Transport Medium Research Articles

Green hydrogen production and use in low- and middle-income countries: A least-cost geospatial modelling approach applied to Kenya

With the rising threat of climate change, green hydrogen is increasingly seen as the high-capacity energy storage and transport medium of the future. This creates an opportunity for low- and middle-income countries to leverage their high renewable energy potential to produce, use, and export low-cost green hydrogen, creating environmental and economic development benefits. While identifying ideal locations for green hydrogen production is critical for countries when defining their green hydrogen strategies, there has been a paucity of adequate geospatial planning approaches suitable to low- and middle-income countries. It is essential for these countries to identify green hydrogen production sites which match demand to expected use cases such that their strategies are economically sustainable. This paper therefore develops a novel geospatial cost modelling method to optimize the location of green hydrogen production across different use cases, with a focus on suitability to low- and middle-income countries. This method is applied in Kenya to investigate the potential hydrogen supply chain for three use cases: ammonia-based fertilizer, freight transport, and export. We find hydrogen production costs of €3.7–9.9/kgH2 are currently achievable across Kenya, depending on the production location chosen. The cheapest production locations are identified to the south and south-east of Lake Turkana. We show that ammonia produced in Kenya can be cost-competitive given the current energy crisis and that Kenya could export hydrogen to Rotterdam with costs of €7/kgH2, undercutting current market prices regardless of the carrier medium. With expected techno-economic improvements, hydrogen production costs across Kenya could drop to €1.8–3.0/kgH2 by 2030.

The study on modeling and simulation of shale multi-scale matrix-fracture system

Shale is a complex porous medium with multi-scale pores and well-developed fracture networks. This paper aims to use modeling and numerical simulation methods to study the transport of shale gas in a complex multi-scale matrix-fracture system. In this study, mathematical modeling and programming was used to establish digital models of shale gas multi-scale matrix and 3D discrete fracture network. Based on the transport mechanisms of shale gas, this study derives the mathematical models of shale gas transport in different transport media, and uses the finite element method to solve and analysis the transport of shale gas in the multi-scale matrix-fracture system. The model is verified by real shale gas field data. The results show that the fractal dimension of organic pores have great effects on shale gas transport. When the fractal dimension is greater than 1.4, the increase on gas production is particularly obvious. Compared with organic pores, the effect of fractal dimension of inorganic pores is smaller. The existence of the fracture network has an effect of up to 25% on gas production, and the optimal fracture density is 200.

Magnetic Refrigeration: An Environment-friendly Cooling Technology

Magnetic Refrigeration: An Environment-friendly Cooling Technology

Networking Operatic Italy Francesca Vella

Enrico Petrella’s funeral march in Jone (1858) might at first seem indistinguishable from other nineteenth-century musical ephemera. Performed by an on-stage banda in Act IV of the once widely performed opera, the ‘lugubrious’ march—as it was named in the autograph score—accompanies the dramatic walk of a wrongly accused lover to his execution. However, the performance history of the march on opera stages—and Jone toured the world extensively in its first decades of performances—would fail to hear its growing presence on Italian city streets. Shortly after the opera’s La Scala premiere, the signature march became a standard in Italian wind-band repertory, where it found new life (and death) in secular funerals across the peninsula and during Holy Week processions in parts of southern Italy. The march grew to function in the Italian cultural consciousness as ‘an inward cipher of death and mourning’ (p. 67). Stories like this, which unspool how an operatic artefact became entangled in Italian culture, pepper Francesca Vella’s recent book, Networking Operatic Italy. In this enticing monograph, artists and operas travel the globe, technologies evolve and malfunction, and literary, archival, and musical sources are put in dialogue in innovative ways. One of the book’s core arguments is that ‘opera has always had a special networking capacity’ (p. 14) Vella ‘networks’—and use of the verb is deliberate—nineteenth-century Italian opera with its supporting media, wider infrastructure of mobility, and surrounding cultural discourses. Her concept of the network is, in part, indebted to Bruno Latour’s actor-network theory and Bill Brown’s thing theory, as the objects central to her narrative are not passive components of opera’s history. Instead, objects, technologies, and ideas shape and condition opera through their affordances or limitations. Across five case studies of interconnected webs of people, ideas, and—of course—operas, Vella addresses transportation and communications media (railroads, wind-bands, voices, newspapers, and the telegraph) in the increasingly mobilized environment of Risorgimento and Liberal-era Italy. Her study of Italian opera journeys to various theatres across Italy, and the reader encounters works by Meyerbeer, Wagner, and Verdi, as well as those of the lesser-known Petrella. The five chapters examine scores of operatic works—most chapters contain hermeneutic readings of specific scenes—and intersect with the many participants and components of opera productions, as uncovered through painstaking archival efforts (the forty pages of endnotes are a treasure trove for any reader).

Performance Evaluation of SARS-CoV-2 Viral Transport Medium Produced by Bangladesh Reference Institute for Chemical Measurements.

A viral transport medium (VTM) was developed following the Centers for Disease Control and Prevention, USA (US-CDC) standard operating procedure (SOP) DSR-052-05 with necessary improvisation and was used for storing coronavirus disease 2019 (COVID-19) swab specimens. Considering Bangladesh's supply chain and storage conditions, improvisation was essential for extending sample storage time while retaining efficiency. In-house VTM was produced using Hank's balanced salt solution (HBSS) supplemented with 1% bovine serum albumin V (BSA), 0.5 µg /mL of gentamicin sulfate, and 100 µg/mL of fluconazole. The produced VTM composition, quality, sterility, specificity, and efficiency were verified in-house and through an independent contract research organization (CRO). An accelerated stability study projected that under the recommended temperature (4 °C), it would remain stable for four months and preserve samples for over a month. The real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) test detected the targeted N gene and ORF1ab gene from the VTM stored samples. Our VTM is equally as effective as the Sansure Biotech VTM in keeping SARS-CoV-2 RNA specimens detectable in rRT-PCR (100% sensitivity and specificity in random and blinded samples). In conclusion, the BRiCM VTM will make the battle against pandemics easier by effectively collecting and storing nasopharyngeal and oropharyngeal swabs for COVID-19 detection.

COVID-19 among Patients Visiting the Department of Emergency of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Because of the unbridled transmissibility of the SARS-CoV-2 worldwide, researchers and healthcare professionals have set a common goal for timely diagnosis and future prevention of the disease. The aim of this study was to find out the prevalence of COVID-19 among patients visiting the Department of Emergency of a tertiary care centre. This descriptive cross-sectional study was conducted among the individuals suspected COVID-19 who had visited the Department of Emergency of a tertiary care centre between 11 January 2021 and 29 December 2021. Ethical approval was taken from Ethical Review Board (Reference number: 2768). Socio-demographic details, clinical symptoms, and two nasopharyngeal swab samples (one in viral transport medium to run RT-PCR and the other for Ag-RDT) were collected from each individual. Convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated. Among the 232 patients, COVID-19 was detected in 108 (46.55%) (40.13-52.97, 95% CI) by Ag-RDT. A total of 44 (39.63%) of age groups 31-40 years were predominantly infected with SARS-CoV-2. The mean age was 32.13±10.80 years and was mostly males 73 (65.77%). Fever was present in 57 (51.35%) and dry cough was present in 50 (45.05%) COVID-19 patients. The prevalence of COVID-19 among hospitalized individuals in this study was higher than in previous studies conducted in similar settings. COVID-19; Nepal; prevalence; SARS-CoV-2.

Olive Oil as a Transport Medium for Bioactive Molecules of Plants?-An In Situ Study.

(1) Caries and erosions still remain a challenge for preventive dentistry. Certain plant extracts have shown beneficial effects in preventive dentistry. The aim of this study was to evaluate the antibacterial, anti-adherent and erosion-protective properties of ellagic acid (EA) as a polyphenolic agent. The combination with olive oil was investigated additionally to verify a possible improved bioactive effect of EA. (2) An in situ study was carried out with six subjects. Individual splints were prepared with bovine enamel specimens. The splints were worn for 1 min (pellicle formation time). Thereafter, 10 min rinses were performed with EA in water/in oil. Bacterial adherence was evaluated by fluorescence microscopy (DAPI, ConA, BacLight) after an 8 h oral exposition time. Additionally, the splints were worn for 30 min to quantify demineralization processes. The ultrastructure of the pellicle was investigated after an oral exposure time of 2 h under a transmission electron microscope. Statistical analysis was performed by Kruskal-Wallis tests, Mann-Whitney U tests and Bonferroni-Holm correction. (3) Rinsing with EA led to a significant reduction of adherent vital and dead bacteria. The combination with olive oil did not improve these outcomes. The assessment of glucan structures after rinsing with EA in water showed significant effects. Significant differences were observed for both rinses in calcium release at pH 3.0. After rinsing with EA in oil, significantly less calcium was released compared to rinsing with EA in water (pH = 3.0). (4) Olive oil is not suitable as a transport medium for lipophilic polyphenols. EA has anti-adherent and antibacterial properties in situ. EA also shows erosion-protective effects, which can be enhanced in combination with olive oil depending on the pH value. Ellagic acid has a neutral pH and could be an opportunity in the treatment of specific patient groups (xerostomia or mucositis).

Metagenomics characterization of respiratory viral RNA pathogens in children under five years with severe acute respiratory infection in the Free State, South Africa.

Prompt detection of viral respiratory pathogens is crucial in managing respiratory infection including severe acute respiratory infection (SARI). Metagenomics next-generation sequencing (mNGS) and bioinformatics analyses remain reliable strategies for diagnostic and surveillance purposes. This study evaluated the diagnostic utility of mNGS using multiple analysis tools compared with multiplex real-time PCR for the detection of viral respiratory pathogens in children under 5 years with SARI. Nasopharyngeal swabs collected in viral transport media from 84 children admitted with SARI as per the World Health Organization definition between December 2020 and August 2021 in the Free State Province, South Africa, were used in this study. The obtained specimens were subjected to mNGS using the Illumina MiSeq system, and bioinformatics analysis was performed using three web-based analysis tools; Genome Detective, One Codex and Twist Respiratory Viral Research Panel. With average reads of 211323, mNGS detected viral pathogens in 82 (97.6%) of the 84 patients. Viral aetiologies were established in nine previously undetected/missed cases with an additional bacterial aetiology (Neisseria meningitidis) detected in one patient. Furthermore, mNGS enabled the much needed viral genotypic and subtype differentiation and provided significant information on bacterial co-infection despite enrichment for RNA viruses. Sequences of nonhuman viruses, bacteriophages, and endogenous retrovirus K113 (constituting the respiratory virome) were also uncovered. Notably, mNGS had lower detectability rate for severe acute respiratory syndrome coronavirus 2 (missing 18/32 cases). This study suggests that mNGS, combined with multiple/improved bioinformatics tools, is practically feasible for increased viral and bacterial pathogen detection in SARI, especially in cases where no aetiological agent could be identified by available traditional methods.

Optimization and Improvement of qPCR Detection Sensitivity of SARS-CoV-2 in Saliva.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been a major public health threat globally, especially during the beginning of the pandemic in 2020. Reverse transcription-quantitative PCR (RT-qPCR) is utilized for viral RNA detection as part of control measures to limit the spread of COVID-19. Collecting nasopharyngeal swabs for RT-qPCR is a routine diagnostic method for COVID-19 in clinical settings, but its large-scale implementation is hindered by a shortage of trained health professionals. Despite concerns over its sensitivity, saliva has been suggested as a practical alternative sampling approach to the nasopharyngeal swab for viral RNA detection. In this study, we spiked saliva from healthy donors with inactivated SARS-CoV-2 from an international standard to evaluate the effect of saliva on viral RNA detection. On average, the saliva increased the cycle threshold (CT) values of the SARS-CoV-2 RNA samples by 2.64 compared to the viral RNA in viral transport medium. Despite substantial variation among different donors in the effect of saliva on RNA quantification, the outcome of the RT-qPCR diagnosis was largely unaffected for viral RNA samples with CT values of <35 (1.55 log10 IU/mL). The saliva-treated viral RNA remained stable for up to 6 h at room temperature and 24 h at 4°C. Further supplementing protease and RNase inhibitors improved the detection of viral RNA in the saliva samples. Our data provide practical information on the storage conditions of saliva samples and suggest optimized sampling procedures for SARS-CoV-2 diagnosis. IMPORTANCE The primary method for detection of SARS-CoV-2 is using nasopharyngeal swabs, but a shortage of trained health professionals has hindered its large-scale implementation. Saliva-based nucleic acid detection is a widely adopted alternative, due to its convenience and minimally invasive nature, but the detection limit and direct impact of saliva on viral RNA remain poorly understood. To address this gap in knowledge, we used a WHO international standard to evaluate the effect of saliva on SARS-CoV-2 RNA detection. We describe the detection profile of saliva-treated SARS-CoV-2 samples under different storage temperatures and incubation periods. We also found that adding protease and RNase inhibitors could improve viral RNA detection in saliva. Our research provides practical recommendations for the optimal storage conditions and sampling procedures for saliva-based testing, which can improve the efficiency of COVID-19 testing and enhance public health responses to the pandemic.

Abstract LB107: A precision DNA methylation test to triage HPV positive women before referral to colposcopy-driven biopsies or ablative treatment in cervical cancer screening clinics worldwide

Abstract Cervical cancer is one of the most common cancers in women. Despite progress in prevention through Human Papilloma Virus (HPV) vaccination and success in early detection of cervical cancer through cytologic screening and HPV detection, there remains an unequal cervical cancer burden in low-resource settings, both in developed and developing countries. We have previously shown that the CervicalMethDx test can provide a Cervical Intraepithelial Neoplasia (CIN) grade 2-3 risk score, by assessing DNA methylation in a panel of three human genes (ZNF516, FKBP6 and INTS1) in samples from the United States (US), Puerto Rico, and Chile. We now tested the performance of the CervicalMethDx test on HPV-positive CIN2 and CIN3 cases (n=113) from Honduras collected from participants in the ESTAMPA clinical trial (NCT01881659). ESTAMPA (EStudio multicéntrico de TAMizaje y triaje de cáncer de cuello uterino con pruebas del virus del PApiloma humano; Spanish acronym) is a multicentric study of cervical cancer screening with HPV testing and assessment of triage methods in Latin America, which has accrued close to 50,000 participants from twelve recruitment centers in nine Latin American countries since 2013. We hypothesized that the CervicalMethDx test can identify HPV positive women most likely to be diagnosed with CIN grades 2 and 3 by anatomic pathologists, before they are referred to colposcopy-driven biopsies. We assessed DNA methylation by quantitative Real Time Methylation Specific PCR (qMSP) analysis of sodium bisulfite-modified genomic DNA. Primers and probes were previously designed to specifically amplify the promoters of the 3 genes of interest and the promoter of a reference gene, β-actin, to assess DNA input. We performed blinded retrospective studies on well-characterized clinical samples in PreservCyt sample transport media (ThinPrep, Hologic), comparing DNA methylation levels in samples from Honduras and 88 HPV-positive previously tested US samples with No Intraepithelial Lesions or Malignancy (NILM), as controls. Our results showed that the CervicalMethDx test can correctly classify 96% of CIN2 (n=62) samples with 92% Sensitivity, 98% Specificity, and an AUC of 0.96 as well as 97% of CIN3 (n=51) samples with 96% Sensitivity, 98% Specificity, and an AUC of 0.97. Moreover, the assay correctly classified 96% of CIN2-CIN3 samples combined (n=113) with 95% Sensitivity, 98% Specificity, and AUC of 0.97, when compared to samples with NILM (n=88). Our results suggest that the CervicalMethDx test is a new and valuable tool to stratify HPV positive women prior to colposcopy-driven biopsies in developed countries and ablative treatment in developing countries, most of which are unnecessary. These results warrant further evaluation of the CervicalMethDX test in prospective, population-based studies, assessing the use of precision DNA methylation algorithms to triage HPV positive women before referral to colposcopy-driven biopsies or ablative treatments in cervical cancer screening clinics world-wide. Citation Format: Laura Palmieri, Fernando Zamuner, Yessy Cabrera, Jafet Ortiz-Quintero, Dieila Giomo De Lima, Ana Purcell-Wiltz, Amanda García-Negrón, Ashley Ramos-López, Mariana Brait, David Sidransky, Annabelle Ferrera, Rafael E. Guerrero-Preston. A precision DNA methylation test to triage HPV positive women before referral to colposcopy-driven biopsies or ablative treatment in cervical cancer screening clinics worldwide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB107.

Transport properties of moisture and ionic chelators in concrete

The transport properties of moisture and ionic chelators in the concrete affect not only the durability of the concrete, but also the effectiveness of the repair material in repairing cracks in the concrete. The transport of water and ionic chelators in the concrete was investigated by capillary absorption tests and ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer). It was found that the smaller the radius of the capillary pore within the concrete, the longer it takes to saturate it with water.The different pore sizes of capillaries take different times to reach saturation, which is one of the reasons for the “square root shift phenomenon” of capillary water absorption in concrete. The higher the initial concentration, the easier it is for the ion chelators to be transported inside the concrete within a certain transport depth range. However, after a certain range of transport depth, the initial concentration does not have a significant effect on the transport of the ion chelators. This is not the same as the transport pattern of nonchelated ions. Comparing the transport processes of chelated and non-chelated ions within the concrete, it was found that chelated ions form aggregation zones when transported within the concrete. The analysis suggests that the repair of pores and cracks within the concrete by the chelating agent promotes the creation of aggregation zones. Other factors such as the presence of chelated ions, the transport medium, changes in porosity, and wet and dry cycles can all influence the formation of chelated ion aggregates.

RAPID DETECTION OF SARS COV-2 INFECTION IN COMPARISION WITH RT-PCR IN TERTIARY CARE HOSPITAL

Objectives: The goal of the present study was to assess the SARS-CoV-2 antigen detection test’s performance features and compare them to the real-time reverse transcription polymerase chain reaction (RT-PCR) test, the gold standard test for the diagnosis of COVID-19 cases. Methods: From October 2020 to May 2021, patients attending the OPD, including those undergoing surgery, at a Tertiary Care Teaching Hospital in Telangana provided 1000 respiratory samples, primarily nasopharyngeal swabs. A skilled technician had collected two nasopharyngeal swabs from each person in a COVID sample collection room while wearing personal protective equipment and following strict infection control procedures. One swab was used for the rapid antigen test given by the standard Q COVID-19 Ag test kit and placed into the extraction buffer tube. Second swab was kept in the viral transport medium and used for Allplex™ 2019-nCoV Assay (Seegene, Korea), which targets envelope gene (E), and RNA dependent RNA polymerase (RdRp) and nucleocapsid (N) genes of SARS CoV-2, was used for SARS-CoV-2 RNA detection according to the manufacturer’s instructions. Results: Out of 1000 samples tested for COVID-19, 623 (63.7%) were males and 377 (36.3%) were females. Out of 1000 samples, 347 samples were RT-PCR positive and 653 were RT-PCR negative. Out of 347 RT-PCR samples positive, 341 were Rapid antigen test positive samples and six were negative. Overall sensitivity and specificity are 98.27% and 99.85%, respectively. Conclusion: The real-time RT-PCR assay’s sensitivity and specificity were comparable to those of the rapid assay for SARS-CoV-2 antigen detection. It can be utilized for contact tracing measures to control the COVID-19 pandemic in places such as border crossings, airports, interregional bus and train stations, and mass testing campaigns needing quick findings. This is especially true in areas with a high prevalence of the disease.

Standardized ready-to-use laboratory protocol to isolate primary human wound associated fibroblasts from infected wound samples for clinical applications

Owing to the importance of fibroblasts in healing of wounds, it is necessary to isolate and culture them under in vitro conditions for the purpose of understanding the wound biology, drug discovery and development of personalized treatment. Although, several fibroblast cell lines are commercially available, they fail to represent the patient associated parameters. However, establishing a primary fibroblast culture, especially from infected wound samples, is challenging as the sample is more prone to contamination and number of live cells will be minimum in heterogeneous population. Also, it takes lot of efforts and resources for optimization of the protocol to get good quality cell lines from wound samples necessitating multiple trials, resulting in large number of clinical samples to be processed. To the best of our knowledge, for the first time we are reporting the standardized protocol to isolate primary human fibroblasts from acute and chronic wound samples. In this study, various parameters such as explant size (1–2 mm), explant drying time (2 min), transportation and growth culture media (antibiotics (working concentrations 1–3) and serum concentration (10%)) have been optimised. This can be altered for specific needs of cell in terms of both quality and quantity. Outcome of the work provides a ready-to-use protocol, which is very useful to those who want to initiate primary fibroblasts cell culture from infected wound samples either for clinical or research purpose. Further, these cultured primary wound associated fibroblasts have various clinical and biomedical applications in tissue grafting, treatment of burns and scars and wound regeneration especially in non-healing chronic wounds.

Evaluation of direct microscopy and culture method for detection of Trichomonas vaginalis in vaginal discharge and urine samples

Abstract: Trichomoniasis has emerged as the most common sexually transmitted disease, and limited data is available on the effective screening technique for the diagnosis of Trichomonas vaginalis (T. vaginalis). This study aimed to compare the ability of two culture media (InPouch TV and Diamond's) to support the growth of clinical isolates of Trichomonas vaginalis and their relative sensitivity for detection of the organism. A total of 343 patients complaining of vaginal discharge of 293 women and urine sample of 50 men were included in the study. From December 2021 to May 2022, from Azadi Teaching Hospital, Private clinics, and Midwifery and Childbearing Hospital in Kirkuk. Three vaginal swabs and a urine sample were screened for trichomoniasis by wet mount microscopy. Diamond Media Culture and Pouch TV were used. The 343 cases studied, 6 women and 1 man were positive by wet mount microscopy, which means 7 (2%) and 336 (98%) were negative. Sterile vaginal swab with centrifugation and urine samples had the highest rate of specificity (85%) to detect TV compared to vaginal swab without centrifugation and Amies Gel Transport Media (AGT) media, which had a lower sensitivity (33% and 16%), respectively. Inpouch TV media was the best culture to grow TV and remained for 10 days, but Local Diamond Modified Media (LDMM) had a poor result for growth of trichomonas vaginalis and only remained alive for 2 days. According to our experiment, the most successful routes of detection are urine and vaginal swab with centrifugation, and Inpouch TV is the unique culture for growth and better than LDMM.

Analyzing the Effectiveness of Different Vaccines against SARS-CoV-2 Infection: A Retrospective Study from Lahore, Pakistan

Coronavirus disease (COVID-19), a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected the entire world, killing approximately 5 million people. The COVID-19 pandemic has raised several questions for the researchers to answer in terms of therapeutics and proteins. Several vaccines against SARS-CoV-2 are now available all around the world. These vaccines showed significant efficacy in clinical trials. However, some individuals become affected by COVID-19 even after vaccination. This study aimed to determine the effectiveness of different vaccines being used in Lahore, Pakistan on the basis of symptoms and relapse. This cross-sectional study was conducted at the Institute of Public health, Mayo Hospital, Lahore, Pakistan. Samples collected from September 18, 2021 to October 18, 2021 were included in the study. The nasopharyngeal swab samples of patients were collected and put in the viral transport medium (VTM) to safely transfer them to the diagnostic lab. Real-time PCR was used for the identification of the virus. The study found that some vaccinated people were affected by SARS-CoV-2 infection; however, the prevalence of the infection in such people was low (9.21%, 93 out of 1010). It was observed that most of the vaccinated patients remained stable. The authors did not commemorate any deaths among them. It was concluded that the vaccines that are currently available and being used have significant efficacy. However, future studies are required to determine their side effects.

Time and temperature stability of Tritrichomonas foetus in phosphate-buffered saline as evaluated by a reverse transcription real-time PCR assay and field analysis.

Tritrichomonas foetus (TF) is a significant reproductive pathogen of cattle, and sample collection, handling, transport, and testing are significant hurdles to surveillance programs. Recent methods have been developed that allow for the direct detection of TF using a reverse transcription real-time PCR (direct RT-qPCR) approach. To evaluate these methods, a comparative analysis was conducted to assess the technical performance of this assay with a commercially available real-time PCR (qPCR) assay. In addition, the evaluation of two types of collection media (PBS and TF transport tube) was conducted that evaluated sample stability from 0 to 3 days when stored at 4°C or 25°C. Extended incubation times for PBS media were also evaluated (5, 7, and 14 days) at both refrigeration and frozen temperatures to evaluate the effect of extended transport time on samples. Limits of detection (LODs), dynamic range, and RNA stability were assessed using lab-cultured TF spiked into samples of normal bovine smegma collected in PBS or TF transport media, and performance was assessed on field samples collected in parallel. 100% agreement was found between direct RT-qPCR and qPCR at 10 parasites/extraction and a LOD of 1 parasite/extraction. Differences in detection were not observed in either collection media when incubated at either temperatures for up to 3 days of incubation. In addition, the extended incubation experiments indicate that samples containing 10 parasites/extraction can be detected at 4°C for 5 days with a mean Cq 26.34 (95% CI: 23.11-29.58) and detected at -20°C for 7 or 14 days, with a mean Cq 29.55 (95% CI: 27.73-31.37). A significant decrease in detectable RNA was observed in samples containing <10 parasites/extraction at -20°C for 14 days, which should be considered for long-term storage. In summary, direct RT-qPCR was found to be equivalent or superior to qPCR and PBS was not significantly different from TF transport media. The findings of the current study allows for more flexibility during sample collection and transport and ultimately enhancement of TF surveillance programs.

Capillary Flow-Driven Microfluidics Combined with a Paper Device for Fast User-Friendly Detection of Heavy Metals in Water.

Human exposure to heavy metals is a concerning global problem because of its detrimental effect on our health and ecosystem. Assessing the levels of these metals is cost- and labor-intensive and nonuser friendly because current analysis approaches typically rely on heavy instrumentations like inductively coupled plasma-mass spectrometry, which is only possible in centralized labs. Hence, simple economical detection methods are in high demand in developing countries and areas with insufficient infrastructure, professional experts, and appropriate environmental treatment. Several microfluidic paper-based analytical devices have been reported as promising alternatives to conventional testing methods for on-site heavy metal detection. Paper-based microfluidics are advantageous because of their simple fabrication, biodegradability, low cost, and ability to operate without pumps. However, typical assay times for current platforms are slow, and they typically rely on pipetting a fixed volume into the assay cards. This adds complexity in actual field scenarios. Here, we report a novel, inexpensive, and straightforward capillary-driven microfluidic device combined with paper for rapid and user-friendly detection of Ni(II), Cu(II), and Fe(III) in water. A colorimetric approach was adopted to quantify these metals. The device was able to produce a homogeneous color signal within 8 s of sample insertion. The limit of detection and limit of quantification were calculated to be 2 and 6.67 ppm for nickel, 0.3 and 1 ppm for Cu, and 1.1 and 3.67 ppm for Fe, respectively. The majority (>90%) of the collected samples showed recovery in the 80-110% range with acceptable accuracy and precision (<15% RSD) for a colorimetric device. This technique can be beneficial for rapidly assessing heavy metal exposure in drinking and surface water at drastically reduced assay time and is the first example of capillary flow-driven microfluidic devices as a transport medium for heavy metal detection.

Polarized light transmission characteristics in a smoky ellipsoidal particle medium.

True natural environments are more complex, and light travels through non-spherical particle media, which can affect the transmission of light. The medium environment of non-spherical particles is more common than that of spherical particles, and some studies have shown that there are differences between spherical and non-spherical particles in polarized light transmission. Therefore, the use of spherical particles instead of non-spherical particles will result in great error. In view of this feature, this paper samples the scattering angle based on the Monte Carlo method, and then constructs a simulation model of a random sampling fitting phase function suitable for ellipsoidal particles. In this study, yeast spheroids and Ganoderma lucidum spores were prepared. The effects of different polarization states and optical thicknesses on the transmission of polarized light at three wavelengths were investigated using ellipsoidal particles with a ratio of 1.5 transverse to vertical axes. The results show that when the concentration of the medium environment increases, the polarized lights of different states all show obvious depolarization, but circularly polarized light has better polarization-preserving characteristics than linearly polarized light, and polarized light with larger wavelengths also shows more stable optical properties. When yeast and Ganoderma lucidum spores were used as the transport medium, the degree of polarization of polarized light had the same trend. However, the equal volume radius of yeast particles is smaller than that of Ganoderma lucidum spores, so when the laser is in the yeast particle medium, the polarization-maintaining property of polarized light is superior. This study provides an effective reference for the variation of polarized light transmission in an atmospheric transmission environment with heavy smoke.

Особенности формирования диффузионных покрытий, полученных комплексной химико-термической обработкой конструкционных сталей

Introduction. The main methods of increasing the efficiency of products made from structural steels are considered. A description of diffusion saturation from liquid metal media solutions (DSLMMS) is given. Also, complex diffusion saturation technology (CDS), including DSLMMS and carburization is shown. The purpose of the work is to reveal the effect of steel composition on the process of formation and elemental composition of diffusion-saturated surface layers (coatings) based on chromium, as well as to establish differences and regularities in the processes of formation of diffusion-saturated coatings after DSLMMS and CDS. The methods of investigation. Cylindrical specimens 20 mm in diameter and 30 mm long were subjected to DSLMMS. The specimens were made of carbon and alloyed steels: St3, 20-Cr13, 40-Cr, 40-Cr13, 12-Cr18-Ni10-Ti. At the same time, some of the specimens were previously subjected to vacuum cementation. An eutectic Pb-Bi with the specified content of Cr was used as a transport medium when executing DSLMMS. Metallographic studies were carried out on microsection prepared according to the standard method. Studies to determine the thickness of coatings and its structure were carried out on the Dura Scan Falcon 500 Microhardness Tester. The elemental composition of the coatings was determined by the method of electron microprobe analysis on a Tescan Lyra 3 scanning electron microscope with the Oxford Ultim MAX PCMA system. Results and discussion. As a result of the research, it was revealed that the formation of saturated coatings occurs with DSLMMS and CDS. At the same time, the thickness of the coatings and its elemental composition depend on the steel grade and the technology used. After DSLMMS concentration of Cr varies from 96.9% to 91.1%. At the same time, the maximum concentration of 96.9% is observed on steel St3. After CDS, on the surfaces of all steel samples, the concentration of Cr decreases in comparison with the coatings obtained by the DSLMMS technology on steels: St3 from 96.9% to 66.8%; 40-Cr from 91.1% to 63.18%; 20-Cr13 from 93.18% to 62.54%; 12-Cr18-Ni10-Ti from 92.92% to 64.77%. The total thickness of diffusion-saturated coatings formed on all the alloys studied ranges from 17 to 17.5 µm.

TECHNOLOGY THE FIRE DETECTION SYSTEM ON THE RAILWAY LINE IS BASED ON IMAGE PROCESSING WITH THE COMPUTER VISION METHOD

The rail transportation system plays a role important as a medium of transportation for the movement of goods and people in large quantities and is one of the modes of cheap transportation, this transportation model evolved from a steam train until it evolves to become more sophisticated using electric and magnetic technology, trains system works well with support from several the first factor is human resources, supporting technology and facilities. The problem with the rail system is that damage to the rails can cause result in the transportation route being blocked and can cause a very fatal accident, Based on these problems, besides the feasibility of the rail system, rail maintenance is a very important key, the railroad track maintenance system is usually carried out periodically. The solution to handle this problem is to use a computer vision method by utilizing surveillance cameras or CCTV installed on railroad crossings able to detect damage, the detection of damage is categorized into a few types first is track damage, due to shifts, fires on rail lines and finally structural damage due to earthquakes or landslides in the railway line area, this technology has been applied to several developed countries. and can monitor a large area and can provide a quick response if a malfunction occurs, the system will be a smart monitoring system but doesn't replace the role of a railway officer but as a tool that will provide complete information where the location of the damage is so that prompt and more effective repair action can be taken.