The detection limit (LD) and the quantification limit (LQ) are important parameters in the validation process. Estimation of these parameters is especially important when trace and ultra-trace ...quantities of analyte are to be detected. When the apparatus response from the analyte is below the detection limit, it does not necessarily mean that the analyte is not present in the sample. It may be a message that the analyte concentration could be below the detection capabilities of the instrument or analytical method. By using a more sensitive detector or a different analytical method it is possible to quantitatively determine the analyte in a given sample. The terms associated with detection capabilities have been present in the scientific literature for at least the past 100years. Numerous terms, definitions and approaches to calculations have been presented during that time period. This paper is an attempt to collect and summarize the principal approaches to the definition and calculation of detection and quantification abilities published from the beginning of 20th century up until the present. Some of the most important methods are described in detail. Furthermore, the authors would like to popularize the knowledge of metrology in chemistry, particularly that part of it which concerns validation of the analytical procedure.
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•Review of over a century of detection capabilities history in analytical chemistry.•We show principal LD and LQ definitions published from at least the past 100years.•Paying attention to new trends in the subject of matter.
The crystal structure of ethiprole {systematic name: 5-amino-1-2,6-di-chloro-4-(tri-fluoro-meth-yl)phen-yl-4-ethane-sulfinyl-1
-imidazole-3-carbo-nitrile}, C
H
Cl
F
N
OS, a phenyl-pyrazole-based ...insecticide, is presented. The pyrazole ring carries four substituents: an N-bound 2,6-di-chloro-4-tri-fluoro-methyl-phenyl ring and C-bound amine, ethane-sulfinyl, and cyano groups. The sulfur atom of the ethane-sulfinyl group is trigonal-pyramidal and stereogenic. The structure exhibits whole-mol-ecule configurational disorder due to superposition of enanti-omers. The crystal packing is dominated by strong N-H⋯O and N-H⋯N hydrogen bonds, which form
(18) and
(12) ring motifs. Since the ethiprole mol-ecule is quite small, and structure solution and refinement were straightforward, the structure presents a convenient instructional example for modelling whole-body disorder of a non-rigid mol-ecule. To this end, a step-by-step overview of the model-building and refinement process is also given. The structure could form the basis of a useful classroom, practical, or workshop-style example.
The title compound represents a textbook example for the arrangement of small molecules and space-group symmetry: in space group
Pnma
the mirror planes should be occupied to ensure efficient space ...filling.
The five-membered heterocycle 1,3,5-trimethyl-1
H
-pyrazole, C
6
H
10
N
2
(
1
) crystallizes in space group
Pnma
with all non-hydrogen atoms of the molecule on the crystallographic mirror plane. This arrangement has been recognized as favorable with respect to space filling by Kitaigorodskii and Wilson, pioneers in the field of crystal packing;
Pnma
represents a particularly rare space group for residues exclusively in a general position. Neighboring molecules in
1
interact
via
non-classical C—H⋯N bonds in the plane and C—H⋯π contacts between adjacent layers. In
Pnma
, crystallographic inversion relates dipolar molecules located on successive mirror planes and results in their head-to-tail arrangement. The interlayer distance in the 010 direction is closely related to the van der Waals radii of C and N.
Background: This article examines how current jurists can deal with a juristic division of the world into abode of "Islam" and "infidelity". The success with which jurists re-evaluate this dichotomy ...will have major impacts on how an Islamic state interacts with non-Muslim governments on the one hand, and Muslims residing temporarily or permanently in a non-Muslim territory on the other.
Methods: Here, an attempt made to review the concepts of Dar Al-Islam and Dar Al-Harb from two perspectives: that of the dialectical limits and liberalization, as discussed in secondary material such as books, research articles, and reports.
Results: this paper has explored and discussed the criteria for identifying Dar Al-Islam and Dar Al-Harb in Islamic jurisprudence.
Conclusions
: This article analyzes the various arguments put forward to establish new ways of peaceful coexisting and maintaining healthy international connections.
We have selected a set of ten diverse crystallography articles to illustrate important moments in the development of our field of science. They are a mixture of ‘science pull and technology push’. ...Ten is an arbitrary number and our choice is personal, so many others might have been chosen.
We have selected a set of ten ‘golden oldies’, diverse crystallography articles to illustrate important moments in the development of our field of science and which form landmark papers in crystallography. They are a mixture of ‘science pull and technology push’. For each of our choices, we firstly created a new title that emphasizes how the paper’s importance worked out from today’s perspective. Then we describe the core details and impacts of each paper, with some quotations and a selected figure or two. Ten is an arbitrary number of highlights and our choice is personal.
The traditional apprenticeship system and modern educational models both contribute to traditional Chinese medicine (TCM) education in unique ways. This study aims to evaluate the advantages and ...disadvantages of these approaches and investigates their potential integration for optimal TCM teaching.
The study employs a comprehensive literature search strategy with specific keywords through Boolean Operators, focusing on articles discussing TCM education, sourced from the databases PubMed, Scopus, and CNKI. For comparative analysis, the study analyzes the advantages and disadvantages of three distinct approaches-traditional, modern, and hybrid-in TCM education. Finally, we use a spider plot methodology to visually evaluate across 11 critical educational aspects for these approaches.
A comprehensive review of 70 articles on TCM education highlights the value of both conventional and modern approaches. Conventional methods often emphasize teacher-centered clinical training that aligns well with the apprenticeship model, serving to bridge formal academic learning with hands-on experience. Modern methods incorporate elements like technology and formal accreditation but caution that the absence of traditional apprenticeship could dilute core TCM principles. One recurring theme across multiple studies is the enduring importance of apprenticeship-a pedagogical cornerstone rooted in TCM's historical and cultural context-as well as its tension with modern methodologies that incorporate online resources and scientific frameworks. An integrated approach attempts to harmonize these strengths but reveals a gap in interactivity, suggesting that incorporating apprenticeship could offer a practical, hands-on method to improve student engagement.
Conventional methods in TCM education emphasize teacher-centered clinical training akin to apprenticeship, modern methods incorporate technological advances and formal accreditation; however, the absence of traditional apprenticeship could compromise core TCM principles, and an integrated model, though striving to harmonize these elements, still falls short in the area of student interactivity.
Antimicrobial resistance is a global health problem and one of the leading concerns in healthcare sector. Bacteriophages are antibacterial agents ubiquitous in nature. With increase in antibiotic ...resistance, use of bacteriophages as therapeutics has become resurgent in recent times. This review focuses on the recent developments in phage therapy and its applications with respect to human infections, animal, food and environment. Moreover, use of phage proteins, bioengineered bacteriophages, and phage derived vaccines is also highlighted. Additionally, the limitations and challenges with regard to implementation of phage therapy, host safety and immune responses are also reviewed in this article.
The article describes the importance of imagination development methods in the development of students’ creative activity. In addition, a methodology for developing pragmatic competence was developed ...based on problem solving technologies. Problematic educational technologies in education, their specific features are highlighted.
An easily accessible experimental set-up to grow large single crystals of two sweeteners readily available in supermarkets, erythritol and xylitol, is described. The crystallization of these ...compounds illustrates the principles of crystallization by evaporation. As these artificial sweeteners are also known to induce a cool sensation in the mouth, the crystal-growing experiment is complemented with a simple calorimetric set-up to demonstrate the endothermic nature of the dissolution of the selected sweeteners in a more quantitative approach by measuring the heat of dissolution (Δ
H
diss
). The choice of these two sweeteners also allows use of the freely available WebCSD and
Mercury
tools to visualize their three-dimensional structure, crystal packing and powder diffractograms, and to deepen stereochemical concepts such as stereoisomers and
meso
compounds.
The article describes the importance of imagination development methods in the development of students’ creative activity. In addition, a methodology for developing cognitive-pragmatic competence ...based on problem-solving technologies was developed. Problematic educational technologies in education, their specific features are revealed in detail.
