Selective Laser Melting of Al-Based Matrix Composites with Al2O3 Reinforcement: Features and Advantages

Aluminum matrix composites (AMC) are of great interest and importance as high-performance materials with enhanced mechanical properties. Al₂O₃ is a commonly used reinforcement in AMCs fabricated by means of various technological methods, including casting and sintering. Selective laser melting (SLM) is a suitable modern method of the fabrication of net-shape fully dense parts from AMC with alumina. The main results, achievements, and difficulties of SLM applied to AMCs with alumina are discussed in this review and compared with conventional methods. It was shown that the initial powder preparation, namely the particle size distribution, sphericity, and thorough mixing, affected the final microstructure and properties of SLMed materials drastically. The distribution of reinforcing particles tends to consolidate the near-melting pool-edges process because of pushing by the liquid–solid interface during the solidification process that is a common problem of various fabrication methods. The achievement of an homogeneous distribution was shown to be possible through both the thorough mixing of the initial powders and the precise optimization of SLM parameters. The strength of the AMCs fabricated by the SLM method was relatively low compared with materials produced by conventional methods, while for superior relative densities of more than 99%, hardness and tribological properties were obtained, making SLM a promising method for the Al-based matrix composites with Al₂O₃.     

1470 nm激光在解剖性切除非肌层浸润性膀胱癌中的临床应用

目的探讨1470 nm激光在解剖性切除非肌层浸润性膀胱癌中的临床疗效。方法回顾性分析2018年1月至2019年12月于本院泌尿外科行1470 nm激光解剖性切除浅表性膀胱肿瘤患者60例的临床资料,所有患者均通过膀胱镜检查和CT或MRI检查,术前诊断为非肌层浸润性膀胱癌。分析1470 nm激光在解剖性切除非肌层浸润性膀胱癌中的应用效果。结果所有患者均顺利完成手术,无中转开放手术,并且术中无并发症,手术时间为10~30 min,平均(15.3±4.9)min,术后冲洗液无色或淡粉色,未见血块,术后1周拔除导尿管。结论1470 nm激光应用于解剖性切除浅表性膀胱肿瘤中效果显著,具有无瘤原则,利于肿瘤分期,可减少闭孔反射。     

飞秒激光辅助超声乳化联合Ahmed青光眼引流阀植入术治疗合并难治性青光眼的白内障

目的：评估飞秒激光辅助超声乳化联合Ahmed青光眼引流阀植入术治疗合并难治性青光眼的白内障的有效性和安全性。

方法：回顾性病例对照研究。2019-10/2021-10入院合并难治性青光眼的白内障患者53例53眼，依据自愿选择分为飞秒激光辅助白内障超声乳化(FLACS)组26例26眼和常规白内障超声乳化(CPCS)组27例27眼。两组分别行FLACS和CPCS联合Ahmed青光眼引流阀植入术。比较两组患者术中超声乳化能量释放量(CDE)、有效超声时间(EPT)的差异和术前与术后抗青光眼药物数量的变化，以及术后观察不同时期(1d，1wk，1、3mo)在提高最佳矫正视力(BCVA)，降低眼压、角膜内皮细胞损伤程度和手术并发症及成功率状况。

结果：FLACS组术中CDE和EPT明显低于CPCS组(t=8.50、5.16； P<0.01、=0.001)。两组术后抗青光眼药物较术前均明显减少(t=9.12、7.76； P=0.011、0.016)，但两组间无差异(t=1.79，P=0.082)。两组术后BCVA均较术前改善，眼压均较术前降低(P<0.05)。FLACS组在术后早期(1d，1wk)BCVA的改善较CPCS组更显著(t=9.74、8.49； P=0.008、0.012)，但在术后1、3mo的BCVA改善程度并无不同(t=0.62、0.44； P=1.415、2.021)。CPCS组在术后随访不同时期的角膜内皮细胞损伤较FLACS组更明显(P<0.05)。术后随访的不同时期FLACS组和CPCS组在控制眼压方面无差异(F_组间=0.64，P_组间=0.421)。FLACS组的手术并发症发生率27%(7/26)较CPCS组89%(24/27)低(χ²=20.95，P<0.01)，其中角膜水肿(8% vs 41%)、前囊撕裂(0 vs 11%)在FLACS组中明显低于CPCS组，后囊破裂(0 vs 7%)、玻璃体脱出(0 vs 4%)及人工晶状体偏位(0 vs 7%)也均发生在CPCS组。但两组的治疗总成功率相近(P=28.718)。

结论：飞秒激光辅助超声乳化联合Ahmed青光眼引流阀植入术可充分发挥联合手术的精准微创可控优势，帮助合并难治性青光眼的白内障患者有效降低眼压及更早获得视力恢复。     

Efficacy of photobiomodulation in the management of tinnitus: A systematic review of randomized control trials

There is a controversy in regards to the efficacy of photobiomodulation (PBM) in the management of tinnitus. The aim was to systematically review randomized controlled trials (RCTs) that assessed the efficacy of PBM (low-level laser therapy) in the management of tinnitus. The focused question was “Is PBM effective in the management of tinnitus?”. Indexed databases were searched up to and including June 2020 using different combinations of the following key words: (a) laser; (b) diode; (c) low-level laser therapy; (d) photobiomodulation; (e) tinnitus; (f) medium-level laser; (g) photo-biomodulation; and (h) low-power laser; and RCTs performed on humans were included. Letters to the editor; case reports/series; commentaries; experimental studies and historic reviews were excluded. The risk of bias was assessed using the modified cochrane collaboration tool. The format of the current systematic review was personalized to summarize the appropriate information. Ten RCTs (2 single-blinded and 8 double-blinded) were included. One study reported 30% and 100% resolution of tinnitus using diode and Neodymium-doped Yttrium Aluminum Garnet lasers; respectively. One study reported that PBM was effective in relieving tinnitus for up to 3 months. Eight studies reported that PBM was ineffective in the management of chronic tinnitus. The risk of bias was high; medium and low in 4; 5 and 1 studies; respectively. The effectiveness of PBM in the management of tinnitus remains debatable. Further power-adjusted and well-designed RCTs with long-term follow-up are needed.     

Er:YAG激光桩道预处理的研究进展

本文回顾了Er:YAG激光活化根管冲洗技术的最新研究进展,包括光子诱导光声流(photon initiated photoacoustic streaming,PIPS)技术和冲击波增强发射光声流(shock wave enhanced emission photoacoustic streaming,SWEEPS)技术,探讨Er:YAG激光预处理桩道的原理、优点以及对纤维桩粘接强度的影响,以期为临床选择适宜的桩道处理方法提供新思路。     

Multivariate optimization of mebeverine analysis using molecularly imprinted polymer electrochemical sensor based on silver nanoparticles

Thin film of a moleculary imprinted polymer (MIP) based on electropolymerization method with sensitive and selective binding sites for mebeverine (MEB) was developed. This film was cast on pencil graphite electrode (PGE) by electrochemical polymerization in solution of pyrrole (PY) and template MEB via cyclic voltammetry scans and further electrodeposition of silver nanoparticles (AgNPs). Several parameters controlling the performance of the silver nano particles MIP pencil graphite electrode (AgNPs-MIP-PGE) including concentration of PY(mM) concentration of mebeverine (mM), number of cycles in electropolymerization, scan rate of CV process (mV. s^?1), deposition time of AgNPs on to the MIP surface (s), stirring rate of loading solution (rpm), electrode loading time (min), pH of Britton–Robinson Buffer (BRB) solution were examined and optimized using multivariate optimization methods such as Plackett–Burman design (PBD) and central composite design (CCD). Two dynamic linear ranges of concentration for the MIP sensor were obtained as. 1 × 10 ^?8 to 1 × 10 ^?6 and 1 × 10 ^?5 to1 × 10^?3 M with the limit of detection (LOD) of 8.6 × 10 ^?9M (S/N = 3). The proposed method was successfully intended for the determination of MEB in real samples (serum, capsule). The sensor was showed highly reproducible response (RSD 1.1%) to MEB concentration.     

两种术式对于胆道结石患者术后胆道压力与胃肠道功能研究

目的探讨微创手术和开腹手术治疗胆道结石患者的临床疗效及对胆道压力和胃肠道功能的影响，分析胆道压力与胃肠功能的相互关系。 方法回顾性分析2016年1月至2018年1月收治的124例胆道结石患者。开腹组60例患者采用开腹手术治疗，微创组64例患者采用腹腔镜下胆道镜内镜联合钬激光碎石术治疗。采用SPSS18.00统计软件分析，术中术后指标、炎性因子检测、术后胆道压测定和胃肠动力指标检测，以均数( ±s)形式录入，采用独立t检验；净石率、术后并发症比较采用χ²检验；胆道压力与胃肠动力指标相关性分析采用Spearman相关分析，以P<0.05表示差异有统计学意义。 结果微创组手术时间、住院天数、住院费用、净石率、并发症率均优于开腹组(P<0.05)；微创组术后3 d、 5 d血清IL－6、 IL－8、 TNF－α浓度、 MTL、 CCK、 VIP水平和胆道压力和均显著低于开腹组(P<0.05)；患者术后胆道压力与胃肠动力指标MTL、 CCK程负相关(r＝－0.632, －0.678; P均<0.05)；VIP水平与胆道压力程正相关(r＝0.712; P<0.05)。 结论腹腔镜下胆道镜内镜联合钬激光碎石术治疗胆道结石临床效果明显，术后机体炎症反、胆道压力、胃肠动力指标更优，且胆道压力与胃肠动力指标具有一定相关性。