During high-speed operation,mixed-flow pumps are susceptible to cavitation,which destabilizes the internal flow,increases energy losses,and degrades hydraulic efficiency.To assess the effectiveness of blade perforatio...During high-speed operation,mixed-flow pumps are susceptible to cavitation,which destabilizes the internal flow,increases energy losses,and degrades hydraulic efficiency.To assess the effectiveness of blade perforation as a cavitation-mitigation strategy,in this study several mixed-flow pump models incorporating perforations were developed.Numerical simulations were performed for configurations with circular holes positioned at different locations along the blade leading edge,and the computational results were validated against experimental measurements.The findings indicate that the location of the perforations plays a decisive role in cavitation suppression.Moving from the blade rim toward the hub along the leading edge,the critical net positive suction head,NPSH_(cr),initially decreases and subsequently increases,while remaining consistently lower than that of the reference non-perforated configuration.The perforations promote the transfer of high-pressure fluid from the pressure side to the suction side of the blade,thereby alleviating local low-pressure regions.This pressure compensation significantly reduces the extent of low-pressure zones in the vicinity of the perforations,leading to a marked suppression of cavitation both locally and downstream of the perforated regions.展开更多
An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc...An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.展开更多
BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limit...BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limited.AIM To evaluate surgical and survival outcomes of patients with perforated GC(PGC)according to the initial treatment strategy.METHODS A retrospective cohort study was conducted including all patients with pathologically confirmed perforated gastric adenocarcinoma treated at a single tertiary cancer center between January 2009 and March 2024.Surgical strategies were categorized as gastrectomy or primary perforation repair.Outcomes analyzed included 30-and 90-day mortality,postoperative major complications,and overall survival(OS).RESULTS Among 1586 GC patients undergoing surgical treatment,36(2.3%)presented with PGC.The mean age was 62.5 years,and 55%were male.American Society of Anesthesiologists(ASA)class III/IV was present in 58.3%,and 83%had stage IV disease,with distant metastasis in 50%.Perforation repair was performed in 26 patients(72.2%),while 10(27.8%)underwent one-stage gastrectomy.ASA III/IV status(57.7%vs 30%,P=0.260)and metastatic disease(57.7%vs 30%,P=0.137)were more frequent in the Perforation Repair Group,though not statistically significant.This group also had a higher rate of diffuse-type and poorly differentiated tumors(P=0.024 and P=0.014,respectively).Thirty-and 90-day mortality were higher in the Perforation Repair Group(61.5%vs 30%,P=0.139;and 65.4%vs 30%,P=0.073),without significance.Three patients initially repaired were later referred for gastrectomy.OS was significantly better in the Gastrectomy Group(P=0.002),with median survival of 8.8 months vs 0.5 months.On multivariable analysis,gastrectomy was independently associated with improved survival(P=0.026).CONCLUSION When clinically feasible,gastrectomy—either immediate or delayed—provides superior survival compared to local perforation repair alone in patients with PGC.展开更多
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 Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abd...BACKGROUND Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abdominal pain and peritoneal signs.By contrast,pneumoretroperitoneum and pneumomediastinum are rare complications and lack typical symptoms,making their diagnosis difficult and often delayed,leading to increased morbidity and mortality.CASE SUMMARY A 66-year-old man presented with lower abdominal pain for 3 days.On examination,his vital signs were stable,and the abdomen was soft with mild distension and left lower quadrant tenderness,but no peritoneal signs were noted.Laboratory tests indicated leukocytosis and a markedly elevated C-reactive protein level.Abdominal computed tomography(CT)revealed focal wall thickening and fat stranding near the rectosigmoid junction as well as pneumoretroperitoneum,pneumomediastinum,and minor pneumoperitoneum.Suspecting hollow organ perforation,an emergent exploratory laparotomy was performed which revealed a retroperitoneal abscess with mesocolonic necrosis,likely due to perforated sigmoid diverticulitis.The patient underwent sigmoid resection with Hartmann’s procedure and retroperitoneal drainage.Follow-up CT on postoperative day 14 confirmed resolution of the free air,and the patient was discharged on postoperative day 40 with an uneventful recovery.CONCLUSION Pneumoretroperitoneum and pneumomediastinum are rare complications of perforated diverticulitis,often with delayed diagnosis due to the absence of peritoneal signs.CT aids detection,and timely surgical intervention is crucial.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
Several issues should be considered before the surgical treatment of gastric ulcer perforations,including morbidity,mortality,and recurrence.However,an oftenoverlooked issue is determining the cause of the perforation...Several issues should be considered before the surgical treatment of gastric ulcer perforations,including morbidity,mortality,and recurrence.However,an oftenoverlooked issue is determining the cause of the perforation.When the perforation is secondary to an underlying and undiagnosed malignancy,stomach resection inadequately treats the oncological disease and may increase postoperative morbidity and require re-surgery.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
BACKGROUND Gastrointestinal tumors are among the most common and deadly cancers globally,with radiotherapy and bevacizumab being key treatment strategies.Radiotherapy uses high-energy radiation to target DNA,reducing ...BACKGROUND Gastrointestinal tumors are among the most common and deadly cancers globally,with radiotherapy and bevacizumab being key treatment strategies.Radiotherapy uses high-energy radiation to target DNA,reducing tumor size and alleviating symptoms.Bevacizumab,a targeted therapy,inhibits angiogenesis and tumor growth,particularly in advanced gastrointestinal cancers.However,both treatments can cause adverse gastrointestinal effects,such as intestinal mucosal damage and perforation.While research on the risk of intestinal perforation has grown,the underlying mechanisms remain underexplored.This study aims to compare the incidence of intestinal perforation and survival rates in patients treated with radiotherapy combined with bevacizumab vs bevacizumab alone.AIM To investigate the effect of radiotherapy on the risk of intestinal perforation in patients with colon cancer treated with bevacizumab.METHODS A total of 70 patients diagnosed with gastrointestinal malignancies admitted to our hospital from January 2023 to December 2024 were selected as research subjects.According to different treatment methods,70 patients were divided into the bevacizumab only group(receiving bevacizumab treatment)and the bevacizumab+radiotherapy group(receiving radiotherapy combined with bevacizumab treatment),with 35 cases in each group.The two groups were compared in terms of clinical efficacy,incidence of intestinal perforation,serum tumor marker levels,overall survival and progression-free survival,levels of angiogenic factors,and adverse reactions.RESULTS Compared with the group treated with bevacizumab alone,the group treated with bevacizumab plus radiotherapy showed significant improvements in effective rate,overall survival,and progression-free survival(P<0.05);the probability of intestinal perforation in the bevacizumab+radiotherapy group was 13.33%,while the probability of intestinal perforation in the bevacizumab group was 0.There was a statistically significant difference in the incidence of intestinal perforation between the two groups(P=0.039).Following treatment,the levels of carbohydrate antigen(CA)125,CA199,and CA153 in patients were significantly reduced(P<0.05).CONCLUSION Radiation therapy may increase the risk of intestinal perforation in colon cancer patients receiving bevacizumab treatment.In clinical applications,the risks of combined use of radiotherapy and bevacizumab should be fully considered and personalized treatment plans should be formulated.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 Patients who have undergone pancreaticoduodenectomy(Whipple procedure)often develop complex late complications that may be diagnostically challenging.We report a rare cause of recurrent fever and abdominal ...BACKGROUND Patients who have undergone pancreaticoduodenectomy(Whipple procedure)often develop complex late complications that may be diagnostically challenging.We report a rare cause of recurrent fever and abdominal pain in such a patient:Fish bone-induced jejunal perforation.This case emphasizes the importance of maintaining suspicion for atypical,non-biliary causes in post-Whipple patients with recurrent symptoms,particularly when conventional tests suggest no biliary obstruction.A thorough linear diagnostic approach and multidisciplinary collaboration are essential.The delay in diagnosis highlights the challenges of interpreting subtle imaging findings and correlating them with clinical symptoms mimicking cholangitis.CASE SUMMARY A 55-year-old female with a Whipple procedure history 10 years earlier presented with recurrent fever and severe abdominal pain.An initial extensive workup,including imaging and laboratory tests,was inconclusive.Only after detailed reevaluation of the computed tomography images revealed a subtle linear hyperdensity and subsequent deep push enteroscopy was an embedded fish bone in the efferent jejunal limb identified and removed endoscopically.CONCLUSION Clinicians should consider gastrointestinal foreign body perforation in the differential diagnosis of recurrent fever and abdominal pain in patients with altered anatomy after Whipple procedure.Critical image review and advanced enteroscopic techniques are invaluable for diagnosing obscure causes in complex cases.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
This study presents a theoretical analysis of the perforation process of finite-thickness metal plates(with a thickness ratio of T_0/D = 0.6–1.5) under normal impact by spherical-nosed projectiles. The model is valid...This study presents a theoretical analysis of the perforation process of finite-thickness metal plates(with a thickness ratio of T_0/D = 0.6–1.5) under normal impact by spherical-nosed projectiles. The model is validated over an impact velocity range of 180–1247 m/s. The entire penetration process is divided into three stages: the crater formation stage, the steady stage, and the shear stage. A thicknessdependent dynamic cavity expansion resistance model is first introduced to quantitatively describe the axial resistance experienced by the projectile during the tip-entry and steady stages. Subsequently, a thickness-related damage parameter is proposed to refine the resistance expression during the transition from the steady stage to the shear stage, thereby eliminating discontinuities in resistance across stages. When the projectile fully perforates the target, the model predicts a gradual decay of resistance to zero as the residual ligament thickness vanishes, which better reflects the actual physical behavior. The model is validated using four sets of experimental conditions. In addition, to illustrate the model's applicability more intuitively, a numerical simulation case from the literature is reproduced, and the resulting resistance-time curve is compared with the model output. The results demonstrate that the proposed model agrees well with experimental data in terms of residual velocity, ballistic limit, and penetration resistance. Finally, a method for adjusting the threshold parameter within the resistance function is provided, and the influence of this coefficient on the model predictions is discussed.展开更多
基金the National Key Research and Development Project of China(No.2019YFB 2005300)the Natural Science Foundation of Jiangsu Province(No.BK20220609)the National Natural Science Foundation of China(Grant Nos.52109106,52409122,and 12272187).
文摘During high-speed operation,mixed-flow pumps are susceptible to cavitation,which destabilizes the internal flow,increases energy losses,and degrades hydraulic efficiency.To assess the effectiveness of blade perforation as a cavitation-mitigation strategy,in this study several mixed-flow pump models incorporating perforations were developed.Numerical simulations were performed for configurations with circular holes positioned at different locations along the blade leading edge,and the computational results were validated against experimental measurements.The findings indicate that the location of the perforations plays a decisive role in cavitation suppression.Moving from the blade rim toward the hub along the leading edge,the critical net positive suction head,NPSH_(cr),initially decreases and subsequently increases,while remaining consistently lower than that of the reference non-perforated configuration.The perforations promote the transfer of high-pressure fluid from the pressure side to the suction side of the blade,thereby alleviating local low-pressure regions.This pressure compensation significantly reduces the extent of low-pressure zones in the vicinity of the perforations,leading to a marked suppression of cavitation both locally and downstream of the perforated regions.
基金Open access funding provided by FCT|FCCN(b-on)the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020.
文摘An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.
文摘BACKGROUND Perforated gastric cancer(GC)is a rare but life-threatening surgical emergency.Optimal surgical management remains controversial,and evidence from highvolume centers,especially in Western countries,is limited.AIM To evaluate surgical and survival outcomes of patients with perforated GC(PGC)according to the initial treatment strategy.METHODS A retrospective cohort study was conducted including all patients with pathologically confirmed perforated gastric adenocarcinoma treated at a single tertiary cancer center between January 2009 and March 2024.Surgical strategies were categorized as gastrectomy or primary perforation repair.Outcomes analyzed included 30-and 90-day mortality,postoperative major complications,and overall survival(OS).RESULTS Among 1586 GC patients undergoing surgical treatment,36(2.3%)presented with PGC.The mean age was 62.5 years,and 55%were male.American Society of Anesthesiologists(ASA)class III/IV was present in 58.3%,and 83%had stage IV disease,with distant metastasis in 50%.Perforation repair was performed in 26 patients(72.2%),while 10(27.8%)underwent one-stage gastrectomy.ASA III/IV status(57.7%vs 30%,P=0.260)and metastatic disease(57.7%vs 30%,P=0.137)were more frequent in the Perforation Repair Group,though not statistically significant.This group also had a higher rate of diffuse-type and poorly differentiated tumors(P=0.024 and P=0.014,respectively).Thirty-and 90-day mortality were higher in the Perforation Repair Group(61.5%vs 30%,P=0.139;and 65.4%vs 30%,P=0.073),without significance.Three patients initially repaired were later referred for gastrectomy.OS was significantly better in the Gastrectomy Group(P=0.002),with median survival of 8.8 months vs 0.5 months.On multivariable analysis,gastrectomy was independently associated with improved survival(P=0.026).CONCLUSION When clinically feasible,gastrectomy—either immediate or delayed—provides superior survival compared to local perforation repair alone in patients with PGC.
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.
文摘BACKGROUND Complications occur in approximately 12%of cases of diverticulitis,with perforation occurring in up to 10%of complications.Typically,patient with perforated diverticulitis present intraperitoneally with abdominal pain and peritoneal signs.By contrast,pneumoretroperitoneum and pneumomediastinum are rare complications and lack typical symptoms,making their diagnosis difficult and often delayed,leading to increased morbidity and mortality.CASE SUMMARY A 66-year-old man presented with lower abdominal pain for 3 days.On examination,his vital signs were stable,and the abdomen was soft with mild distension and left lower quadrant tenderness,but no peritoneal signs were noted.Laboratory tests indicated leukocytosis and a markedly elevated C-reactive protein level.Abdominal computed tomography(CT)revealed focal wall thickening and fat stranding near the rectosigmoid junction as well as pneumoretroperitoneum,pneumomediastinum,and minor pneumoperitoneum.Suspecting hollow organ perforation,an emergent exploratory laparotomy was performed which revealed a retroperitoneal abscess with mesocolonic necrosis,likely due to perforated sigmoid diverticulitis.The patient underwent sigmoid resection with Hartmann’s procedure and retroperitoneal drainage.Follow-up CT on postoperative day 14 confirmed resolution of the free air,and the patient was discharged on postoperative day 40 with an uneventful recovery.CONCLUSION Pneumoretroperitoneum and pneumomediastinum are rare complications of perforated diverticulitis,often with delayed diagnosis due to the absence of peritoneal signs.CT aids detection,and timely surgical intervention is crucial.
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Several issues should be considered before the surgical treatment of gastric ulcer perforations,including morbidity,mortality,and recurrence.However,an oftenoverlooked issue is determining the cause of the perforation.When the perforation is secondary to an underlying and undiagnosed malignancy,stomach resection inadequately treats the oncological disease and may increase postoperative morbidity and require re-surgery.
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.
文摘BACKGROUND Gastrointestinal tumors are among the most common and deadly cancers globally,with radiotherapy and bevacizumab being key treatment strategies.Radiotherapy uses high-energy radiation to target DNA,reducing tumor size and alleviating symptoms.Bevacizumab,a targeted therapy,inhibits angiogenesis and tumor growth,particularly in advanced gastrointestinal cancers.However,both treatments can cause adverse gastrointestinal effects,such as intestinal mucosal damage and perforation.While research on the risk of intestinal perforation has grown,the underlying mechanisms remain underexplored.This study aims to compare the incidence of intestinal perforation and survival rates in patients treated with radiotherapy combined with bevacizumab vs bevacizumab alone.AIM To investigate the effect of radiotherapy on the risk of intestinal perforation in patients with colon cancer treated with bevacizumab.METHODS A total of 70 patients diagnosed with gastrointestinal malignancies admitted to our hospital from January 2023 to December 2024 were selected as research subjects.According to different treatment methods,70 patients were divided into the bevacizumab only group(receiving bevacizumab treatment)and the bevacizumab+radiotherapy group(receiving radiotherapy combined with bevacizumab treatment),with 35 cases in each group.The two groups were compared in terms of clinical efficacy,incidence of intestinal perforation,serum tumor marker levels,overall survival and progression-free survival,levels of angiogenic factors,and adverse reactions.RESULTS Compared with the group treated with bevacizumab alone,the group treated with bevacizumab plus radiotherapy showed significant improvements in effective rate,overall survival,and progression-free survival(P<0.05);the probability of intestinal perforation in the bevacizumab+radiotherapy group was 13.33%,while the probability of intestinal perforation in the bevacizumab group was 0.There was a statistically significant difference in the incidence of intestinal perforation between the two groups(P=0.039).Following treatment,the levels of carbohydrate antigen(CA)125,CA199,and CA153 in patients were significantly reduced(P<0.05).CONCLUSION Radiation therapy may increase the risk of intestinal perforation in colon cancer patients receiving bevacizumab treatment.In clinical applications,the risks of combined use of radiotherapy and bevacizumab should be fully considered and personalized treatment plans should be formulated.
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 Patients who have undergone pancreaticoduodenectomy(Whipple procedure)often develop complex late complications that may be diagnostically challenging.We report a rare cause of recurrent fever and abdominal pain in such a patient:Fish bone-induced jejunal perforation.This case emphasizes the importance of maintaining suspicion for atypical,non-biliary causes in post-Whipple patients with recurrent symptoms,particularly when conventional tests suggest no biliary obstruction.A thorough linear diagnostic approach and multidisciplinary collaboration are essential.The delay in diagnosis highlights the challenges of interpreting subtle imaging findings and correlating them with clinical symptoms mimicking cholangitis.CASE SUMMARY A 55-year-old female with a Whipple procedure history 10 years earlier presented with recurrent fever and severe abdominal pain.An initial extensive workup,including imaging and laboratory tests,was inconclusive.Only after detailed reevaluation of the computed tomography images revealed a subtle linear hyperdensity and subsequent deep push enteroscopy was an embedded fish bone in the efferent jejunal limb identified and removed endoscopically.CONCLUSION Clinicians should consider gastrointestinal foreign body perforation in the differential diagnosis of recurrent fever and abdominal pain in patients with altered anatomy after Whipple procedure.Critical image review and advanced enteroscopic techniques are invaluable for diagnosing obscure causes in complex cases.
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 (Grant Nos.U2341244,12172179,11772160)。
文摘This study presents a theoretical analysis of the perforation process of finite-thickness metal plates(with a thickness ratio of T_0/D = 0.6–1.5) under normal impact by spherical-nosed projectiles. The model is validated over an impact velocity range of 180–1247 m/s. The entire penetration process is divided into three stages: the crater formation stage, the steady stage, and the shear stage. A thicknessdependent dynamic cavity expansion resistance model is first introduced to quantitatively describe the axial resistance experienced by the projectile during the tip-entry and steady stages. Subsequently, a thickness-related damage parameter is proposed to refine the resistance expression during the transition from the steady stage to the shear stage, thereby eliminating discontinuities in resistance across stages. When the projectile fully perforates the target, the model predicts a gradual decay of resistance to zero as the residual ligament thickness vanishes, which better reflects the actual physical behavior. The model is validated using four sets of experimental conditions. In addition, to illustrate the model's applicability more intuitively, a numerical simulation case from the literature is reproduced, and the resulting resistance-time curve is compared with the model output. The results demonstrate that the proposed model agrees well with experimental data in terms of residual velocity, ballistic limit, and penetration resistance. Finally, a method for adjusting the threshold parameter within the resistance function is provided, and the influence of this coefficient on the model predictions is discussed.
