Photochemistry of Group 14 1,1,1-Trimethyl-2,2,2-triphenyldimetallanes (Ph3MM‘Me3; M, M‘ = Si, Ge). Direct Detection and Characterization of Silene and Germene Reactive Intermediates

2000 ◽  
Vol 19 (16) ◽  
pp. 3232-3241 ◽  
Author(s):  
William J. Leigh ◽  
Nicholas P. Toltl ◽  
Paula Apodaca ◽  
Madeli Castruita ◽  
Keith H. Pannell
Keyword(s):  
Direct Detection ◽  
Reactive Intermediates ◽  
Group 14

Detection and characterization of Leptospira spp. in dogs diagnosed with kidney and/or liver disease in Selangor, Malaysia

2021 ◽  
pp. 104063872110245
Author(s):  
Sabri A. Rahman ◽  
Kuan H. Khor ◽  
Siti Khairani-Bejo ◽  
Seng F. Lau ◽  
Mazlina Mazlan ◽  
...  
Keyword(s):  
Liver Disease ◽  
Mortality Rate ◽  
Direct Detection ◽  
Bacterial Disease ◽  
Pathogenic Leptospira ◽  
Wide Range ◽  
Leptospira Spp ◽  
Rrna Sequencing ◽  
The Common

Leptospirosis is a serious bacterial disease that affects both humans and animals. A wide range of symptoms have been described in humans; the disease in dogs is commonly associated with kidney and/or liver disease. In Malaysia, information about the common serovars infecting dogs is limited. Therefore, we investigated the occurrences of leptospirosis in 124 pet dogs diagnosed with kidney and/or liver disease. Blood, urine, abdominal effusion, and/or kidney and liver were collected from the dogs. Based on microscopic agglutination testing, 53 of 124 (42.7%) dogs were seropositive for leptospiral exposure. Sera were frequently positive to serovars Bataviae ( n = 12), Javanica ( n = 10), and Icterohaemorrhagiae ( n = 10). Direct detection using PCR showed that 42 of 124 (33.9%) of the whole blood and 36 of 113 (31.9%) urine samples were positive for pathogenic Leptospira spp. By PCR, 2 of 23 (9.1%) kidney and 2 of 23 (9.1%) liver were positive for pathogenic Leptospira spp. Abdominal effusion from 4 dogs were PCR-positive for pathogenic Leptospira spp. The species detected were L. interrogans, L. borgpetersenii, L. kirschneri, and L. kmetyi by partial 16S rRNA sequencing. We further identified and characterized 11 Leptospira spp. isolates from 8 dogs as serovars Bataviae, Javanica, and Australis. The mortality rate of the Leptospira-infected dogs was high (18 of 53; 34%).

scholarly journals Time-Resolved Spectroscopic Study of N,N-Di(4-bromo)nitrenium Ions in Selected Solutions

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3182 ◽  
Author(s):  
Lili Du ◽  
Xin Lan ◽  
Zhiping Yan ◽  
Ruixue Zhu ◽  
David Phillips
Keyword(s):  
Transient Absorption ◽  
Direct Detection ◽  
Reaction Pathway ◽  
Addition Reactions ◽  
Time Resolved ◽  
Nitrenium Ions ◽  
Future Studies ◽  
Nitrenium Ion ◽  
Design Time

Nitrenium ions are important reactive intermediates in chemistry and biology. In this work, femtosecond and nanosecond transient absorption (fs-TA and ns-TA) along with nanosecond time-resolved resonance Raman (ns-TR3) experiments were employed to examine the photochemical pathways of N-(4,4′-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF4− (salt (DN) from just absorption of a photon of light to the production of the important N,N-di(4-bromophenyl)nitrenium ion 2. In acetonitrile (MeCN), the formation of halogenated diarylnitrenium ion 2 was observed within 4 ps, showing the vibrational spectra with strong intensity. The nucleophilic adduct reaction of ion 2 with H2O was also examined in aqueous solutions. The direct detection of the unique ortho adduct intermediate 3 shows that there is an efficient and exclusive reaction pathway for 2 with H2O. The results shown in this paper give new characterization of 2, which can be used to design time-resolved spectroscopy investigations of covalent addition reactions of nitrenium ions with other molecules in future studies.

Photochemical Characterization of Paddy Water during Rice Cultivation: Formation of Reactive Intermediates for As(III) Oxidation

2021 ◽  
pp. 117721
Author(s):  
Yu Zeng ◽  
Guodong Fang ◽  
Qinglong Fu ◽  
Dionysios D. Dionysiou ◽  
Xiaolei Wang ◽  
...  
Keyword(s):  
Reactive Intermediates ◽  
Rice Cultivation ◽  
Paddy Water

Oxypeucedanin is a mechanism-based inactivator of CYP2B6 and CYP2D6

2021 ◽  
Vol 22 ◽  
Author(s):  
Kehan Zhang ◽  
Yilin Li ◽  
Yao Fu ◽  
Tiantian Cui ◽  
Qian Wang ◽  
...  
Keyword(s):  
Pain Relief ◽  
Liver Microsomes ◽  
Reactive Intermediates ◽  
Enzyme Inactivation ◽  
Time Dependent ◽  
Reactive Metabolites ◽  
Angelica Dahurica ◽  
Dependent Inhibition ◽  
Microsomal Incubation

Background: Herbal medicine Angelica dahurica is widely employed for the treatment of rheumatism and pain relief in China. Oxypeucedanin is a major component of the herb. Objectives : The objectives of this study are aimed at the investigation of mechanism-based inactivation of CYP2B6 and CYP2D6 by oxypeucedanin, characterization of the reactive metabolites associated with the enzyme inactivation, and identification of the P450s participating in the bioactivation of oxypeucedanin. Methods : Oxypeucedanin was incubated with liver microsomes or recombinant CYPs2B6 and 2D6 under designed conditions, and the enzyme activities were measured by monitoring the generation of the corresponding products. The resulting reactive intermediates were trapped with GSH and analyzed by LC-MS/MS. Results : Microsomal incubation with oxypeucedanin induced a time-, concentration-, and NADPH-dependent inhibition of CYPs2B6 and 2D6 with kinetic values of KI/kinact 1.82 µM/0.07 min-1 (CYP2B6) and 8.47 µM/0.044 min-1 (CYP2D6), respectively. Ticlopidine and quinidine attenuated the observed time-dependent enzyme inhibitions. An epoxide and/or γ-ketoenal intermediate(s) derived from oxypeucedanin was/were trapped in microsomal incubations. CYP3A4 was the primary enzyme involved in the bioactivation of oxypeucedanin. Conclusion : Oxypeucedanin was a mechanism-based inactivator of CYP2B6 and CYP2D6. An epoxide and/or γ-ketoenal intermediate(s) may be responsible for the inactivation of the two enzymes.

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