Model following control with discrete time SMC for time-delayed bilateral control systems

This paper proposes a new algorithm based on model following control to recover the uncompensated slave disturbance on time delayed motion control systems having contact with environment. In the previous works, a modified Communication Disturbance Observer (CDOB) was shown to be successful in ensuring position tracking in free motion under varying time delay. However, experiments show that due to the imperfections in slave plant Disturbance Observer (DOB) when there is rapid change of external force on the slave side, as in the case of environment contact, position tracking is degraded. This paper first analyzes the effect of environment contact for motion control systems with disturbance observers. Following this analysis, a model following controller scheme is proposed to restore the ideal motion on the slave system. A virtual plant is introduced which accepts the current from the master side and determines what the position output would be if there was no environment. Based on the error bet ween actual system and model system, a discrete time sliding mode controller is designed which enforces the real slave system to track the virtual slave output. In other words, convergence of slave position to the master position is achieved even though there is contact with environment. Experimental verification of the proposed control scheme also shows the improvement in slave position tracking under contact forces

Design and control of laser micromachining workstation

The production process of miniature devices and microsystems requires the utilization of non-conventional micromachining techniques. In the past few decades laser micromachining has became micro-manufacturing technique of choice for many industrial and research applications. This paper discusses the design of motion control system for a laser micromachining workstation with particulars about automatic focusing and control of work platform used in the workstation. The automatic focusing is solved in a sliding mode optimization framework and preview controller is used to control the motion platform. Experimental results of both motion control and actual laser micromachining are presented

Nörodejeneratif Hastalıklarda Umut Verici Bir Terapötik Hedef: Sestrin-2

Alzheimer, Parkinson, Huntington ve amyotrofik lateral skleroz dâhil olmak üzere nörodejeneratif hastalıklar günümüz dünyasında giderek daha yaygın hale gelen, multifaktöriyel ve ilerleyici tipte hastalıklardır. Nörodejeneratif bozuklukların yaygın etiyolojilerinin başında yaşlanma, oksidatif stres ve mitokondriyal disfonksiyon gelmektedir. Nörodejeneratif hastalıkların tedavisinde kullanılan güncel ilaçlar hastanın yaşam kalitesini iyileştirse de hastalığın gelişimini ve ilerlemesini yavaşlatan veya önleyen bir tedavi henüz mevcut değildir. Bu ilaçların en büyük dezavantajı ise kronik kullanımlarında ciddi yan etkilerle karşılaşılmasıdır. Bu kapsamda yeni terapötik hedeflere yönelik uzun vadede yan etki profili düşük yeni ajanlara ihtiyaç duyulmaktadır. Son zamanlarda gerçekleştirilen çalışmalarda, stresle indüklenebilir bir metabolik protein olan Sestrin-2’nin reaktif oksijen türlerini baskıladığı, metabolizma ve inflamasyonu düzenlediği ve genotoksisite ve oksidatif stres, mitokondriyal disfonksiyon, endoplazmik retikulum stresi ve hipoksi dâhil olmak üzere çeşitli zararlı uyaranlara karşı hücresel koruma sağladığı gösterilmiştir. Sestrin-2’nin düzenlenmesi ve sinyal mekanizmalarına ilişkin çığır açan araştırmalarla, potansiyel rolü ve konak yanıtındaki önemi konusundaki bilgilerimiz önemli derecede artmış olsa da Sestrin-2’nin nörodejeneratif hastalıklarda işlevleri için daha fazla çalışmaya ihtiyaç duyulmaktadır. Bu çalışmada, nörodejeneratif hastalıklarda önemli bir terapötik hedef olma potansiyeline sahip Sestrin-2’ye dikkat çekmek amacıyla literatürdeki bilgiler detaylı bir şekilde derlenmiştir

Fibrin sealant as a carrier for sustained delivery of antibiotics

Objective: To evaluate the activity and sustained release of antibiotics from fibrin sealant against common strains of ocular bacteria. Methods: Vancomycin, ceftazidime, moxifloxacin and lomefloxacin were incorporated into fibrin sealant in the shape of discs. Each antibiotic disc and control fibrin disc without drug was tested in vitro against standard bacterial strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae and Pseudomonas aeroginosa. After 24 hours of incubation at 37 °C, the discs were transferred to new plates of bacteria and triplicated for each antibiotic. Results: All antibiotic discs demonstrated detectable activity after 24 hours. Vancomycin had the longest duration of activity (4 days) on the S. pneumonia grown plate. The moxifloxacin discs showed a prolonged inhibition of S. aureus and S. pneumonia for 3 days and inhibited the other strains for 2 days. Conclusion: Fibrin sealants provided prolonged drug delivery, which indicates that antibiotic-loaded fibrin clots could be useful for early ocular postoperative care and treatment. J Clin Exp Invest 2014; 5 (2): 194-19

Bioactive, functional and edible film-forming properties of isolated hazelnut (Corylus avellana L.) meal proteins

This study aimed characterization of bioactive, functional and edible film making properties of isolated proteins from untreated (HPI), hot extracted (HPI-H), acetone washed (HPI-AW), and acetone washed and hot extracted (HPC-AW-H) hazelnut meals. The most bioactive protein extract was HPC-AW-H, followed by HPI-AW, HPI-H and HPI, based on antioxidant activity (TEAC and ORAC: 158-461mmolTrolox/kg), iron chelation (60.7-126.7mmolEDTA/kg), angiotensin-converting enzyme inhibition (IC50: 0.57-1.0mg/mL) and antiproliferative activity on colon cancer cells (IC50: 3.0-4.6mg/ml). Protein contents of HPI, HPI-H and HPI-AW (93.3-94.5%) were higher than that of HPC-AW-H (86.0%), but HPC-AW-H showed the best pH-solubility profile. The extracts showed good oil absorption (7.4-9.4g/g) and foaming, but limited water holding and gelling capacities, and emulsion stability. The protein extracts gave transparent, yellowish to brownish and reddish colored and water soluble edible films. The HPI gave the lightest colored films with acceptable mechanical properties (elongation up to 144% and tensile strength up to 4.9MPa). 1-D and 2-D electrophoresis clearly showed the molecular and isoelectric profiles of hazelnut proteins. The overall results of this study showed that the bioactive, solubility and gelation properties of hazelnut proteins could be improved by simple processes like acetone washing and/or heat treatment. The hazelnut proteins are valuable as multipurpose food ingredients.Foundation of Izmir Institute of Technology (IZTECH

Investigating of Mechanical Properties of Mortars Based on Fly Ash and Blast Furnace Slag Activated with Alkali

Alkali activated mortars obtained from granulated blast furnace slag and fly ash were used instead of Portland cement by activating with alkali. Sodium silicate and sodium hydroxide were activated blast furnace slag and fly ash. Mortar samples were prepared 40x40x160 mm as prismatic samples according to TS EN 196-1 and they were cured at room temperature. Compressive and flexural strength of the mortar samples including blast furnace slag and fly ash were investigated by experimenting

Heel Pain

Topuk ağrısı, toplumda yaygın olarak görülen ve klinisyenlerle hasta popülasyonunu sıkça karşı karşıya getiren klinik bir durumdur. Topuk ağrısının lokal ve sistemik etkenler başlığı altında bir çok nedeni olabilir. Yumuşak doku kökenli lokal ağrı nedenleri arasında başta plantar fasiit, topuk yağ yastığı atrofisi olmak üzere tendinopatiler, tuzak nöropatiler ve bursit sayılabilir. Lokal kemik doku nedenleri arasında ise öncelikle haglund deformitesi, apofizit ve kalkaneus stres kırıkları sayılabilir. Sistemik nedenler etiyolojide çok fazla yer almazlarHeel pain is a frequent problem confronted by clinicians. Various local or systemic irregularities can cause heel pain. Local causes arising from soft tissue are mainly plantar fasciitis, heel fat pad atrophy tendinopathies trap neuropathies and bursitis.Local tissue irregularities causing heel pain are mainly heglund deformity apophysitis and calcaneus stress fractures . Systemic causes are not frequent in the etiology of heel pai

On the Collisional Damping of Giant Dipole Resonance

Collisional damping widths of giant dipole excitations are calculated in Thomas-Fermi approximation by employing the microscopic in-medium cross-sections of Li and Machleidt and the phenomenological Gogny force. The results obtained in both calculations compare well, but account for about 25-35% of the observed widths in $^{120}Sn$ and $^{208}Pb$ at finite temperatures.Comment: Latex, 13 pages, 4 figure

Wavelet packet transform-based compression for teleoperation

This paper introduces a codec scheme for compressing the control and feedback signals in networked control and teleoperation systems. The method makes use of Wavelet Packet Transform (WPT) and Inverse Wavelet Packet Transform (IWPT) for coding and decoding operations, respectively. Data compression is carried out in low-pass filter output by reducing the sampling rate, and in high-pass filter output by truncating the wavelet coefficients. The proposed codec works on both directions of signal transmission between a master robot and a slave robot over a networked motion control architecture. Following the formulation of the compression/decompression methodology, experimental validation is conducted on a single-degree-of-freedom motion control system. In the experiments, responses from different Wavelet structures are analyzed and a comparative study is carried out considering the factors of compression rate, reconstruction power error and real-time computational complexity. It is confirmed that the controller using the proposed compression algorithm performs very close to the uncompressed one while enabling transmission of much less data over the network

Wavelet packet transform based compression for bilateral teleoperation

This paper introduces a codec scheme for compressing the control and feedback signals in bilateral control systems. The method makes use of Wavelet Packet Transform (WPT) and Inverse Wavelet Packet Transform (IWPT) for coding and decoding operations respectively. Data compression is carried out in low pass filter output by reducing the sampling rate; and in high pass filter output by truncating the wavelet coefficients. The proposed codec works on both directions of signal transmission between a master robot and a slave robot over a networked motion control architecture. Following the formulation of the compression/decompression methodology, experimental validation is conducted on a single degree of freedom (DOF) motion control system. In the experiments, responses from different Wavelet structures are analyzed and a comparative study is carried out considering the factors of compression rate, reconstruction power error and real time computational complexity. It is confirmed that the controller using the proposed compression algorithm performs very close to the uncompressed one while enabling transmission of much less data over network