Checkerboard Plate Research Articles

In Situ Measurement of 2-D Crystal Size Distribution During Cooling Crystallization Process via a Binocular Telecentric Imaging System

In this paper, a novel in-situ measurement method with stereoscopic image analysis is proposed for monitoring crystal length and width distributions during a cooling crystallization process, based on a binocular telecentric imaging system. Firstly, a stereoscopic imaging calibration model is established for using binocular telecentric cameras to conduct in-situ measurement during a cooling crystallization process. Secondly, an enhanced algorithm is presented to improve matching crystal images from binocular image pairs, based on in-situ image preprocessing and segmentation. Thirdly, four key corners related to crystal length and width are determined by using the boundary features of matched crystal image projections. Finally, the length and width of each crystal are computed based on the reconstructed key corners in three-dimensional (3D) coordinate space, by using the established stereoscopic calibration model. Experimental validation on the proposed stereoscopic imaging calibration model and 3D reconstruction of key corners is carried out via in-situ measurement of a microscale checkerboard plate inserted into a cooling crystallizer. In-situ measurements of crystal length and width distributions during the cooling crystallization process of β-form L-glutamic acid are conducted to verify the effectiveness and advantage of the proposed measurement method.

Standardization of resazurin use in susceptibility testing of natural products against yeasts in planktonic cells and in biofilms formation

Natural products, such as the ethanolic propolis extract (PE), have been shown to be a safe and effective therapeutic alternative for the treatment of fungal skin and nail diseases. However, the presence of the resin and the physicochemical characteristics of the extract sometimes difficult the reading and determination of breakpoints of the in vitro tests, evidencing the need for alternatives that facilitate the reading. The present study aimed to standardize the use of resazurin in tests of susceptibility of PE with planktonic yeast cells and biofilm forms. The antifungal activity of PE was determined by minimum inhibitory concentration (MIC) and we observed that, for all Candida spp. tested, the most reproducible MIC results were obtained when resazurin was placed after 24 hours of incubation and remained more 24 hours with yeasts plus PE. For encapsulated yeasts, there was no dye reduction and color transition. Resazurin was also used for the evaluation of minimal biofilm inhibitory concentration and minimal biofilm eradication concentration and it was metabolized and reproduced the action of PE on Candida biofilms. In addition, microdilution checkerboard plates were made with the dye, which assisted reading the result of the interaction between PE and nystatin. We observed that the resin, the color and the turbidity of the PE slightly changed the color of the resazurin in high concentrations of the extract and did not impair the reading. Therefore, the resazurin standardization tests were proven to be efficient and grounds that it should be used as an auxiliary methodology for reading and interpretation of the susceptibility tests for non-encapsulated yeasts with natural products, which form turbidity or precipitation, such as propolis.

Antifungal efficacy of isavuconazole and liposomal amphotericin B in a rabbit model of Exserohilum rostratum meningoencephalitis: A preclinical paradigm for management of CNS phaeohyphomycosis.

Treatment options for Exserohilum rostratum meningoencephalitis and other causes of phaeohyphomycosis of the central nervous system (CNS) are limited, while mortality and morbidity remain high. We therefore evaluated isavuconazole, a new antifungal triazole in comparison to liposomal amphotericin B (LAMB), in vitro and in the rabbit model of Exserohilum rostratum meningoencephalitis. We hypothesized that isavuconazole alone or in combination with LAMB or micafungin may be alternative options for treatment of CNS phaeohyphomycosis. We therefore investigated the in vitro antifungal activity of isavuconazole alone or in combination with amphotericin B deoxycholate (DAMB) or micafungin and efficacy of treatment with isavuconazole and LAMB in a rabbit model of experimental E. rostratum meningoencephalitis. Combination checkerboard plates were used to determine the minimum inhibitory concentrations, minimal lethal concentrations, fractional inhibitory concentration indices, and Bliss surface analysis of isavuconazole and amphotericin B deoxycholate (DAMB), either alone or in combination. As there were no in vitro synergistic or antagonistic interactions for either combination of antifungal agents against the E. rostratum isolates, in vivo studies were conducted with isavuconazole and LAMB as monotherapies. Rabbits were divided in following groups: treated with isavuconazole at 60 mg/kg/d (ISAV60), LAMB at 5.0 (LAMB5), 7.5 (LAMB7.5), and 10 mg/kg/d (LAMB10), and untreated controls (UC). In ISAV60-, LAMB5-, LAMB7.5-, and LAMB10-treated rabbits, significant reductions of fungal burden of E. rostratum in cerebral, cerebellar, and spinal cord tissues (P < 0.01) were demonstrated in comparison to those of UC. These antifungal effects correlated with significant reduction of CSF (1→3)-β-D-glucan levels vs UC (P < 0.05). These data establish new translational insights into treatment of CNS phaeohyphomycosis.

Investigation of Antioxidant and Cytotoxic Effects of Biotechnologically Produced Carotenoids from Rhodobacter sphaeroides O.U. 001

Karotenoidler güçlü antioksidan özelliklerinden dolayı dikkat çekmektedirler. Bu çalışmada, Rhodobacter sphaeroides O.U. 001'den ekstrakte edilen karotenoidlerin antioksidan ve antiproliferatif etkileri araştırıldı. Bunun için, R. sphaeroides O.U. 001 önce 5 L'lik bir biyoreaktörde çoğaltıldı. Daha sonra, çözücü olarak aseton kullanılarak R. sphaeroides O.U.001'den karotenoidler ekstrakte edildi. Karotenoid ekstraktının, vinkristin ve paklitaksele dirençli hücrelerin (MCF-7/Vinc, MCF-7/Pac) proliferasyonuna etkileri MTT sitotoksisite testi ile araştırıldı. Karotenoid ekstraktı ve kanser ilaçları arasındaki etkileşimin hücreler üzerindeki etkisi dama tahtası plaka tekniği ile değerlendirildi. Karotenoid ekstraktın antioksidan aktivitesi ise 2, 2 - difenil, 1-pikril hidrazil (DPPH) radikal süpürücü aktivite tayin yöntemi ile belirlendi. Ekstraksiyon sonucunda, önemli miktarda karotenoid verimi elde edildi (80.69 mg karotenoid/g kuru hücre ağırlığı). Karotenoid ekstraktının hücre proliferasyonu üzerinde inhibitör etkisinin olmadığı ve antikanser ilaçlarla etkileşiminin antagonistik olduğu bulundu. Bunlara ek olarak, elde edilen karotenoid ekstraktının DPPH antioksidan etkisi, (IC 50 değeri) 25 µg/mL olarak hesaplandı. Sonuç olarak, biyoteknolojik yolla üretilen bakteriyel karotenoidlerin, kanser hücrelerinde sitotoksik etki göstermeden önemli antioksidan aktiviteye sahip oldukları gösterilmiştir.

An omnidirectional 3D sensor with line laser scanning

An active omnidirectional vision owns the advantages of the wide field of view (FOV) imaging, resulting in an entire 3D environment scene, which is promising in the field of robot navigation. However, the existing omnidirectional vision sensors based on line laser can measure points only located on the optical plane of the line laser beam, resulting in the low-resolution reconstruction. Whereas, to improve resolution, some other omnidirectional vision sensors with the capability of projecting 2D encode pattern from projector and curved mirror. However, the astigmatism property of curve mirror causes the low-accuracy reconstruction. To solve the above problems, a rotating polygon scanning mirror is used to scan the object in the vertical direction so that an entire profile of the observed scene can be obtained at high accuracy, without of astigmatism phenomenon. Then, the proposed method is calibrated by a conventional 2D checkerboard plate. The experimental results show that the measurement error of the 3D omnidirectional sensor is approximately 1mm. Moreover, the reconstruction of objects with different shapes based on the developed sensor is also verified.

The Effective Modulus of Random Checkerboard Plates

We investigate the elastic effective modulus Eeff of two-dimensional checkerboard specimens in which square tiles are randomly assigned to one of two component phases. This is a model system for a wide class of multiphase polycrystalline materials such as granitic rocks and many ceramics. We study how the effective stiffness is affected by different characteristics of the specimen (size relative to the tiles, stiff fraction, and modulus contrast between the phases) and obtain analytical approximations to the probability distribution of Eeff as a function of these parameters. In particular, we examine the role of percolation of the soft and stiff phases, a phenomenon that is important in polycrystalline materials and composites with inclusions. In small specimens, we find that the onset of percolation causes significant discontinuities in the effective modulus, whereas in large specimens, the influence of percolation is smaller and gradual. The analysis is an extension of the elastic homogenization methodology of Dimas et al. (2015, “Random Bulk Properties of Heterogeneous Rectangular Blocks With Lognormal Young's Modulus: Effective Moduli,” ASME J. Appl. Mech., 82(1), p. 011003), which was devised for blocks with lognormal spatial variation of the modulus. Results are validated through Monte Carlo simulation. Compared with lognormal specimens with comparable first two moments, checkerboard plates have more variable effective modulus and are on average less compliant if there is prevalence of stiff tiles and more compliant if there is prevalence of soft tiles. These differences are linked to percolation.

薬剤耐性&lt;i&gt;Pseudomonas aeruginosa&lt;/i&gt;に対する抗菌薬併用効果検査の検討

Drug resistant Pseudomonas aeruginosa is responsible for severe nosocomial infections, and combination therapy is needed. We studied antibiotic combination effects by “break-point checkerboard Plate (BC plate)” and disk diffusion susceptibility test against drug resistant P. aeruginosa. Thirty-three strains of multi-drug resistant P. aeruginosa (MDRP) and metallo β lactamase (MBL) produced P. aeruginosa collected from February 2010 to June 2012 were tested using BC plate ‘eiken’ (Eiken Chemical Co. Ltd, Tokyo, Japan) to evaluate the effect with combined antibiotics. The isolates have combined effect rather than single drug effect were tested using KB disk (Eiken Chemical Co. Ltd, Tokyo, Japan). As a result, there were higher zone of inhibition against some isolates for AMK/AZT, CL/AZT, CL/RFP and RFP/AZT, and the other isolates were not strong zone (≤0.5 mm). Therefore, disk diffusion susceptibility test for MDRP and MBL produced P. aeruginosa is able to determine antibiotic combination effects when it is recognized apparent zone.

多剤耐性緑膿菌感染症治療のために実施したBCプレートでの抗菌薬併用効果と治療効果の検討

多剤耐性緑膿菌感染症治療のために実施したBCプレートでの抗菌薬併用効果と治療効果の検討

Research and application of visual location technology for solder paste printing based on machine vision

A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro. One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

A C-Arm Fluoroscopy-Guided Progressive Cut Refinement Strategy Using a Surgical Robot

We describe a new method to cut a precise, high-quality femoral cavity in Revision Total Hip Replacement surgery (RTHR) using a surgical robot and an intra-operative C-arm fluoroscope. With respect to previous approaches, our method contains several new features. (1) We describe a novel checkerboard plate designed to correct the geometric distortion within fluoroscopic images. Unlike previous distortion correction devices, the plate does not completely obscure any part of the image, and the distortion correction algorithm works well even when there are some overlaid objects in the field of view. (2) Also included are a novel corkscrew fiducial object designed to be integrated with the robot end-effector, and a 6D pose estimation algorithm based on the two-dimensional (2D) projection of the corkscrew, used in robot-imager registration and imager co-registration. (3) In addition, we develop a cavity location algorithm, which utilizes image subtraction and 2D anatomy contour registration techniques. (4) Finally, we propose a progressive cut refinement strategy, which progressively improves the robot registration during the procedure. We have conducted several experiments, in both simulated and in vitro environments. The results indicate that our strategy is a promising method for precise orthopedic procedures like total hip replacement.

A C-arm fluoroscopy-guided progressive cut refinement strategy using a surgical robot.

We describe a new method to cut a precise, high-quality femoral cavity in Revision Total Hip Replacement surgery (RTHR) using a surgical robot and an intra-operative C-arm fluoroscope. With respect to previous approaches, our method contains several new features. (1) We describe a novel checkerboard plate designed to correct the geometric distortion within fluoroscopic images. Unlike previous distortion correction devices, the plate does not completely obscure any part of the image, and the distortion correction algorithm works well even when there are some overlaid objects in the field of view. (2) Also included are a novel corkscrew fiducial object designed to be integrated with the robot end-effector, and a 6D pose estimation algorithm based on the two-dimensional (2D) projection of the corkscrew, used in robot-imager registration and imager co-registration. (3) In addition, we develop a cavity location algorithm, which utilizes image subtraction and 2D anatomy contour registration techniques. (4) Finally, we propose a progressive cut refinement strategy, which progressively improves the robot registration during the procedure. We have conducted several experiments, in both simulated and in vitro environments. The results indicate that our strategy is a promising method for precise orthopedic procedures like total hip replacement.