BACKGROUND Ependymoma with lipomatous differentiation is a rare type of ependymoma.The ZFTA fusion-positive supratentorial ependymoma is a novel tumor type in the 2021 World Health Organization classification of centr...BACKGROUND Ependymoma with lipomatous differentiation is a rare type of ependymoma.The ZFTA fusion-positive supratentorial ependymoma is a novel tumor type in the 2021 World Health Organization classification of central nervous system tumors.ZFTA fusion-positive lipomatous ependymoma has not been reported to date.CASE SUMMARY We reported a case of a 15-year-old Chinese male who had a sudden convulsion lasting approximately six minutes.Magnetic resonance imaging showed a round cystic shadow of approximately 1.9 cm×1.5 cm×1.9 cm under the right parieto-occipital cortex.Microscopic examination showed characteristic perivascular pseudorosettes and adipose differentiation in the cytoplasm.Immunohisto-chemical staining showed that the tumor cells were negative for cytokeratin,NeuN,Syn and p53,but positive for GFAP,vimentin and S-100 protein.Signi-ficant punctate intracytoplasmic EMA immunoreactivity was observed.The level of Ki-67 was about 5%.Genetic analysis revealed ZFTA:RELA fusion.A cranio-tomy with total excision of the tumor was performed.The follow-up time was 36 months,no evidence of disease recurrence was found in magnetic resonance imaging.CONCLUSION Based on these findings,the patient was diagnosed as a ependymoma with ZFTA fusion and lipomatous differentiation.This case report provides information on the microscopic morphological features of ependymoma with ZFTA fusion and lipomatous differentiation,which can help pathologists to make a definitive diagnosis of this tumor.展开更多
BACKGROUND Wilson's disease(WD)is a rare metabolic disorder of copper accumulation in organs such as liver,brain,and cornea.Diagnoses and treatments are challenging in settings,where advanced diagnostic tests are ...BACKGROUND Wilson's disease(WD)is a rare metabolic disorder of copper accumulation in organs such as liver,brain,and cornea.Diagnoses and treatments are challenging in settings,where advanced diagnostic tests are unavailable,copper chelating agents are frequently scarce,healthcare professionals lack disease awareness,and medical follow-ups are limited.Prompt diagnoses and treatments help prevent complications,improve patients’quality of life,and ensure a normal life expectancy.The clinical presentations and outcomes of WD can vary within a single family.CASE SUMMARY We present the cases of two siblings(19 and 27 years)from a consanguineous family in rural Ecuador,diagnosed as having WD during a family screening.The male patient,diagnosed at age 19 after his brother’s death from acute liver failure,presented with compensated cirrhosis,neurological symptoms,and bilateral Kayser-Fleischer rings.He developed progressive neurological deterioration during an irregular treatment with D-penicillamine due to medication shortages.His condition improved upon switching to trientine tetrahydrochloride,and his neurological symptoms improved over an 8-year period of follow-ups.The female patient,diagnosed at age 10,exhibited only biochemical alterations.Her treatment history was similar;however,she remained asymptomatic without disease progression over the same follow-up period.We discuss the potential influence of epigenetic mechanisms and modifier genes on the various phenotypes,emphasizing the need for research in these areas to optimize therapeutic strategies.CONCLUSION Our patients’medical histories show how early diagnosis and treatment can prevent disease progression;and,how suboptimal treatments impact disease outcomes.展开更多
BACKGROUND Acquired hemophilia A (AHA) is a rare and potentially severe bleeding disordercaused by circulating autoantibodies against factor Ⅷ (FⅧ). In approximately50% of the patients, the condition is associated w...BACKGROUND Acquired hemophilia A (AHA) is a rare and potentially severe bleeding disordercaused by circulating autoantibodies against factor Ⅷ (FⅧ). In approximately50% of the patients, the condition is associated with autoimmune diseases,cancers, medication use, pregnancy, and the post-partum period. Bullous pemphigoid(BP) is a chronic autoimmune subepidermal blistering disease associatedwith tissue-bound and circulating autoantibodies against BP antigens 180 (BP180)and 230 (BP230). AHA-associated BP has a high mortality rate;hence, the understandingof this disease must improve.CASE SUMMARY A 69-year-old man presented with erythema, blisters, blood blisters, and crustsaccompanied by severe pruritus for more than 20 days, and ecchymosis andswelling on his left upper arm for 3 days. Pathological examination revealed asubepidermal blister that contained eosinophils. Laboratory tests showed that theBP180 autoantibody levels had increased, isolated activated partial thromboplastintime was notably prolonged (115.6 s), and coagulation FⅧ activity wasextremely low (< 1.0%). Furthermore, the FⅧ inhibitor titer had greatlyincreased (59.2 Bethesda units). Therefore, the patient was diagnosed as having BP associated with AHA, prescribed 0.05% topical halometasone cream, and transferred to a higher-level hospitalfor effective treatment;however, he died after 2 days.CONCLUSION AHA associated BP is rare, dangerous, and has a high mortality rate. Therefore, its timely diagnosis and effectivetreatment are necessary.展开更多
BACKGROUND Extramedullary plasmacytoma(EMP)represents one of the rarer forms of plasma cell malignancies,capable of impacting a variety of tissues and organs throughout the body.The majority of EMP cases are predomina...BACKGROUND Extramedullary plasmacytoma(EMP)represents one of the rarer forms of plasma cell malignancies,capable of impacting a variety of tissues and organs throughout the body.The majority of EMP cases are predominantly found in the head and neck region,especially within the laryngopharynx,as well as in the gastrointestinal tract.While there have been documented instances of oropharyngeal involvement in EMP cases in the academic literature,it is important to note that EMP specifically affecting the uvula is exceedingly uncommon.Furthermore,it is noteworthy that over 60% of epithelial carcinomas in the upper respiratory tract and oropharynx tend to metastasize to the cervical lymph nodes,indicating a propensity for regional spread in these types of cancers.In this context,we present a rare case of extramedullary plasmacytoma where the uvula served as the initially affected site.This case emphasizes the need for heightened awareness among clinicians regarding such unusual comorbidities,as early recognition and diagnosis can significantly influence patient management and treatment outcomes.In addition,a review of the relevant literature is included to further educate and inform healthcare professionals about this rare presentation,ultimately aiming to enhance clinical understanding and improve patient care in similar situations.CASE SUMMARY A 51-year-old man was admitted to our hospital because of a slowly enlarging neck mass.A physical examination revealed a palpable left lymph node,and magnetic resonance imaging(MRI)of the oropharynx and the neck showed a soft tissue mass in the oropharynx and enlargement of multiple lymph nodes in the neck.The soft tissue mass was diagnosed as plasmacytoma by immunohistochemical analysis.Monoclonal immunoglobulins and bone marrow biopsy showed normal results.Therefore,we diagnosed that as EMP of the uvula.After four cycles of adjuvant chemotherapy dominated by bortezomib,MRI reexamination showed a significant reduction of the mass in the oropharynx and the cervical lymph nodes.Afterwards,the λ light chain returned to normal levels.There was no evidence of evolution to multiple myeloma.CONCLUSION We have reported a rare case of extramedullary plasmacytoma with the uvula as the first affected site and the relevant literature is reviewed to improve clinicians'awareness of such rare comorbidities.展开更多
BACKGROUND Autologous fat injection in facial reconstruction is a common cosmetic surgery.Although cerebral fat embolism(CFE)as a complication is rare,it carries serious health risks.CASE SUMMARY We present a case of ...BACKGROUND Autologous fat injection in facial reconstruction is a common cosmetic surgery.Although cerebral fat embolism(CFE)as a complication is rare,it carries serious health risks.CASE SUMMARY We present a case of a 29-year-old female patient who developed acute CFE following facial fat filling surgery.After the surgery,the patient experienced symptoms including headache,nausea,vomiting,and difficulty breathing,which was followed by neurological symptoms such as slurred speech and left-sided weakness.Comprehensive physical examination and auxiliary investigations,including blood tests,head and neck computed tomography angiography,and cranial magnetic resonance diffusion-weighted imaging,were performed upon admission.The clinical diagnosis was acute cerebral embolism following facial fat filling surgery.Treatment included measures to improve cerebral circulation,dehydration for intracranial pressure reduction,nutritional support,and rehabilitation therapy for left limb function.The patient showed a significant improvement in symptoms after 2 weeks of treatment.She recovered left limb muscle strength to grade 5,had clear speech,and experienced complete relief of headache.CONCLUSION Our case highlights the potential occurrence of severe complications in patients undergoing fat injection in facial reconstruction.To prevent these complications,plastic surgeons should enhance their professional knowledge and skills.展开更多
BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resol...BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resolve,several treatment options have been suggested for this condition.CASE SUMMARY In this paper,we report a case of corticosteroid injection induced lipoatrophy treated with autologous whole blood(AWB)injection,as the condition had been unresponsive to fractional laser therapy.A 29-year-old female patient visited the dermatology clinic complaining of skin depression on her right buttock area,which had appeared six months earlier.There had been only subtle improvement at the margins after fractional CO2 laser treatment;therefore,after obtaining informed consent from the patient,AWB treatment was initiated.One month after the first AWB injection,the size and depth of the lesion had noticeably improved,and a slight improvement was also observed in discoloration.CONCLUSION Close observation is the initial treatment of choice for steroid induced skin atrophy;however,for patients in need of immediate cosmetic improvement,AWB injection may be a safe and cost-effective alternative.展开更多
BACKGROUND Primary squamous cell carcinoma(SCC)of the renal parenchyma is extremely rare,with only nine cases reported.CASE SUMMARY This study reports a 51-year-old man with primary SCC of the renal parenchyma.The pat...BACKGROUND Primary squamous cell carcinoma(SCC)of the renal parenchyma is extremely rare,with only nine cases reported.CASE SUMMARY This study reports a 51-year-old man with primary SCC of the renal parenchyma.The patient was admitted with recurrent dull pain and discomfort in the right lumbar region,which had worsened over 2 weeks,accompanied by painful gross hematuria.SCC antigen(SCCA)levels were elevated,and imaging revealed a renal mass with associated calculi.The patient underwent laparoscopic unilateral nephrectomy and lymph node dissection.Postoperative pathology confirmed highly differentiated SCC with necrosis in the right renal parenchyma,with negative renal pelvis and ureter.The pathological stage was Pt3aN1M0.Four months after surgery,the tumor recurred with involvement of the liver,right psoas major muscle,and inferior vena cava.The patient refused chemotherapy and succumbed to the disease 6 months postoperatively due to disease progression.CONCLUSION We report a case of primary SCC of the renal parenchyma,a rare renal malignancy.The clinical symptoms,laboratory tests,and imaging findings are nonspecific,making accurate and timely diagnosis challenging.According to the literature,for patients with renal calculi accompanied by a renal mass,elevated serum SCCA levels,and magnetic resonance imaging showing cystic or cystic-solid masses within the kidney with pseudocapsules and heterogeneous mild enhancement,the possibility of this disease should be considered.展开更多
BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and te...BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in theliterature.CASE SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical level.After the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival overgrowth.Cone-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival overgrowth.CONCLUSION This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.展开更多
BACKGROUND The classification of uterine sarcomas is based on distinctive morphological and immunophenotypic characteristics,increasingly supported by molecular genetic diagnostics.Data on neurotrophic tyrosine recept...BACKGROUND The classification of uterine sarcomas is based on distinctive morphological and immunophenotypic characteristics,increasingly supported by molecular genetic diagnostics.Data on neurotrophic tyrosine receptor kinase(NTRK)gene fusionpositive uterine sarcoma,potentially aggressive and morphologically similar to fibrosarcoma,are limited due to its recent recognition.Pan-TRK immunohistochemistry(IHC)analysis serves as an effective screening tool with high sensitivity and specificity for NTRK-fusion malignancies.CASE SUMMARY We report a case of a malignant mesenchymal tumor originating from the uterine cervix,which was pan-TRK IHC-positive but lacked NTRK gene fusions,accompanied by a brief literature review.A 55-year-old woman presented to the emergency department with abdominal pain and distension,exhibiting significant ascites and multiple solid pelvic masses.Pelvic examination revealed a tumor encompassing the uterine cervix,extending to the vagina and uterine corpus.A punch biopsy of the cervix indicated NTRK sarcoma with positive immunochemical pan-TRK stain.However,subsequent next generation sequencing revealed no NTRK gene fusion,leading to a diagnosis of poorly differentiated,advanced-stage sarcoma.CONCLUSION The clinical significance of NTRK gene fusion lies in potential treatment with TRK inhibitors for positive sarcomas.Identifying such rare tumors is crucial due to the potential applicability of tropomyosin receptor kinase inhibitor treatment.展开更多
BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular ...BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular free wall rupture(FWR)occurs in approximately 2%of AMI patients and is notably rare in patients with non-STEMI.Types of cardiac rupture include left ventricular FWR,ventricular septal rupture,and papillary muscle rupture.The FWR usually leads to acute cardiac tamponade or electromechanical dissociation,where standard resuscitation efforts may not be effective.Ventricular septal rupture and papillary muscle rupture often result in refractory heart failure,with mortality rates over 50%,even with surgical or percutaneous repair options.CASE SUMMARY We present a rare case of an acute non-STEMI patient who suffered sudden FWR causing cardiac tamponade and loss of consciousness immediate before undergoing coronary angiography.Prompt resuscitation and emergency open-heart repair along with coronary artery bypass grafting resulted in successful patient recovery.CONCLUSION This case emphasizes the risks of AMI complications,shares a successful treatment scenario,and discusses measures to prevent such complications.展开更多
BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a ...BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a case in which CCRT had a reduction effect preoperatively.A 73-year-old woman with pyelonephritis was referred to our hospital.Computed tomography revealed right hydronephrosis and a 6-cm pelvic mass.Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB)revealed squamous cell carci-noma.The patient was diagnosed with MT of MCT.Due to her poor general con-dition and renal malfunction,we selected CCRT,expecting fewer adverse effects.After CCRT,her performance status improved,and the tumor size was reduced;surgery was performed.Five months postoperatively,the patient developed dis-semination and lymph node metastases.Palliative chemotherapy was ineffective.She died 18 months after treatment initiation.CONCLUSION EUS-FNB was useful in the diagnosis of MT of MCT;CCRT suppressed the disea-se and improved quality of life.展开更多
BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of t...BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of the flexor pollicis longus(FPL)at the musculotendinous junction.Possible treatments include direct tendon suture or tendon transfer,most commonly from the ring finger.To optimize function and avoid donor finger complications,we performed thumb replantation with flexion restoration using brachioradialis(BR)tendon transfer with palmaris longus(PL)tendon graft.CASE SUMMARY A 20-year-old left-handed male was admitted for a complete traumatic left thumb amputation following an accident while sliding from the top of a handrail.The patient presented with skin and bone avulsion at the MCP I,avulsion of the FPL tendon at the musculotendinous junction(zone 5),avulsion of the extensor pollicis longus tendon(zone T3),and avulsion of the thumb’s collateral arteries and nerves.The patient was treated with two stage thumb repair.The first intervention consisted of thumb replantation with MCP I arthrodesis,resection of avulsed FPL tendon and implantation of a silicone tendon prosthesis.The second intervention consisted of PL tendon graft and BR tendon transfer.Follow-up at 10 months showed good outcomes with active interphalangeal flexion of 70°,grip strength of 45 kg,key pinch strength of 15 kg and two-point discrimination threshold of 4 mm.CONCLUSION Flexion restoration after complete thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.展开更多
A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules...A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.展开更多
This study presents an analytical solution of thermal and mechanical displacements, strains, and stresses for a thick-walled rotating spherical pressure vessel made of functionally graded materials (FGMs). The pressur...This study presents an analytical solution of thermal and mechanical displacements, strains, and stresses for a thick-walled rotating spherical pressure vessel made of functionally graded materials (FGMs). The pressure vessel is subject to axisymmetric mechanical and thermal loadings within a uniform magnetic field. The material properties of the FGM are considered as the power-law distribution along the thickness. Navier’s equation, which is a second-order ordinary differential equation, is derived from the mechanical equilibrium equation with the consideration of the thermal stresses and the Lorentz force resulting from the magnetic field. The distributions of the displacement, strains, and stresses are determined by the exact solution to Navier’s equation. Numerical results clarify the influence of the thermal loading, magnetic field, non-homogeneity constant, internal pressure, and angular velocity on the magneto-thermo-elastic response of the functionally graded spherical vessel. It is observed that these parameters have remarkable effects on the distributions of radial displacement, radial and circumferential strains, and radial and circumferential stresses.展开更多
The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common...The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.展开更多
Plastic limit load of viscoplastic thick-walled cylinder and spherical shell subjected to internal pressure is investigated analytically using a strain gradient plasticity theory. As a result, the current solutions ca...Plastic limit load of viscoplastic thick-walled cylinder and spherical shell subjected to internal pressure is investigated analytically using a strain gradient plasticity theory. As a result, the current solutions can capture the size effect at the micron scale. Numerical results show that the smaller the inner radius of the cylinder or spherical shell, the more significant the scale effects. Results also show that the size effect is more evident with increasing strain or strain-rate sensitivity index. The classical plastic-based solutions of the same problems are shown to be a special case of the present solution.展开更多
Cooling strength is one of the important factors affecting microstructure and properties of gas cylinders during quenching process,and reasonable water spray volume can effectively improve the quality of gas cylinders...Cooling strength is one of the important factors affecting microstructure and properties of gas cylinders during quenching process,and reasonable water spray volume can effectively improve the quality of gas cylinders and reduce production costs.To find the optimal water spray parameters,a fluid-solid coupling model with three-phase flow was established in consideration of water-vapor conversion.The inner and outer walls of gas cylinder with the dimensions of d914 mm×38 mm×12000 mm were quenched using multi-nozzle water spray system.The internal pressure,average heat transfer coefficient(have)and stress of the gas cylinder under different water spray volumes during quenching process were studied.Finally,the mathematical model was experimentally verified.The results show that both the internal pressure and have increase along with the increase of spray volume.The internal pressure increases slowly first and then rapidly,but have increases rapidly first and then slowly.To satisfy hardenability of gas cylinders,the minimum spray volume should not be less than 40 m^3/(h·m).The results of stress indicate that water spray quenching will not cause deformation of bottle body in the range of water volume from 40 to 290 m^3/(h·m).展开更多
We suppose that in order to maintain high accuracy of holes and to lower residual stresses after cold expansion of thick-walled cylinders, which undergo cross-section plastic deformation, it is necessary to perform ax...We suppose that in order to maintain high accuracy of holes and to lower residual stresses after cold expansion of thick-walled cylinders, which undergo cross-section plastic deformation, it is necessary to perform axial plastic compression and subsequent cold expansion with small interferences. To test this hypothesis, we studied hoop, radial and axial residual stresses in cylinders made of carbon steel AISI 1050 with hole diameter of 5 mm, outer diameter of 15 mm and length of 30 mm by Sachs method as well as accuracy of expanded holes. It is found that double cold expansion with total interference equal to 5.1% generates hoop residual stresses with largest absolute value equal to 284 MPa and ensures high holes accuracy(IT7). After plastic compression with strain equal to 0.5 and 1% the mentioned stresses reduced to 120 and 75 MPa respectively,and accuracy of the holes reduced as well. Subsequent cold expansion with small interference equal to 0.9% helps to restore holes accuracy(IT7)gained by double cold expansion and ensure that absolute value of hoop residual stresses(177 MPa) is lower compared to double cold expansion.展开更多
At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consistof sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite.These fo...At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consistof sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite.These formations are being encountered when drilling boreholes to the depth of up to 2 0 0 m. To studythe behaviour of these materials, thick-walled hollow cylinder (TWHC) and solid cylindrical syntheticspecimens were designed and prepared by adding Portland cement and water to sand grains. The effectsof different parameters such as water and cement contents, grain size distribution and mixture curingtime on the characteristics of the samples were studied to identify the mixture closely resembling theformation at the drilling site. The Hoek triaxia! cell was modified to allow the visual monitoring of graindebonding and borehole breakout processes during the laboratory tests. The results showed the significanceof real-time visual monitoring in determining the initiation of the borehole breakout. The sizescaleeffect study on TWHC specimens revealed that with the increasing borehole size, the ductility ofthe specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged.Under different confining pressures the lateral strain at the initiation point of boreholebreakout is considerably lower in a larger size borehole (2 0 mm) compared to that in a smaller one(10 mm). Also, it was observed that the level of peak strength increment in TWHC specimens decreaseswith the increasing confining pressure.展开更多
In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material const...In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material constants as some specific function forms displayed in pre-studies, we firstly give the volume fractions of different constituents of the functionally graded material(FGM) cylinder and then determine the expressions of the material constants. With the use of the Voigt method, the corresponding analytical solutions of displacements in the radial direction, the strain and stress components, and the perturbation magnetic field vector are derived. In the numerical part, the effects of the volume fraction on the displacement, strain and stress components, and the magnetic perturbation field vector are investigated. Moreover, by some appropriate choices of the material constants, we find that the obtained results in this paper can reduce to some special cases given in the previous studies.展开更多
文摘BACKGROUND Ependymoma with lipomatous differentiation is a rare type of ependymoma.The ZFTA fusion-positive supratentorial ependymoma is a novel tumor type in the 2021 World Health Organization classification of central nervous system tumors.ZFTA fusion-positive lipomatous ependymoma has not been reported to date.CASE SUMMARY We reported a case of a 15-year-old Chinese male who had a sudden convulsion lasting approximately six minutes.Magnetic resonance imaging showed a round cystic shadow of approximately 1.9 cm×1.5 cm×1.9 cm under the right parieto-occipital cortex.Microscopic examination showed characteristic perivascular pseudorosettes and adipose differentiation in the cytoplasm.Immunohisto-chemical staining showed that the tumor cells were negative for cytokeratin,NeuN,Syn and p53,but positive for GFAP,vimentin and S-100 protein.Signi-ficant punctate intracytoplasmic EMA immunoreactivity was observed.The level of Ki-67 was about 5%.Genetic analysis revealed ZFTA:RELA fusion.A cranio-tomy with total excision of the tumor was performed.The follow-up time was 36 months,no evidence of disease recurrence was found in magnetic resonance imaging.CONCLUSION Based on these findings,the patient was diagnosed as a ependymoma with ZFTA fusion and lipomatous differentiation.This case report provides information on the microscopic morphological features of ependymoma with ZFTA fusion and lipomatous differentiation,which can help pathologists to make a definitive diagnosis of this tumor.
文摘BACKGROUND Wilson's disease(WD)is a rare metabolic disorder of copper accumulation in organs such as liver,brain,and cornea.Diagnoses and treatments are challenging in settings,where advanced diagnostic tests are unavailable,copper chelating agents are frequently scarce,healthcare professionals lack disease awareness,and medical follow-ups are limited.Prompt diagnoses and treatments help prevent complications,improve patients’quality of life,and ensure a normal life expectancy.The clinical presentations and outcomes of WD can vary within a single family.CASE SUMMARY We present the cases of two siblings(19 and 27 years)from a consanguineous family in rural Ecuador,diagnosed as having WD during a family screening.The male patient,diagnosed at age 19 after his brother’s death from acute liver failure,presented with compensated cirrhosis,neurological symptoms,and bilateral Kayser-Fleischer rings.He developed progressive neurological deterioration during an irregular treatment with D-penicillamine due to medication shortages.His condition improved upon switching to trientine tetrahydrochloride,and his neurological symptoms improved over an 8-year period of follow-ups.The female patient,diagnosed at age 10,exhibited only biochemical alterations.Her treatment history was similar;however,she remained asymptomatic without disease progression over the same follow-up period.We discuss the potential influence of epigenetic mechanisms and modifier genes on the various phenotypes,emphasizing the need for research in these areas to optimize therapeutic strategies.CONCLUSION Our patients’medical histories show how early diagnosis and treatment can prevent disease progression;and,how suboptimal treatments impact disease outcomes.
基金Supported by Traditional Chinese Medicine Research Program of Hebei Provincial Administration of Traditional Chinese Medicine,No.2025313 and No.2025448.
文摘BACKGROUND Acquired hemophilia A (AHA) is a rare and potentially severe bleeding disordercaused by circulating autoantibodies against factor Ⅷ (FⅧ). In approximately50% of the patients, the condition is associated with autoimmune diseases,cancers, medication use, pregnancy, and the post-partum period. Bullous pemphigoid(BP) is a chronic autoimmune subepidermal blistering disease associatedwith tissue-bound and circulating autoantibodies against BP antigens 180 (BP180)and 230 (BP230). AHA-associated BP has a high mortality rate;hence, the understandingof this disease must improve.CASE SUMMARY A 69-year-old man presented with erythema, blisters, blood blisters, and crustsaccompanied by severe pruritus for more than 20 days, and ecchymosis andswelling on his left upper arm for 3 days. Pathological examination revealed asubepidermal blister that contained eosinophils. Laboratory tests showed that theBP180 autoantibody levels had increased, isolated activated partial thromboplastintime was notably prolonged (115.6 s), and coagulation FⅧ activity wasextremely low (< 1.0%). Furthermore, the FⅧ inhibitor titer had greatlyincreased (59.2 Bethesda units). Therefore, the patient was diagnosed as having BP associated with AHA, prescribed 0.05% topical halometasone cream, and transferred to a higher-level hospitalfor effective treatment;however, he died after 2 days.CONCLUSION AHA associated BP is rare, dangerous, and has a high mortality rate. Therefore, its timely diagnosis and effectivetreatment are necessary.
基金Supported by Hunan Innovative Province Construction Special Task Book,No.2021SK4050Innovation Platform and Talent Program of Hunan Province,No.2023JJ30609.
文摘BACKGROUND Extramedullary plasmacytoma(EMP)represents one of the rarer forms of plasma cell malignancies,capable of impacting a variety of tissues and organs throughout the body.The majority of EMP cases are predominantly found in the head and neck region,especially within the laryngopharynx,as well as in the gastrointestinal tract.While there have been documented instances of oropharyngeal involvement in EMP cases in the academic literature,it is important to note that EMP specifically affecting the uvula is exceedingly uncommon.Furthermore,it is noteworthy that over 60% of epithelial carcinomas in the upper respiratory tract and oropharynx tend to metastasize to the cervical lymph nodes,indicating a propensity for regional spread in these types of cancers.In this context,we present a rare case of extramedullary plasmacytoma where the uvula served as the initially affected site.This case emphasizes the need for heightened awareness among clinicians regarding such unusual comorbidities,as early recognition and diagnosis can significantly influence patient management and treatment outcomes.In addition,a review of the relevant literature is included to further educate and inform healthcare professionals about this rare presentation,ultimately aiming to enhance clinical understanding and improve patient care in similar situations.CASE SUMMARY A 51-year-old man was admitted to our hospital because of a slowly enlarging neck mass.A physical examination revealed a palpable left lymph node,and magnetic resonance imaging(MRI)of the oropharynx and the neck showed a soft tissue mass in the oropharynx and enlargement of multiple lymph nodes in the neck.The soft tissue mass was diagnosed as plasmacytoma by immunohistochemical analysis.Monoclonal immunoglobulins and bone marrow biopsy showed normal results.Therefore,we diagnosed that as EMP of the uvula.After four cycles of adjuvant chemotherapy dominated by bortezomib,MRI reexamination showed a significant reduction of the mass in the oropharynx and the cervical lymph nodes.Afterwards,the λ light chain returned to normal levels.There was no evidence of evolution to multiple myeloma.CONCLUSION We have reported a rare case of extramedullary plasmacytoma with the uvula as the first affected site and the relevant literature is reviewed to improve clinicians'awareness of such rare comorbidities.
基金Supported by The National Natural Science Foundation of China,No.82171334The Chongqing Science and Health Joint Medical Research Project,No.2024MSXM155.
文摘BACKGROUND Autologous fat injection in facial reconstruction is a common cosmetic surgery.Although cerebral fat embolism(CFE)as a complication is rare,it carries serious health risks.CASE SUMMARY We present a case of a 29-year-old female patient who developed acute CFE following facial fat filling surgery.After the surgery,the patient experienced symptoms including headache,nausea,vomiting,and difficulty breathing,which was followed by neurological symptoms such as slurred speech and left-sided weakness.Comprehensive physical examination and auxiliary investigations,including blood tests,head and neck computed tomography angiography,and cranial magnetic resonance diffusion-weighted imaging,were performed upon admission.The clinical diagnosis was acute cerebral embolism following facial fat filling surgery.Treatment included measures to improve cerebral circulation,dehydration for intracranial pressure reduction,nutritional support,and rehabilitation therapy for left limb function.The patient showed a significant improvement in symptoms after 2 weeks of treatment.She recovered left limb muscle strength to grade 5,had clear speech,and experienced complete relief of headache.CONCLUSION Our case highlights the potential occurrence of severe complications in patients undergoing fat injection in facial reconstruction.To prevent these complications,plastic surgeons should enhance their professional knowledge and skills.
基金Supported by The New Faculty Research Grant of Pusan National University,2023The Research Grant of the Chungbuk National University in 2023.
文摘BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resolve,several treatment options have been suggested for this condition.CASE SUMMARY In this paper,we report a case of corticosteroid injection induced lipoatrophy treated with autologous whole blood(AWB)injection,as the condition had been unresponsive to fractional laser therapy.A 29-year-old female patient visited the dermatology clinic complaining of skin depression on her right buttock area,which had appeared six months earlier.There had been only subtle improvement at the margins after fractional CO2 laser treatment;therefore,after obtaining informed consent from the patient,AWB treatment was initiated.One month after the first AWB injection,the size and depth of the lesion had noticeably improved,and a slight improvement was also observed in discoloration.CONCLUSION Close observation is the initial treatment of choice for steroid induced skin atrophy;however,for patients in need of immediate cosmetic improvement,AWB injection may be a safe and cost-effective alternative.
文摘BACKGROUND Primary squamous cell carcinoma(SCC)of the renal parenchyma is extremely rare,with only nine cases reported.CASE SUMMARY This study reports a 51-year-old man with primary SCC of the renal parenchyma.The patient was admitted with recurrent dull pain and discomfort in the right lumbar region,which had worsened over 2 weeks,accompanied by painful gross hematuria.SCC antigen(SCCA)levels were elevated,and imaging revealed a renal mass with associated calculi.The patient underwent laparoscopic unilateral nephrectomy and lymph node dissection.Postoperative pathology confirmed highly differentiated SCC with necrosis in the right renal parenchyma,with negative renal pelvis and ureter.The pathological stage was Pt3aN1M0.Four months after surgery,the tumor recurred with involvement of the liver,right psoas major muscle,and inferior vena cava.The patient refused chemotherapy and succumbed to the disease 6 months postoperatively due to disease progression.CONCLUSION We report a case of primary SCC of the renal parenchyma,a rare renal malignancy.The clinical symptoms,laboratory tests,and imaging findings are nonspecific,making accurate and timely diagnosis challenging.According to the literature,for patients with renal calculi accompanied by a renal mass,elevated serum SCCA levels,and magnetic resonance imaging showing cystic or cystic-solid masses within the kidney with pseudocapsules and heterogeneous mild enhancement,the possibility of this disease should be considered.
基金Supported by 2021 Disciplinary Construction Project in School of Dentistry,Anhui Medical University,No.2021kqxkFY05.
文摘BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in theliterature.CASE SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical level.After the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival overgrowth.Cone-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival overgrowth.CONCLUSION This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.
基金Supported by Grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute,funded by the Ministry of Health&Welfare,Republic of Korea,No.RS-2022-KH129889.
文摘BACKGROUND The classification of uterine sarcomas is based on distinctive morphological and immunophenotypic characteristics,increasingly supported by molecular genetic diagnostics.Data on neurotrophic tyrosine receptor kinase(NTRK)gene fusionpositive uterine sarcoma,potentially aggressive and morphologically similar to fibrosarcoma,are limited due to its recent recognition.Pan-TRK immunohistochemistry(IHC)analysis serves as an effective screening tool with high sensitivity and specificity for NTRK-fusion malignancies.CASE SUMMARY We report a case of a malignant mesenchymal tumor originating from the uterine cervix,which was pan-TRK IHC-positive but lacked NTRK gene fusions,accompanied by a brief literature review.A 55-year-old woman presented to the emergency department with abdominal pain and distension,exhibiting significant ascites and multiple solid pelvic masses.Pelvic examination revealed a tumor encompassing the uterine cervix,extending to the vagina and uterine corpus.A punch biopsy of the cervix indicated NTRK sarcoma with positive immunochemical pan-TRK stain.However,subsequent next generation sequencing revealed no NTRK gene fusion,leading to a diagnosis of poorly differentiated,advanced-stage sarcoma.CONCLUSION The clinical significance of NTRK gene fusion lies in potential treatment with TRK inhibitors for positive sarcomas.Identifying such rare tumors is crucial due to the potential applicability of tropomyosin receptor kinase inhibitor treatment.
文摘BACKGROUND The incidence of acute myocardial infarction(AMI)is rising,with cardiac rupture accounting for approximately 2%of deaths in patients with acute ST-segment elevation myocardial infarction(STEMI).Ventricular free wall rupture(FWR)occurs in approximately 2%of AMI patients and is notably rare in patients with non-STEMI.Types of cardiac rupture include left ventricular FWR,ventricular septal rupture,and papillary muscle rupture.The FWR usually leads to acute cardiac tamponade or electromechanical dissociation,where standard resuscitation efforts may not be effective.Ventricular septal rupture and papillary muscle rupture often result in refractory heart failure,with mortality rates over 50%,even with surgical or percutaneous repair options.CASE SUMMARY We present a rare case of an acute non-STEMI patient who suffered sudden FWR causing cardiac tamponade and loss of consciousness immediate before undergoing coronary angiography.Prompt resuscitation and emergency open-heart repair along with coronary artery bypass grafting resulted in successful patient recovery.CONCLUSION This case emphasizes the risks of AMI complications,shares a successful treatment scenario,and discusses measures to prevent such complications.
文摘BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a case in which CCRT had a reduction effect preoperatively.A 73-year-old woman with pyelonephritis was referred to our hospital.Computed tomography revealed right hydronephrosis and a 6-cm pelvic mass.Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB)revealed squamous cell carci-noma.The patient was diagnosed with MT of MCT.Due to her poor general con-dition and renal malfunction,we selected CCRT,expecting fewer adverse effects.After CCRT,her performance status improved,and the tumor size was reduced;surgery was performed.Five months postoperatively,the patient developed dis-semination and lymph node metastases.Palliative chemotherapy was ineffective.She died 18 months after treatment initiation.CONCLUSION EUS-FNB was useful in the diagnosis of MT of MCT;CCRT suppressed the disea-se and improved quality of life.
文摘BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of the flexor pollicis longus(FPL)at the musculotendinous junction.Possible treatments include direct tendon suture or tendon transfer,most commonly from the ring finger.To optimize function and avoid donor finger complications,we performed thumb replantation with flexion restoration using brachioradialis(BR)tendon transfer with palmaris longus(PL)tendon graft.CASE SUMMARY A 20-year-old left-handed male was admitted for a complete traumatic left thumb amputation following an accident while sliding from the top of a handrail.The patient presented with skin and bone avulsion at the MCP I,avulsion of the FPL tendon at the musculotendinous junction(zone 5),avulsion of the extensor pollicis longus tendon(zone T3),and avulsion of the thumb’s collateral arteries and nerves.The patient was treated with two stage thumb repair.The first intervention consisted of thumb replantation with MCP I arthrodesis,resection of avulsed FPL tendon and implantation of a silicone tendon prosthesis.The second intervention consisted of PL tendon graft and BR tendon transfer.Follow-up at 10 months showed good outcomes with active interphalangeal flexion of 70°,grip strength of 45 kg,key pinch strength of 15 kg and two-point discrimination threshold of 4 mm.CONCLUSION Flexion restoration after complete thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.
基金Project(2009ZX04005-031-11)supported by the Major National Science and Technology Special Project of ChinaProject(KP200911)supported by the Research Fund of State Key Laboratory of Solidification Processing of ChinaProject(B08040)supported by the"111"Project of China
文摘A thermal-mechanical and micro-macro coupled finite element(FE) model for the hot extrusion process of large-scale thick-walled Inconel 625 pipe was developed based on the DEFORM-2D platform.Then,the influence rules of the key extrusion parameters on the average grain size and grain uniformity of the extruded pipe were revealed.The results show that with the increase of initial billet temperature,extrusion speed and friction coefficient,the grain uniformity is firstly improved and then deteriorated.Larger extrusion ratio leads to more uniform grain distribution.With the increase of initial billet temperature,the average grain size of the pipe first decreases and then increases.Additionally,larger extrusion ratio can bring smaller average grain size.The extrusion speed and friction coefficient have slight effects on the average grain size of the extruded pipe.
文摘This study presents an analytical solution of thermal and mechanical displacements, strains, and stresses for a thick-walled rotating spherical pressure vessel made of functionally graded materials (FGMs). The pressure vessel is subject to axisymmetric mechanical and thermal loadings within a uniform magnetic field. The material properties of the FGM are considered as the power-law distribution along the thickness. Navier’s equation, which is a second-order ordinary differential equation, is derived from the mechanical equilibrium equation with the consideration of the thermal stresses and the Lorentz force resulting from the magnetic field. The distributions of the displacement, strains, and stresses are determined by the exact solution to Navier’s equation. Numerical results clarify the influence of the thermal loading, magnetic field, non-homogeneity constant, internal pressure, and angular velocity on the magneto-thermo-elastic response of the functionally graded spherical vessel. It is observed that these parameters have remarkable effects on the distributions of radial displacement, radial and circumferential strains, and radial and circumferential stresses.
基金Projects(50874047,51074014,51174014)supported by the National Natural Science Foundation of China
文摘The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.
基金supported by the Ph. D. Programs Foundation of Ministry of Education of China(No. 20050403002)
文摘Plastic limit load of viscoplastic thick-walled cylinder and spherical shell subjected to internal pressure is investigated analytically using a strain gradient plasticity theory. As a result, the current solutions can capture the size effect at the micron scale. Numerical results show that the smaller the inner radius of the cylinder or spherical shell, the more significant the scale effects. Results also show that the size effect is more evident with increasing strain or strain-rate sensitivity index. The classical plastic-based solutions of the same problems are shown to be a special case of the present solution.
基金Project(51674096)supported by the National Natural Science Foundation of ChinaProject(E2016203119)supported by Hebei Natural Science Foundation of ChinaProject(18211045)supported by the Key Research and Development Foundation in Hebei Province of China
文摘Cooling strength is one of the important factors affecting microstructure and properties of gas cylinders during quenching process,and reasonable water spray volume can effectively improve the quality of gas cylinders and reduce production costs.To find the optimal water spray parameters,a fluid-solid coupling model with three-phase flow was established in consideration of water-vapor conversion.The inner and outer walls of gas cylinder with the dimensions of d914 mm×38 mm×12000 mm were quenched using multi-nozzle water spray system.The internal pressure,average heat transfer coefficient(have)and stress of the gas cylinder under different water spray volumes during quenching process were studied.Finally,the mathematical model was experimentally verified.The results show that both the internal pressure and have increase along with the increase of spray volume.The internal pressure increases slowly first and then rapidly,but have increases rapidly first and then slowly.To satisfy hardenability of gas cylinders,the minimum spray volume should not be less than 40 m^3/(h·m).The results of stress indicate that water spray quenching will not cause deformation of bottle body in the range of water volume from 40 to 290 m^3/(h·m).
基金Lyudmila Petrova for invaluable metrological support. A.I.D. also thanks RFBR grant no. 15-08-01511a
文摘We suppose that in order to maintain high accuracy of holes and to lower residual stresses after cold expansion of thick-walled cylinders, which undergo cross-section plastic deformation, it is necessary to perform axial plastic compression and subsequent cold expansion with small interferences. To test this hypothesis, we studied hoop, radial and axial residual stresses in cylinders made of carbon steel AISI 1050 with hole diameter of 5 mm, outer diameter of 15 mm and length of 30 mm by Sachs method as well as accuracy of expanded holes. It is found that double cold expansion with total interference equal to 5.1% generates hoop residual stresses with largest absolute value equal to 284 MPa and ensures high holes accuracy(IT7). After plastic compression with strain equal to 0.5 and 1% the mentioned stresses reduced to 120 and 75 MPa respectively,and accuracy of the holes reduced as well. Subsequent cold expansion with small interference equal to 0.9% helps to restore holes accuracy(IT7)gained by double cold expansion and ensure that absolute value of hoop residual stresses(177 MPa) is lower compared to double cold expansion.
基金supported by the Deep Exploration Technologies Cooperative Research Centre whose activities are funded by the Australian Government’s Research Programme
文摘At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consistof sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite.These formations are being encountered when drilling boreholes to the depth of up to 2 0 0 m. To studythe behaviour of these materials, thick-walled hollow cylinder (TWHC) and solid cylindrical syntheticspecimens were designed and prepared by adding Portland cement and water to sand grains. The effectsof different parameters such as water and cement contents, grain size distribution and mixture curingtime on the characteristics of the samples were studied to identify the mixture closely resembling theformation at the drilling site. The Hoek triaxia! cell was modified to allow the visual monitoring of graindebonding and borehole breakout processes during the laboratory tests. The results showed the significanceof real-time visual monitoring in determining the initiation of the borehole breakout. The sizescaleeffect study on TWHC specimens revealed that with the increasing borehole size, the ductility ofthe specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged.Under different confining pressures the lateral strain at the initiation point of boreholebreakout is considerably lower in a larger size borehole (2 0 mm) compared to that in a smaller one(10 mm). Also, it was observed that the level of peak strength increment in TWHC specimens decreaseswith the increasing confining pressure.
基金supported by the National Natural Science Foundation of China(No.11772041)
文摘In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material constants as some specific function forms displayed in pre-studies, we firstly give the volume fractions of different constituents of the functionally graded material(FGM) cylinder and then determine the expressions of the material constants. With the use of the Voigt method, the corresponding analytical solutions of displacements in the radial direction, the strain and stress components, and the perturbation magnetic field vector are derived. In the numerical part, the effects of the volume fraction on the displacement, strain and stress components, and the magnetic perturbation field vector are investigated. Moreover, by some appropriate choices of the material constants, we find that the obtained results in this paper can reduce to some special cases given in the previous studies.