Design of a chattering-free integral terminal sliding mode approach for DFIG-based wind energy systems

This article proposes a Fuzzy Second Order Integral Terminal Sliding Mode (FSOITSM) control approach for DFIG-based wind turbines subject to grid faults and parameter variations. Since traditional terminal sliding mode control (SMC) suffers from singularity, a novel integral terminal sliding manifold is proposed to eliminate chattering and improve the wind turbine's performance in the presence of faults and disturbances. A fuzzy system is proposed to auto-tune the controllers' gains and ensures the invariance of the sliding surfaces even under heavy uncertainties, thus further improving the reliability and performance of the proposed controller. The performance of the proposed approach was assessed under various operating conditions. A comparison analysis with a standard SMC approach as well as the state of the art in voltage sag mitigation was also carried over. Reliability, robustness, and power availability under faulty grid conditions are among the main features of the proposed approach. In addition, the proposed approach exhibited chattering free dynamics and enabled the finite time convergence of the sliding manifold and overcame the singularity problem associated with standard TSMC.     

第一跖列三平面截骨联合其余跖骨基底截骨治疗中重度跖内收型■外翻的早期疗效

目的探讨第1跖列三平面截骨联合其余跖骨基底截骨治疗中重度跖内收型[足母]外翻的早期疗效。方法2012年2月-2016年9月,收治10例(12足)中重度跖内收型[足母]外翻患者。男1例(2足),女9例(10足);年龄21~55岁,平均34.5岁。病程3~10年,平均5.8年。根据改良Sgarlato测量法对跖内收分度:中度4足、重度8足。术前美国矫形足踝协会(AOFAS)评分为(46.4±9.3)分;跖内收角(metatarsus adductus angle,MAA)为(25.41±3.66)°,[足母]外翻角(hallux valgus angle,HVA)为(41.42±9.67)°,第1-2跖骨间角(first-second intermetatarsal angle,1-2IMA)为(10.72±2.26)°。采用第1跖列三平面截骨联合其余跖骨基底截骨以及外侧软组织松解术治疗。结果术后切口均Ⅰ期愈合。患者均获随访,随访时间18~24个月,平均21.4个月。1例(1足)术后出现转移性跖痛,对症处理后症状消失。X线片复查示截骨部位均愈合,愈合时间为2.4~3.2个月,平均2.8个月。末次随访时,MAA为(8.42±0.71)°、HVA为(13.29±1.03)°、1-2IMA为(4.41±0.48)°,AOFAS评分为(89.8±5.9)分,均较术前明显改善(P<0.05)。结论第1跖列三平面截骨联合其余跖骨基底截骨治疗中重度跖内收型[足母]外翻,可获得较好早期疗效。     

Combined Medial Column Primary Arthrodesis,Middle Column Open Reduction Internal Fixation,and Lateral Column Pinning for Treatment of Lisfranc Fracture-Dislocation Injuries

Lisfranc fracture-dislocation can be a devastating injury with significant long-term sequelae, including degenerative joint disease, progressive arch collapse, and chronic pain that can be potentiated if not effectively treated. We present a case to demonstrate our preferred surgical approach, consisting of combined medial column primary arthrodesis, middle column open reduction internal fixation, and lateral column pinning, with the primary goal of minimizing common long-term complications associated with Lisfranc injuries. We present the case of a typical patient treated according to this combined surgical approach to highlight our patient selection criteria, rationale, surgical technique, and operative pearls. A 36-year-old male who had sustained a homolateral Lisfranc fracture-dislocation injury after falling from a height initially underwent fasciotomy for foot compartment syndrome. The subsequent repair 16 days later involved primary first tarsometatarsal joint fusion, open reduction internal fixation of the second and third tarsometatarsal joints, and temporary pinning of the fourth and fifth tarsometatarsal joints. He progressed well postoperatively, exhibiting an American College of Foot and Ankle Surgeons forefoot score of 90 of 100 at 1 year after surgery with no need for subsequent treatment. Lisfranc fracture-dislocations often exhibit primary dislocation to the medial column and are conducive to arthrodesis to stabilize the tarsometatarsal complex. The middle column frequently involves comminuted intra-articular fractures and will often benefit from less dissection required for open reduction internal fixation instead of primary fusion. We propose that this surgical approach is a viable alternative technique for primary treatment of Lisfranc fracture-dislocation injuries.     

Rare Presentation of Foot Postaxial Polydactyly

Polydactyly is a prevalent birth anomaly observed in the foot, and a number of classification systems have been suggested for this condition. Postaxial (fifth or little toe) polydactyly is the most common type. We encountered an exceedingly rare presentation of foot postaxial polydactyly that, to our inspection, had neither been previously classified nor described in published studies. In the present report, we have described an otherwise healthy 2-year-old female who had presented to our clinic with an isolated, extra little toe on her left foot. Foot radiographs revealed the presence of all 5 metatarsals; however, the fifth metatarsal was blocked and did not give rise to the fifth toe. Instead, the fifth (medial normal) and sixth (lateral extra) toes had originated from a single, separate accessory bud from the fourth metatarsal, and the main fourth metatarsal had given rise to the normal fourth toe. The lateral sixth toe was excised, and a periosteal sleeve of the excised extra toe was used for reconstruction of the lateral collateral ligament. We propose that this heretofore unmentioned presentation of postaxial polydactyly be added to the existing systems of classification of pedal polydactyly. A review of the published data pertaining to pedal polydactyly has also been presented.     

Observed Changes in Radiographic Measurements of the First Ray after Frontal Plane Rotation of the First Metatarsal in a Cadaveric Foot Model

We observed the changes in the angular measurements commonly used in the evaluation of the first metatarsal and first metatarsophalangeal joint in cadaveric specimens before and after frontal plane rotation of the first metatarsal. Measurements of the first and second intermetatarsal angle (IMA), hallux abductus angle, proximal articular set angle, and tibial sesamoid position (TSP) were taken after varying degrees of varus and valgus rotation of the first metatarsal. Standard dorsoplantar radiographs were taken at 0°, 10°, 20°, and 30° of valgus rotation of the first metatarsal and repeated at 10°, 20°, and 30° varus rotation of the first metatarsal. The data were analyzed using a mixed linear model to compare the change in each angle measurement over the range of valgus and varus rotation. The change in the TSP was significant in both valgus and varus rotations (p = .0004 and p = .028, respectively), an increase in valgus rotation causing an increase in the TSP and an increase in varus rotation causing a decrease in TSP. The change in the IMA was significant compared with valgus rotation (p = .028), showing that as the valgus rotation increased, the IMA also increased. However, compared with the varus rotation, the correlation was not significant (p = .18). The proximal articular set angle and hallux abductus angle measurements, compared with metatarsal rotation, showed positive trends but were not statistically significant. From our results and a review of the published data, we have hypothesized that frontal plane rotation of the first metatarsal is an integral component of hallux abducto valgus pathologic features, specifically in relation to the TSP and IMA.     

超声诊断孕早中期胎盘植入

目的观察孕早中期超声诊断胎盘植入的价值。方法回顾性分析经引产手术证实的10例孕早中期胎盘植入的临床资料,观察孕早中期胎盘植入的超声声像图特点。结果 10例中,9例有剖宫产手术史。术前超声诊断胎盘植入6例,主要表现为胎盘低置,胎盘与子宫肌层间界限不清,胎盘后血流信号丰富、肌层变薄。术前超声漏诊4例。引产后48h复查超声,10例均见宫内胎盘植入残留表现。结论胎盘与子宫肌层间界限不清、胎盘后血流信号丰富及肌层变薄等二维超声图像特点对诊断孕早中期胎盘植入具有高度临床价值。     

c-Jun NH2-terminal kinase-induced proteasomal degradation of c-FLIPL/S and Bcl2 sensitize prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine

Tetrandrine, a constituent of Chinese herb Stephania tetrandra, causes cell death in prostate cancer, but the molecular mechanisms leading to apoptosis is not known. Here we demonstrated that tetrandrine selectively inhibits the growth of prostate cancer PC3 and DU145 cells compared to normal prostate epithelial PWR-1E cells. Tetrandrine-induced cell death in prostate cancer cells is caused by reactive oxygen species (ROS)-mediated activation of c-Jun NH₂-terminal kinase (JNK1/2). JNK1/2-mediated proteasomal degradation of c-FLIP_L/S and Bcl₂ proteins are key events in the sensitization of prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine. Tetrandrine-induced JNK1/2 activation caused the translocation of Bax to mitochondria by disrupting its association with Bcl₂ which was accompanied by collapse of mitochondrial membrane potential (MMP), cytosolic release of cytochrome c and Smac, and apoptotic cell death. Additionally, tetrandrine-induced JNK1/2 activation increased the phosphorylation of Bcl₂ at Ser70 and facilitated its degradation via the ubiquitin-mediated proteasomal pathway. In parallel, tetrandrine-mediated ROS generation also caused the induction of ligand-independent Fas-mediated apoptosis by activating procaspase-8 and Bid cleavage. Inhibition of procaspase-8 activation attenuated the cleavage of Bid, loss of MMP and caspase-3 activation suggest that tetrandrine-induced Fas-mediated apoptosis is associated with the mitochondrial pathway. Furthermore, most of the signaling effects of tetrandrine on apoptosis were significantly attenuated in the presence of antioxidant N-acetyl-l-cysteine, thereby confirming the involvement of ROS in these events. In conclusion, the results of the present study indicate that tetrandrine-induced apoptosis in prostate cancer cells is initiated by ROS generation and that both intrinsic and extrinsic pathway contributes to cell death.     

Optimization of secondary drying condition for desired residual water content in a lyophilized product using a novel simulation program for pharmaceutical lyophilization

The aim of this study was to optimize the shelf temperature and the drying time, mainly dependent on the residual water content of a lyophilized product using a novel simulation program for the secondary drying of lyophilization. The simulation program was developed based upon heat transfer formulas, two empirical formulas, and a modified Fick’s second law. When a preliminary lyophilization run of secondary drying was carried out, the equilibrium product temperature at the end of secondary drying under various shelf temperatures was accurately predicted by the heat transfer formulas. The apparent diffusion coefficient of water, D_eff, and the apparent equilibrium residual water content, W_e, under the predicted equilibrium product temperature were estimated by two empirical formulas. These estimated D_eff and W_e allow the modified Fick’s second law to predict the residual water content in the lyophilized product. Using the developed simulation program, it was verified that the secondary drying condition to achieve the desired residual water content in the lyophilized product was successfully predicted. Therefore, the simulation program can be used to effectively design the secondary drying condition of lyophilization cycles without a trial and error approach.