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White, R. L., D. S. Burgess, M. Manduru, and J. A. Bosso. "Comparison of three different in vitro methods of detecting synergy: time-kill, checkerboard, and E test." Antimicrobial Agents and Chemotherapy 40, no. 8 (August 1996): 1914–18. http://dx.doi.org/10.1128/aac.40.8.1914.
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An in vitro method of detecting synergy which is simple to perform, accurate, and reproducible and has the potential for clinical extrapolation is desirable. Time-kill and checkerboard methods are the most widely used techniques to assess synergy but are time-consuming and labor-intensive. The Epsilometer test (E test), a less technically demanding test, has not been well studied for synergy testing. We performed synergy testing of Escherichia coli ATCC 35218, Enterobacter cloacae ATCC 23355, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 29213 with various combinations of cefepime or ceftazidime with tobramycin or ciprofloxacin using time-kill, checkerboard, and E test techniques. Time-kill testing was performed against each organism alone and in combinations at one-fourth times the MIC (1/4 x MIC) and 2 x MIC. With checkerboard tests, the same combinations were studied at concentrations ranging from 1/32 x to 4 x MIC. Standard definitions for synergy, indifference, and antagonism were utilized. E test strips were crossed at a 90 degree angle so the scales met at the MIC of each drug alone, and the fractional inhibitory concentrations index was calculated on the basis of the resultant zone on inhibition. All antimicrobial combinations demonstrated some degree of synergy against the test organisms, and antagonism was infrequent. Agreement with time-kill testing ranged from 44 to 88% and 63 to 75% by the checkerboard and E test synergy methods, respectively. Despite each of these methods utilizing different conditions and endpoints, there was frequent agreement among the methods. Further comparisons of the E test synergy technique with the checkerboard and time-kill methods are warranted.
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Supriadi, S., D. Darmawan, and R. Septiawan. "Checkerboard test implementation into ionospheric tomography for SuGAr data." Journal of Physics: Conference Series 1130 (November 2018): 012037. http://dx.doi.org/10.1088/1742-6596/1130/1/012037.
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Khang, Byung-Geun, and Edward A. Essock. "Apparent Relative Motion from a Checkerboard Surround." Perception 26, no. 7 (July 1997): 831–46. http://dx.doi.org/10.1068/p260831.
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To better understand the Ouchi illusion in which a stationary picture generates illusory relative motion, the spatial properties of the constituent elements of the rectangular checkerboard background were examined. Results of experiment 1 revealed that the largest illusion was obtained with elements of approximately 20–30 min in width and 4–6 min in height, an orientation of the constituents that was orthogonal to that of the test grating, and a phase shift of the alternate stripes that was close to 180°. In experiment 2 it was found that the illusion increased in magnitude with increasing achromatic contrast but was minimal with a pattern of high chromatic contrast near isoluminance. In experiment 3, two test patches were presented simultaneously in the checkerboard background and were varied independently in their orientation to explore whether or not their motions were perceived as coherent (common fate). Patches having identical orientations, and nearly orthogonal to the surround, were synchronized more strongly than those having reflected orientations. Hysteresis related to the gain control of spatially overlapping visual units differing in their polarity (ON/OFF) was discussed as a possible cause of this phenomenon.
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Owen, Lucy, and Katie Laird. "Synergistic Combinations of Antibiotics with Cumin, Oregano and Rosewood Oils as a Strategy to Preserve the Antibiotic Repertoire." Current Traditional Medicine 5, no. 4 (October 15, 2019): 337–53. http://dx.doi.org/10.2174/2215083805666190521102152.
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Background: Formulations employing synergistic combinations of antibiotics with Essential Oils (EOs) could help preserve the antibiotic repertoire by improving their activity against resistant bacteria. Objective: Antimicrobial interactions between double and triple combinations of EOs, EO components and antibiotics were determined using the checkerboard method. The most active triple combinations were then assessed by a time-kill assay. Methods: Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species. Results: Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species. Conclusion: Positive interactions support the use of EOs or EO components to enhance antibiotic efficacy against antibiotic resistant bacteria. The EO-antibiotic combinations tested by the time kill assay were indifferent; therefore, the observed antimicrobial activity did not arise from synergistic mechanisms as indicated by the checkerboard method. Investigation of other synergistic combinations identified by the checkerboard method could reveal more promising candidates.
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Orhan, G., A. Bayram, Y. Zer, and I. Balci. "Synergy Tests by E Test and Checkerboard Methods of Antimicrobial Combinations against Brucella melitensis." Journal of Clinical Microbiology 43, no. 1 (January 1, 2005): 140–43. http://dx.doi.org/10.1128/jcm.43.1.140-143.2005.
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Sarnthein, Johannes, Maria Andersson, Michael B. Zimmermann, and Dominik Zumsteg. "High test–retest reliability of checkerboard reversal visual evoked potentials (VEP) over 8 months." Clinical Neurophysiology 120, no. 10 (October 2009): 1835–40. http://dx.doi.org/10.1016/j.clinph.2009.08.014.
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Burns, K. C. "Meta-community structure of vascular epiphytes in a temperate rainforest." Botany 86, no. 11 (November 2008): 1252–59. http://dx.doi.org/10.1139/b08-084.
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I quantified the occurrence of all vascular plant species inhabiting 43 Thuja plicata Donn ex D. Don trees in a temperate rainforest in British Columbia, Canada, to test whether (i) epiphyte species richness increased with tree diameter, and (ii) epiphyte distributions showed evidence for nestedness, checkerboard distributions, or compartmentalization. Nine vascular plant species were observed growing epiphytically. One species ( Polypodium glycyrrhiza Eat.) is an obligate epiphyte, while the remainder typically occurred on the forest floor. Smaller host trees (<0.5 m in diameter) lacked vascular epiphytes, and species richness increased with host diameter. No evidence for nested or checkerboarded distributions was observed. However, epiphyte distributions were compartmentalized, owing to five similar shrub species that tended to co-occur jointly, generating sharp turnover in species composition between host trees with and without shrubs. The lack of co-occurrence patterns indicative of interspecific interactions among epiphytes indicates that the epiphyte meta-community is structured stochastically from species that normally grow terrestrially.
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Kalkanci, Ayse, Murat Dizbay, Nuran Sari, Burce Yalcin, Isil Fidan, Dilek Arman, and Semra Kustimur. "Fluconazole, caspofungin, voriconazole in combination with amphotericin B." Open Medicine 5, no. 2 (April 1, 2010): 194–97. http://dx.doi.org/10.2478/s11536-010-0010-0.
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AbstractCombined antifungal therapy has been suggested to enhance the efficacy and reduce the toxicity of antifungal agents. The aim of the study was to investigate the in vitro synergistic activity of caspofungin, voriconazole, and fluconazole with amphotericin B against ten isolates of Candida parapsilosis and Candida albicans strains which were resistant to azoles or amphotericin B. Three different antifungal combinations (amphotericin B [AP] — caspofungin [CS], amphotericin B — fluconazole [FL], and AP — voriconazole [VO]) were evaluated for in vitro synergistic effect by the microdilution checkerboard and E-test methods. For the majority of strains, the combination test showed indifferent activity. Via the E-test method, synergistic activity was seen in 3 strains in response to AP-CS combination treatment and in one strain after administration of AP-FL; however, no synergy was observed in response to combination treatment with P-VO. Antagonistic activity was the result in 1 strain treated with AP-CS as well as in 6 strains treated with AP-FL and AP-VO combinations. Via the microdilution test, no synergistic activity was seen after treatment with all 3 combinations. Antagonistic activity was the result in 2 strains with AP-CS, in 6 strains with AP-VO and in 5 strains with AP-FL combinations. Agreement between the checkerboard and E-test methods was observed to be approximately 72%. These combinations may be used in the case of antifungal resistance.
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Stone, Christopher, and Larry Bull. "For Real! XCS with Continuous-Valued Inputs." Evolutionary Computation 11, no. 3 (September 2003): 299–336. http://dx.doi.org/10.1162/106365603322365315.
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Many real-world problems are not conveniently expressed using the ternary representation typically used by Learning Classifier Systems and for such problems an interval-based representation is preferable. We analyse two interval-based representations recently proposed for XCS, together with their associated operators and find evidence of considerable representational and operator bias. We propose a new interval-based representation that is more straightforward than the previous ones and analyse its bias. The representations presented and their analysis are also applicable to other Learning Classifier System architectures. We discuss limitations of the real multiplexer problem, a benchmark problem used for Learning Classifier Systems that have a continuous-valued representation, and propose a new test problem, the checkerboard problem, that matches many classes of real-world problem more closely than the real multiplexer. Representations and operators are compared using both the real multiplexer and checkerboard problems and we find that representational, operator and sampling bias all affect the performance of XCS in continuous-valued environments.
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Sasidharan, Nishanth Kumar, Sreerag Ravikumar Sreekala, Jubi Jacob, and Bala Nambisan. "In VitroSynergistic Effect of Curcumin in Combination with Third Generation Cephalosporins against Bacteria Associated with Infectious Diarrhea." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/561456.
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Diarrhea is one of the leading causes of morbidity and mortality in humans in developed and developing countries. Furthermore, increased resistance to antibiotics has resulted in serious challenges in the treatment of this infectious disease worldwide. Therefore, there exists a need to develop alternative natural or combination drug therapies. The aim of the present study was to investigate the synergistic effect of curcumin-1 in combination with three antibiotics against five diarrhea causing bacteria. The antibacterial activity of curcumin-1 and antibiotics was assessed by the broth microdilution method, checkerboard dilution test, and time-kill assay. Antimicrobial activity of curcumin-1 was observed against all tested strains. The MICs of curcumin-1 against test bacteria ranged from 125 to 1000 μg/mL. In the checkerboard test, curcumin-1 markedly reduced the MICs of the antibiotics cefaclor, cefodizime, and cefotaxime. Significant synergistic effect was recorded by curcumin-1 in combination with cefotaxime. The toxicity of curcumin-1 with and without antibiotics was tested against foreskin (FS) normal fibroblast and no significant cytotoxicity was observed. From our result it is evident that curcumin-1 enhances the antibiotic potentials against diarrhea causing bacteria inin vitrocondition. This study suggested that curcumin-1 in combination with antibiotics could lead to the development of new combination of antibiotics against diarrhea causing bacteria.
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Hess, C., and A. P. Stroele. "Modeling of real defect outlines and parameter extraction using a checkerboard test structure to localize defects." IEEE Transactions on Semiconductor Manufacturing 7, no. 3 (1994): 284–92. http://dx.doi.org/10.1109/66.311331.
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Bae, Seongman, Min-Chul Kim, Su-Jin Park, Hee Sueng Kim, Heungsup Sung, Mi-Na Kim, Sung-Han Kim, et al. "In VitroSynergistic Activity of Antimicrobial Agents in Combination against Clinical Isolates of Colistin-Resistant Acinetobacter baumannii." Antimicrobial Agents and Chemotherapy 60, no. 11 (September 6, 2016): 6774–79. http://dx.doi.org/10.1128/aac.00839-16.
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ABSTRACTEmerging resistance to colistin in clinicalAcinetobacter baumanniiisolates is of growing concern. Since current treatment options for these strains are extremely limited, we investigated thein vitroactivities of various antimicrobial combinations against colistin-resistantA. baumannii. Nine clinical isolates (8 from bacteremia cases and 1 from a pneumonia case) of colistin-resistantA. baumanniiwere collected in Asan Medical Center, Seoul, South Korea, between January 2010 and December 2012. To screen for potential synergistic effects, multiple combinations of two antimicrobials among 12 commercially available agents were tested using the multiple-combination bactericidal test (MCBT). Checkerboard tests were performed to validate these results. Among the 9 colistin-resistant strains, 6 were pandrug resistant and 3 were extensively drug resistant. With MCBT, the most effective combinations were colistin-rifampin and colistin-teicoplanin; both combinations showed synergistic effect against 8 of 9 strains. Colistin-aztreonam, colistin-meropenem, and colistin-vancomycin combinations showed synergy against seven strains. Colistin was the most common constituent of antimicrobial combinations that were active against colistin-resistantA. baumannii. Checkerboard tests were then conducted in colistin-based combinations. Notably, colistin-rifampin showed synergism against all nine strains (100%). Both colistin-vancomycin and colistin-teicoplanin showed either synergy or partial synergy. Colistin combined with another β-lactam agent (aztreonam, ceftazidime, or meropenem) showed a relatively moderate effect. Colistin combined with ampicillin-sulbactam, tigecycline, amikacin, azithromycin, or trimethoprim-sulfamethoxazole demonstrated limited synergism. Using MCBT and checkerboard tests, we found that only colistin-based combinations, particularly those with rifampin, glycopeptides, or β-lactams, may confer therapeutic benefits against colistin-resistantA. baumannii.
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Trampert, Jeannot, Andreas Fichtner, and Jeroen Ritsema. "Resolution tests revisited: the power of random numbers." Geophysical Journal International 192, no. 2 (December 5, 2012): 676–80. http://dx.doi.org/10.1093/gji/ggs057.
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Abstract We propose a simple method where the inversion of synthetic data, corresponding to a zero-mean random input vector, is used to infer the average horizontal and vertical resolution lengths of tomographic models. The method works well if the resolution operator has a diagonally dominant structure. This assumption, although often verified in seismic tomography, can be tested by simply cross-correlating the input with the output of the synthetic simulation. The method is as efficient as a single checkerboard test, but reveals more easily interpretable information.
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Sun, Shujuan, Yan Li, Qiongjie Guo, Changwen Shi, Jinlong Yu, and Lin Ma. "In Vitro Interactions between Tacrolimus and Azoles against Candida albicans Determined by Different Methods." Antimicrobial Agents and Chemotherapy 52, no. 2 (December 3, 2007): 409–17. http://dx.doi.org/10.1128/aac.01070-07.
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ABSTRACT Combination therapy could be of use for the treatment of fungal infections, especially those caused by drug-resistant fungi. However, the methods and approaches used for data generation and result interpretation need further optimizing. The fractional inhibitory concentration index (FICI) is the most commonly used method, but it has several drawbacks in characterizing antifungal drug interaction. Alternatively, some new methods can be used such as the ΔE model (difference between the predicted and measured fungal growth percentages) and the response surface approach, which uses the concentration-effect relationship over the whole concentration range instead of just the MIC. In the present study, in vitro interactions between tacrolimus (FK506) and three azoles—fluconazole (FLC), itraconazole (ITR), and voriconazole (VRC)-against Candida albicans were evaluated by the checkerboard microdilution method and time-killing test. The intensity of the interactions was determined by visual reading and the spectrophotometric method in a checkerboard assay, and the nature of the interactions was assessed by nonparametric models of FICI and ΔE. Colony counting and colorimetric viable detection methods (2,3-bis {2-methoxy-4-nitro-5-[(sulfenylamino) carbonyl]-2H-tetrazolium hydroxide} [XTT] reduction test) were used for evaluating the combination antifungal effects over time. Synergistic and indifferent effects were found for the combination of FK506 and azoles against azole-sensitive strains, while strong synergy was found against azole-resistant strains analyzed by FICI. The ΔE model gave more consistent results with FICI. The positive interactions were also confirmed by the time-killing test. Our findings suggest a potential role for combination therapy with calcineurin pathway inhibitors and azoles to augment activity against resistant C. albicans.
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Leelaporn, Amornrut. "Activity of Antimicrobial Combinations Against Extensively Drug-Resistant Acinetobacter baumannii as Determined by Checkerboard Method and E-test." Siriraj Medical Journal 72, no. 3 (April 20, 2020): 214–18. http://dx.doi.org/10.33192/smj.2020.29.
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Zhang, Xiaoling, Qingduan Meng, and Liwen Zhang. "Dependence of the Deformation of 128×128 InSb Focal-plane Arrays on the Silicon Readout Integrated Circuit Thickness." Open Electrical & Electronic Engineering Journal 9, no. 1 (June 15, 2015): 170–74. http://dx.doi.org/10.2174/1874129001509010170.
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The square checkerboard buckling deformation appearing in indium antimonide infrared focal-plane arrays (InSb IRFPAs) subjected to the thermal shock tests, results in the fracturing of the InSb chip, which restricts its final yield. In light of the proposed three-dimensional modeling, we proposed the method of thinning a silicon readout integrated circuit (ROIC) to level the uneven top surface of InSb IRFPAs. Simulation results show that when the silicon ROIC is thinned from 300 μm to 20 μm, the maximal displacement in the InSb IRFPAs linearly decreases from 7.115 μm to 0.670 μm in the upward direction, and also decreases linearly from 14.013 μm to 1.612 μm in the downward direction. Once the thickness of the silicon ROIC is less than 50 μm, the square checkerboard buckling deformation distribution presenting in the thicker InSb IRFPAs disappears, and the top surface of the InSb IRFPAs becomes flat. All these findings imply that the thickness of the silicon ROIC determines the degree of deformation in the InSb IRFPAs under a thermal shock test, that the method of thinning a silicon ROIC is suitable for decreasing the fracture probability of the InSb chip, and that this approach improves the reliability of InSb IRFPAs.
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Pénzes, Judit, and Mária Benkő. "Novel parvovirus from the worm lizard Trogonophis wiegmanni — First virus ever detected in amphisbaenian hosts." Acta Veterinaria Hungarica 62, no. 2 (June 1, 2014): 284–92. http://dx.doi.org/10.1556/avet.2014.010.
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To explore the diversity of some DNA viruses in reptiles, a continuous screening is going on, in our laboratory, by PCR using different consensus primers designed for the detection of the most conserved genome regions of adeno-, herpes- and parvoviruses. The test material consists essentially of dead specimens collected randomly from private pet owners, local pet shops, or at occasional exotic pet fairs. Here we report the partial sequence of a putative novel parvovirus obtained from a dead checkerboard worm lizard(Trogonophis wiegmanni)that had been wild-caught in its native habitat. An in-house-developed PCR with consensus primers targeting the gene of the parvoviral capsid protein was used. Other PCRs, intended to detect certain large DNA viruses, remained negative. The sequence of the PCR product indicated the presence of a hitherto unknown parvovirus in the internal organs of the checkerboard worm lizard. In phylogeny reconstruction, the novel sequence clustered with the members of theDependovirusgenus of theParvoririnaesubfamily, closest to the branch of snake adeno-associated virus. Since we could not demonstrate the presence of a potential helper virus, the putative amphisbaenian parvovirus supposedly can replicate autonomously. This is the first virus infection ever detected in any members of the suborder Amphisbaenia, and only the third parvoviral sequence obtained from any reptilian host.
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Mun, Su-Hyun, Ok-Hwa Kang, Dae-Ki Joung, Sung-Bae Kim, Yun-Soo Seo, Jang-Gi Choi, Young-Seob Lee, et al. "Combination Therapy of Sophoraflavanone B against MRSA:In VitroSynergy Testing." Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/823794.
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Sophoraflavanone B (SPF-B), a known prenylated flavonoid, was isolated from the roots ofDesmodium caudatum. The aim of this study was to determine the antimicrobial synergism of SPF-B combined with antibiotics against methicillin-resistantStaphylococcus aureus(MRSA). MRSA, a multidrug-resistant pathogen, causes both hospital- and community-acquired infections worldwide. The antimicrobial activity of SPF-B was assessed by the broth microdilution method, checkerboard dilution test, and time-kill curve assay. The MIC of SPF-B for 7 strains ofS. aureusranges from 15.6 to 31.25 μg/mL determined. In the checkerboard method, the combinations of SPF-B with antibiotics had a synergistic effect; SPF-B markedly reduced the MICs of theβ-lactam antibiotics: ampicillin (AMP) and oxacillin (OXI); aminoglycosides gentamicin (GET); quinolones ciprofloxacin (CIP) and norfloxacin (NOR) against MRSA. The time-kill curves assay showed that a combined SPF-B and selected antibiotics treatment reduced the bacterial counts below the lowest detectable limit after 24 h. These data suggest that the antibacterial activity of SPF-B against MRSA can be effectively increased through its combination with three groups of antibiotics (β-lactams, aminoglycosides, and quinolones). Our research can be a valuable and significant source for the development of a new antibacterial drug with low MRSA resistance.
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Basri, Dayang Fredalina, Lee Wee Xian, Nur Indah Abdul Shukor, and Jalifah Latip. "Bacteriostatic Antimicrobial Combination: Antagonistic Interaction between Epsilon-Viniferin and Vancomycin against Methicillin-ResistantStaphylococcus aureus." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/461756.
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Stilbenoids have been considered as an alternative phytotherapeutic treatment against methicillin-resistantStaphylococcus aureus(MRSA) infection. The combined effect ofε-viniferin and johorenol A with the standard antibiotics, vancomycin and linezolid, was assessed against MRSA ATCC 33591 and HUKM clinical isolate. The minimum inhibitory concentration (MIC) value of the individual tested compounds and the fractional inhibitory concentration index (FICI) value of the combined agents were, respectively, determined using microbroth dilution test and microdilution checkerboard (MDC) method. Only synergistic outcome from checkerboard test will be substantiated for its rate of bacterial killing using time-kill assay. The MIC value ofε-viniferin against ATCC 33591 and johorenol A against both strains was 0.05 mg/mL whereas HUKM strain was susceptible to 0.1 mg/mL ofε-viniferin. MDC study showed that only combination betweenε-viniferin and vancomycin was synergistic against ATCC 33591 (FICI 0.25) and HUKM (FICI 0.19). All the other combinations (ε-viniferin-linezolid, johorenol A-vancomycin, and johorenol A-linezolid) were either indifferent or additive against both strains. However, despite the FICI value showing synergistic effect forε-viniferin-vancomycin, TKA analysis displayed antagonistic interaction with bacteriostatic action against both strains. As conclusion,ε-viniferin can be considered as a bacteriostatic stilbenoid as it antagonized the bactericidal activity of vancomycin. These findings therefore disputed previous report thatε-viniferin acted in synergism with vancomycin but revealed that it targets similar site in close proximity to vancomycin’s action, possibly at the bacterial membrane protein. Hence, this combination has a huge potential to be further studied and developed as an alternative treatment in combating MRSA in future.
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Majhi, Arnab, Ajeya Nandi, Rana Adhikary, Sayantika Mahanti, and Biswadev Bishayi. "In vitro susceptibility of a penicillin-resistant and tolerable isolate of Streptococcus pneumoniae to combination therapy." Journal of Infection in Developing Countries 9, no. 07 (July 30, 2015): 702–9. http://dx.doi.org/10.3855/jidc.4711.
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Introduction: Preference for combination therapy to treat infection due to multidrug-resistant S. pneumoniae (MDRSP) has not been well elucidated in previous studies. Methodology: In the present study, 19 antibiotics in combinations were tested against an MDRSP isolate. In vitro susceptibility studies including minimum inhibitory concentration (MIC), minimal bactericidal concentrations (MBC) and disk agar diffusion (DAD), tolerance to resistant antibiotics, checkerboard assay, time-kill curve, hemolytic assay, and autolysis assay were performed on the test strain to study its in vitro susceptibility to combination therapy. Results: From the checkerboard assay and time-kill curve, it was observed that a combination of levofloxacin (MIC, 16 µg/mL) and ceftriaxone (MIC, 2 µg/mL), at sub-MIC concentration was synergistic and most effective against the MDRSP isolate (penicillin MIC, > 64 µg/mL). Hemolytic activities also increased significantly with combination therapy compared to monotherapy (p < 0.05). Moreover, the hemolytic activity of levofloxacin in combination with ceftriaxone was better than ciprofloxacin plus ceftriaxone or cefepime. The autolysis rate was also found to increase rapidly within one hour of exposure to levofloxacin plus ceftriaxone, and this was found to be significantly different from the other combinations at the fifth and sixth hour post incubation (p < 0.05). Conclusions: This data suggests that this combination is bactericidal in vitro, and requires further studies in in vivo models for treatment against MDRSP infections.
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Olajuyigbe, Olufunmiso O., and Roger M. Coopoosamy. "Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract ofAcacia mearnsiiDe Wild. against Drug-Resistant Bacterial Isolates." Evidence-Based Complementary and Alternative Medicine 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/423751.
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Background.This study was aimed at evaluating the antibacterial activity of the acetone extract ofA. mearnsiiand its interactions with antibiotics against some resistant bacterial strains.Methods.The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract.Results.The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception ofS. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibitEnterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are inμg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity.Conclusion.The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases.
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Ismail, T. F., and T. Yoshida. "In vitro activity of some essential oils alone and in combination against the fish pathogen Nocardia seriolae." Polish Journal of Veterinary Sciences 20, no. 3 (September 26, 2017): 559–66. http://dx.doi.org/10.1515/pjvs-2017-0068.
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Abstract Microplate resazurin assay was applied to investigate the in vitro activity of four essential oils (EOs); cinnamon (Cinnamomum zeylanicum), thyme (Thymus vulgaris), lemongrass (Cymbopogon flexuosus) and tea tree (Melaleuca alternifolia) oils against 80 clinical isolates of the fish pathogen Nocardia seriolae. The checkerboard test was then used to determine the possible synergistic effect of EOs combination against reference type strains of fish nocardiosis. All tested EOs had antibacterial activity against N. seriolae isolates. Among the tested EOs, cinnamon and thyme oils both exhibited the lowest minimum inhibitory concentrations (MICs) with 5-160 and 10-160 μg/ml, respectively. The activities of lemongrass and tea tree EOs were noted to be less effective with MICs of 20-640 and 160->5120 μg/ml, respectively. The checkerboard panel of cinnamon-thyme EOs combination against N. seriolae ATCC43993 demonstrated a synergistic effect with a fractional inhibitory concentration (FIC) index of 0.75. For N. salmonicida ATCC27463, the combination panel showed an additive effect with an FIC index of 1.0. For N. asteroides ATCC19247, the combination panel demonstrated an indifference effect with an FIC index of 1.125. These results indicate that thyme and cinnamon oils alone or the combination of them at a given ratio has a promising potent clinical significance in the treatment of fish nocardiosis. Despite the promising results given by our in vitro studies, the clinical benefits of these EOs combinations can only be determined through carefully designed in vivo experimental studies.
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Mahadlek, J., Juree Charoenteeraboon, and T. Phaechamud. "Combination Effects of the Antimicrobial Agents and Cinnamon Oil." Advanced Materials Research 506 (April 2012): 246–49. http://dx.doi.org/10.4028/www.scientific.net/amr.506.246.
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The use of antimicrobial combination may be interesting because it can decrease doses and side effects of antimicrobial agents. The cinnamon essential oil was examined with respect to antimicrobial modifying activity. The combination effect of antimicrobial agents (doxycycline hyclate, ciprofloxacin HCl and metronidazole) and cinnamon oil was evaluated by checkerboard method to obtain a fractional inhibitory concentration (FIC) index. The effect of metronidazole+doxycycline hyclate and metronidazole+ciprofloxacin hydrochloride combinations were additive against Staphylococcus aureus. The indifference FIC index was observed only with the doxycycline hyclate+ciprofloxacin HCl combination. Combinations of cinnamon oil and all antimicrobial agents showed the additive effects against S. aureus. These results indicated that the antimicrobial activity of cinnamon oil was generally additive to all test antimicrobial agents.
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PINTO, Paulo Sérgio de Arruda, Adelaide José VAZ, Pedro Manuel Leal GERMANO, and Paulo Mutuko NAKAMURA. "ELISA test for the diagnosis of cysticercosis in pigs using antigens of Taenia solium and Taenia crassiceps cysticerci." Revista do Instituto de Medicina Tropical de São Paulo 42, no. 2 (April 2000): 71–79. http://dx.doi.org/10.1590/s0036-46652000000200003.
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In the present study ELISA was standardized for the diagnosis of swine cysticercosis based on necropsy parameters and confirmed positive and negative control sera. Serum samples from pigs with other infections were also assayed to determine possible cross-reactions. Four antigens were assayed: from Taenia crassiceps vesicular fluid (VF-Tcra) and crude larvae extract (T-Tcra), and from Taenia solium extracts of scolex (S-Ts) and of larvae (T-Ts). A checkerboard evaluation of antigen, serum and conjugate dilutions, as well as the use of Tween-20 and skim cow milk in wash and blocking solution had a marked effect on improving ELISA performance. All the antigens showed a good performance, but VF-Tcra was the best, with 96.0% and 80.0% sensitivities for cut-offs respectively at 2sd and 3sd, and corresponding specificities of 97.5% and 100.0%. Cross-reactivity was observed only with hydatidosis and ascaridiosis. In view of the high performance observed, the ELISA test should be recommended for the diagnosis of cysticercosis in suspected swine in slaughterhouses and for the screening of cysticercosis in swine production. These results will support integrated measures of cysticercosis control throughout the chain of swine production, effectively contributing to public health.
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Novi Haryanti, Iskandarsyah, and Yeva Rosana. "Sinergicity test of silver nanoparticles and clindamycin against Staphylococcus aureus." International Journal of Research in Pharmaceutical Sciences 11, no. 1 (February 8, 2020): 1192–98. http://dx.doi.org/10.26452/ijrps.v11i1.1957.
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Acne is a chronic inflammatory disease. The pathogenesis of acne is multifactorial; one of them is caused by an overgrowth of microbes like S. aureus. Clindamycin is one of the antibiotics recommended for acne therapy. Still, the use of clindamycin causes various side effects such as changes in intestinal function associated with intestinal flora, pseudomembranous colitis, and increases the risk of resistance. Silver nanoparticles are potent antimicrobials, have broad-spectrum activity, and can reduce the development of resistance. Despite having potent activity, the long-term use of silver nanoparticles is reported to have side effects argyria. The use of antimicrobial combinations is a strategy to reduce side effects and increase the effectiveness of therapy. Antimicrobial combinations can use low concentrations but still have the potential to inhibit microbial growth. This research aim is to determine the antibacterial synergism of a combination of silver nanoparticles and clindamycin against S. aureus. Determination of the minimum inhibitory concentration (MIC) of silver nanoparticles, clindamycin, and synergism test was carried out by microdilution using 96-well microplates. Synergy test is carried out using the Checkerboard method by calculating the value of the Fractional Index Concentration (FIC). The results showed the MIC values of silver nanoparticles and clindamycin were 16 µg/ml and 64 µg/ml, respectively. The synergy test of the combination of silver nanoparticles yielding an FIC value of 0.75. Based on the result of the study, it was concluded that the combination of silver nanoparticles and clindamycin had partial synergy properties. The Minimum bactericidal Concentration (MBC) value clindamycin alone compared in combination with silver nanoparticles 16 µg/ml reduces from 256 µg/ml to 128 µg/ml. Combinations of silver nanoparticle and clindamycin are the potential to reduce side effects and overcome resistance.
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do AV Sá, Lívia G., Cecília R. da Silva, Rosana de S Campos, João B. de A Neto, Letícia S. Sampaio, Francisca BSA do Nascimento, Fátima DD Barroso, et al. "Synergistic anticandidal activity of etomidate and azoles against clinical fluconazole-resistant Candida isolates." Future Microbiology 14, no. 17 (November 2019): 1477–88. http://dx.doi.org/10.2217/fmb-2019-0075.
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Aim: The purpose of this study was to evaluate the effect of etomidate alone and in combination with azoles on resistant strains of Candida spp. in both planktonic cells and biofilms. Materials & methods: The antifungal activity of etomidate was assessed by the broth microdilution test; flow cytometric procedures to measure fungal viability, mitochondrial transmembrane potential, free radical generation and cell death; as well detection of DNA damage using the comet assay. The interaction between etomidate and antifungal drugs (itraconazole and fluconazole) was evaluated by the checkerboard assay. Results: Etomidate showed antifungal activity against resistant strains of Candida spp. in planktonic cells and biofilms. Etomidate also presented synergism with fluconazole and itraconazole in planktonic cells and biofilms. Conclusion: Etomidate showed antifungal activity against Candida spp., indicating that it is a possible therapeutic alternative.
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Reinisch, N., B. A. Sitte, C. M. Kähler, and C. J. Wiedermann. "Human chorionic gonadotrophin: a chemoattractant for human blood monocytes, neutrophils and lymphocytes." Journal of Endocrinology 142, no. 1 (July 1994): 167–70. http://dx.doi.org/10.1677/joe.0.1420167.
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Abstract Treatment of rats with human chorionic gonadotrophin (hCG) induced in the testes an inflammation-like reaction characterized by migration of leukocytes into the interstitial space. In order to find out whether hCG acts in a direct manner in this process, we tested peripheral human blood leukocyte attraction by hCG in vitro. Chemotaxis through cellulose nitrate to gradients of test substances was measured using a 48-well microchemotaxis chamber. Human CG was found to be a potent attractor of neutrophils, monocytes and lymphocytes in vitro in the picomolar concentration range. Checkerboard analyses revealed that the type of migration depends on positive concentration gradients of hCG. The chemoattractant nature of hCG is consistent with its having a role to play in regulation of tissue accumulation of these cells within the reproductive tract. Journal of Endocrinology (1994) 142, 167–170
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Hashimoto, Newton, Fabrício José Benati, Flávio Lauretti, Rosa Elisa Carvalho Linhares, and Carlos Mitihiko Nozawa. "Development of an enzyme immunoassay for poliovirus antigens." Brazilian Archives of Biology and Technology 50, no. 1 (January 2007): 39–44. http://dx.doi.org/10.1590/s1516-89132007000100005.
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An indirect solid-phase enzyme immunoassay (EIA) was developed for the detection of poliovirus antigen. Virus antigen was obtained in LLC-MK2 cell cultures and used to prepare antibodies in rabbit and guinea pig. Antibodies were evaluated by double immunodiffusion and neutralization test. Optimal concentrations of guinea pig and rabbit immunoglobulins were determined by checkerboard titration. Microtitre plates were coated with 15.0 µg/ml guinea pig anti-polio immunoglobulin and rabbit anti-polio immunoglobulin at the concentration of 7.94 µg/ml was used as detecting antibody. The standard curve with eight different antigen concentrations in eight replicates resulted in a coefficient of variation (CV) between 2.1% to 7.8%. The dose-response relationship was determined by simple linear regression with a coefficient of correlation (R²) equal to 96.4%. The assay detected a minimum of 2.3 µg/ml poliovirus antigen.
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HEINRICH, THOMAS STEPHAN, and MICHAEL BACH. "Contrast adaptation: Paradoxical effects when the temporal frequencies of adaptation and test differ." Visual Neuroscience 19, no. 4 (July 2002): 421–26. http://dx.doi.org/10.1017/s0952523802194041.
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Previous studies of human contrast adaptation employing visually evoked potentials (VEP) have revealed contradictory results, namely, either a reduction or an enhancement in VEP amplitude. In a cross-adaptation experiment, we explored the possibility that differences in the temporal frequency of adapting and test patterns played a role. Phase-reversing checkerboard stimuli [1-deg check size, temporal frequency 8.5 or 17 reversals per second (rps)] served as adaptation and test pattern with contrasts of 0 or 97%. In 13 subjects, we recorded both retinal (PERG) and cortical (VEP) steady-state responses simultaneously. In a balanced block design, all four combinations of the temporal adaptation and test frequencies were employed. Contrast adaptation reduced the PERG amplitude by about 20% in every temporal condition (P < 0.001). The VEP amplitude was strongly affected by adaptation, but the effect differed in magnitude and sign depending on condition: With identical adaptation and test frequency, amplitude was reduced by 15% (P = 0.07) at 8.5 rps and by 38% at 17 rps (P < 0.05). Adapting at 8.5 rps and testing at 17 rps had a tiny (14%) insignificant effect, whereas adapting at 17 rps and testing at 8.5 rps revealed an amplitude enhancement of 27% (P < 0.05). These strong temporal cross-adaptation effects (in the VEP, but not in the PERG) suggest that the adaptable cortical mechanisms (gain control) can be narrowly tuned in their temporal properties. A sizable adaptation effect can even change its sign when varying the temporal frequency by a factor of two. This finding resolves contradictions between previous VEP adaptation studies and reconciles them with psychophysical findings.
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JAMES, ANDREW C., RASA RUSECKAITE, and TED MADDESS. "Effect of temporal sparseness and dichoptic presentation on multifocal visual evoked potentials." Visual Neuroscience 22, no. 1 (January 2005): 45–54. http://dx.doi.org/10.1017/s0952523805221053.
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Multifocal VEP (mfVEP) responses were obtained from 13 normal human subjects for nine test conditions, covering three viewing conditions (dichoptic and left and right monocular), and three different temporal stimulation forms (rapid contrast reversal, rapid pattern pulse presentation, and slow pattern pulse presentation). The rapid contrast reversal stimulus had pseudorandomized reversals of checkerboards in each visual field region at a mean rate of 25 reversals/s, similar to most mfVEP studies to date. The rapid pattern pulse presentation had pseudorandomized presentations of a checkerboard for one frame, interspersed with uniform grey frames, with a mean rate of 25 presentations/s per region per eye. The slow pattern pulse stimulus had six presentations/s per region per eye. Recording time was 5.3 min/condition. For dichoptic presentation slow pattern pulse responses were 4.6 times larger in amplitude than the contrast reversal responses. Binocular suppression was greatest for the contrast reversal stimulus. Consideration of the signal-to-noise ratios indicated that to achieve a given level of reliability, slow pattern pulse stimuli would require half the recording time of contrast reversal stimuli for monocular viewing, and 0.4 times the recording time for dichoptically presented stimuli. About half the responses to the slow pattern pulse stimuli had peak value exceeding five times their estimated standard error. Responses were about 20% smaller in the upper visual field locations. Space–time decomposition showed that responses to slow pattern pulse were more consistent across visual field locations. We conclude that the pattern pulse stimuli, which we term temporally sparse, maintain the visual system in a high contrast gain state. This more than compensates for the smaller number of presentations in the run, and provides signal-to-noise advantages that may be valuable in clinical application.
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Bajaksouzian, S., M. A. Visalli, M. R. Jacobs, and P. C. Appelbaum. "Antipneumococcal activities of cefpirome and cefotaxime, alone and in combination with vancomycin and teicoplanin, determined by checkerboard and time-kill methods." Antimicrobial Agents and Chemotherapy 40, no. 9 (September 1996): 1973–76. http://dx.doi.org/10.1128/aac.40.9.1973.
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The checkerboard titration method was used to test the synergy of cefpirome and cefotaxime with teicoplanin or vancomycin against 35 penicillin-susceptible, 34 penicillin-intermediate, and 31 penicillin-resistant pneumococci. The MICs at which 50 and 90% of isolates are inhibited (MIC50s and MIC90s, respectively) of both cefpirome and cefotaxime were 0.016 and 0.06 microgram/ml, respectively, for penicillin-susceptible strains and 0.125 and 0.5 microgram/ml, respectively, for penicillin-intermediate strains. The MIC50s and MIC90s of cefotaxime for penicillin-resistant strains were 1.0 and 2.0 micrograms/ml, respectively, and those of cefpirome were 0.5 and 1.0 microgram/ml, respectively. All pneumococci were inhibited by cefpirome at MICs of < or = 1.0 microgram/ml. The MIC50s and MIC90s of vancomycin and teicoplanin (0.25 and 0.25 microgram/ml and 0.03 and 0.03 microgram/ml, respectively) did not differ for the three groups. Checkerboard synergy studies showed that cefpirome and vancomycin showed synergy for 31 strains (fractional inhibitory concentration [FIC] indices, < or = 0.5) cefpirome and teicoplanin showed synergy for 18 strains, cefotaxime and vancomycin showed synergy for 51 strains, and cefotaxime and teicoplanin showed synergy for 27 strains. Cefpirome and vancomycin had FIC indices indicating indifference (2.0) for two strains, and cefotaxime and vancomycin had FIC indices indicating indifference for one strain. All other FIC indices indicating indifference or additivity were > 0.5 to 1.0. No FIC indices indicating antagonism (> 4.0) were found. Synergy between beta-lactams and glycopeptides for three susceptible, three intermediate, and three resistant strains were tested by the time-kill assay, and all combinations were synergistic by this method. Synergy between cephalosporins and glycopeptides can be demonstrated and may be useful for the treatment of pneumococcal infections, especially meningitis.
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Meese, Tim S., and Mark A. Georgeson. "Spatial Filter Combination in Human Pattern Vision: Channel Interactions Revealed by Adaptation." Perception 25, no. 3 (March 1996): 255–77. http://dx.doi.org/10.1068/p250255.
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Above threshold, two superimposed sinusoidal gratings of the same spatial frequency (eg 1 cycle deg−1), of equal moderate contrast (eg C1 = C2 = 6%), and with orientations of ±45°, usually look like a compound structure containing vertical and horizontal edges (ie a blurred checkerboard). These feature orientations are very different from the dominant filter orientations in a wavelet-type (eg simple-cell) transform of the stimulus, and so present a serious challenge to conventional models of orientation coding based on labelled linear filters. Previous experiments on perceived structure in static plaids have led to the view that the outputs of tuned spatial filters are combined in a stimulus-dependent way, before features such as edges are extracted. Here an adaptation paradigm was used to investigate the cross-channel interactions that appear to underlie the spatial-filter-combination process. Reported are two aftereffects of selective adaptation: (i) adaptation to a 1 cycle deg−1 plaid whose component orientations are intermediate to those in a 1 cycle deg−1 test plaid ‘breaks’ perceptual combination of the components in the test plaid; (ii) adapting to a 3 cycles deg−1 plaid whose component orientations match those in a 1 cycle deg−1 test plaid facilitates perceptual combination of the components in the test plaid. The results are taken as evidence that spatial channels remote from those most responsive to a test plaid play a crucial role in determining whether the test plaid segments or coheres perceptually.
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Triches, Thaisa Cezária, Luciene Cristina de Figueiredo, Magda Feres, Sérgio Fernando Torres de Freitas, Gláucia Santos Zimmermann, and Mabel Mariela Rodríguez Cordeiro. "Microbial Reduction by Two Chemical-Mechanical Protocols in Primary Teeth with Pulp Necrosis and Periradicular Lesion - An In Vivo Study." Brazilian Dental Journal 25, no. 4 (2014): 307–13. http://dx.doi.org/10.1590/0103-6440201302416.
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The objective of this study was to determine the efficacy of chemical-mechanical procedures of two endodontic protocols for septic content reduction of root canals from primary teeth with pulp necrosis and periradicular lesion. Twenty-four primary root canals with pulp necrosis and periradicular lesion were divided into two treatment groups (n=12): multiple-visit and single-visit protocols. Samples were collected using sterile paper points before and after endodontic cleaning followed by microbiological identification through checkerboard DNA-DNA hybridization. Statistical analysis was performed using Proportion Test for score=0 comparing the findings before and after treatment for each group (Wilcoxon's test) as well as the differences in scores between protocols (Mann-Whitney's test) (p<0.05). Data were expressed as prevalence (presence or absence) and estimate of the average count (x105 cells) of each species. Differences in proportions of score=0 prior to treatment were non-significant (p=0.415), demonstrating equivalence between groups. A significant increase in score=0 was detected after treatment for both groups (p<0.0001). Single-visit protocol achieved a significantly greater reduction in mean scoring following endodontic treatment (p=0.024). Both protocols were capable of significantly reducing septic content in root canals of primary teeth with periradicular lesion. Moreover, single-visit protocol showed greater efficacy in reducing endodontic infection.
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Irawati, Selvi Misnia, Alutsyah Luthfian, and Agus Laesanpura. "SUBSURFACE STRUCTURE OF BATURAGUNG ESCARPMENT REVEALED THROUGH THREE-DIMENSIONAL GRAVITY INVERSION." Jurnal Geofisika Eksplorasi 7, no. 1 (March 19, 2021): 17–29. http://dx.doi.org/10.23960/jge.v7i1.125.
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Baturagung Escarpment is an essential tectonic element of Java Island because it represents a transition from the Southern Mountain Block to the Kendeng Basin. This study has succeeded in producing a three-dimensional model of the Baturagung Escarpment subsurface using gravity anomaly data. The data are distributed along a regional scale transect, whose resolving capability has been tested using a checkerboard test. Our proposed geophysical model can fit the observed data very well, with a 0.77% RMS error. This model exhibits a structural depression bounded by high basement blocks below the Baturagung Escarpment, one of the basement block outcrops at Jiwo Hills. The maximum width of the depression is 10 km, with a depth exceeding 3 km in some places. The depression might be formed because of an extensional tectonic regime that prevailed during the Palaeogene, followed by volcanic arc loads' emplacement up to the early Miocene.
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Wei Chun, Quek, Pang Wai Leong, Chan Kah Yoong, Lee It Ee, and Chung Gwo Chin. "HDL Modelling of Low-CostMemory Fault Detection Tester." Journal of Engineering Technology and Applied Physics 2, no. 2 (December 15, 2020): 17–23. http://dx.doi.org/10.33093/jetap.2020.2.2.3.
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Memory modules are widely used in varies kind of electronics system design. The capacity of the memory modules has increased rapidly since the past few years in order to satisfy the high demand from the end-users. The memory modules’ manufacturers demand more units of automatic test equipment (ATE)to increase the production rate. However, the existing ATE used in the industry to carry out the memory testing is too costly(at least a million dollars per ATE tester). The low-cost memory testers are urgently needed to increase the production rate of the memory module. This has in spired us to design a low-cost memory tester. A low-cost memory fault detection tester with all the major fault detection algorithms that used in industry is modelled using Very High Speed Integrated Circuit Hardware Description Language (VHDL) in this paper to support the need of the low-cost ATE memory tester. The fault detection algorithms modelled are MATS+ (Modified Algorithm Test Sequence), MATS++, March C, March C-, March X ,March Y, zero-one and checkerboard scan tests. PERL program is used to analyse the simulation results and a log file will be generated at the end of the memory test. Extensive simulation and experimental test results show that the memory tester modelled covers all the memory test algorithms used in the industry. The low-cost memory fault detection tester designed provides the 100% fault detection coverage for all memory defects.
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Estiri, Zahra, and Keyvan Hejazi. "Prediction of Overweight/Obesity by Anthropometric Indices in Male Students." Physical Treatments: Specific Physical Therapy Journal 11, no. 2 (January 1, 2021): 131–38. http://dx.doi.org/10.32598/ptj.11.2.274.11.
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Purpose: Anthropometric indices such as body mass index, Waist Circumference (WC), Waist-to-Hip Ratio (WHR), and Waist-to-Height Ratio (WHtR) are used to identify adolescent obesity and overweight because of their easiness, safety, and accuracy of measurement. This study aimed to evaluate the anthropometric indices in predicting overweight/obesity in male students. Methods: In this descriptive-analytical study, 162 male students of Hakim Sabzevari University, Sabzevar City, Iran, were selected by a simple stratified-random sampling method. The checkerboard and New York test were used to check for musculoskeletal abnormalities. Body composition indices, including height, weight, body mass index, WC, hip circumference, WHR, and WHtR, were measured. The obtained data were analyzed by ANOVA test and Receiver Operating Characteristics (ROC). Results: Mean values WC, WHR, the WHtR in different groups of body mass index were significantly different. The area under the curve for WC (P=0.001), WHR (P=0.001), and WHtR (P=0.001) had a significant difference, too. Conclusion: The present study showed that the area under the curve for WHR has better detective ability for overweight and obesity than other variables such as WC and WHtR.
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Gonzalez, C. F., E. M. Provin, L. Zhu, and D. J. Ebbole. "Independent and Synergistic Activity of Synthetic Peptides Against Thiabendazole-Resistant Fusarium sambucinum." Phytopathology® 92, no. 8 (August 2002): 917–24. http://dx.doi.org/10.1094/phyto.2002.92.8.917.
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Two heptapeptides with broad antifungal activity were identified and assessed for their ability to act synergistically with thiabendazole. The hexapeptide 66–10 was the progenitor of the heptapeptides and exhibited minimal inhibitory concentrations (MICs) of 9.3 to 9.8 μg/ml for thiabendazole (TBZ) resistant Fusarium sambucinum strains (MIC of 186 to 312 μg/ml). Heptapeptide derivatives 77–3 and 77–12 exhibited MICs between 3.8 and 7.5 μg/ml against the same strains. Incubation of conidia or mycelia with the peptide 77–3 showed that treated fungal structures were stained by the membrane impermeant dye SYTOX Green indicating disruption of membranes. Conidia incubated with peptide 77–3 at 10 μg/ml showed a 91 ± 3.6% reduction in viability in 15 min. A checkerboard method was used to test the peptides and TBZ individually and in combination to determine potential synergistic activity. The results indicate that small peptides can act synergistically with TBZ against TBZ-resistant F. sambucinum.
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Kurdi, Mohammad. "A Structural Optimization Framework for Multidisciplinary Design." Journal of Optimization 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/345120.
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This work describes the development of a structural optimization framework adept at accommodating diverse customer requirements. The purpose is to provide a framework accessible to the optimization research analyst. The framework integrates the method of moving asymptotes into the finite element analysis program (FEAP) by exploiting the direct interface capability in FEAP. Analytic sensitivities are incorporated to provide a robust and efficient optimization search. User macros are developed to interface the design algorithm and analytic sensitivity with the finite element analysis program. To test the optimization tool and sensitivity calculations, three sizing and one topology optimization problems are considered. In addition, flutter analysis of a heated panel is analyzed as an example of coupling to nonstructural discipline. In sizing optimization, the calculated semianalytic sensitivities match analytic and finite difference calculations. Differences between analytic designs and numerical ones are less than 2.0% and are attributed to discrete nature of finite elements. In the topology problem, quadratic elements are found robust at resolving checkerboard patterns.
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MATTIS, DANIEL C. "ON THE ORIGIN OF d-WAVE PAIR FUNCTIONS IN HIGH-Tc SUPERCONDUCTIVITY." International Journal of Modern Physics B 20, no. 23 (September 20, 2006): 3279–305. http://dx.doi.org/10.1142/s0217979206035606.
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We argue that the usual Hubbard's model produces only s-wave pairing functions and, even then, only at unphysically large values of the lumped parameter J≡4t2/U. It follows that a reliable theory of high-Tc superconductivity has to include additional features if it is to reproduce the d-wave gap. We test the effects of an alternating potential caused by a charge stripe, on the ground state of the Hubbard model in strong-coupling. If we "fine tune" we do find the d-waves. However, a better-formulated version of a three-band model yields a sturdier theory of pair formation in high-Tc superconductivity. The coupling constant g1=t2/V factors out, hence it serves only to establish the unit of energy; the underlying Hamiltonian is universal. We outline the principal properties of this model, including the intimate relation between charge-density stripes and the d-wave pair function, its rejection of 45° stripes (checkerboard pattern), and other concerns.
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Enemchukwu, Chizoba Mercy, Angus Nnamdi Oli, Ebere Innocent Okoye, Nonye Treasure Ujam, Emmanuel O. Osazuwa, George Ogonna Emechebe, Kenneth Nchekwube Okeke, Christian Chukwuemeka Ifezulike, Obiora Shedrack Ejiofor, and Jude Nnaemeka Okoyeh. "Winning the War against Multi-Drug Resistant Diarrhoeagenic Bacteria." Microorganisms 7, no. 7 (July 10, 2019): 197. http://dx.doi.org/10.3390/microorganisms7070197.
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Drug-resistant-diarrhoeagenic bacteria are currently emerging healthcare challenge. This study investigated the effects of Vernonia amygdalina, Garcinia kola, tetracycline and metronidazole combinations on such bacteria. Agar well diffusion method was employed to determine the inhibitory effects of the herbal extracts on diarrhoeagenic bacteria while Time-Kill Assay was used to determine bactericidal effects of the extracts against test isolates. Interactions between plant extracts and antibiotics were investigated using Checkerboard assay. Minimum inhibitory concentrations of the extracts against the bacterial isolates ranged between 3.125–50 mg/mL, while those of tetracycline and metronidazole ranged from 30–50 μg/mL. Synergism was observed against B. cereus and S. aureus for metronidazole + aqueous G. kola at all ratios. Generally, the combinations aqueous G. kola + ethanolic G. kola and aqueous G. kola + ethanolic V. amygdalina showed more pronounced synergism against the Staphylococcus aureus than B. cereus isolates with the fractional inhibition concentration (FIC) indices ranging from 0.32–0.95. Synergism of tetracycline + crude extracts and metronidazole combinations were more pronounced on the test isolates and especially on the Gram-negative organisms with FIC indices ranging from 0.41–0.91. Conclusion: The herbal extracts combinations and extracts–antibiotics combinations are synergistic on diarrhoeagenic bacteria at defined combination ratios.
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Shah, Pratibha Jinesh. "ANTIBACTERIAL ACTIVITY OF AQUEOUS GARLIC EXTRACT ON BETA-LACTAMASE PRODUCING ACINETOBACTER ISOLATES FROM SKIN AND SOFT TISSUE INFECTIONS." Asian Journal of Pharmaceutical and Clinical Research 9, no. 6 (November 1, 2016): 152. http://dx.doi.org/10.22159/ajpcr.2016.v9i6.13960.
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Objective: The present study evaluates the antibacterial effect of aqueous garlic extract (AGE) on beta-lactamase producing Acinetobacter strains isolated from skin and soft tissue infections (SSTIs).Methods: A total of 41 non-duplicate strains of Acinetobacter isolated from SSTIs specimens were tested for their antibiotic susceptibility pattern by Kirby-Bauer disk diffusion method. Ceftazidime-resistant Acinetobacter strains were screened for beta-lactamase production by Phenotypic confirmatory disc diffusion test (PCDDT) and E-test. Antibacterial activity of AGE was examined by the disc diffusion method and the minimum inhibitory concentration (MIC) of AGE and Cefotaxime was determined by the agar dilution technique. The combined activity of AGE and Cefotaxime was evaluated by calculating the fractional inhibitory concentration (FIC) index by the checkerboard method.Results: 21 Acinetobacter strains were confirmed to be beta-lactamase producers, out of which 6 were Metallo-beta-lactamase (MBL) producers, 3 were Ambler Class C (AmpC) and 12 were multiple beta-lactamase producers. AGE exhibited significant antibacterial activity as the observed zones of inhibition ranged from 18 - 31 mm against the test strains. The MIC of AGE was in the range of 0.5% - 2% (2.5 mg/ml – 10 mg/ml) with a mean of 0.86% (4.28 mg/ml). 11 test strains showed synergism, 5 strains exhibited additive and indifferent effect, each. By HPLC analysis the concentration of allicin was found to be 0.20, expressed as percentage w/w.Conclusion: It can be stated that aqueous garlic extract might have therapeutic value against beta-lactamase producing Acinetobacter isolates from SSTIs.
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Devi, Varadharajan Subhadra, Dr Ushanandhini, Kuppusamy AsokKumar, Muthuswamy UmaMaheswari, Andichettiar Thirumalaisamy Sivashanmugham, and Puliyath Jagannath. "Synergistic Antibacterial Activity of Cassia auriculata L. Flowers and Ofloxacin." Bangladesh Journal of Microbiology 28, no. 2 (September 5, 2012): 92–94. http://dx.doi.org/10.3329/bjm.v28i2.11824.
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A cost effective antimicrobial agent for multi drug resistant organisms, based on the synergistic activity of ofloxacin with ethanolic extract of flowers of Cassia auriculata was determined. The Minimum Inhibition Concentration (MIC) of ethanolic extract using 3 different Gram-positive bacteria, such as Staphylococcus aureus NCIM 2127 and Bacillus subtilis NCIM 2010, and Gram-negative bacteria Escherichia coli NCIM 2118 was found to be around 1024 to 2048 mg/ml. The synergistic activity varied using checkerboard synergy technique. The results of the conducted experiments showed in vitro interactions between antimicrobial agents and plant extract were additive against the strains tested, it also showed synergistic effects between combination of antibiotics and plant extracts with significant reduction in the MICs of the test antibiotics against these strains. It showed maximum synergistic activity against Gram-negative species. The higher synergistic rate was attained against E. coli NCIM 2118, and lowest synergistic shows against S. aureus NCIM 2127. DOI: http://dx.doi.org/10.3329/bjm.v28i2.11824 Bangladesh J Microbiol, Volume 28, Number 2, December 2011, pp 92-94
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Quirynen, M., R. Vogels, M. Pauwels, A. D. Haffajee, S. S. Socransky, N. G. Uzel, and D. van Steenberghe. "Initial Subgingival Colonization of ‘Pristine’ Pockets." Journal of Dental Research 84, no. 4 (April 2005): 340–44. http://dx.doi.org/10.1177/154405910508400409.
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The treatment of periodontitis/peri-implantitis involves the reduction/eradication of periopathogens. After therapy, beneficial and pathogenic species recolonize the subgingival area. The dynamics of recolonization and especially the role of the supragingival environment in this process are still not well-understood. This prospective, split-mouth study followed the early colonization of ‘pristine’ pockets created during implant surgery (16 partially edentulous patients), to record the time needed before a complex subgingival flora could be established with the supragingival area as the single source. Four subgingival plaque samples were taken from shallow and medium pockets around implants (test), and neighboring teeth (undisturbed microbiota as reference) 1, 2, and 4 wks after abutment connection. Checkerboard DNA-DNA hybridization and culture data revealed a complex microbiota (including several pathogenic species) in the pristine pockets within a wk, with a minimal increase in counts up to 4 wks. Analysis of these data demonstrated that, even with the supragingival environment as the single source for colonizing bacteria, a complex subgingival microbiota can develop within 1 wk.
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Ozbek Celik, Berna, Emel Mataraci-Kara, and Mesut Yilmaz. "Effects of Various Antibiotics Alone or in Combination with Doripenem againstKlebsiella pneumoniaeStrains Isolated in an Intensive Care Unit." BioMed Research International 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/397421.
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Colistin, tigecycline, levofloxacin, tobramycin, and rifampin alone and in combination with doripenem were investigated for their in vitro activities and postantibiotic effects (PAEs) onKlebsiella pneumoniae. The in vitro activities of tested antibiotics in combination with doripenem were determined using a microbroth checkerboard technique. To determine the PAEs,K. pneumoniaestrains in the logarithmic phase of growth were exposed for 1 h to antibiotics, alone and in combination. Recovery periods of test cultures were evaluated using viable counting after centrifugation. Colistin, tobramycin, and levofloxacin produced strong PAEs ranging from 2.71 to 4.23 h, from 1.31 to 3.82 h, and from 1.35 to 4.72, respectively, in a concentration-dependent manner. Tigecycline and rifampin displayed modest PAEs ranging from 1.18 h to 1.55 h and 0.92 to 1.19, respectively. Because it is a beta-lactam, PAEs were not exactly induced by doripenem (ranging from 0.10 to 0.18 h). In combination, doripenem scarcely changed the duration of PAE of each tested antibiotic alone. The findings of this study may have important implications for the timing of doses duringK. pneumoniaetherapy with tested antibiotics.
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Khang, Byung-Geun, and Edward A. Essock. "A Motion Illusion from Two-Dimensional Periodic Patterns." Perception 26, no. 5 (May 1997): 585–97. http://dx.doi.org/10.1068/p260585.
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The spatial properties of a motion illusion (the Ouchi illusion) that occurs in a stationary pattern were examined by means of a variety of two-dimensional periodic patterns (formed by multiplying pairs of various one-dimensional periodic functions). In two experiments, observers rated the magnitude of the illusion. The results showed that (1) patterns having large energy and steep saddle-shaped contrast gradients tended to generate stronger illusions, (2) the composite pattern made up of the sum of the fundamental and harmonic components exhibited a stronger illusion than either the fundamental or the harmonic pattern, (3) patterns possessing an element orientation and phase shift similar to those of a rectangular checkerboard, and with element sizes of 15–50 min in width and 4–8 min in height yielded a larger illusion, (4) equiluminant colors largely abolished the effect, and (5) blurring the boundary between the test and surround did not reduce the illusion. Interactions between spatially overlapping ON and OFF units was discussed as a possible underlying cause of this phenomenon.
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Zhang, Lulu, Hui Lin, Wei Liu, Baodi Dai, Lan Yan, YongBing Cao, and Yuan-Ying Jiang. "Antifungal Activity of the Ethanol Extract fromFlos Rosae Chinensiswith Activity against Fluconazole-Resistant ClinicalCandida." Evidence-Based Complementary and Alternative Medicine 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4780746.
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This study was designed to investigate the antifungal activity of a hydroalcoholic extract fromFlos Rosae Chinensis(FRC) combined with fluconazole (FCZ) against clinical isolates ofCandida albicansresistant to FCZ. The minimum inhibitory concentration (MIC) of FRC was determined using a checkerboard microdilution assay. The synergistic effects of the combination of FRC and FCZ against clinical isolates ofC. albicansresistant to FCZ were further confirmed by constructing time-growth curves and performing an agar diffusion test. FRC alone exerted efficient antifungal activities againstC. albicanswithin a MIC80ranging from 20 μg/ml to 40 μg/ml. FRC failed to enhance the effects of FCZ against sensitiveC. albicansstrains, although it rendered FCZ-resistantC. albicansmore sensitive. These results were further confirmed by the result of in vivo study. Our study is the first to discover that FRC can inhibit the growth ofC. albicansto a certain degree. An FRC antifungal mechanism study showed that FRC strengthens FCZ to inhibit the action of ergosterol biosynthesis by promoting the transformation of lanosterol to eburicol, suggesting that the antifungal mechanism of FRC involves the inhibition of ergosterol biosynthesis.
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Rovai, Emanuel da Silva, Felipe de Souza Matos, Warley David Kerbauy, Flávia Goulart da Rosa Cardoso, Frederico Canato Martinho, Luciane Dias de Oliveira, Marcia Carneiro Valera, and Cláudio Antonio Talge Carvalho. "Microbial Profile and Endotoxin Levels in Primary Periodontal Lesions with Secondary Endodontic Involvement." Brazilian Dental Journal 30, no. 4 (July 2019): 356–62. http://dx.doi.org/10.1590/0103-6440201902471.
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Abstract This study was carried out to investigate the microbial profile and endotoxin levels of endodontic-periodontal lesions of periodontal origin. Periodontal and endodontic samples were taken from periodontal pockets and necrotic root canals of 10 teeth with endodontic-periodontal lesions. Evidencing of 40 different bacterial species were determined in each endodontic and periodontal sample using the checkerboard DNA-DNA hybridization method and Kinetic chromogenic LAL assay was used for quantification of endotoxins. Fisher’s exact test correlated the bacterial species with the endodontic or periodontal microbiota. The endotoxin levels (EU/mL) found in samples of the root canal and periodontal pocket were compared by the Wilcoxon test (p<0.05). Bacteria and LPS units were found in 100% of the endodontic and periodontal samples. The species E. faecium, P. acnes, G. morbillorum, C. sputigena and L. buccalis were strongly correlated with the endodontic microbiota and P. nigrescens with the periodontal microbiota. P. intermedia, P. endodontalis and V. parvula were more prevalent in both endodontic and periodontal microbiots. The endotoxin levels in the periodontal pocket (89600 EU/mL) were significantly higher than in the root canal (2310 EU/mL). It was concluded that the microbiota present in the periodontal and endodontic tissues is similar, with a higher prevalence of species of the orange complex and a higher level of endotoxin in the periodontal pockets.
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Al-Najjar, Raghda S., Nehaya M. Al-Aubody, Salah Z. Al-Asadi, and Majid Alabbood. "Pattern-Reversal Visual Evoked Potentials Tests in Persons with Type 2 Diabetes Mellitus with and without Diabetic Retinopathy." Neurology Research International 2020 (August 24, 2020): 1–7. http://dx.doi.org/10.1155/2020/1014857.
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Background. Currently, diabetic retinopathy (DR) has a wide recognition as a neurovascular rather than a microvascular diabetic complication with an increasing need for enhanced detection approaches. Pattern-reversal visual evoked potentials (PRVEPs) test, as an objective electrophysiological measure of the optic nerve and retinal function, can be of great value in the detection of diabetic retinal changes. Objectives. The use of two sizes of checkerboard PRVEPs testing to detect any neurological changes in persons with type 2 diabetes mellitus (T2DM) with and without a clinically detected DR. Also, to compare the results according to the candidate age, duration, and glycemic status of T2DM. Methods. This study included 50 candidates as group A with T2DM and did not have a clinically detected DR and 50 candidates as group B with T2DM and had a clinically detected early DR and 50 candidates as controls who were neither diabetic nor had any other medical or ophthalmic condition that might affect PRVEPs test results. The PRVEPs were recorded in the consultant unit of ophthalmology in Almawani Teaching Hospital. Monocular PRVEPs testing of both eyes was done by using large (60 min) and small (15 min) checks to measure N75 latency and P100 latency and amplitude. Results. There was a statistically significant P100 latency delay and P100 amplitude reduction in both groups A and B in comparison with the controls. The difference between groups A and B was also significant. In both test results of groups A and B, the proportions of abnormal P100 latency were higher than those of P100 amplitude with a higher abnormal proportions in 15 min test. Conclusions. The PRVEP test detected neurological changes, mainly as conductive alterations affecting mostly the foveal region prior to any overt DR clinical changes, and these alterations were heightened by the presence of DR clinical changes.
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Zhang, Yuan, Gang Xu, Lu Zhang, Jiakai Zhao, Pinpin Ji, Yaning Li, Baoyuan Liu, et al. "Development of a double monoclonal antibody–based sandwich enzyme-linked immunosorbent assay for detecting canine distemper virus." Applied Microbiology and Biotechnology 104, no. 24 (November 7, 2020): 10725–35. http://dx.doi.org/10.1007/s00253-020-10997-y.
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Abstract Canine distemper virus (CDV) infection causes mass mortality in diverse carnivore species. For effective virus surveillance, rapid and sensitive assays are needed to detect CDV in field samples. In this study, after BABL/c mice were immunized with recombinant CDV-fusion (F) protein, monoclonal antibodies (mAbs) against recombinant CDV-F protein (designated 1A5, 1A6, and 7D5) were produced using traditional hybridoma cell technology. Next, capture antibody (1A6, 800 ng/well) and horseradish peroxidase (HRP)–conjugated detection antibody (HRP-7D5, 1:100, 500 ng/well) were used in a double monoclonal antibody–based sandwich enzyme-linked immunosorbent assay (ELISA) for CDV detection after optimization of both mAb amounts per well using a checkerboard titration test. Based on sandwich ELISA test results for 120 known CDV-negative samples, the cutoff value for a positive result was set to an OD450 nm value ≥ 0.196. As compared with test results obtained from commercial immune colloidal gold test strips, the low limits of detection for the two assays were revealed to be 100 TCID50 per 100 μL. In addition, the sandwich ELISA agreed 100% and 96.4% with commercial immune colloidal gold test strips when testing serum and stool samples. The sandwich ELISA assay provided statistically similar CDV detection. Thus, the sandwich ELISA developed here to detect CDV in fecal and serum samples provided good sensitivity, high specificity, and good reproducibility and should serve as an ideal method for large-scale surveillance of CDV infections in carnivores. Key points • Three CDV mAbs that recognized different epitopes and bound to virion were generated. • The sandwich ELISA based mAbs to detect CDV in fecal and serum samples was developed. • The sandwich ELISA is an ideal method for detecting CDV infections in the field.
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Sawaya, Raja, Helen Sawaya, and Gilbert Youssef. "Pattern reversal visual evoked potentials in adults: variability with age." Clinical & Investigative Medicine 40, no. 6 (December 17, 2017): 252. http://dx.doi.org/10.25011/cim.v40i6.29126.
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Purpose: Pattern reversal visual evoked potential (PRVEP) is an electrophysiological test for evaluating the visual pathway. This study measured the changes in the latencies and amplitudes of the PRVEP with age and gender in normal subjects. Methods: Healthy participants (n=81; 162 total eyes), between the ages of 20 and 92 years were recruited for the study. Stimulation was performed monocularly with a high-contrast (>50%) black-white checkerboard pattern with a check size of 30° at a reversal rate of 2 Hz, a band-pass of 1-100 Hz, a sweep of 250 msec and an average of 150 stimulations in a dark room. Mean and standard deviations for three latencies (N75, P100 and N145) and the amplitude (N75-P100) for each decade were measured. Results: There was a linear trend by age for all three latencies, indicating that the higher age groups had longer latencies. The latencies decreased in the 5th decade before increasing in the higher age groups. The amplitude of N75-P100 decreased with age. The P100 latencies were longer in males than females in all age groups and the difference increased with increasing age.