length of 8 mm,a cylindrical segment length of 6.4 mm,and a fillet radius of 2 mm.展开更多
In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle...In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle Fatigue(MLCF)life of perforated structures.First,fatigue tests are carried out on three center-perforated structures,aiming to assess their fatigue life under various strengthening conditions.These tests reveal significant variations in fatigue life,accompanied by an examination of crack initiation through the analysis of fatigue fracture surfaces.Second,an innovative fatigue life prediction methodology is applied to perforated structures,which not only forecasts the initiation of fatigue cracks but also traces the progression of damage within these structures.It leverages an elastoplastic constitutive model integrated with damage and a damage evolution model under cyclic loads.The accuracy of this approach is validated by comparison with test results,falling within the three times error band.Finally,we explore the impact of various strengthening techniques,including cross-sectional reinforcement and cold expansion,on the fatigue life and damage evolution of these structures.This is achieved through an in-depth comparative analysis of both experimental data and computational predictions,which provides valuable insights into the behavior of perforated structures under fatigue conditions in practical applications.展开更多
BACKGROUND Gastric ulcer perforation is a critical condition that can lead to significant morbidity and mortality if not promptly addressed.It is often the result of chronic peptic ulcer disease,which is characterized...BACKGROUND Gastric ulcer perforation is a critical condition that can lead to significant morbidity and mortality if not promptly addressed.It is often the result of chronic peptic ulcer disease,which is characterized by a breach in the gastric wall due to ulceration.Surgical intervention is essential for managing this life-threatening complication.However,the optimal surgical technique remains debatable among clinicians.Various methods have been employed,including simple closure,omental patch repair,and partial gastrectomy,each with distinct advantages and disadvantages.Understanding the comparative efficacy and postoperative outcomes of these techniques is crucial for improving patient care and surgical decision-making.This study addresses the need for a comprehensive analysis in this area.AIM To compare the efficacy and postoperative complications of different surgical methods for the treatment of gastric ulcer perforation.METHODS A retrospective analysis was conducted on 120 patients who underwent surgery for gastric ulcer perforation between September 2020 and June 2023.The patients were divided into three groups based on the surgical method:Simple closure,omental patch repair,and partial gastrectomy.The primary outcomes were the operative success rate and incidence of postoperative complications.Secondary outcomes included the length of hospital stay,recovery time,and long-term quality of life.RESULTS The operative success rates for simple closure,omental patch repair,and partial gastrectomy were 92.5%,95%,and 97.5%,respectively.Postoperative complications occurred in 20%,15%,and 17.5%of patients in each group,respectively.The partial gastrectomy group showed a significantly longer operative time(P<0.001)but the lowest rate of ulcer recurrence(2.5%,P<0.05).The omental patch repair group demonstrated the shortest hospital stay(mean 7.2 days,P<0.05)and fastest recovery time.CONCLUSION While all three surgical methods showed high success rates,omental patch repair demonstrated the best overall outcomes,with a balance of high efficacy,low complication rates,and shorter recovery time.However,the choice of the surgical method should be tailored to individual patient factors and the surgeon’s expertise.展开更多
Whipple shields as sacrificial bumpers,safeguard the satellites against extremely fast,different-sized projectiles traveling through space in the low earth orbit.Typical Whipple shields comprise a front and rear plate...Whipple shields as sacrificial bumpers,safeguard the satellites against extremely fast,different-sized projectiles traveling through space in the low earth orbit.Typical Whipple shields comprise a front and rear plate,separated by a gap or space.Recent advancements have explored the use of foam,cellular cores,and alternative materials such as ceramics instead of aluminium for the plates.In the current work,the effect of including fluid cores(air/water)sandwiched between the front and rear plates,on the response to hypervelocity impact was explored through a numerical approach.The numerical simulation consisted of hypervelocity impact by a 2 mm diameter,stainless steel projectile,launched at speeds of 3 e9 km/s with a normal impact trajectory towards the Whipple shield.The front and rear bumpers,made of AA6061-T6,were each 1 mm thick.A space of 10 mm was taken between the plates(occupied by fluid).The key metrics analyzed were the perforation characteristics,stages of the debris cloud generation and propagation,energy variations(internal,kinetic and plastic work),temperature variations,and the fragmentation summary.From the computational analysis,employing water-core in Whipple shields could prevent the rear bumper perforation till 6 km/s,lower the peak temperatures at the front bumper perforation zones and debris tip,and generate fewer,larger fragments.展开更多
Dear Editor,We report two rare cases of ocular perforating injuries caused by acupuncture needles.Both cases were approved by the Ethics Committee of Xi’an People’s Hospital(Xi’an No.4 Hospital)(KJLL-Z-K-2023060).W...Dear Editor,We report two rare cases of ocular perforating injuries caused by acupuncture needles.Both cases were approved by the Ethics Committee of Xi’an People’s Hospital(Xi’an No.4 Hospital)(KJLL-Z-K-2023060).Written informed consents were obtained from the patients.Acupuncture is an integral part of traditional Chinese medicine,and is widely used for the treatment of systemic diseases and ophthalmologic diseases^([1-8]),such as paralysis caused by stroke^([4]),diabetes^([7]),dry eye disease^([8]),pigmentary degeneration of retina,macular degeneration,glaucoma,and optic atrophy^([6]).Improper acupuncture technique can lead to accidents.展开更多
BACKGROUND Gastrointestinal(GI)perforation(GP)repair is a surgical procedure to promptly seal perforations in the GI tract to prevent further leakage.After surgery,patients often experience a high metabolic state due ...BACKGROUND Gastrointestinal(GI)perforation(GP)repair is a surgical procedure to promptly seal perforations in the GI tract to prevent further leakage.After surgery,patients often experience a high metabolic state due to trauma,infection,and posto-perative stress.In the Enhanced Recovery After Surgery(ERAS)protocol,early enteral nutrition is a key strategy for promoting postoperative recovery.Com-pared with parenteral nutrition,enteral nutrition more effectively meets the physiological needs of the GI system,promotes the recovery of gut function,and reduces the risk of GI infections.AIM To evaluate the clinical efficacy of early enteral nutrition support in patients undergoing GP repair within the ERAS protocol.METHODS This retrospective study analyzed 66 patients who underwent GP repair.Patients were divided into a control group(n=32),managed with a traditional nutritional regimen,primarily consisting of total parenteral nutrition;and an observation group(n=34),which included those who received early enteral nutrition support as part of the ERAS protocol.This study examined the time to first postoperative flatus and bowel movement,changes in nutritional and immune function,inflam-matory markers on postoperative days 1 and 5,and adverse reactions.RESULTS The observation group had significantly shorter times to the first postoperative flatus and bowel movement than the control group(P<0.05).On postoperative day 5,the observation group demonstrated higher nutritional and immune function levels than the control group(P<0.05),while C-reactive protein levels were significantly lower(P<0.05).The overall incidence of adverse reactions in the observation group was 8.82%(3/34),which was lower than the 28.13%(9/32)observed in the control group(P<0.05).CONCLUSION Early enteral nutritional support facilitates GI recovery after GP repair.It improves nutritional status,enhances immune function,and attenuates inflammatory responses while also demonstrating a favorable safety profile.展开更多
文摘BACKGROUND Motorcycle accidents often result in abdominal trauma in patients seeking emergency care.Injuries to the hollow viscera,including the duodenum,jejunum,urinary bladder,and colorectum,are relatively common.In contrast,owing to the protective function of the anterior rib cage,gastric rupture is exceptionally rare,with an incidence of<1.7%.Gastric rupture typically occurs in the anterior wall and rarely presents as multiple ruptures.This report describes an unusual case of multiple gastric ruptures resulting from blunt trauma.CASE SUMMARY A 21-year-old man,who was involved in a motorcycle collision at 70 km/hour after consuming a large meal,presented with hypotension.Physical examination revealed abdominal tenderness.Laboratory test results indicated elevated amylase,lipase,and liver enzyme levels.Computed tomography showed pneumoperitoneum,hemoperitoneum,and gastric wall discontinuation,suggesting gastric perforation alongside pancreatic,splenic,and hepatic injuries.Angiographic embolization was performed because of active contrast leakage in the left gastric and right gastroepiploic arteries.Emergency laparotomy revealed substantial blood loss,hematoma,and gastric contents scattered throughout the abdominal cavity.Two 10 cm gastric perforations in the anterior and posterior walls were identified,as well as severe liver damage,splenic injury,and pancreatic contusion.Surgical interventions included primary closure of the gastric wall,splenectomy,and partial hepatectomy.After temporary abdominal closure,the patient underwent a second surgery without further bleeding.The gastric repair site was resected and reinforced for optimal tissue healing.CONCLUSION Gastric rupture following blunt trauma is fatal.However,patients without severe complications can recover through surgical interventions and postoperative care.
基金supported by the National Natural Science Foundation of China under Grant Nos.12172205,11872236,and 12072183.
文摘Lithium ion batteries are important for new energy technologies and manufacturing systems.However,enhancing their capacity and cycling stability poses a significant challenge.This study proposes a novel method,i.e.,modifying current collectors with perforations,to address these issues.Lithium ion batteries with mechanically perforated current collectors are prepared and tested with charge/discharge cycles,revealing superior capacity as well as enhanced electrochemical stability over cycles.Impedance spectroscopy,scanning electron microscopy,and peeling tests are conducted to investigate the underlying mechanisms.Higher peel resistance,minimized interface cracking,and reduced electrical impedance are found in the perforated electrodes after cycles.Investigations indicate that the perforation holes on current collectors allow the active materials coating on the two sides of the current collector to bind together and,thus,lead to enhanced adhesion between the current collector and active layer.Mechanical simulation illustrates the role of perforated current collectors in curbing interface cracking during lithiation,while electrochemical simulation shows that the interfacial cracking hinders the diffusion of lithium ions,thereby increasing battery impedance and reducing the cyclic performance.This investigation reveals the potential of designing non-active battery components to enhance battery performance,advocating a nuanced approach to battery design emphasizing structural integrity and interface optimization.
基金funded by the Project of the Hubei Provincial Department of Science and Technology(Grant No.2022CFB957)the Project of Hubei Engineering University of Teaching Research(Grant No.JY2024032)+1 种基金Ministry of Education University-Industry Cooperation Collaborative Education Project(Grant No.220903584161245)College Students’Innovation and Entrepreneurship Training Program(Grant Nos.DC2024031,DC2024032).
文摘The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.
文摘Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal diseases.During the last few years,the incidence rate of perforations in colonoscopic procedures has increased,especially in therapeutic colonoscopies.The recent advancements in endoscopic techniques and gastrointestinal tumoral resection procedures such as endoscopic mucosal resection,endoscopic full-thickness resection,and endoscopic submucosal dissection(ESD)could be a risk factor for this increased risk.The incidence rate of mortality of serious colonoscopic perforations is 7.1%.The management plan for these perforations starts with conservative treatment in mild cases,endoscopic closure,and surgical management in severe cases.Recently,endoluminal vacuum therapy was found to be effective in the management of colorectal perforations and this has been reported in multiple case reports.This editorial provides an overview of the current guidelines for the management of iatrogenic colorectal perforations.These insights are from the perspectives of endoscopists and gastroenterologists.We also present a management algorithm based on the guidelines of the European Society of Gastrointestinal Endoscopy,the American Gastroenterological Association,and the World Society of Emergency Surgery.We also discussed in brief the use of endoluminal vacuum therapy in colorectal perforations.
文摘A theoretical analysis on the perforation of Weldox 460E steel plates struck by flat-nosed projectiles is presented using a previously developed model within a unified framework.This model contains a dimensionless empirical equation to describe the variation of energy absorbed through global deformation as a function of impact velocity.The study further investigates the energy absorption mechanisms of Weldox 460E steel plates,with particular focus on the“plateau”phenomenon,i.e.,limited increase in ballistic limit with increasing plate thickness.This phenomenon is explained and compared with results from previously studied 2024-T351 aluminium plates.The model predictions agree well with experimental data for Weldox 460E steel plates impacted by flat-nosed projectiles,including:relationship between global deformation and impact velocity,ballistic limit,residual velocity,and critical conditions for the transition of failure modes.Moreover,the model effectively predicts the“plateau”phenomenon observed in intermediate plate thickness range.It is also found that the indentation absorption energy contributes a significantly larger fraction of the total absorption energy in Weldox 460E steel plates perforated by flat-nosed projectiles than in 2024-T351 aluminium plates,due to the differences in material properties.
基金Supported by Jiaxing Science and Technology Plan Project,No.2024AD30035.
文摘BACKGROUND Pediatric perforated appendicitis(PPA)is a severe acute condition requiring surgical intervention and postoperative antibiotic therapy.Antibiotic selection differs significantly among pediatric centers,and an ideal postoperative antiinfective approach for PPA management has yet to be established.AIM To examine the spectrum of pathogenic bacteria in pediatric PPA and to summarize the postoperative experience with carbapenem(CBP)and cephalosporin(CPS)antibiotics.METHODS We retrospectively analyzed medical records of 65 children(43 boys,22 girls;mean age 6.92±3.41 years)with PPA who underwent surgery at our hospital between December 2019 and August 2022.Data were collected in September 2023.Based on postoperative antibiotic selection,patients were divided into CBP(32 cases)and CPS(33 cases)groups.Chi-square and T-tests compared recovery outcomes,while univariate and multivariate regression models identified independent factors affecting postoperative recovery.RESULTS There were no significant differences between the two groups in gender,age,weight,height,body mass index,baseline ear temperature,or heart rate(P>0.05).Escherichia coli(40.00%)and Pseudomonas aeruginosa(24.62%)were the most common pathogens in PPA.Postoperative analysis showed significantly shorter C-reactive protein(CRP)recovery times in the CPS group than in the CBP group[(6.18±1.84)vs(8.12±3.48)days,P=0.009].Univariate logistic regression indicated CPS selection(OR=0.32,95%CI:0.10-0.97,P=0.044)was significantly associated with a higher CRP recovery rate within 7 days.Multivariate analysis confirmed CPS selection(OR=3.49,95%CI:1.19-10.24,P=0.023)as an independent factor affecting CRP recovery within 7 days postoperatively.CONCLUSION The choice of CBP or CPS independently affects CRP recovery within 7 days.CBP offers no advantage over CPS in treating PPA,with CPS also demonstrating favorable clinical outcomes.
文摘BACKGROUND Intestinal obstruction(IO)in pregnancy,though rare(1:1500-1:66000),carries high maternal(6%-10%)and fetal mortality(26%).Adhesions from prior surgery are the leading cause.Diagnosis is often delayed due to symptom overlap with nor-mal pregnancy,increasing risks of perforation and sepsis.CASE SUMMARY A 25-year-old gravida 2 para 1 woman at 28 weeks of gestation presented with 1-week constipation,feculent vomiting,and abdominal distension.She had a history of exploratory laparotomy in 2015 for blunt abdominal trauma.The diagnosis of IO in pregnancy was confirmed via abdominopelvic ultrasound and clinical findings.Interventions included conservative measures(nasogastric tube decompression,enemas)followed by emergency laparotomy with bowel resec-tion/anastomosis.Despite surgical management,the patient succumbed to septic shock.CONCLUSION High clinical suspicion,expedited cross-sectional imaging(computed tomogra-phy/Magnetic resonance imaging),and emergent surgery are critical to reduce mortality.
基金supported by the Sinopec Technology Research and Development Project(No.30000000-22-ZC0607-0235,No.33550000-22-ZC0607-0009)the National Natural Science Foundation of China(No.52334002).
文摘Natural gas hydrate widely exists in the South China Sea as clean energy.A three-phase transition layer widely exists in low permeability Class I hydrates in the Shenhu offshore area.Therefore,taking into account the low-permeability characteristics with an average permeability of 5.5 mD and moderate heterogeneity,a 3-D geological model of heterogeneous Class I hydrate reservoirs with three-phase transition layers is established by Kriging interpolation and stochastic modeling method,and a numerical simulation model is used to describe the depressurization production performance of the reservoir.With the development of depressurization,a specific range of complete decomposition zones appear both in the hydrate and transition layers.The entire decomposition zone of the whole reservoir tends to outward and upward diffusion.There is apparent methane escape in the three-phase transition layer.Due to the improvement of local permeability caused by the phase transition of hydrate dissociation,some methane accumulation occurs at the bottom of the hydrate layer,forming a local methane enrichment zone.The methane migration trends in reservoirs are mainly characterized by movement toward production wells and hydrate layers under the influence of gravity.However,due to the permeability limitation of hydrate reservoirs,many fluids have not been effectively produced and remain in the reservoir.Therefore,to improve the effective pressure drop of the reservoir,the perforation method and pressure reduction method were optimized by analyzing the influencing factors based on the gas production rate.The comparative study demonstrates that perforating through the free gas layer combined with one-time depressurization can enhance the effective depressurization and improve production performance.The gas production rate from perforating through the free gas layer can be twice as high as that from perforating through the transition layer.This study can provide theoretical support for the utilization of marine energy.
文摘It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,which is related to a change in the mode of failure.No theoretical model has so far explained this phenomenon satisfactorily.This paper presents a combined numerical and theoretical study on the perforation of 2024-T351 aluminum plates struck by flat-nosed projectiles.First,numerical simulations are performed to investigate the failure mechanisms/deformation modes of the aluminum plates.Then,a theoretical model is proposed based on the numerical results and the experimental observations within a unified framework.The model takes into account the main energy absorbing mechanisms and the corresponding energies absorbed are determined analytically.In particular,a dimensionless equation is suggested to describe the relationship between global deformations and impact velocity.It transpires that the model predictions are in good agreement with the test data and the numerical results for the perforation of 2024-T351 aluminum plates struck by rigid flat-nosed projectiles in terms of residual velocity,ballistic limit,relationship between global deformations and impact velocity,and transition of failure modes.It also transpires that the present model can predict the“plateau”phenomenon,which shows a slight increase in ballistic limit as plate thickness increases.Furthermore,the energy absorption mechanisms are discussed on the basis of the theoretical analysis.
文摘Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperative preparation,especially concerning computed tomography(CT) and magnetic resonance imaging of the donor site.The objective of this study was to aid the surgical approach to the LAP flap in female patients by precisely determining the characteristics of the lumbar perforators.Methods: We retrospectively reviewed the computed tomographic angiography images of 20 patients who underwent evaluation of the perforator positions from the four lumbar arteries.Four characteristics were studied:length,diameter,path of the lumbar pedicle,and thickness of the tissues available for transfer.Results: We analyzed 20 CT images,identifying 149 perforating vessels of the lumbar artery.The most suitable perforator for flap harvesting was the L4 perforator,which exhibited a larger diameter,a greater number of perforasomes,and a higher percentage of the cutaneous-septal tract.Conclusion: The LAP flap is a viable option for breast reconstruction and as a free flap in women.The L4 perforator artery is the most suitable for harvesting,owing to its superior perfusion capacity,diameter,and course;however,an interposition graft may be required to lengthen the vascular pedicle.
文摘BACKGROUND Peptic ulcer disease(PUD)during pregnancy is extremely rare.Perforated peptic ulcer(PPU)during pregnancy has high maternal and fetal mortality.Symptoms attributed to pregnancy and other diagnoses make the diagnosis of preoperative PPU during pregnancy and puerperium challenging.AIM To identify predictive factors for early diagnosis and treatment,and the association between the diagnosis and maternal/neonatal outcomes.METHODS We searched PubMed,PubMed Central,and Google Scholar.Articles were analyzed following preferred reporting items for systematic reviews and metaanalysis.The search items included:‘ulcer’,‘PUD’,‘pregnancy’,‘puerperium’,‘postpartum’,‘gravid’,‘labor’,‘perforated ulcer’,‘stomach ulcer’,‘duodenal ulcer’,‘peptic ulcer’.Additional studies were extracted by reviewing reference lists of retrieved studies.We included all available full-text cases and case series.Demographic,clinical,obstetric,diagnostic and treatment parameters,and outcomes were collected.RESULTS Forty-three cases were collected.The mean maternal age was 30.9 years;36.6%were multiparous,and 63.4%were nulliparous or primiparous,with multiparas being older than primiparas.Peptic ulcer perforated in 44.2%of postpartum and 55.8%of antepartum patients.Antepartum PPU incidence increased with advancing gestation 2.3%in the first,7%in the second,and 46.5%in the third trimester.The most common clinical findings were abdominal tenderness(72.1%),rigidity(34.9%),and distension(48.8%).Duodenal ulcer predominated(76.7%).In 79.5%,the time from delivery to surgery or vice versa was>24 hours.The maternal mortality during the third trimester and postpartum was 10%and 31.6%,respectively.The trimester of presentation did not influence maternal mortality.The fetal mortality was 34.8%,with all deaths in gestational weeks 24-32.CONCLUSION Almost all patients with PPU in pregnancy or puerperium presented during the third trimester or the first 8 days postpartum.Early intervention reduced fetal mortality but without influence on maternal mortality.Maternal mortality did not depend on the use of X-ray imaging,perforation location,delivery type,trimester of presentation,and maternal age.Explorative laparoscopy was never performed during pregnancy,only postpartum.
文摘BACKGROUND Acute abdominal pain is one of the most common gastrointestinal symptoms.The etiology of acute abdomen can be challenging for gastroenterologists to establish.Cecal foreign body is a rare cause of cecal perforation.CASE SUMMARY We report a 35-year-old male from China who initially exhibited symptoms suggestive of acute appendicitis.However,during a minimally invasive colonoscopy procedure,the authors found that a wooden toothpick caused the perforation.The patient presented to our emergency department with a 2 days history of right lower abdominal pain and low grade fever.The patient was in good health and had eaten fish 2 days earlier.Physical examination revealed mild pain with positive rebound tenderness in the right lower abdomen.However,computed tomography of the abdomen confirmed a strip of high-density shadows protruding beyond the intestinal cavity outline,with a small amount of peritoneal seepage in the ileocecal area.Combined with the medical history,the possibility of foreign body perforation by a fishbone and peripheral peritonitis were considered.However,the high-density shadow was identified as a wooden toothpick,which was removed via a minimally invasive procedure using a foreign body forceps under colonoscopy.The patient's condition improved significantly within 5 days after treatment.CONCLUSION We emphasize the importance of a detailed patient history,accurate diagnosis and proper treatment in patients with acute abdomen.
基金supported by the National Natural Science Foundation of China(Project No.52166004)the National Key Research and Development Program of China(Project No.2022YFC3902000)+2 种基金the Major Science and Technology Special Project of Yunnan Province(Project Nos.202202AG050007202202AG050002)the Research on the Development of Complete Sets of Technology for Extraction of Aromatic Substances from Tobacco Waste and Its Application,Applied Research-Pyrolysis Process Technology Research(2023QT01).
文摘In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.
基金Supported by Key Technology Research and Development Program of Shandong Province(No.2022CXGC010505)Natural Science Foundation of Shandong Province(No.ZR2019BH065)+1 种基金Taishan Scholars Program(No.20221110)the Innovation Project of Shandong Academy of Medical Sciences.
文摘AIM:To investigate the clinical signs of blepharokeratoconjunctivitis(BKC)and evaluate the efficacy of penetrating keratoplasty(PKP)for the disease.METHODS:Sixteen patients(16 eyes)with BKC complicated by corneal perforation hospitalised at Shandong Eye Hospital were retrospectively analyzed.All patients received PKP.Participants were assessed for symptoms,clinical manifestations,the activity and damage grading of BKC.A paired t-test was used to compare the uncorrected visual acuity(UCVA)before and after surgery for the perforated eye.RESULTS:The mean age of the patients was 16.3y.Blurred vision is the most common discomfort,followed by redness,and then photophobia.The duration of ocular discomfort lasted for 3.2y,on average.Three(18.8%)participants were associated with rosacea,while 11(68.8%)patients had recurrent chalazion or hordeolum.Demodex in eyelash follicles was positive in 11(68.8%)cases.All corneal perforations were≤3.0 mm in diameter.The perforation was located mainly in the inferior cornea(68.8%).The mean area of corneal vascularisation was 3.0 quadrants.All patients manifested bilateral BKC,with the perforated eyes ranked as severely damaged and presenting with severe inflammation.Most contralateral eyes manifested mild damage with no active inflammation.Majority(68.8%)of the perforated eyes were treated with PKP using a minimal graft.The UCVA increased significantly at the final follow-up(mean,21mo;P<0.001),with the manifestation of BKC alleviated greatly.None of the patients developed immune rejection or other serious complications.CONCLUSION:BKC combined with corneal perforation occurs mainly among young people with a long history of ocular discomfort.PKP,especially using a minimal graft,is an effective and safe option for treating the disease.
基金The authors gratefully acknowledge the financial support by the National Natural Science Foundation of China(No.52405272)the CNOOC’s major project during the 14th Five-Year Plan period“Key Technologies and Equipment for Measurement,Recording,and Testing-Development and Engineering of Integrated Perforation Technology Equipment Based on Reservoir Geology”and the National Science Foundation of Jiangsu Province(No.BK20220533).
文摘Hydraulic sandblasting perforation plays a crucial role in the fracturing and reconstruction of unconventional oil and gas reservoirs.The jet nozzle is an essential part of the hydraulic perforation tool.Insufficient penetration depth,caused by excessive jet distances,presents challenges during the perforation process.To overcome this,an optimization design of the nozzle structure is required to enhance the perforation efficiency.In this paper,a computational fluid-dynamic model for conical-cylindrical nozzles has been elaborated.To further improve the rock-breaking efficiency of the jet nozzle,a fillet design is introduced at the nozzle inlet section.The SST k-ωmodel is employed to account for turbulent flow effects in submerged conditions.The results indicate that the nozzle’s geometric parameters greatly influence the flow characteristics.The orthogonal experimental method is employed to optimize the flow channel structure of the nozzle,taking the length of constant velocity core as the evaluation index.The following optimized geometric parameters for the conical-cylindrical nozzle have been determined accordingly:a cylindrical segment diameter of 3.2 mm,a contraction angle of 12°,a contraction segment length of 8 mm,a cylindrical segment length of 6.4 mm,and a fillet radius of 2 mm.
基金support from the National Natural Science Foundation of China(No.12472072)the Fundamental Research Funds for the Central Universities,China.
文摘In this research,we introduce an innovative approach that combines the Continuum Damage Mechanics-Finite Element Method(CDM-FEM)with the Particle Swarm Optimization(PSO)-based technique,to predict the Medium-Low-Cycle Fatigue(MLCF)life of perforated structures.First,fatigue tests are carried out on three center-perforated structures,aiming to assess their fatigue life under various strengthening conditions.These tests reveal significant variations in fatigue life,accompanied by an examination of crack initiation through the analysis of fatigue fracture surfaces.Second,an innovative fatigue life prediction methodology is applied to perforated structures,which not only forecasts the initiation of fatigue cracks but also traces the progression of damage within these structures.It leverages an elastoplastic constitutive model integrated with damage and a damage evolution model under cyclic loads.The accuracy of this approach is validated by comparison with test results,falling within the three times error band.Finally,we explore the impact of various strengthening techniques,including cross-sectional reinforcement and cold expansion,on the fatigue life and damage evolution of these structures.This is achieved through an in-depth comparative analysis of both experimental data and computational predictions,which provides valuable insights into the behavior of perforated structures under fatigue conditions in practical applications.
文摘BACKGROUND Gastric ulcer perforation is a critical condition that can lead to significant morbidity and mortality if not promptly addressed.It is often the result of chronic peptic ulcer disease,which is characterized by a breach in the gastric wall due to ulceration.Surgical intervention is essential for managing this life-threatening complication.However,the optimal surgical technique remains debatable among clinicians.Various methods have been employed,including simple closure,omental patch repair,and partial gastrectomy,each with distinct advantages and disadvantages.Understanding the comparative efficacy and postoperative outcomes of these techniques is crucial for improving patient care and surgical decision-making.This study addresses the need for a comprehensive analysis in this area.AIM To compare the efficacy and postoperative complications of different surgical methods for the treatment of gastric ulcer perforation.METHODS A retrospective analysis was conducted on 120 patients who underwent surgery for gastric ulcer perforation between September 2020 and June 2023.The patients were divided into three groups based on the surgical method:Simple closure,omental patch repair,and partial gastrectomy.The primary outcomes were the operative success rate and incidence of postoperative complications.Secondary outcomes included the length of hospital stay,recovery time,and long-term quality of life.RESULTS The operative success rates for simple closure,omental patch repair,and partial gastrectomy were 92.5%,95%,and 97.5%,respectively.Postoperative complications occurred in 20%,15%,and 17.5%of patients in each group,respectively.The partial gastrectomy group showed a significantly longer operative time(P<0.001)but the lowest rate of ulcer recurrence(2.5%,P<0.05).The omental patch repair group demonstrated the shortest hospital stay(mean 7.2 days,P<0.05)and fastest recovery time.CONCLUSION While all three surgical methods showed high success rates,omental patch repair demonstrated the best overall outcomes,with a balance of high efficacy,low complication rates,and shorter recovery time.However,the choice of the surgical method should be tailored to individual patient factors and the surgeon’s expertise.
文摘Whipple shields as sacrificial bumpers,safeguard the satellites against extremely fast,different-sized projectiles traveling through space in the low earth orbit.Typical Whipple shields comprise a front and rear plate,separated by a gap or space.Recent advancements have explored the use of foam,cellular cores,and alternative materials such as ceramics instead of aluminium for the plates.In the current work,the effect of including fluid cores(air/water)sandwiched between the front and rear plates,on the response to hypervelocity impact was explored through a numerical approach.The numerical simulation consisted of hypervelocity impact by a 2 mm diameter,stainless steel projectile,launched at speeds of 3 e9 km/s with a normal impact trajectory towards the Whipple shield.The front and rear bumpers,made of AA6061-T6,were each 1 mm thick.A space of 10 mm was taken between the plates(occupied by fluid).The key metrics analyzed were the perforation characteristics,stages of the debris cloud generation and propagation,energy variations(internal,kinetic and plastic work),temperature variations,and the fragmentation summary.From the computational analysis,employing water-core in Whipple shields could prevent the rear bumper perforation till 6 km/s,lower the peak temperatures at the front bumper perforation zones and debris tip,and generate fewer,larger fragments.
基金Supported by Shaanxi Provincial Science and Technology Development Plan Project(No.2024SFYBXM-327).
文摘Dear Editor,We report two rare cases of ocular perforating injuries caused by acupuncture needles.Both cases were approved by the Ethics Committee of Xi’an People’s Hospital(Xi’an No.4 Hospital)(KJLL-Z-K-2023060).Written informed consents were obtained from the patients.Acupuncture is an integral part of traditional Chinese medicine,and is widely used for the treatment of systemic diseases and ophthalmologic diseases^([1-8]),such as paralysis caused by stroke^([4]),diabetes^([7]),dry eye disease^([8]),pigmentary degeneration of retina,macular degeneration,glaucoma,and optic atrophy^([6]).Improper acupuncture technique can lead to accidents.
文摘BACKGROUND Gastrointestinal(GI)perforation(GP)repair is a surgical procedure to promptly seal perforations in the GI tract to prevent further leakage.After surgery,patients often experience a high metabolic state due to trauma,infection,and posto-perative stress.In the Enhanced Recovery After Surgery(ERAS)protocol,early enteral nutrition is a key strategy for promoting postoperative recovery.Com-pared with parenteral nutrition,enteral nutrition more effectively meets the physiological needs of the GI system,promotes the recovery of gut function,and reduces the risk of GI infections.AIM To evaluate the clinical efficacy of early enteral nutrition support in patients undergoing GP repair within the ERAS protocol.METHODS This retrospective study analyzed 66 patients who underwent GP repair.Patients were divided into a control group(n=32),managed with a traditional nutritional regimen,primarily consisting of total parenteral nutrition;and an observation group(n=34),which included those who received early enteral nutrition support as part of the ERAS protocol.This study examined the time to first postoperative flatus and bowel movement,changes in nutritional and immune function,inflam-matory markers on postoperative days 1 and 5,and adverse reactions.RESULTS The observation group had significantly shorter times to the first postoperative flatus and bowel movement than the control group(P<0.05).On postoperative day 5,the observation group demonstrated higher nutritional and immune function levels than the control group(P<0.05),while C-reactive protein levels were significantly lower(P<0.05).The overall incidence of adverse reactions in the observation group was 8.82%(3/34),which was lower than the 28.13%(9/32)observed in the control group(P<0.05).CONCLUSION Early enteral nutritional support facilitates GI recovery after GP repair.It improves nutritional status,enhances immune function,and attenuates inflammatory responses while also demonstrating a favorable safety profile.
