Counting Method Research Articles

Synthesis and antibacterial activity of silver doped zinc sulfide/chitosan bionanocomposites: A new frontier in biomedical applications

Numerous microbial species have caused infectious diseases worldwide, which have become a social burden and a menace to the community. So, there is a need to develop antimicrobial materials and specialized materials for biomedical applications. In the present investigation, we report the simple synthesis, the physicochemical, and antibacterial activity of Silver doped zinc sulfide (ZnS: Ag) capped with Chitosan (CS) to produce ZnS: Ag/CS bionanocomposites (BNCs). The prepared BNCs was evaluated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and UV–Vis spectroscopy. According to the XRD results, ZnS: Ag/CS particles with semicrystalline chitosan/hexagonal ZnS phase structures and an average crystallite size in the range of 30–40 nm was formed. According to FESEM images, a spherical/hexagonal shape of ZnS: Ag particles embedded in the polymeric chitosan matrix. The colony counting method was employed to investigate the antibacterial activity on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The results revealed that ZnS: Ag particles and ZnS: Ag/CS BNCs have stronger antibacterial activities than pure CS and ZnS. The reduction percentage of ZnS: Ag/CS BNCs against S. aureus and E. coli after 6 h of treatment was >99.9 % and 70 % respectively. These findings suggest that ZnS: Ag/CS BCs not only offer superior antimicrobial properties compared to individual ZnS and CS but also have great potential for advancing biomedical applications due to their enhanced antibacterial performance. The simplicity of the synthesis method and the use of non-toxic materials like chitosan make this a sustainable approach for developing antimicrobial agents, which is a key advantage of this study.

Efficacy of Glycyrrhizin as an Intracanal Medicament on Bacterial Load Reduction in Primary Infected Root Canals: A Randomized Clinical Trial.

This study was done to clinically investigate the efficacy of glycyrrhizin-based intracanal medication (ICM) compared to calcium hydroxide Ca(OH)2 and Ledermix on the bacterial counts inside the root canals of necrotic teeth with chronic periapical periodontitis. Thirty-six patients having single-rooted and single-canaled necrotic teeth with chronic periapical periodontitis were enrolled in this research. Aseptic control measures were taken before clinical steps. Access cavity preparation was done. First bacteriological samples (S1) were collected immediately after access cavity preparation and before cleaning and shaping inside the root canals. Cleaning and shaping were performed on the root canals. Patients were randomly allocated into 3 groups according to the type of intracanal medicament used [Ca(OH)2, Ledermix, Glycyrrhizin]. Second bacteriological samples (S2) were collected after 1 week from placing the ICMs. S1 and S2 were transferred to the lab of microbiology for culturing on blood agar dishes in anaerobic conditions, and the bacteria on the plates were enumerated as colony-forming units (CFUs) by the manual counting method. The anti-bacterial efficacy of the ICM was estimated by the percentage reduction in the bacterial colonies from S1 to S2. All tested ICM documented a significant reduction in the CFUs from S1 to S2 (p < 0.05). Regarding S1, there was no significant difference between the three tested materials (p > 0.05). Regarding S2, Glycyrrhizin and Ledermix showed significantly lower CFUs than Ca(OH)2. There was no significant difference between Glycyrrhizin and Ledermix. Under the conditions of the present study, Glycyrrhizin and Ledermix showed comparable antimicrobial effects that were better than the commonly used Ca(OH)2 ICM. Glycyrrhizin may be a promising ICM. Herbal medicine can be considered as an alternative antimicrobial material for root canal disinfection because it has many benefits, like low toxicity, absence of microbial resistance, and favorable antimicrobial efficacy. This study highlights the clinical efficacy of Glycyrrhizin as a promising ICM. How to cite this article: Eltantawi AR, Abdel-Razik GM, Elhawary YM, et al. Efficacy of Glycyrrhizin as an Intracanal Medicament on Bacterial Load Reduction in Primary Infected Root Canals: A Randomized Clinical Trial. J Contemp Dent Pract 2024;25(6):540-546.

Fetal Vertebral Chondrostasis—Significance of Excessive Cartilage in Vertebral Bodies of Newborns

Introduction: We describe an abnormality in fetal and neonatal vertebral bodies whose most conspicuous characteristic is an increase in cartilaginous matrix within cancellous osseous trabeculae. We have termed this finding fetal chondrostasis (FC). Methods: We initiated a retrospective review of autopsy reports in which this condition had been prospectively diagnosed during a 36-year period. The Chalkley point counting method was applied to histologic sections of vertebral bodies to assess the relative components of cartilage, bone, and bone marrow. The results were compared to those of three control groups whose causes of death were prematurity, birth trauma, and infection. Results: We found that on average, the cartilaginous content in the FC group was considerably greater in both preterm and term infants when compared to controls. FC seemed to evolve from diminished activity in the cartilaginous growth zone resulting in formation of excessively broad cartilaginous columns. These subsequently suffered from delayed resorption following their incorporation within cancellous bony trabeculae. Conclusion: Excess cartilage within cancellous bone of vertebral centra in newborns is merely one aspect of disturbed intrauterine osseous development but is seemingly more readily discernible than other features at this site. The most common clinical correlates for FC were multiple congenital anomalies, congenital heart disease, intrauterine growth retardation, prematurity, and certain maternal factors.

Influence of walkability parameters on people’s mobility in a pilgrimage town: a case study of Nanjungud, India

ABSTRACT Pilgrimage represents a sacred journey to religiously significant places. Recent studies highlight a 35 times increase in travel to pilgrimage sites from 1991 to 2019 in India. This surge in pilgrim numbers underscores the growing need for improved mobility infrastructure to ensure a comfortable environment. The study investigates the relationship between street-level walkability indicators on mobility within a pilgrimage town, Nanjungud in India. Through field surveys, we documented four crucial environmental indicators tailored for Indian conditions: sidewalk availability, green view, aspect ratio, and connectivity. Both vehicle and pedestrian volumes are measured using gate count method at 22 different locations of the study area on weekdays and weekends. SPSS is utilized for analysing the correlation. The findings reveal a statistically significant, albeit moderate, correlation between sidewalk availability and pedestrian volume during day time (0.446). However, pedestrians were observed walking on the streets where the sidewalks are discontinuous. Additionally, there tends to be less of green view in the most populated streets, and a noticeable negative correlation of aspect ratio with sidewalk availability (−0.444). The study highlights the need to prioritize improvements in sidewalk infrastructure and urban shading enhancing the overall pilgrimage experience.

Demonstration of shape analysis of neutron resonance transmission spectrum measured with a laser-driven neutron source

Laser-driven neutron sources (LDNSs) can generate strong short-pulse neutron beams, which are valuable for scientific studies and engineering applications. Neutron resonance transmission analysis (NRTA) is a nondestructive technique used for determining the areal density of each nuclide in a material sample using pulsed thermal and epithermal neutrons. Herein, we report the first successful NRTA performed using an LDNS driven by the Laser for Fast Ignition Experiment at the Institute of Laser Engineering, Osaka University. The key challenge was achieving a well-resolved resonance transmission spectrum for material analysis using an LDNS with a limited number of laser shots in the presence of strong background noise. We addressed this by employing a time-gated 6Li\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{6}{\ extrm{Li}}$$\\end{document}-glass scintillation neutron detector to measure the transmission spectra, reducing the impact of electromagnetic noise and neutron and gamma-ray flashes. Output waveforms were recorded for each laser shot and analyzed offline using a counting method. This approach yielded a spectrum with distinct resonances, which were attributed to 115In\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{115}\\,{\ extrm{In}}$$\\end{document} and 109Ag\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{109}{\ extrm{Ag}}$$\\end{document}, as confirmed through neutron transmission simulation. The spectrum was analyzed using the least-square nuclear-resonance fitting program, REFIT, demonstrating the possibility of using an LDNS for nondestructive areal-density material characterization.

Humidity-responsive pectin/AgNPs/ZnO composite films with high antimicrobial and UV-proof functions

ZnO nanoparticles and Ag nanoparticles (AgNPs) tend to agglomerate when used individually, and high Ag+concentrations can cause cytotoxicity. To address these issues, we synthesized carboxymethyl cellulose (CMC)-based antimicrobial mimetic peptides (AMPMs) by introducing amphiphilic cations on the surface of CMC using a chemical grafting method. Bis-formaldehyde-formylated AMPMs were prepared through the directional oxidation of AMPMs with periodate and used as the reducing agent to synthesize AgNPs on the surface of pectin in situ for the preparation of a pectin/AgNPs/ZnO composite film. The physical and chemical properties of the films were characterized and analyzed by SEM (EDS), TEM, XRD, and UV spectroscopy. The results showed that the film's surface was smooth and flat, with small, well-stabilized AgNPs and uniformly dispersed ZnO. The film retained the original crystalline form of pectin, but exhibited altered crystallinity, indicating that the method employed was very mild. A systematic evaluation of the film’s antimicrobial performance using the dynamic growth curve, inhibition zone, and colony counting methods showed that AgNPs and ZnO imparted excellent, long-lasting antimicrobial activity to the film (98 %). Additionally, the films exhibited good flexibility, excellent ultraviolet protection (99.9 %), biocompatibility, and biodegradability. Notably, the film was sensitive to humidity, as demonstrated by its humidity-responsive bionic application. This study provides a promising reference and strategy for advancing the development of multifunctional polysaccharide-based nanocomposites.

Associations between end stage renal disease and HLA polymorphisms in the Guangxi Zhuang population

To investigate the genetic relationship between end stage renal disease (ESRD) and human leukocyte antigen (HLA) alleles in the Guangxi Zhuang population. We performed polymerase chain reaction reversed sequence-specific oligonucleotide (PCR-rSSO) in 325 patients with ESRD and genotyped the HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 loci. The direct counting method was used to determine the frequencies of HLA alleles, and Arlequin software (version 3.5.2.2) was used for haplotypic frequency analyses to compare the included ESRD patients with 350 healthy donors from the Guangxi Zhuang population. In our study, 120 HLA alleles, 284 HLA-A-B-DRB1 haplotypes, and 332 HLA-A-C-B-DRB1-DQB1 haplotypes were detected. We found that only A*11:01-B*15:02-DRB1*12:02 had a positive association with ESRD (P = 0.001, Pc = 0.020, OR = 3.106, 95% CI = 1.497–6.446) after Bonferroni correction; thus, individuals with this haplotype may be susceptible to ESRD. A*11:01-B*15:02-DRB1*12:02 is a potentially valuable haplotype for evaluating the risk of ESRD in the Guangxi Zhuang population.

Advancing environmental remediation through tailored TiO2 nanomaterials in water and air purification

This study investigates the green synthesis of TiO2 nanoparticles at varying concentrations (0 %, 0.1 %, 2.5 %, 5 %, and 10 %) using Viola betonicifolia plant extract, focusing on their application in environmental purification, specifically in water and air decontamination. X-ray diffraction (XRD) analysis confirmed the anatase crystal structure of TiO2 nanoparticles, with an average crystallite size of approximately 22 nm. Transmission electron microscopy (TEM) revealed a median diameter of around 22 nm, corroborating the findings from XRD. The effectiveness of these TiO2 nanomaterials was evaluated through bench-scale models simulating real-world conditions, targeting a broad range of pollutants, including heavy metals, organic dyes, volatile organic compounds (VOCs), and microbial pathogens. Advanced analytical techniques such as High-performance liquid chromatography (HPLC), Inductively coupled plasma mass spectrometry (ICP-MS), and microbial plate count methods quantified the pollutant removal efficiency, demonstrating the significant potential of the synthesized TiO2 nanoparticles. Dynamic light scattering (DLS) analysis showed a mean hydrodynamic diameter of 22 nm and a polydispersity index (PDI) below 0.1, indicating a uniform size distribution. The FTIR spectrum revealed a broad absorption band at 3400 cm−1, corresponding to O–H stretching vibrations, indicative of hydroxyl groups crucial for the photocatalytic activity of TiO2. The UV–visible spectroscopy indicated a maximum absorption at 642 nm, associated with the п-п* transition. Photocatalytic degradation of methylene blue under UV irradiation achieved a degradation efficiency of 94 % after 120 min, underscoring the superior efficiency of the green synthesis method.

GROSS ALPHA/BETA ACTIVITY DETERMINATIONIN DRINKING WATER PROFICIENCY TESTS

Water intended for drinking purposes has to be analyzed first for gross alpha/beta activity according to national and international standards and recommendations. According to Albanian legislation, Article 6, the gross alpha/beta radioactivity concentration in water, should be below the level of 0.1 Bq/L and 1 Bq/L respectively for human consumption. Our laboratory participated in an interlaboratory comparison organized by IAEA Terrestrial Environmental Laboratory under suggestion of ALMERA members. Proficiency Test among environmental radioactivity monitoring laboratories for the determination of gross alpha/beta activity concentration in drinking water and contaminated surfaces (2018, 2020). Independent standard methods were used for the reference value determination. Each sample was pretreated on site with nitric acid until reaching a pH level below 2. By creating relatively non-polar surfaces, this procedure avoids a loss of radionuclide fractions due to absorption into the walls of the containers.The Gross alpha/beta activity measurements were done using gas-flow proportional counter (GPC) method. The total dissolved solids should not exceed a surface density of 5 mg/cm2 for gross alpha determination and 10 mg/cm2 for gross beta determination The performance of participating laboratories was evaluated with respect to the reference values using relative deviations. The results presented from our laboratory in both inter comparisons (IAEA-TEL-2018-03) and (IAEA-TEL-2020-03) were all acceptable. The laboratory for the measurement of gross alpha/beta radioactivity and our Institute as a part of Tirana University is in the process of accreditation, so far the participation in the inter comparisons exercise is very important.

Assessment of bird diversity and abundance in Mai-Nigus artificial reservoir and surrounding semi-forest in Tigray Region, Northern Ethiopia

BackgroundArtificial reservoirs are alternative habitats for bird diversity, and knowledge of the diversity and abundance of bird species contribute to the management of the ecosystem. This study was conducted to investigate the species diversity and abundance of birds in Mai-Nigus reservoir and its surrounding semi-forest from July 2022 to March 2023. Point count method with a total of fifteen count stations at an interval of 50 m radius was used to study the diversity and abundance of bird species in the semi-forest habitat while total count employed on the reservoir.ResultsA total of 123 bird species comprising endemic and globally threatened species were identified. Order Passeriformes had the highest number of species followed by Charadriiformes and Pelecaniformes. Family Scolopacidae was the most abundant followed by Ardeidae, Ploceidae and Anatidae. Bird species richness and abundance were not significantly varied across seasons and habitats (P > 0.05). The highest species diversity (H´=3.96) were recorded in the Semi-forest during the wet season, whereas the least was recorded from reservoir during the dry season (H´=2.66). The highest and lowest species evenness of birds was recorded in Semi-forest (E = 0.725) and reservoir (E = 0.448) during the dry season, respectively. Most birds that inhabited the area had frequent relative abundance followed by uncommon and common species.ConclusionMai-Nigus reservoir and surrounding habitat host high bird diversity and this requires critical conservation concerns for the long-term survival of birds.

High -resolution Time Interval Measurement Research based on FPGA

In modern scientific research and engineering practice, high -precision measurement of time interval between two or more physical events is often required. After years of development, there are currently many ways to measure a variety of high -precision time interval. If you implement different technologies, it can be divided into two categories: simulation and numbers. The simulation method is mainly to convert T to voltage by charging capacitance and then convert it into a digital amount through the modulus. However, the traditional simulation methods include the shortcomings of temperature sensitivity and long conversion time. Therefore, digital methods are generally used to achieve measurement. Common digital measurement methods include direct counting method, tap latency method, and cursor method. However, common measurement methods cannot meet actual needs. Therefore, this article relies on the FPGA platform to achieve a time interval measurement method with resolution to Ana second -level.

Overstayed Migratory Bird Species on The Coast of Banda Aceh City, Aceh Province

Bird migration is a critical ecological phenomenon influenced by various factors such as temperature changes, food availability, and reproductive cycles. Understanding the dynamics of migratory bird populations within specific regions is essential for conservation efforts. This study aims to identify migratory bird species within Banda Aceh City, focusing on the phenomenon of overstaying migratory birds. Conducted between April and June 2022, data collection took place in several locations, employing the concentration count method. Descriptive data analysis was performed to catalog bird species, and the Shannon-Wiener index was utilized to assess biodiversity. Results revealed the presence of four shorebird species. The study underscores the importance of protecting migratory bird populations in urban environments and highlights the potential impacts of their loss or disruption. Joint conservation efforts are crucial to safeguarding these species, and favorable conditions may encourage some individuals from commonly migrating species to remain in urban areas.

Portable real-time determination of Escherichia coli O157:H7 and Staphylococcus aureus based on smartphones and hydrogels

The aptamers functionalized orange-emission carbon dots (OCDs) and green-emission carbon dots (GCDs) had dual-emission peaks with single excitation. Tungsten disulfide nanosheets (WS2 NSs)-triggered fluorescence quenching achieved the ratiometric fluorescence determination of Escherichia coli O157:H7 (E. coli O157:H7) and Staphylococcus aureus (S. aureus) with wide ranges of 18–1.8 × 106 and 37–3.7 × 107 CFU/mL and low detection limits of 8 and 20 CFU/mL, respectively. The results in real sample with recoveries of 90–101 % and RSD < 4.12 % were no significant difference from standard plate counting method. Meanwhile, the dual-color CDs were further adopted in the smartphone-assisted hydrogel platform and achieved speedy, sensitive, portable and real-time determination of E. coli O157:H7 and S. aureus in real samples. This work has not only developed ratiometric fluorescence detection and constructed a portable hydrogel platform, but also provided a unique strategy in developing a time-efficient and easy-to-use portable device in food safety monitoring.

A drill pipe counting method based on skeleton action recognition

A drill pipe counting method based on skeleton action recognition

Water quality index of selected borehole locations in Jos North LGA of Plateau State, Nigeria

Prevalence of water borne diseases is a public health concern. The study assessed the quality of selected borehole waters in Jos North for their potability. The physicochemical parameters were assessed in addition to chlorides, phosphates, nitrates, and sulphates, total solids, total dissolved solids, total suspended solids, total hardness, using standard methods. Atomic absorption spectrophotometry used for elemental analysis of samples for manganese, lead, cadmium, copper and zinc. microbial analysis was carried out to test for presence of anaerobic bacteria, coliforms, Escherichia coli, Salmonella typhi, yeast and mould, Staphylococcus aureus using the plate count method. Water Quality Index by Weighted Arithmetic Index Method. Results ranged from 22.19-56.22 mg/L (chlorides), 0.00-0.07 mg/L (phosphates), 0.11-0.19 mS/cm (conductivity), 141.40-169.40 mg/L (alkalinity) and 86.70-160 mg/L (TSS). Kyan Primary school had Mn 0.632 mg/L against 0.500mg/L recommended by WHO. Microbial analysis revealed that Kyan primary school had 1 cfu per 100 mL water for E. coli, Salmonella typhi, yeast and mould. This indicated faecal contamination. The WQI revealed Village hostel, Kyan Village, Gadabiu had values of 6.54, 19.41, 10.97 are potable, Government College, Angwan Jarawa, Kyan Primary school had 28.90, 61.50, 93.60 are potable, poor, very poor, not potable.

Surgical instrument counting: Current practice and staff perspectives on technological support

BackgroundSurgical instrument counting is a manual, attention-intensive task of the operating room (OR) nurse. Many labour-saving technologies have been proposed, but implementation remains challenging. Knowledge of current counting methods and staff preferences could guide future developments towards effective application. ApproachWe observed OR nurses counting materials and instruments in 50 surgical procedures performed by various surgical specialties in a regional teaching hospital in Delft, The Netherlands. Additionally, we surveyed them on their preferences concerning the methods of counting. Key findingsVariations in approaches of surgical counting were observed, with OR nurses using multiple strategies and counting techniques to manage disruptions and limit workload. Interest in using supportive technology is limited to the preoperative and postoperative phase. RelevanceThis research relates observational data to staff preferences. Our findings may guide future developments of labour-saving innovations regarding surgical counting towards developing more effective applications and to ensure successful implementation.

Avian diversity in river levee forest: the effect of microscale heterogeneity

Introduction: Levee forests exhibit a vertical stratification that may contribute to structural complexity allowing a great diversity of birds to thrive on the islands. In deltaic ecosystems there is scarce or no data to prove it. Objectives: To assess variations in the composition of the bird community within levee forests. Methods: Two areas of protected wetlands belonging to the Paraná River Delta in Argentina were sampled for three years. A comparative analysis of richness, abundance, and diversity was performed in different levee forests using the point count method. Results: Three distinct types of levee forests -open, intermediate, and closed- were identified based on the structure of their vegetation, hosting a total of 85 bird species. Variation in avian community structure among forest types revealed greater diversity in open forests during winter (3.26 ± 0.13, P &lt; 0.01) and spring (3.58 ± 0.05, P &lt; 0.01), and greater richness in autumn (35.33 ± 3.01, P &lt; 0.01). The closed forests exhibited increased diversity during autumn (3.16 ± 0.13, P &lt; 0.05) and summer (3.24 ± 0.06, P &lt; 0.05), along with elevated abundance in autumn (114 ± 13.70, P &lt; 0.05) and richness in spring (39.17 ± 4.71, P = 0.01). Due to the evolutionary history between sites, significant variation was observed in the most recently created national park, influencing abundance in winter (141 ± 22.06, P &lt; 0.01) and spring (176 ± 12.83, P &lt; 0.01), as well as diversity in winter (3.25 ± 0.10, P &lt; 0.01) and spring (3.50 ± 0.10, P &lt; 0.01). Conclusions: The microhabitat in the different levee forests allows the birds to organize differently. Focusing on microspatial dynamics is key to a deep understanding of the biological processes within subtropical islands and to plan conservation strategies and demonstrate the transition of a recovering riparian forest towards its natural state, where the pulse of the river and the effect of seasonality do not stop operating.

Comparative assessment of plate count and PMA-qPCR methods for modeling the growth of lactic acid bacteria in smoked Turkey ham

This study compared the quantitative polymerase chain reaction (qPCR) method combined with propidium monoazide (PMA) and the plate count (PC) method, both combined with predictive modeling, to describe the behavior of lactic acid bacteria (LAB) in vacuum-packaged sliced smoked turkey ham (STH). The PMA-qPCR method does not allow the DNA amplification of died cells but allow the amplification of viable cells, including the non-culturable. The standard curves relating quantification cycle (Cq) and log10 CFU/g demonstrated good linearity (R2 > 0.95), evidencing its accuracy and reproducibility. These curves were used to quantify Leuconostoc mesenteroides and Weissella viridescens in artificially inoculated STH samples stored at different isothermal temperatures (8, 10, 12, 16 and 20 °C). Firstly, the PMA-qPCR and PC methods were compared, and the analysis demonstrated a good correlation (R2 = 0.99) and agreement between the results. However, the PC method underestimated the quantification of W. viridescens cells by 0.76 log10 CFU/g at 8 °C, suggesting bacterial stress at this temperature, which was not observed for L. mesenteroides. In terms of growth, the maximum specific growth rate increased with rising temperature for both LAB. Predictive modeling indicated that the growth of L. mesenteroides and W. viridescens at 8 °C suggests a shelf life of approximately 4.25 days for STH based on PC data, and 4.13 days based on PMA-qPCR data. In conclusion, the PMA-qPCR method presented an advantage in terms of accuracy, especially under bacterial stress conditions, and proved to be a promising alternative for the quantification of LAB in refrigerated ready-to-eat meat products. The predictive models used were suitable for describing microbial growth, reinforcing the importance of the PMA-qPCR method in shelf life and food safety studies.

Uncertainty in the number of contributor estimation methods applied to a Y-STR profile

Maximum allele count (MAC) and total allele count (TAC) methods are widely used for estimating the number of contributors (NoC) of autosomal short tandem repeat (STR) profile in many forensic laboratories. In this study, we applied NoC estimation methods to mixed Y-STR profiles and evaluated its uncertainty and performance. For the MAC method, as recent Y-STR typing kits involve single- and multi-copy loci, we defined “MAC-single” for use across only single-copy loci and “MAC-multi” for use across only multi-copy loci. We generated a dataset containing 120,000 Y-STR profiles for a one to six-person mixture in silico based on previously reported haplotype frequencies of 27 Y-STR loci in Yfiler Plus for the U.S. population (reported by NIST) and the Henan Han population. The dataset was randomly split into a training set and a test set. The training set was used to construct a TAC distribution (TAC curve), whereas the test set was used to calculate the performance metrics (accuracy, precision, recall, and F1-score). In addition, the effect of the upper limit of NoC considered for estimation on overall accuracy was evaluated. The overall accuracies of MAC-single, MAC-multi, and TAC methods when the upper limit of NoC was set to six-person were 0.7920, 0.4329, and 0.7877 for the U.S. population and 0.8207, 0.4609, and 0.8385 for the Henan Han population. Our results suggest that the MAC-single and TAC methods can estimate the NoC for mixed Y-STR profiles with high levels of accuracy.

TDCRPy: A python package for TDCR measurements

The TDCR (Triple-to-Double Coincidence Ratio) measurement technique is a primary standardization method used by metrology laboratories to accurately determine the activity of radioactive solutions, particularly for radionuclides unsuitable for traditional coincidence counting methods, such as pure beta emitters. The TDCR method leverages a liquid scintillation counter equipped with three photomultiplier tubes (PMTs). This paper introduces TDCRPy, a novel Python package developed by the BIPM, designed to calculate detection efficiency of liquid scintillation counters using Monte Carlo simulations and decay data evaluations from the Decay Data Evaluation Project (DDEP). The software simulates particle interactions within the liquid scintillation counter, utilizing pre-calculated probability distributions for energy deposition. Comparisons with the PENNUC/NUR code and tests with measurement from the BIPM.RI(II)-K1.Co-60 key comparison demonstrate the potential of TDCRPy. This open-source package is distributed at https://pypi.org/project/TDCRPy and available for collaborative development on GitHub https://github.com/RomainCoulon/TDCRPy, where detailed user documentation can be found.