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Salman Ali Khan,Tauseef Ahmed,Fazli Akram,Jihee Bae,Soo Yong Choi,Tran Thi Thanh,Mingyu Kim,송태권,성연수,Myong‑Ho Kim,Soonil Lee 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.3
In this study, 0.65Bi1.05FeO3–0.35BaTiO3 (BF-35BT) lead-free piezoelectric ceramics were prepared using a conventional solid-state method to determine the effects of sintering temperature on their microstructures and electrical properties. The average grain size increased with sintering temperature, but not significantly, and the relative density of the ceramics increased and then decreased at high sintering temperatures due to the volatilization of Bi2O3. At the optimal sintering temperature (1030 °C), BF-35BT ceramics showed minimum coercive field (Ec) with enhanced remanent polarization (Pr) and consequently resulted in a high converse piezoelectric coefficient (d* 33) value of 305 pm/V. The results indicate that the optimum sintering temperature, maximum relative density, and appropriate grain size, which are significantly related to the domain size and configuration, as well as the minimum concentration of associated charged defects, are critical factors that influence the piezoelectric performance of BF-35BT ceramics.
Khan, Salman,Shehzad, Omer,Jin, Hong-Guang,Woo, Eun-Rhan,Kang, Sam Sik,Baek, Sa Wang,Kim, Jinwoong,Kim, Yeong Shik American ChemicalSociety and AmericanSociety of Ph 2012 Journal of natural products Vol.75 No.1
<P>Phytochemical investigation of Leonurus japonicus has led to the isolation of a labdane diterpene derivative, 15,16-epoxy-3 alpha-hydroxylabda-8,13(16),14-trien-7-one (1), which was tested for its in vitro anti-inflammatory effects. The results demonstrated that 1 exhibits an inhibitory effect on LPS-stimulated RAW 264.7 macrophages. The anti-inflammatory action shown by 1 suppressed LPS-induced NE-kappa B activation, resulting in the down-regulation of iNOS and COX-2 protein expression, attributable to the inhibitory action of LPS-induced NO and PGE(2) production. Compound 1 inhibited LPS-induced phosphorylation and the degradation of inhibitory kappa B (I kappa B alpha) and decreased the nuclear translocation of p50 and p65. In addition, 1 exhibited an inhibitory effect on LPS-induced NE-kappa B-DNA and AP-1-DNA binding activity, using an electrophoretic mobility shift assay with NE-kappa B- and AP-1-specific P-32-labeled probes. The LPS-induced mitogen-activated protein kinases (p-JNK, p-p38, and p-ERK) and p-Akt were inhibited after 30 and 10 min of LPS stimulation, respectively. In addition, TNF-alpha production was suppressed by 1.</P>
Salman Muhmmad,Bashar Noor Ul,Kiran Uzma,Shafiq Zuhra,Khan Fareesa,Khan Raees,Hussain Farrukh,Bangash Sudhair Abbas,Yasin Ahmad,Ahmad Shabir 한국미생물·생명공학회 2022 한국미생물·생명공학회지 Vol.50 No.1
Triclosan (TCS) is an antimicrobial agent used in various human personal care products against both gram-positive and gram-negative bacteria. The purpose of this study was to evaluate the presence of TCSresistant bacteria in sewage water in Peshawar, Khyber Pakhtunkhwa (KPK), Pakistan, for the first time. TCS-supplemented Luria Bertani (LB) agar was used to isolate TCS-tolerant bacteria. A total of 17 TCSresistant isolates were randomly selected from a large pool of bacteria that showed growth on TCS-supplemented LB agar. Based on gram staining and physiochemical characteristics, the isolated strains were identified as Salmonella typhi (n = 6), Escherichia coli (n = 4), Citrobacter freundii (n = 4), Proteus mirabilis (n = 1), Enterobacter cloacae (n = 1), and Pseudomonas aeruginosa (n = 1). The Triclosan mean minimum inhibitory concentrations (MICs) for the isolates of Salmonella typhi, Escherichia coli, Citrobacter freundii, Proteus mirabilis, Enterobacter cloacae, and Pseudomonas aeruginosa were 23.66 μg ml-1, 18.75 μg ml-1, 42 μg ml-1, 32 μg ml-1, 64 μg ml-1, and 128 μg ml-1, respectively. The antibiogram revealed that all isolates were resistant to penicillin G (100%) and linezolid (100%), followed by ampicillin (94%), tetracycline (76%), tazobactam (76%), sulbactam/cefoperazone (64%), polymyxin PB (58%), amikacin (29.41%), aztreonam (29.41%), imipenem (5%), and gentamicin (5%). This is the first known study regarding the isolation of TCStolerant bacteria from sewage water in Peshawar, KPK, Pakistan. It was concluded that all the TCS-resistant isolates were multidrug resistant (MDR) gram-negative rod-shaped bacteria, mostly belonging to the Enterobacteriaceae family.
Salman Khan,Eun Myoung Shin,Sa Wang Baek,Jinwoong Kim,Yeong Shik Kim 한국당과학회 2011 한국당과학회 학술대회 Vol.2011 No.1
Leonurus japonica (syn L. heterophyllus Sweet) or Chinese motherwort is a herbaceous annual of pantropical distribution of the Lamiaceae family. Extracts of aerial parts are used in Chinese medicine for various purposes such as heart anti-arrhythmic, sedative, antimicrobial, anticoagulant, antioxidant and anti-tumoral properties, as well as booster of the immune response. The present study illustrated that, the water and 70% ethanol extracts of L. japonica exhibited no significant effect on NO and NF-κB SEAP reporter gene assay, using LPS-stimulated RAW264.7 cells. Several metabolites have been isolated from L. japonicus that substantiate the recorded activities. Five compounds were tested for anti-inflammatory effect. Leonurine, rutine, genkwanine, and stachydrine hydrochloride showed no promising effect on NO and NF-κB. On the other hand, the novel labdan diterpene derivative, 15, 16-epoxy-3-hydroxylabda-8, 13(16), 14-trien-7-one, exhibited potent inhibitory effect on the iNOS and COX-2 protein expression using LPS-stimulated RAW264.7 cells, macrophages. As a mechanism of anti-inflammatory action shown by 15,16-epoxy-3-hydroxylabda-8,13(16), 14-trien-7-one, suppression of nuclear factor (NF)-κB activation has been documented. Furthermore, the labdan compound exhibited significant inhibitory effect on LPS-medicated NF-κB-DNA binding and AP-1-DNA binding activitiesusing electrophoretic mobility shift assay (EMSA) 32P-labeled NF-κB and AP-1 probes. Taken together, labdan diterpene 15, 16-epoxy-3-hydroxylabda-8, 13(16), 14-trien-7-one, suppressed LPS-induced NF-κB activation, resulting down-regulation of iNOS and COX-2 protein expression, which was attributable to its inhibitory action of LPS-induced NO and PGE2 production. These results may contribute to the anti-inflammatory activity of 15, 16-epoxy-3-hydroxylabda-8, 13(16), 14-trien-7-one.
Khan Salman,Han Chun,Iqbal Awais,Guan Chao,Zhao Changming 한국미생물학회 2023 The journal of microbiology Vol.61 No.10
Elevation gradients, often regarded as “natural experiments or laboratories”, can be used to study changes in the distribution of microbial diversity related to changes in environmental conditions that typically occur over small geographical scales. We obtained bacterial sequences using MiSeq sequencing and clustered them into operational taxonomic units (OTUs). The total number of reads obtained by the bacterial 16S rRNA sequencing analysis was 1,090,555, with an average of approximately 45,439 reads per sample collected from various elevations. The current study observed inconsistent bacterial diversity patterns in samples from the lowest to highest elevations. 983 OTUs were found common among all the elevations. The most unique OTUs were found in the soil sample from elevation_2, followed by elevation_1. Soil sample collected at elevation_6 had the least unique OTUs. Actinobacteria, Protobacteria, Chloroflexi were found most abundant bacterial phyla in current study. Ammonium nitrogen ( NH4 +-N), and total phosphate (TP) are the main factors influencing bacterial diversity at elevations_ 1. pH was the main factor influencing the bacterial diversity at elevations_2, elevation_3 and elevation_4. Our results provide new visions on forming and maintaining soil microbial diversity along an elevational gradient and have implications for microbial responses to environmental change in semiarid mountain ecosystems.