Review on laser directed energy deposited aluminum alloys

Lightweight aluminum(Al)alloys have been widely used in frontier fields like aerospace and automotive industries,which attracts great interest in additive manufacturing(AM)to process high-value Al parts.As a mainstream AM technique,laser-directed energy deposition(LDED)shows good scalability to meet the requirements for large-format component manufacturing and repair.However,LDED Al alloys are highly challenging due to their inherent poor printability(e.g.low laser absorption,high oxidation sensitivity and cracking tendency).To further promote the development of LDED high-performance Al alloys,this review offers a deep understanding of the challenges and strategies to improve printability in LDED Al alloys.The porosity,cracking,distortion,inclusions,element evaporation and resultant inferior mechanical properties(worse than laser powder bed fusion)are the key challenges in LDED Al alloys.Processing parameter optimizations,in-situ alloy design,reinforcing particle addition and field assistance are the efficient approaches to improving the printability and performance of LDED Al alloys.The underlying correlations between processes,alloy innovation,characteristic microstructures,and achievable performances in LDED Al alloys are discussed.The benchmark mechanical properties and primary strengthening mechanism of LDED Al alloys are summarized.This review aims to provide a critical and in-depth evaluation of current progress in LDED Al alloys.Future opportunities and perspectives in LDED high-performance Al alloys are also outlined.

Thin-walled and large-sized magnesium alloy die castings for passenger car cockpit:Application,materials,and manufacture

In order to effectively reduce energy consumption and increase range mile,new energy vehicles represented by Tesla have greatly aroused the application of integrated magnesium(Mg)alloy die casting technology in automobiles.Previously,the application of Mg alloys in automobiles,especially in automotive cockpit components,is quite extensive,while it has almost disappeared for a period of time due to its relatively high cost,causing a certain degree of information loss in the application technology of Mg alloy parts in automobiles.The rapid development of automotive technology has led to a higher requirement for the automotive components compared with those traditional one.Therefore,whatever the components themselves,or the Mg alloy materials and die casting process have to face an increasing challenge,needing to be upgraded.In addition,owing to its high integration characteristics,the application of Mg alloy die casting technology in large-sized and thin-walled automotive parts has inherent advantages and needs to be expanded urgently.Indeed,it necessitates exploring advance Mg alloys and new product structures and optimizing die casting processes.This article summarizes and analyzes the development status of thin-walled and large-sized die casting Mg alloy parts in passenger car cockpit and corresponding material selection methods,die casting processes as well as mold design techniques.Furthermore,this work will aid researchers in establishing a comprehensive understanding of the manufacture of thin-walled and large-sized die casting Mg alloy parts in automobile cockpit.It will also assist them in developing new Mg alloys with improved comprehensive performance and new processes to meet the high requirements for die casting automotive components.

Chemotherapy combined with bevacizumab for small cell lung cancer with brain metastases:A case report

BACKGROUND Small cell lung cancer(SCLC)is a common and aggressive subtype of lung cancer.It is characterized by rapid growth and a high mortality rate.Approximately 10%of patients with SCLC present with brain metastases at the time of diagnosis,which is associated with a median survival of 5 mo.This study aimed to summarize the effect of bevacizumab on the progression-free survival(PFS)and overall survival of patients with brain metastasis of SCLC.CASE SUMMARY A 62-year-old man was referred to our hospital in February 2023 because of dizziness and numbness of the right lower extremity without headache or fever for more than four weeks.The patient was diagnosed with limited-stage SCLC.He received 8 cycles of chemotherapy combined with maintenance bevacizumab therapy and achieved a PFS of over 7 mo.CONCLUSION The combination of bevacizumab and irinotecan effectively alleviated brain metastasis in SCLC and prolonged PFS.

Ceramic particles reinforced copper matrix composites manufactured by advanced powder metallurgy:preparation, performance, and mechanisms

Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties,thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and electrical conductivity.This greatly expands the applications of copper as a functional material in thermal and conductive components,including electronic packaging materials and heat sinks,brushes,integrated circuit lead frames.So far,endeavors have been focusing on how to choose suitable ceramic components and fully exert strengthening effect of ceramic particles in the copper matrix.This article reviews and analyzes the effects of preparation techniques and the characteristics of ceramic particles,including ceramic particle content,size,morphology and interfacial bonding,on the diathermancy,electrical conductivity and mechanical behavior of copper matrix composites.The corresponding models and influencing mechanisms are also elaborated in depth.This review contributes to a deep understanding of the strengthening mechanisms and microstructural regulation of ceramic particle reinforced copper matrix composites.By more precise design and manipulation of composite microstructure,the comprehensive properties could be further improved to meet the growing demands of copper matrix composites in a wide range of application fields.

Solitary intraosseous neurofibroma in the mandible mimicking a cystic lesion:A case report and review of literature

BACKGROUND Neurofibromas are benign tumors of a neurogenic origin.If these tumors occur without any other signs of neurofibromatosis,they are classified as isolated neurofibromas.Neurofibromas in the oral cavity mostly occur within soft tissues,indicating that solitary intraosseous neurofibromas in the mandible are rare.Due to the absence of specific clinical manifestations,early diagnosis and treatment of these tumors are difficult to achieve.CASE SUMMARY A 37-year-old female patient visited our hospital due to numbness and swelling of the gums in the right lower molar area that had persisted for half a month.The patient’s overall condition and intraoral examination revealed no significant abnormalities.She was initially diagnosed with a cystic lesion in the right mandible.However,after a more thorough examination,the final pathological diagnosis was confirmed to be neurofibroma.Complete tumor resection and partial removal of the right inferior alveolar nerve were performed.As of writing this report,there have been no signs of tumor recurrence for nine months following the surgery.CONCLUSION This case report discusses the key features that are useful for differentiating solitary intraosseous neurofibromas from other cystic lesions.

Hyperprogression after anti-programmed death-1 therapy in a patient with urothelial bladder carcinoma:A case report

BACKGROUND Immune checkpoint inhibitors,including programmed death-ligand 1(PD-L1)and programmed death-1(PD-1)have recently been approved to treat locally advanced and metastatic urothelial carcinoma(UC).However,some patients experience rapid tumor progression rather than any clinical benefit from anti-PDL1/PD-1 therapy.CASE SUMMARY A 73-year-old woman with bladder UC showed the progression of multiple metastases after surgery and chemotherapy for over 12 mo.The patient could not tolerate further chemotherapy.Next-generation sequencing was performed,and the results indicated that the tumor mutational burden was 6.4 mutations/Mb.The patient received the anti-PD-L1 agent toripalimab combined with albuminbound paclitaxel.Compared with the baseline staging before immunotherapy,the patient had a treatment failure time of<2 mo,an increase in tumor burden of>50%,and a>2-fold increase in progression,indicating hyperprogression.CONCLUSION Selecting patients most likely to respond to treatment with immunotherapeutic agents remains challenging.For older patients with advanced UC who have already exhausted multi-line chemotherapy options,immunotherapy should be used prudently if no effective biomarker is available.Further studies are required to clarify the causes and mechanisms of hyperprogression.

糖尿病患者血清microRNA-152表达水平与血脂代谢、胰岛素抵抗的相关性

目的探讨糖尿病患者血清microRNA-152(miR-152)表达水平与血脂代谢、胰岛素抵抗的相关性。方法选取2018年1月—2018年11月在攀枝花市中西医结合医院就诊的血糖异常患者109例,分为2型糖尿病(T2DM)前期组(Pre-T2DM组)45例和T2DM组64例;另取同期该院门诊部健康体检者70例为对照组。检测血清空腹胰岛素(FINS)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、空腹血糖(FBG)水平,评估稳态胰岛素评价指数(HOMA-IR)与胰岛β细胞功能指数(HOMA-β);并分析miR-152与血脂水平及FBG、FINS、HOMA-IR、HOMA-β的相关性。结果与对照组相比,Pre-T2DM组、T2DM组患者血清miR-152、FBG、FINS、TG、TC、LDL-C、HOMA-IR较高(P <0.05),HDL-C、HOMA-β较低(P <0.05);与Pre-T2DM组相比,T2DM组患者血清miR-152、FBG、FINS、TG、TC、LDL-C、HOMA-IR较高(P <0.05),HDL-C、HOMA-β较低(P <0.05)。T2DM患者miR-152与TG、TC、LDL-C、FBG、FINS、HOMA-IR呈正相关(r=0.844、0.755、0.833、0.528、0.576和0.635,均P <0.05),与HDL-C、HOMA-β呈负相关(r=-0.655和-0.603,均P <0.05)。多因素一般Logistic回归分析结果显示,血清FBG[O^R=2.305(95%CI:1.369,3.882)]和miR-152[O^R=2.831(95%CI:1.736,4.618)]升高是影响胰岛素抵抗的危险因素。结论 T2DM患者血清miR-152上调,其可能通过调节血脂代谢影响T2DM病情发展。

Application of nanoparticles in cast steel:An overview

The innovative and environmentally friendly methodologies for comprehensively enhancing the performances of high-strength steels without damage to plasticity,toughness and heat/corrosion/fatigue resistance are being developed.In recent years,nanoparticles elevate the field of high-strength steel.It is proposed that nanoparticles have the potential to replace conventional semi-coherent intermetallic compounds,carbides and alloying to optimize the steel.The fabrication process is simplified and the cost is lower compared with the traditional methods.Considerable research effort has been directed towards high-performance cast steels reinforced with nanoparticles due to potential application in major engineering.Nanoparticles are found to be capable of notably optimizing the nucleation behavior and precipitate process.The prominently optimized microstructure configuration and performances of cast steel can be acquired synchronously.In this review,the lattice matching and valence electron criterion between diverse nanoparticles and steel are summarized,and the existing various preparation methods are compared and analyzed.At present,there are four main methods to introduce nanoparticles into steel:external nanoparticle method,internal nanoparticle method,in-situ reaction method,and additive manufacturing method.These four methods have their own advantages and limitations,respectively.In this review,the synthesis,selection principle and strengthening mechanism of nanoparticles in cast steels for the above four methods are discussed in detail.Moreover,the main preparation methods and microstructure manipulation mechanism of the steel reinforced with different nanoparticles have been systematically expatiated.Finally,the development and future potential research directions of the application of nanoparticles in cast steel are prospected.

Concomitant paraganglioma and thyroid carcinoma:A case report

BACKGROUND Paraganglioma/pheochromocytoma and medullary thyroid carcinoma can coexist and are often found in multiple endocrine neoplasia(MEN). However,very few cases highlight papillary thyroid carcinoma. We present herein a rare case of head and neck paraganglioma associated with papillary thyroid carcinoma.CASE SUMMARY A 51-year-old man presented to our department with right-sided neck swelling and hypertension. Physical examination showed neck masses with obvious pulsation. Concentrations of serum calcium, phosphorus, parathormone, thyroid stimulating hormone, free thyroxine, and calcitonin were within normal limits.Enhanced computed tomography revealed an irregular solid nodule, located in the carotid artery bifurcation. A low-density nodule of the thyroid isthmus with a spot-like dense shadow was also detected. The diagnosis of carotid body tumor was raised and an ultrasound-guided fine needle aspiration biopsy of the thyroid nodule revealed papillary thyroid carcinoma. The patient underwent surgery for lesion excision, total thyroidectomy, and neck dissection, and the pathology was reported as paraganglioma and papillary carcinoma. Genetic studies showed negative results for germline mutation of succinate dehydrogenase subunit D on 11q23. He was treated with ^(131)I after surgery and remained disease-free so far.CONCLUSION The presence of concomitant paraganglioma and thyroid papillary carcinoma could be either coincidental or a result of an unknown mutation.

4-73离心风机直叶片加强筋的优化分析

本文针对4-73NO14.9D离心风机叶轮强度问题,使用Solidworks建模,用ANSYS WORKBENCH进行强度计算,提出了强度通用优化算法,并利用此算法计算叶轮加强筋焊接位置、加强筋的形状及修正方向。通过ANSYS计算不同位置加强筋叶轮的应力,得到最优的加强平面。在此位置设置加强筋,叶轮Von Mises应力最小,叶轮强度最好。经过ANSYS WORKBENCH模态分析验证,说明本文方对优化叶片加强筋是有效可行的。

Signal Acquisition and Processing Method for Capacitive Electromagnetic Flowmeter

A kind of signal acquisition circuit and the related signal processing method of the capacitanceelectromagnetic flowmeter (EMF) were introduced. The circuit can eliminate the influence of distributed capacitanceon the input impedance of the operational amplifier, and greatly improve the input impedance of the detection circuitto overcome the disadvantage of high signal source impedance. The rotating capacitor filter is a signal processingmethod based on the phase-sensitive detection technology. It can extract the weak signal from the strong and widebandbackground noise, so it is very suitable for the processing of capacitive electromagnetic flow signals. Throughthe comparison of the signal amplitude obtained at different flow rates and the comparison of signal spectrumcomponents before and after the filter, the effectiveness of the bootstrap signal acquisition circuit and rotatingcapacitor filtering method is verified.

Familial left cervical neurofibromatosis 1 with scoliosis:A case report

BACKGROUND Neurofibromatosis type 1(NF1)is an inherited autosomal dominant disorder affecting many parts of the body with caféau lait spots,skeletal deformity,and scoliosis.A familial case of NF1 with scoliosis and a painless mass had not yet been reported.CASE SUMMARY We describe the case of a 15-year-old male patient with a painless lump on the left side of his neck for 10 years and scoliosis.His right shoulder was about 5 cm lower than the left,the left side of his face was deformed,and the left submandibular skin was relaxed.The folding and drooping were obvious and movement was poor.Computed tomography revealed the involvement of the neck,upper chest wall,and surrounding left shoulder,accompanied by bone changes and scoliosis.Histological evaluation showed subepidermal pale blue mucoid degeneration,fibrous fusiform cells in the dermis in a fascicular,woven arrangement.His mother had the same medical history.The diagnosis was neurofibromatosis of the left neck.Various parts of the tumor tissue were serially resected during several visits.Eight months after surgery,there was a slight tendency to regrow.CONCLUSION This case of slow-progressing NF1 highlights the importance of early diagnosis and treatment to reduce its impact on the patient’s growth and development.

Mucoepidermoid carcinoma in the infratemporal fossa: A case report

BACKGROUND Mucoepidermoid carcinoma is the most common primary epithelial salivary gland malignancy.It mostly occurs in the major or intraoral minor salivary glands but rarely in the infratemporal fossa.Here,we present a case of aggressive mucoepidermoid carcinoma in the infratemporal fossa with neck lymph node metastasis and also discuss diagnostic and treatment strategies.CASE SUMMARY A 39-year-old woman with a mass located in the right submandibular area presented to our department.Physical examination revealed lymphadenopathy on the right submandibular side measuring 2.5 cm×3 cm that was hard and had poor mobility.Results of nasal endoscopy were unremarkable.Ultrasound examination revealed an enlarged lymph node at level II of the right side.Fine needle aspiration cytology of the metastatic lymph node revealed malignant cells with infection.Contrast-enhanced computed tomography revealed an enhancing ill-defined soft tissue mass in the right infratemporal region.Positron emission tomography/computed tomography revealed hyperintensity in the right infratemporal fossa along with lymphadenopathy at level II of the right-side lymph node.The patient underwent extended resection of the primary tumor,and ipsilateral radical neck dissection was also completed.Hematoxylin-eosin staining and immunohistochemistry revealed a high-grade mucoepidermoid carcinoma.No signs and symptoms of recurrence of the neoplasm were present after 20 mo of follow-up.CONCLUSION Positron emission tomography/computed tomography play a key role in primary tumor localization.Furthermore,histopathology and immunohistochemistry play pivotal roles in disease diagnosis.

Unveiling the Contribution of Lactic Acid to the Passivation Behavior of Ti-6Al-4V Fabricated by Laser Powder Bed Fusion in Hank’s Solution

In actual physiological environments,bacteria can activate the immune system and release lactic acid.However,the detailed contribution of lactic acid to the passivation behavior of titanium(Ti)alloys is still unclear.The current work investigated the in vitro passivation behavior of Ti-6Al-4V(TC4)alloys fabricated by laser powder bed fusion in Hank's solution with and without adding lactic acid.Electrochemical methods,inductively coupled plasma atomic emission spectrometer,and X-ray photoelectron spectroscopy were jointly used.Adding lactic acid decreases the corrosion resistance of samples by degrading the formed passive film.The film formed in the(lactic acid)-containing solution exhibits a higher level of oxygen vacancies and a lower thickness,attributed to the suppressed formation of Ti^(4+)transformed from Ti^(3+)and Ti^(2+).Moreover,the presence of lactic acid would increase the open circuit potential,relieve the ions release,and hinder the deposition of calcium phosphates within 24 h immersion.