Photodynamic antimicrobial activity of new porphyrin derivatives against methicillin resistant Staphylococcus aureus

Hüseyin Taşlı,Ayşe Akbıyık,Nermin Topaloğlu,Vildan Alptüzün,Sülünay Parlar 한국미생물학회 2018 The journal of microbiology Vol.56 No.11

Methicillin resistant Staphylococcus aureus (MRSA) with multiple drug resistance patterns is frequently isolated from skin and soft tissue infections that are involved in chronic wounds. Today, difficulties in the treatment of MRSA associated infections have led to the development of alternative approaches such as antimicrobial photodynamic therapy. This study aimed to investigate photoinactivation with cationic porphyrin derivative compounds against MRSA in in-vitro conditions. In the study, MRSA clinical isolates with different antibiotic resistance profiles were used. The newly synthesized cationic porphyrin derivatives (PM, PE, PPN, and PPL) were used as photosensitizer, and 655 nm diode laser was used as light source. Photoinactivation experiments were performed by optimizing energy doses and photosensitizer concentrations. In photoinactivation experiments with different energy densities and photosensitizer concentrations, more than 99% reduction was achieved in bacterial cell viability. No decrease in bacterial survival was observed in control groups. It was determined that there was an increase in photoinactivation efficiency by increasing the energy dose. At the energy dose of 150 J/cm2 a survival reduction of over 6.33 log10 was observed in each photosensitizer type. While 200 μM PM concentration was required for this photoinactivation, 12.50 μM was sufficient for PE, PPN, and PPL. In our study, antimicrobial photodynamic therapy performed with cationic porphyrin derivatives was found to have potent antimicrobial efficacy against multidrug resistant S. aureus which is frequently isolated from wound infections.

Microstructure Evolution and Interface Stability of Thermal Barrier Coatings with Vertical Type Cracks in Cyclic Thermal Exposure

Lu, Z.,Myoung, S. W.,Kim, H. S.,Kim, M. S.,Lee, J. H.,Jung, Y. G.,Jang, J. C.,Paik, U. Springer Science + Business Media 2013 Journal of thermal spray technology Vol.22 No.5

AN IMPROVED ANALYTICAL CONSTITUTIVE RELATION FOR NORMAL WEIGHT HIGH-STRENGTH CONCRETE

Z. H. LU,Y. G. ZHAO 한국소성가공학회 2008 한국소성가공학회 컨퍼런스 Vol.2008 No.10

Structural damage detection based on Chaotic Artificial Bee Colony algorithm

H.J. Xu,Z.H. Ding,Z.R. Lu,J.K. Liu 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.6

A method for structural damage identification based on Chaotic Artificial Bee Colony (CABC) algorithm is presented. ABC is a heuristic algorithm with simple structure, ease of implementation, good robustness but with slow convergence rate. To overcome the shortcoming, the tournament selection mechanism is chosen instead of the roulette mechanism and chaotic search mechanism is also introduced. Residuals of natural frequencies and modal assurance criteria (MAC) are used to establish the objective function, ABC and CABC are utilized to solve the optimization problem. Two numerical examples are studied to investigate the efficiency and correctness of the proposed method. The simulation results show that the CABC algorithm can identify the local damage better compared with ABC and other evolutionary algorithms, even with noise corruption.

100KW DC Arc Plasma of CVD System for Low Cost Large Area Diamond Film Deposition

Lu, F.X.,Zhong, G.F.,Fu, Y.L.,Wang, J.J.,Tang, W.Z.,Li, G.H.,Lo, T.L.,Zhang, Y.G.,Zang, J.M.,Pan, C.H.,Tang, C.X.,Lu, Y.P. The Korean Ceramic Society 1996 The Korean journal of ceramics Vol.2 No.4

In the present paper, a new type of DC arc plasma torch is disclosed. The principles of the new magnetic and fluid dynamic controlled large orifice long discharge tunnel plasma torch is discussed. Two series of DC Plasma Jet diamond film deposition equipment have been developed. The 20kW Jet equipped with a $\Phi$70 mm orifice torch is capable of deposition diamond films at a growth rate as high as 40$\mu\textrm{m}$/h over a substrate area of $\Phi$65 mm. The 100kW high power Jet which is newly developed based on the experience of the low power model is equipped with a $\Phi$120 mm orifice torch, and is capable of depositing diamond films over a substrate area of $\Phi$110 mm at growth rate as high as 40 $\mu\textrm{m}$/h, and can be operated at gas recycling mode, which allows 95% of the gases be recycled. It is demonstrated that the new type DC plasma torch can be easily scaled up to even higher power Jet. It is estimated that even by the 100kW Jet, the cost for tool grade diamond films can be as low as less than $4/carat.

Structural damage detection based on residual force vector and imperialist competitive algorithm

Z.H. Ding,R.Z. Yao,J.L. Huang,M. Huang,Z. R. Lu 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.6

This paper develops a two-stage method for structural damage identification by using modal data. First, the Residual Force Vector (RFV) is introduced to detect any potentially damaged elements of structures. Second, data of the frequency domain are used to build up the objective function, and then the Imperialist Competitive Algorithm (ICA) is utilized to estimate damaged extents. ICA is a heuristic algorithm with simple structure, which is easy to be implemented and it is effective to deal with high-dimension nonlinear optimization problem. The advantages of this present method are: (1) Calculation complexity can be decreased greatly after eliminating many intact elements in the first step. (2) Robustness, ICA ensures the robustness of the proposed method. Various damaged cases and different structures are investigated in numerical simulations. From these results, anyone can point out that the present algorithm is effective and robust for structural damage identification and is also better than many other heuristic algorithms.

Eruption dynamics of CO₂-driven cold-water geysers: Crystal, Tenmile geysers in Utah and Chimayo geyser in New Mexico

Watson, Z.T.,Han, W.S.,Keating, E.H.,Jung, N.H.,Lu, M. North-Holland Pub. Co ; Elsevier Science Ltd 2014 Earth and planetary science letters Vol.408 No.-

The CO<SUB>2</SUB> bubble volume fraction, eruption velocity, flash depth and mass emission of CO<SUB>2</SUB> were determined from multiple wellbore CO<SUB>2</SUB>-driven cold-water geysers (Crystal and Tenmile geysers, in Utah and Chimayo geyser in New Mexico). At shallow depths the bubble volume fraction ranges from 0 to 0.8, eruption velocities range from 2 to 20 m/s and flash depths are predominately shallow ranging from 5 to 40 m below the surface. Annual emission of CO<SUB>2</SUB> is estimated to be (4.77+/-1.92)x10<SUP>3</SUP>, (6.17+/-1.73)x10<SUP>1</SUP>, (6.54+/-0.57)x10<SUP>1</SUP>t/yr for Crystal, Tenmile and Chimayo geysers, respectively. These estimates are coherent with Burnside et al. (2013) showing that the rate of CO<SUB>2</SUB> leakage from wellbores is greater than fault-parallel or diffuse CO<SUB>2</SUB> leakage. The geyser plumbing geometry consists of a vertical wellbore which allows for the upward migration of CO<SUB>2</SUB>-rich fluids due to artesian conditions. The positive feedback system of a CO<SUB>2</SUB>-driven eruption occurs within the well. Active inflow of CO<SUB>2</SUB> into the regional aquifers through faulted bedrock allows geysering to persist for decades. Crystal geyser erupts for over 24 h at a time, highlighting the potential for a wellbore in a natural environment to reach relatively steady-state high velocity discharge. Mitigating high velocity CO<SUB>2</SUB>-driven discharge from wellbores will, however, be easier than mitigating diffuse leakage from faults or into groundwater systems.

Development of the 3.7 GHz LHCD System on HL-2A

B. Lu,M. Huang,H. Zeng,X. Y. Bai,X. H. Mao,Z. H. Lu,J. Liang,Z. H. Kang,M. W. Wang,K. Feng,H. Wang,C. Wang,J. Q. Wang,S. Wei,T. Yao,Y. N. Bu,J. Feng,G. Y. Cheng,S. D. Song,D. H. Xia,J. Rao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A 2 MW-3.7 GHz lower hybrid current drive (LHCD) system is under development for physicsexperiments on the HL-2A device. The RF Power is generated by four TH2103A klystron amplifiersand propagates in the TE10 mode through WR284 waveguides. The transmission lines with a lengthof 20 m to 30 m are pressurized with 2 bars of nitrogen to decrease the possibility of arcing. Thelauncher, based on the passive-active multi-junction (PAM) concept, has been developed and iscurrently being realized. It was designed for a power spectrum peaked at Nk = 2.75 with goodcoupling properties over a wide range of plasma parameters. The four klystrons are fed by ahigh-voltage power supply (HVPS) based on the pulse step modulation (PSM) concept with a fastswitch-off time of less than ten μs. This system is expected to be in operation within 1 years and willexplore many international thermonuclear experimental reactor (ITER) related LH experiments inthe following years.

Nonlinear compensation for non-contact electronic joystick with a single hall sensor

Jin, H.Z.,Lu, H.,Cho, S.K.,Lee, J.M. IET 2008 IET science, measurement & technology Vol.2 No.1

<P>A new non-contact electronic joystick using a single hall-sensor, which detects a horizontal vector in the magnetic field, is demonstrated. Furthermore, the nonlinear characteristics between the output of the hall-sensor and the movement of the joystick bar are compensated to be linear. The dynamic horizontal vector of the magnetic flux is detected by the hall-sensor, whereas a permanent magnet is rotated with the joystick bar, which has a two-dimensional detecting area. Using the nonlinear adjustment equations, the output signals of the hall-sensor become linear, giving higher accuracy in two-dimensional movement. Through real experiments, it is shown that the single hall-sensor structure mechanism is superior to the dual-sensor structure in sensing two-dimensional motion without offset.</P>

Damage and vibrations of nuclear power plant buildings subjected to aircraft crash part I: Model test

Li, Z.R.,Li, Z.C.,Dong, Z.F.,Huang, T.,Lu, Y.G.,Rong, J.L.,Wu, H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.9

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.