scholarly journals Quantitative analysis of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives, potential DHFR inhibitors: an integrated crystallographic and theoretical study

RSC Advances ◽  
2020 ◽  
Vol 10 (60) ◽  
pp. 36806-36817
Author(s):  
Lamya H. Al-Wahaibi ◽  
Kushumita Chakraborty ◽  
Nora H. Al-Shaalan ◽  
Mohamed Yehya Annavi Syed Majeed ◽  
Olivier Blacque ◽  
...  

Qualitative and quantitative analyses of hydrogen and chalcogen bonds in two pyrimidine-5-carbonitrile derivatives are described.

Author(s):  
N. A. Al-Abkal ◽  
E. Kh. Metwally ◽  
S. R. Alezzbawy ◽  
Kh. Y. Orabi ◽  
Sh. H. Alshammari

Aim: To compare the main and additive components of heroin trafficked in the Stateof Kuwait during 2012 with those components of heroin traded recently in the country during 2016 and 2017, and to provide a satisfactory explanation for the increase in deaths among heroin addicts during the period2011 -2018. Study Design: Selected samples of non-pure powder heroin seized in Kuwait during 2016 and 2017, with pure heroin and a set of10 pure different heroin component standards, all have been quantitatively analyzed in the Forensic Laboratories. Place and Duration of Study: All qualitative and quantitative analyses for 2016 and 2017 samples were conducted in the Forensic Laboratories of the General Department of Criminal Evidences – Ministry of Interior – State of Kuwait. Methodology: By using Gas Chromatography/Mass Spectrometry (GC/MS) to qualitative and quantitative analysis have been made on a total of hundred samples of non-pure powder heroin seized in Kuwait during the years 2016 and 2017, in addition to ten pure standards. Results: The concentration of the diacetylmorphine (active substance of heroin) in Kuwait during the year 2017 are much higher than the concentration during the year 2016. The additive substances (adulterants) for the years 2016 and 2017, are shared with the year 2012 by the component's paracetamol, caffeine and diazepam with different concentrations. But new adulterants in recent years are recorded in samples 2016 and 2017, including methamphetamine, dextromethorphan, and methylphenidate which is absent in 2016 samples. Conclusion: The concentration % of illicit heroin traded in Kuwait as diacetylmorphine has increase from 10% to 50% for year 2016, and further from 30% - 70% for year 2017, which marks identified a substantial rising in the purity of heroin. In addition, additive substances in the two years include paracetamol (acetaminophen), caffeine and diazepam, previously recorded in 2012. However, totally different new adulterates are recorded in 2016 and 2017 samples, including methamphetamine, dextromethorphan, and methylphenidate. All new three adulterates are detected in quite a few numbers of samples with methylphenidate recorded in a very low concentration of 0. 01 mg. Both new adulterates and higher purity of heroin constitute the main reasons for rising the rate of deaths between heroin addicts in recent years. Also, recent UN reports (12,18) provide evidence that the GC countries Afghanistan, Iran and Pakistan are still manufacturing and trading the above mentioned new adulterates.


Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3463
Author(s):  
Miao Tian ◽  
Chunjuan Yang ◽  
Jing Yang ◽  
Hongrui Dong ◽  
Lu Liu ◽  
...  

In this study, the constituents of a Corydalis bungeana Turcz extract were qualitatively analyzed using gradient elution with a mobile phase of 0.2% acetic acid and acetonitrile. We obtained comprehensive insight into the constituents of C. bungeana Turcz extracts through the quantitative analysis of 14 compounds by comparison with authentic reference standards, and tentatively identified an additional 44 compounds through electrospray ionization mass spectrometry (ESI–MS) and tandem MS detection. The separation was successfully achieved using an Agilent SB-C18 column (1.8 µm, 150 × 2.1 mm; Agilent, Santa, CA, USA). A tandem quadrupole spectrometer was operated in either full-scan mode or multiple reaction monitoring (MRM) for the qualitative and quantitative analyses of the constituents, respectively. Validation data (inter-day and intra-day combined) for accuracy and precision ranged from −4.80% to 4.73%, and 0.30% to 4.97%, respectively. An ultrahigh performance liquid chromatographic–ESI–tandem MS (UHPLC–ESI–MS/MS) method for qualitative of C. bungeana Turcz (C. bungeana) extract and the quantification of 14 alkaloids, namely, A–N, was developed and validated. Quantitative analysis involved gradient elution with a mobile phase of 0.1% acetic acid and methanol for 45 min. The separation was successfully achieved using a Waters SB-C18 column (1.8 µm, 100 mm × 2.1 mm, Waters, Milford, Massachusetts, USA). The repeatability and stability of the method also met USFDA criteria with CV values lower than 5%. The limit of detection of the 14 alkaloids ranged from 9.74 to 13.00 ng/mL, whereas the linearities of the standard curves were between 0.9991 and 0.9995. In total, 15 commercial samples from 11 different sources were analyzed.


2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Tao Liu ◽  
Jing Hu ◽  
Li Yong ◽  
Gang Zhang ◽  
Yi Zhang ◽  
...  

By-products (phenyl salicylate, phenyl 4-hydroxybenzoate, and xanthone) from transesterification between phenol and dimethyl carbonate (DMC) were qualitatively analyzed by gas chromatography-mass spectrometry, and a gas chromatographic method with directed injection for simultaneous quantitative analysis of the product (DPC) and by-products of the transesterification has been established. Based on the results of qualitative and quantitative analyses, the mechanism of the by-products generation was preliminarily deduced. The sample for quantitative analysis was directly diluted in acetone, and related compounds were separated on an HP-5 capillary column and detected by a hydrogen flame ionization detector (FID). The product and by-products were well separated, the correlation coefficients (r) within the concentration range of 1.0 μg/mL–100 μg/mL were ≥0.9997, the relative standard deviations were between 0.5% and 4.4%, spiked recoveries were between 91.5% and 105.6%, and detection limits were between 0.11 and 0.18 μg/mL. The established method is simple, rapid, accurate, sensitive, and highly specific. It is suitable for simultaneous qualitative and quantitative analyses of the product and by-products of transesterification between phenol and DMC.


2019 ◽  
Vol 43 (3) ◽  
pp. 391-401 ◽  
Author(s):  
Ahmed A. Alsultan ◽  
Caren van Roekel ◽  
Maarten W. Barentsz ◽  
Arthur J. A. T. Braat ◽  
Pieter Jan van Doormaal ◽  
...  

Abstract Purpose To evaluate the efficacy of coil embolization to obtain intrahepatic redistribution in patients undergoing radioembolization. Materials and Method All patients treated with radioembolization at our institute were retrospectively analyzed, and all cases in which a tumor-feeding vessel was coil-embolized were selected. Two nuclear medicine physicians visually assessed the effect of redistribution. Furthermore, the redistribution of microspheres was measured by quantifying the activity distributed to the coil-embolized (dependent) segment relative to the other (non-dependent) segments and to the tumor(s) in that segment. Quantitative analysis was performed on post-treatment 90Y-PET and 166Ho-SPECT using Simplicit90Y software. Lesion response was measured according to RECIST 1.1 criteria at 3 months post-treatment. Results Out of 37 cases, 32 were suitable for quantitative analysis and 37 for qualitative analysis. In the qualitative analysis, redistribution was deemed successful in 69% of cases. The quantitative analysis showed that the median ratio of the activity to the dependent embolized segments and the non-dependent segments was 0.88 (range 0.26–2.05) and 0.80 (range 0.19–1.62) for tumors in dependent segments compared with tumors in non-dependent segments. Using a cutoff ratio of 0.7 (30% lower activity concentration in comparison with the rest of the liver), 57% of cases were successful. At 3 months post-treatment, 6% of dependent tumors had partial response, 20% progressive disease, and 74% stable disease. In non-dependent tumors, this was, respectively, 16%, 20%, and 64%. Conclusion Coil embolization of hepatic arteries to induce redistribution of microspheres has a limited success rate. Qualitative assessment tends to overrate redistribution.


2020 ◽  
Vol 103 (5) ◽  
pp. 1400-1405
Author(s):  
Mengru Cao ◽  
Yingkai Liu ◽  
Hanwen Yuan ◽  
Yixing Qiu ◽  
Qingling Xie ◽  
...  

Abstract Background Chewable areca products are popular in Asian countries, including India, Pakistan, Malaysia, and China. The major alkaloids present in areca products are guvacine, arecaidine, guvacoline, and arecoline which cause carcinogenicity and addiction. Objective The objective of this study was the quantitative analysis of the alkaloid content of areca chewable products from different countries and regions using HPLC-UV, as well as the benefit of their safety evaluation products. Method An HPLC-UV method was established for qualitative and quantitative analyses of 65 batches of areca chewable products from different countries and regions. Additionally, similarity evaluation of chromatographic fingerprints was applied for data analysis. Results These results reveal a significant variation in the levels of areca alkaloids among tested products, specifically guvacoline (0.060–1.216 mg/g), arecoline (0.376–3.592 mg/g), guvacine (0.028–1.184 mg/g), and arecaidine (0.184–1.291 mg/g). There were significant differences in the alkaloid content of areca chewable products from different producing areas. Conclusions The method will be useful in the safety evaluation of different areca chewable products. Highlights The established HPLC-UV method can be adopted for safety evaluation of areca chewable products from different countries and regions due to its general applicability.


Author(s):  
Sebastien Bacher ◽  
Steven David Hajdu ◽  
Yael Maeder ◽  
Vincent Dunet ◽  
Tom Hilbert ◽  
...  

Abstract Objectives To determine and compare the qualitative and quantitative diagnostic performance of a single sagittal fast spin echo (FSE) T2-weighted Dixon sequence in differentiating benign and malignant vertebral compression fractures (VCF), using multiple readers and different quantitative methods. Methods From July 2014 to June 2020, 95 consecutive patients with spine MRI performed prior to cementoplasty for acute VCFs were retrospectively included. VCFs were categorized as benign (n = 63, mean age = 76 ± 12 years) or malignant (n = 32, mean age = 63 ± 12 years) with a best valuable comparator as a reference. Qualitative analysis was independently performed by four radiologists by categorizing each VCF as either benign or malignant using only the image sets provided by FSE T2-weighted Dixon sequences. Quantitative analysis was performed using two different regions of interest (ROI1-2) and three methods (signal drop, fat fraction (FF) from ROIs, FF maps). Diagnostic performance was compared using ROC curves analyses. Interobserver agreement was assessed using kappa statistics and intraclass correlation coefficients (ICC). Results The qualitative diagnostic performance ranged from area under the curve (AUC) = 0.97 (95% CI: 0.91–1.00) to AUC = 0.99 (95% CI: 0.95–1.0). The quantitative diagnostic performance ranged from AUC = 0.82 (95% CI: 0.73–0.89) to AUC = 0.97 (95% CI: 0.91–0.99). Pairwise comparisons showed no statistical difference in diagnostic performance (all p > 0.0013, Bonferroni-corrected p < 0.0011). All five cases with disagreement among the readers were correctly diagnosed at quantitative analysis using ROI2. Interobserver agreement was excellent for both qualitative and quantitative analyses. Conclusions A single FSE T2-weighted Dixon sequence can be used to differentiate benign and malignant VCF with high diagnostic performance using both qualitative and quantitative analyses, which can provide complementary information. Key Points • Qualitative analysis of a single FSE T2-weighted Dixon sequence yields high diagnostic performance and excellent observer agreement for differentiating benign and malignant compression fractures. • The same FSE T2-weighted Dixon sequence allows quantitative assessment with high diagnostic performance. • Quantitative data can readily be extracted from the FSE T2-weighted Dixon sequence and may provide complementary information to the qualitative analysis, which may be useful in doubtful cases.


Conjecturas ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 243-257
Author(s):  
Fillipe Marini ◽  
Jefferson Santos Alves da Costa ◽  
Maria José Ramos da Silva ◽  
Aline Carneiro de Paula ◽  
Ivane de Pontes Moura

The objective of this study was to compare the performance of landraces and commercial varieties to identify which variety is the most suitable for family farmers. The experimental design was a completely randomized block design with three replicates and 10 varieties. Qualitative and quantitative parameters were evaluated in the useful plot. The qualitative analyses were performed in the field with the participation of farmers, who scored the evaluated parameters as 1 - poor, 2 - average, 3 - good, or 4 - excellent. Quantitative analyses were performed without the participation of farmers. The data obtained (qualitative and quantitative) were subjected to analysis of variance, and the means were compared by the Scott-Knott test (p<0.05). The Pontinha and Adelaide varieties had the best quality variables in the farmers’ view. In the quantitative analysis, the landrace varieties showed similar results to the commercial varieties, but the highest yields were obtained with Pontinha and Adelaide. The results of the qualitative and quantitative assessments reaffirm the importance of farmers’ knowledge of corn cultivation in the studied municipality.


Author(s):  
Jerrold L. Abraham

Inorganic particulate material of diverse types is present in the ambient and occupational environment, and exposure to such materials is a well recognized cause of some lung disease. To investigate the interaction of inhaled inorganic particulates with the lung it is necessary to obtain quantitative information on the particulate burden of lung tissue in a wide variety of situations. The vast majority of diagnostic and experimental tissue samples (biopsies and autopsies) are fixed with formaldehyde solutions, dehydrated with organic solvents and embedded in paraffin wax. Over the past 16 years, I have attempted to obtain maximal analytical use of such tissue with minimal preparative steps. Unique diagnostic and research data result from both qualitative and quantitative analyses of sections. Most of the data has been related to inhaled inorganic particulates in lungs, but the basic methods are applicable to any tissues. The preparations are primarily designed for SEM use, but they are stable for storage and transport to other laboratories and several other instruments (e.g., for SIMS techniques).


Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
T Jankovic ◽  
G Zdunic ◽  
K Savikin ◽  
I Beara ◽  
N Mimica-Dukić

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