Synthesis of some NH-derivatives of ciprofloxacin as antibacterial and antifungal agents

Five NH-derivatives of ciprofloxacin (2-6) have been prepared by acetylation/benzoylation on ciprofloxacin (1) in order to carry out screening for antibacterial activities on some Gram-positive and Gram-negative bacteria. The antifungal activity of these compounds has also been made against Candida albicans. All of the derivatives have shown enhanced activities against Gram-negatives bacteria than parent antibiotic, ciprofloxacin among which compounds 2 and 6 are the most potent agents. Regarding the antifungal activity all of the compounds have shown highest activity than ciprofloxacin. All the compounds have been characterized with spectral analysis

Stumps of Eucalyptus globulus as a source of antioxidant and antimicrobial polyphenols

These past years have seen an enormous development of the area of natural antioxidants and antimicrobials. Eucalyptus globulus is widely cultivated in subtropical and Mediterranean regions in intensive short rotation coppice plantations. In the Portuguese context, E. globulus is the third species in terms of forest area. The stump is the basal part of the tree, including the near-the-ground stem portion and the woody roots that remain after stem felling. The purpose of this work was to study the phytochemical profile and to evaluate the antioxidant and antimicrobial properties of several crude stump wood and stump bark extracts of E. globulus, comparing it with similar extracts of E. globulus wood (industrial chips). The results showed the presence of high concentrations of total phenolic compounds (>200 mg GAE/g extract) and flavonoids (>10 mg QE/g extract) in E. globulus stump extracts. Generally the stump wood extracts stands out from the other ones, presenting the highest percentages of inhibition of linoleic acid oxidation. It was also possible to conclude that the extracts were more active against Gram-positive bacteria, presenting low MIC values. This study thus provides information supporting the economic valorization of E. globulus stump woodinfo:eu-repo/semantics/publishedVersio

Isolation, identification, and characterization of resistant bacteria to antibiotics from pharmaceutical effluent and study of their antibiotic resistance

Pharmaceutical effluents primarily enter aquatic environments through the discharge of treated and untreated wastewater from various sources, including hospitals, pharmaceutical manufacturing facilities, and households. Microbes sourced from pharmaceutical effluents such as Pseudomonas spp. pose a significant public health concern because of their high levels of resistance to multiple drugs and extreme multidrug resistance. Therefore, the present study was conducted for the isolation, identification, and molecular characterization of selected isolates from pharmaceutical effluents and also determined their antibiotic sensitivity patterns. From June 2016 to March 2017, a study was conducted on four well-known pharmaceutical companies specializing in antibiotic production in Dhaka and Gazipur. Four wastewater samples were collected from various origins and then brought to the Bacteriology laboratory for microbiological examination. Twelve pure isolates were obtained and characterized through cultural and biochemical tests while molecular identification of Pseudomonas spp. was performed using the 16S rRNA gene sequence. Twelve commercially available antibiotics were used for antibiotic sensitivity tests using Kirby-Bauer disk diffusion methods. We isolated the most predominant isolates, Pseudomonas aeruginosa (41.67%), followed by Bacillus spp. (33.33%) and Staphylococcus spp. (25%) respectively. Among 12 antibiotics, ciprofloxacin is 100% sensitive against P. aeruginosa, while the remaining 11 antibiotics are 100% resistant. Bacillus spp. showed 100% resistance to all antibiotics while 50% sensitive to vancomycin and 100% to chloramphenicol, respectively. Staphylococcus spp. was 100% resistant to all antibiotics. Our research suggested that P. aeruginosa is the reservoir of antibiotic resistance genes and spreads disease to humans from the environment. The findings of this study, i.e., the isolation, identification, and characterization of antibiotic-resistant bacteria from pharmaceutical effluent have highlighted, comprehended, and mitigated the dissemination of antibiotic resistance and opportunistic bacteria

Cross Sectional TEM Characterization of Epitaxial Silicon Film Grown using Hot Wire Chemical Vapor Deposition

We have investigated epitaxial growth of poly crystalline intrinsic silicon film grown on glass and Si/SiO2 substrate using hot wire chemical vapour deposition technique. We have grown 20 nm nucleation layer at 400°C followed by an epitaxial growth of 200 nm thick at 600°C. Than 800 nm thick layer was grown on top using high hydrogen silane ratio of 15:5. Hydrogen soaking was performed for well passivated film. Evaluation of different layers was performed using cross sectional transmission electron microscopy. Poly crystalline as well as epitaxial and columnar growth regions were well observed

Visible Light Controlled Release of Anticancer Drug through Double Activation of Prodrug

We designed and synthesized a novel double activatable prodrug system (drug–linker–deactivated photosensitizer), containing a photocleavable aminoacrylate-linker and a deactivated photosensitizer, to achieve the spatiotemporally controlled release of parent drugs using visible light. Three prodrugs of CA-4, SN-38, and coumarin were prepared to demonstrate the activation of deactivated photosensitizer by cellular esterase and the release of parent drugs by visible light (540 nm) via photounclick chemistry. Among these prodrugs, nontoxic coumarin prodrug was used to quantify the release of parent drug in live cells. About 99% coumarin was released from the coumarin prodrug after 24 h of incubation with MCF-7 cells followed by irradiation with low intensity visible light (8 mW/cm²) for 30 min. Less toxic prodrugs of CA-4 and SN-38 killed cancer cells as effectively as free drugs after the double activation

Site-Specific and Far-Red-Light-Activatable Prodrug of Combretastatin A‑4 Using Photo-Unclick Chemistry

Although tissue-penetrable light (red and NIR) has great potential for spatiotemporally controlled release of therapeutic agents, it has been hampered because of the lack of chemistry translating the photonic energy to the cleavage of a chemical bond. Recently, we discovered that an aminoacrylate group could be cleaved to release parent drugs after oxidation by SO and have called this “photo-unclick chemistry”. We demonstrate its application to far-red-light-activated prodrugs. A prodrug of combretastatin A-4 (CA4) was prepared, CMP–L–CA4, where CMP is dithiaporphyrin, a photosensitizer, and L is an aminoacrylate linker. Upon irradiation with 690 nm diode laser, the aminoacrylate linker of the prodrug was cleaved, rapidly releasing CA4 (>80% in 10 min) in CDCl₃. In tissue culture, it showed about a 6-fold increase in its IC₅₀ in MCF-7 after irradiation, most likely because of the released CA4. Most significantly, CMP–L–CA4 had better antitumor efficacy in vivo than its noncleavable (NC) analog, CMP–NCL–CA4. This is the first demonstration of the in vivo efficacy of the novel low-energy-light-activatable prodrug using the photo-unclick chemistry

Electrical Characterization and Doping Uniformity Measurement during Crystalline Silicon Solar Cell Fabrication Using Hot Probe Method

The parameters of crystalline semiconductor such as types of semiconductor, uniformity of impurity concentration of doped wafer, majority charge carrier concentration, sheet resistivity of doped wafer surface play an important role in solar cell fabrication process during emitter diffusion, that is the most critical step. In this paper, we have used a low cost in house made hot probe measurement setup. A hot plate was used to heat up the wafer up to 100°C. Two k-type thermocouples were placed simultaneously in contact with the hot and cold surface of the wafer to measure the temperature in situ for both hot and cold probe. We have used two copper probes with a voltmeter connected to measure the potential difference (thermoelectric voltage) between two probes for various temperatures up to 100°C with an interval of 10°C. We have taken measurement for commercial silicon wafer (thickness 200 µm) and one side polished 4 inch diameter Si wafer (thickness 660 µm) to determine the wafer type (n-type or p-type). We also calculated thermo-power or Seebeck coefficient from the voltage vs. time curve, that is constant for particular substrate. As a process monitoring tool for solar cell fabrication process, after n-type diffusion using POCl3 on p-type silicon wafer of thickness 200 µm, we have done wafer mapping that gives us the information of doping uniformity over the whole surface of wafer both front and back side  &nbsp