Diffusion Method
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Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 229
Author(s):  
Clara Luisa Domínguez-Delgado ◽  
Zubia Akhtar ◽  
Godfrey Awuah-Mensah ◽  
Braden Wu ◽  
Hugh David Charles Smyth

Emulsification-diffusion method is often used to produce polymeric nanoparticles. However, their numerous and/or lengthy steps make it difficult to use widely. Thus, a modified method using solvent blends (miscible/partially miscible in water, 25–100%) as the organic phases to overcome these disadvantages and its design space were investigated. To further simplify the process, no organic/aqueous phase saturation and no water addition after the emulsification step were performed. Biodegradable (PLGA) or pH-sensitive (Eudragit® E100) nanoparticles were robustly produced using low/medium shear stirring adding dropwise the organic phase into the aqueous phase or vice versa. Several behaviors were also obtained: lowering the partially water-miscible solvent ratio relative to the organic phase or the poloxamer-407 concentration; or increasing the organic phase polarity or the polyvinyl alcohol concentration produced smaller particle sizes/polydispersity. Nanoparticle zeta potential increased as the water-miscible solvent ratio increased. Poloxamer-407 showed better performance to decrease the particle size (~50 nm) at low concentrations (≤1%, w/v) compared with polyvinyl alcohol at 1–5% (w/v), but higher concentrations produced bigger particles/polydispersity (≥600 nm). Most important, an inverse linear correlation to predict the particle size by determining the solubility parameter was found. A rapid method to broadly prepare nanoparticles using straightforward equipment is provided.


Author(s):  
Anitha Akilan ◽  
Josephine Anthony ◽  
Revathi Kasthuri

Aims: To evaluate the antibacterial activity of Padikara Parpam against Extended-Spectrum Beta-Lactamase (ESBL) producing Escherichia Coli and Klebsiella Pneumoniae using agar well diffusion method. To identify ESBL producing bacteria by phenotypic confirmatory test using disk diffusion method. Study Design: Analysis of Antibacterial activity of Padikara Parpam using agar well diffusion method. Place and Duration of Study: Central Research Laboratory, Meenakshi Academy of higher Education and Research, Chennai, between June 2021 and November 2021. Methodology: Clinical isolates of ESBL were isolated by subculture into MacConkey agar and was identified by phenotypic confirmatory test. Padikara parpam's antibacterial activity was evaluated using the Agar well diffusion method at different concentrations of 0.5 %, 1 %, 1.5 %, and 2 % drugs. 30 µg Cefotaxime and 30 µg amoxicillin-clavulanic acid disk were used as controls to standardize the antibacterial activity test and to identify the ESBL by phenotypic confirmatory test. Results: In this study, Padikara parpam at various doses of 0.5 %, 1 %, 1.5 %, and 2 %, revealed significant antibacterial efficacy against ESBL producing bacteria. Padikara parpam was more active against ESBL Escherichia coli than ESBL Klebsiella pneumoniae. As a result, it may be recommended as an antibacterial agent against ESBL. Conclusion: Our findings suggest that Siddha Herbo mineral formulations of padikara parpam hold phenomenal antimicrobial activity against ESBL producing bacteria. Based on our findings, the drug may be prescribed successfully for urinary tract infections, which is caused by ESBL producing bacteria.


Author(s):  
Honeysmita Das ◽  
A.K. Samanta ◽  
Sanjeev Kumar ◽  
P. Roychoudhury ◽  
Kalyan Sarma ◽  
...  

Background: Management of ever growing multidrug resistant (MDR) bacteria becomes one of the biggest threats to public health worldwide. The situation is worsening due to lack of new generation antimicrobials in the arsenal of the clinicians. Development of new alternatives to the conventional antimicrobial agents is the need of the hour to control the menace of AMR. Plants based products are attractive alternatives with proven efficacy but needs scientific investigation to explore their potential antimicrobial, antibiofilm and antiquorum sensing activities against major bacterial pathogens of human and animals. The present study was conducted to explore the antimicrobial, antibiofilm and antiquorum sensing activity of aqueous and methanol extracts of leaf, flower, fruit and stem of the Himalayan yellow raspberry (Rubus ellipticus) against clinical isolates of Staphylococcus aureus and Escherichia coli. Methods: E. coli and S. aureus were isolated and identified from diarrhoeic pigs and poultry and mastitic milk of cattle of Mizoram, respectively. Leaf, flower, fruit and stem/bark of R. ellipticus were collected from Mizoram and extracted by methanol and aqueous solvents. The antimicrobial activity and MIC was determined by well diffusion method and 96 wells microtiter plate method, respectively. Antibiofilm activity of plant extracts was determined in 96 well tissue culture plate. Antiquorum sensing activity was determined by disc diffusion method. Result: Methanol leaf extract exhibited antimicrobial activity against S. aureus with 19 mm and 7 mm zone of inhibition at 200 mg/mL and 12.5 mg/mL, respectively. Methanol fruit extract also showed antimicrobial activity against S. aureus only. Highest and lowest activities were observed at 200 mg/mL and 25 mg/mL concentrations with 15 mm and 7 mm zone of inhibition, respectively. No antimicrobial activities by either of the extracts were observed against E. coli isolates. The MIC of R. ellipticus methanol leaf and fruit extracts against S. aureus was 0.203125 mg/mL and 0.8125 mg/mL, respectively. The methanol leaf (86.60%) and stem (85.60%) extracts of R. ellipticus showed significant antibiofilm activity against S. aureus isolates, whereas methanol fruit (89.20%) extracts exhibited antibiofilm activity against E. coli isolates at the concentration of 0.05 mg/mL. Significant antiquorum sensing (QS) activities was exhibited by the methanol leaf extract of R. ellipticus at 200 mg/mL concentration against E. coli. This is the first ever report on antibiofilm and anti QS activities of the R. ellipticus plant extracts against E. coli and S. aureus bacteria.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yafeng Feng ◽  
Xianguo Liu

Video event detection and annotation work is an important content of video analysis and the basis of video content retrieval. Basketball is one of the most popular types of sports. Event detection and labeling of basketball videos can help viewers quickly locate events of interest and meet retrieval needs. This paper studies the application of anisotropic diffusion in video image smoothing, denoising, and enhancement. An improved form of anisotropic diffusion that can be used for video image enhancement is analyzed. This paper studies the anisotropic diffusion method for coherent speckle noise removal and proposes a video image denoising method that combines anisotropic diffusion and stationary wavelet transform. This paper proposes an anisotropic diffusion method based on visual characteristics, which adds a factor of video image detail while smoothing, and improves the visual effect of diffusion. This article discusses how to apply anisotropic diffusion methods and ideas to video image segmentation. We introduced the classic watershed segmentation algorithm and used forward-backward diffusion to process video images to reduce oversegmentation, introduced the active contour model and its improved GVF Snake, and analyzed the idea of how to use anisotropic diffusion and improve the GVF Snake model to get a new GGVF Snake model. In the study of basketball segmentation of close-up shots, we propose an improved Hough transform method based on a variable direction filter, which can effectively extract the center and radius of the basketball. The algorithm has good robustness to basketball partial occlusion and motion blur. In the basketball segmentation research of the perspective shot, the commonly used object segmentation method based on the change area detection is very sensitive to noise and requires the object not to move too fast. In order to correct the basketball segmentation deviation caused by the video noise and the fast basketball movement, we make corrections based on the peak characteristics of the edge gradient. At the same time, the internal and external energy calculation methods of the traditional active contour model are improved, and the judgment standard of the regional optimal solution and segmentation validity is further established. In the basketball tracking research, an improved block matching method is proposed. On the one hand, in order to overcome the influence of basketball’s own rotation, this article establishes a matching criterion that has nothing to do with the location of the area. On the other hand, this article improves the diamond motion search path based on the basketball’s motion correlation and center offset characteristics to reduce the number of searches and improve the tracking speed.


Nova ◽  
2021 ◽  
Vol 19 (37) ◽  
pp. 121-134
Author(s):  
Lidia Po Catalao Dionisio ◽  
Alejandro Manuel Labella ◽  
María Palma ◽  
Juan José Borrego

Aim. In vitro antimicrobial activities of seven wines (5 reds and 2 whites) from the Douro region (Iberian Peninsule) against eleven clinical strains of Helicobacter pylori were evaluated. Methods. The disk diffusion method, using Columbia Agar supplemented with horse blood (CAB), were used to determine the antimicrobial properties of some wine components against H. pylori strains. Potential interactions of antioxidants contained in the wines and two antimicrobials (amoxicillin and metronidazole) were studied by the disk diffusion method. Results. All the tested strains showed growth in CAB supplemented with 9% of the tested wines but none of them grew in media supplemented with 45% and 67.5% of wine. Similarly, all the tested strains grew in media with the concentration of proanthocyanidins present in the different types of the studied wines. The Minimal Inhibitory Concentration (MIC) values of the wine antioxidant components tested (benzoic acid, catechin, quercetin, and resveratrol) indicate that resveratrol was the most powerful inhibitory substance against H. pylori. An effect of potentiation between amoxicillin and metronidazole and the antioxidants tested was also established. The interaction of amoxicillin and resveratrol or metronidazole and catechin increased the antimicrobial activity against H. pylori. Conclusions. The results obtained suggested a potential role of resveratrol as a chemopreventive agent for H. pylori infection.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Dawei Luo ◽  
Jian Zhang ◽  
Yu Liang ◽  
Jianling Ni ◽  
Fangming Wang ◽  
...  

Here, organic-inorganic hybrid molecular compounds based on copper(I) bromide have been synthesized by slow-diffusion method. The inorganic modules of these two structures are Cu2Br42− anion, and the inorganic modules are coordinated to cationic organic ligands via Cu-N coordinative bonds. Both of these compounds are luminescent, emitting green emissions under UV excitation.


Author(s):  
Snježana Hodžić ◽  
Amela Hercegovac ◽  
Nijaz Tihić ◽  
Darja Husejnagić ◽  
Aldijana Avdić ◽  
...  

Aims: The aims of this study was to investigate the susceptibility of extended-spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae clinical isolates to antibiotics and essential oils - Origanum compactum, Origanum majorana and Thymus serpyllum. Study Design: Study included 30 isolates of Klebsiella pneumoniae obtained from clinical material provided from the University Clinical Center Tuzla. Place and Duration of Study: Department of Biology, Faculty of Science, University of Tuzla, BiH, between September 2019 to September 2020. Methodology: Antibiotic susceptibility testing was performed by the Kirby-Bauer disk diffusion method. The following commercially available antibiotic discs were used: amoxicillin (30µg), cefalexin (30 µg), gentamicin (10 µg), amikacin (30 µg), imipenem (10 µg), piperacillin (75µg), ampicilin (10 µg), meropenem (10 µg), ciprofloksacin (10 µg), ceftazidim (30 µg), cefotaksim (30 µg), ceftriaxone (30 µg), cefepime (30 µg) and aztreonam (30 µg). The antibacterial effect of the essential oils was tested for ESBL K. pneumoniae isolates using the diffusion method according to Clinical laboratory standards institute (CLSI) guidelines. Results: O. compactum and O. majorana essential oils showed the same antimicrobial activity with 80.0% effect on ESBL K. pneumoniae isolates, Thymus serpyllum EO showed antimicrobial activity of 60.0%. The lowest MIC value had the O. compactum essential oil (MIC 6 mg/ml-10.5 mg/ml), followed by the T. serpyllum (MIC 17.2 mg/ml-43 mg/ml), while the O. majorana essential oil showed MIC values in range from 11 mg/ml to 39 mg/ml. Conclusion: The results of the study showed the exceptional sensitivity of ESBL K. pneumoniae clinical isolates to the essential oils from Origanum and Thymus genera, which highly suggests their potential application in the struggle against these pathogens in the future.


2021 ◽  
Vol 33 (4) ◽  
pp. 1-5
Author(s):  
Mustafa W Abdul Kareem ◽  
Zainab A Al Dhaher

Background: The interest in herbal extracts as antimicrobial agents has increased over the past few years in endodontic therapy. Nasturtium officinale (watercress) is a promising plant with great medicinal values. This study aimed to investigate the antifungal activity of watercress oil in combination with calcium hydroxide against Candida albicans as intracanal medicament. Materials and Methods: Candida albicans was isolated from patients with necrotic root canal or failed root canal treatment. The sensitivity of Candida albicans to different concentrations of watercress oil extract was determined by using the agar well diffusion method in comparison with calcium hydroxide paste. The agar plate method was used to determine the minimum fungicidal concentration (MFC) of the tested oil against the fungus. The combination of the oil extract of Nasturtium officinale with calcium hydroxide was evaluated and compared to calcium hydroxide paste with iodoform by using the agar well diffusion method. Results: The oil extract exhibited antifungal activity against Candida albicans, this activity was found to be increased as the concentration of extract increased. The tested combination of watercress oil extract with calcium hydroxide revealed larger inhibition zones than the ones formed by each tested agent individually. Conclusion: The oil extract of Nasturtium officinale is active against Candida albicans suggesting its potential to be used as an intracanal medicament alone or in combination with calcium hydroxide.


Author(s):  
S. Mabel Parimala ◽  
A. Antilin Salomi

People use plants to treat infections, and this has led to search of antimicrobials from medicinal plants. In this work, we evaluated the ethanol extract of Syzygium cumini seeds for their antibacterial and antifungal activities. Extraction was performed by maceration method using ethanol. The antimicrobial efficacy of the extract was assessed by agar well diffusion method against ten bacterial species, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Staphylococcus aureus and Streptococcus mutans, and five fungal species, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Candida albicans and Mucor sp. Minimum inhibitory concentrations (MICs) of the extract were determined by resazurin microtiter plate assay.  Phytochemicals in the extract was identified by gas chromatography mass spectrometry (GC-MS) information.  In agar well diffusion method, Gram-negative bacteria such as P. aeruginosa and S. marcescens, Gram-positive bacteria such as B. subtilis and E. faecalis and fungi A. fumigatus were more susceptible showing larger zones of inhibition.  In resazurin method, low MICs were recorded for bacteria, B. cereus (<7.8 µg) and P. aeruginosa (15.6 µg) and fungi, A. fumigatus (31.2 µg).  Fifteen compounds were identified by GC-MS profiling of the extract.  The antimicrobial activity of the extract can be rightly related to the secondary metabolites in the ethanol extract of Syzygium cumini seeds.


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