Limited Quantity Research Articles

FireMatch: A semi-supervised video fire detection network based on consistency and distribution alignment

Deep learning techniques have greatly enhanced the performance of fire detection in videos. However, video-based fire detection models heavily rely on labeled data, and the process of data labeling is particularly costly and time-consuming, especially when dealing with videos. Considering the limited quantity of labeled video data, we propose a semi-supervised fire detection model called FireMatch, which is based on consistency regularization and adversarial distribution alignment. Specifically, we first combine consistency regularization with pseudo-label. For unlabeled data, we design video data augmentation to obtain corresponding weakly augmented and strongly augmented samples. The proposed model predicts weakly augmented samples and retains pseudo-label above a threshold, while training on strongly augmented samples to predict these pseudo-labels for learning more robust feature representations. Secondly, we generate video cross-set augmented samples by adversarial distribution alignment to expand the training data and alleviate the decline in classification performance caused by insufficient labeled data. Finally, we introduce a fairness loss to help the model produce diverse predictions for input samples, thereby addressing the issue of high confidence with the non-fire class in fire classification scenarios. The FireMatch achieved an accuracy of 76.92% and 91.80% on two real-world fire datasets, respectively. The experimental results demonstrate that the proposed method outperforms the current state-of-the-art semi-supervised classification methods.

Risk factors related to surgical wound infection after caesarean section: A systematic review and meta‐analysis

AbstractSurgical site infection (SSI) is one of the common postoperative complications after caesarean section for pregnant women. Previous studies have investigated the risk factors for SSI in pregnant women undergoing caesarean delivery. Whereas big differences in research results exist, and the correlation coefficients of different research results are quite different. A meta‐analysis was conducted to examine the risk factors related to SSI in pregnant women undergoing caesarean delivery. We searched English databases to collect case–control studies or cohort studies published between 1 January 2015 and 15 November 2023, including PubMed, Web of Science and ScienceDirect. The risk of bias of the included studies was assessed via Newcastle‐Ottawa Scale. The analysis was performed using RevMan 5.4.1 tool. A total of 24 articles (n = 581, 895) were selected in this meta‐analysis. The following risk factors were presented to be significantly correlated with SSI in pregnant women following caesarean delivery: smoking (odds ratio [OR] = 1.64, 95% confidence interval [CI] [1.31, 2.04]), previous caesarean section (OR = 1.46, 95% CI [1.18, 1.82]), multiple vaginal examinations (OR = 2.92, 95% CI [1.91, 4.46]), membrane rupture (OR = 1.68, 95% CI [1.19, 2.38]), hypertensive disorders (OR = 1.85, 95% CI [1.33, 2.57]), diabetes mellitus (OR = 1.36, 95% CI [1.18, 1.57]), high body mass index (OR = 1.57, 95% CI [1.35, 1.84]). Occurrence of SSI is influenced by a variety of factors. Thus, we should pay close attention to high‐risk subjects and take crucial targeted interventions to lower the SSI risk after caesarean section. Owing to the limited quality and quantity of the included studies, more rigorous studies with adequate sample sizes are needed to verify the conclusion.

Residual Shrinkage ViT with Discriminative Rebalancing Strategy for Small and Imbalanced Fault Diagnosis

In response to the challenge of small and imbalanced Datasets, where the total Sample size is limited and healthy Samples significantly outweigh faulty ones, we propose a diagnostic framework designed to tackle Class imbalance, denoted as the Dual-Stream Adaptive Deep Residual Shrinkage Vision Transformer with Interclass–Intraclass Rebalancing Loss (DSADRSViT-IIRL). Firstly, to address the issue of limited Sample quantity, we incorporated the Dual-Stream Adaptive Deep Residual Shrinkage Block (DSA-DRSB) into the Vision Transformer (ViT) architecture, creating a DSA-DRSB that adaptively removes redundant signal information based on the input data characteristics. This enhancement enables the model to focus on the Global receptive field while capturing crucial local fault discrimination features from the extremely limited Samples. Furthermore, to tackle the problem of a significant Class imbalance in long-tailed Datasets, we designed an Interclass–Intraclass Rebalancing Loss (IIRL), which decouples the contributions of the Intraclass and Interclass Samples during training, thus promoting the stable convergence of the model. Finally, we conducted experiments on the Laboratory and CWRU bearing Datasets, validating the superiority of the DSADRSViT-IIRL algorithm in handling Class imbalance within mixed-load Datasets.

Artificial intelligence in groundwater management: Innovations, challenges, and future prospects

The integration of Artificial Intelligence (AI) in groundwater management is a transformative stage, characterized by innovation and challenges. This research paper explores the multilayered application of AI in this field, dividing its contributions, addressing its associated challenges, and revealing the prospects of future potential. AI-driven innovations are designed to revolutionize groundwater management, providing precise predictive modeling, real-time monitoring, and data integration. However, these innovations face challenges such as interpretability issues, specialized technical expertise requirements, and limited data quality and quantity for effective AI model performance. In the future, AI holds significant promise in groundwater management. Advanced AI models can yield improved predictions of groundwater behavior, identify vulnerable areas prone to pollution and depletion, prompt proactive interventions, and foster collaborative platforms among scientists, policymakers, and local communities. Collaborative platforms driven by AI offer potential for synergistic engagement among scientists, policymakers, and local communities, collectively guiding groundwater resource management. Embracing AI's potential while addressing its challenges remains pivotal for sustainable and resilient groundwater management practices. By embracing AI's potential while addressing its challenges, the landscape of groundwater resource management will continue to evolve.

Production of Mature Recombinant Human Activin A in Transgenic Rice Cell Suspension Culture.

Activin A belongs to the transforming growth factor (TGF) family member, which exhibits a wide range of biological activities, including the regulation of cellular proliferation and differentiation and the promotion of neuronal survival. The isolation of AA from natural sources can only produce limited quantities of this bioactive protein. In this study, the whole gene of the precursor form of recombinant human activin A (rhAA) contains a signal peptide, and a pro-region and a mature region were cloned into an expression vector under the control of the rice α-amylase 3D (RAmy3D) promoter. To obtain the mature (active) form of rhAA, an enterokinase cleavage site was inserted between the pro-region and mature region of rhAA. The rice seed (Oryza sativa L. cv. Dongjin) was transformed with recombinant vectors by the Agrobacterium-mediated method, and the integration of the target gene into the plant genome was confirmed by genomic PCR. The transcript expression of rhAA in transgenic rice calli was confirmed by a Northern blot analysis of mRNA. The production of rhAA was verified by Western blot analysis and ELISA. The accumulation of secreted rhAA in the culture medium was purified by Ni2+-NTA. The mature form of AA was released from the precursor form of rhAA after proteolytically processing with enterokinase. Western blot shows that the mature AA was split into monomer and homodimer with molecular weights of 14 kDa and 28 kDa under reducing and non-reducing conditions, respectively. These results suggest that the mature form of rhAA could be produced and purified using transgenic rice cell suspension culture.

Socio-cultural norms in the local food system and potential implications for women’s dietary quality in rural northern Ghana

Women’s activities within the local food system are linked to their dietary quality. Their ability to consume a nutritious diet may be influenced by socio-cultural norms; often, the influence of these norms has not been adequately studied. This study examined how socio-cultural norms linked with rural food systems can potentially exert adverse effects on women’s diets. The study was conducted in two rural communities, Yilkpene and Kpachilo, in Northern Ghana, between May and July 2016. Both selected study communities were chosen because they had similar population sizes, dietary patterns, and access to social services. Using a qualitative approach, sixteen key informant interviews with community and institutional leaders, 11 focus group discussions comprising 87 community members, and forty 24-hour dietary recall interviews with women of reproductive age were used to explore the nature of the local food system linked with socio-cultural norms. Transcribed interviews were coded and analyzed, thematically, using pre-determined and emerging themes. A total of 143 women and men participated in the study with women dominating the sample. The components of the food system in both communities were constructed, primarily, around men. Quantities, quality, and varieties of produce, its distribution, and intra-household allocation were dominated by male perceptions and practices that determine access and ownership of productive resources, and pre-determined roles and responsibilities of household members. Men dominated production of economic crops (cereals, and legumes); women produced vegetables, and limited quantities of legumes and cereals, mainly for home consumption. Men controlled allocation of cereals for household meal preparation; more expensive complementary ingredients were provided by women. Although women prepared household meals, men received the ‘lion’s share’ of nutrient-dense components. Forty-five percent of women could not meet minimum dietary diversity of at least five food groups in their diets. The local food system in Northern Ghana is dominated by gender-driven socio-cultural norms, which constitutes a potential barrier to women achieving dietary adequacy. Interventions should deliberately address these culturally-established barriers, especially in contexts where subsistence farming is the main source of livelihood. Key words: Food system, Socio-cultural norms, Barriers, Women, dietary quality

Catalyzing Battery Materials Research via Lab‐Made, Sub‐Ampere‐Hour‐Scale Pouch Cells, and Long‐Term Electrochemical Monitoring by a Reparable Reference Electrode

AbstractBattery materials research is of crucial importance to the development of next‐generation batteries. However, the transition from lab‐scale studies, typically in gram quantities, to industrially relevant ones (i.e., kilogram scale) has been holding back by challenges in scale‐up synthesis and a lack of reliable approaches to verify the electrochemical performance of the lab‐made materials. Here the design and assembly procedures of sub‐Ah‐scale pouch cells that provide validations of several lab‐made Li‐ion and Na‐ion cathode materials available in a limited quantity (<5 g) are reported. These lab‐made pouch cells show superior cycle stability and consistency over the widely used coin cells, exemplified by multiple Ni‐rich layered oxide‐graphite full batteries retaining 84.29 ± 0.16% of the initial capacities over 1000 cycles. A four‐electrode pouch cell with a reparable reference electrode is further designed to monitor impedance growth and Li plating during long‐term electrochemical tests. It can be further integrated with in situ ultrasonic imaging to enable multi‐modal studies. This work provides a powerful platform to evaluate and boost the technology readiness levels of laboratory‐discovered battery materials.

A Sustainable Bio-Filler for Epoxy Composites: Use of Pistachio Shell Powder

The use of natural materials has become a crucial concern for humanity due to the limited quantity of petroleum-based products and their harmful impact on nature. The use of natural materials is inevitable for a greener and more sustainable world. Transforming agricultural industrial waste into a high-value product or a source of fuel can significantly benefit our country's economy and environment. Pistachio shell is one of the agro-industrial wastes and is abundant in our country. Our country can benefit economically and environmentally by utilizing and repurposing discarded shells, whether as fuel or as a valuable commodity. In this study, the shells of pistachios grown in Şanlıurfa were crushed in a stone mortar and reduced to certain sizes and turned into powder. Later, this powder was used as a bio-filler material for epoxy resin. Powders were used at 1% and 2% additive ratios and homogeneous mixing was carried out using both magnetic and ultrasonic mixers. The mechanical properties of the obtained biofilled epoxies were investigated and their microstructures were analyzed. Tensile test, bending test and hardness test were performed as mechanical tests and densities were measured. An improvement of 8% and 15% was detected in the maximum tensile and bending strength, respectively. The hardness and density values also increased by 8% and 1.7%, respectively. As a result of the microstructure analysis, no air bubbles were formed in the samples and no agglomeration occurred. Obtained results revealed that pistachio shell grown in Şanlıurfa can be used as bio-filler material.

Sustainability reporting harmonisation? A utopian endeavour for European agri-food companies

Regulatory harmonisation stands as a central issue in the European Union (EU), playing a key role in achieving the single market. Accounting harmonisation, in particular, has been the subject of different regulatory frameworks, mainly directives. However, the literature suggests that the implementation of these directives within the EU does not consistently meet its harmonisation goals due to diverse legal, cultural, and business interpretations among the Member States. In the realm of social and environmental accounting, Directive 2014/95/EU (NFRD) compels specific companies to prepare and present Sustainability Reports (SRs), with the primary goal of enhancing the availability of sustainability information while also fostering greater consistency and comparability. Nevertheless, the flexibility afforded by this Directive may give rise to divergences among the national regulations of the EU Member States, as has been the case previously. Therefore, this study aims to analyse the success of the NFRD in harmonising sustainability disclosure by examining the quantity and homogeneity of such information disclosed in the SRs of 100 large agri-food companies in Italy, the Netherlands, Germany, and Spain. To do so, a content analysis and non-parametric tests were applied. The findings show a limited performance and high heterogeneity in disclosure across countries, suggesting that the NFRD has fallen short of harmonising national regulations on disclosing sustainability information.

Reliable Organic Carbonyl Electrode Materials Enabled by Electrolyte and Interfacial Chemistry Regulation.

ConspectusLithium-ion batteries (LIBs) have achieved great success and dominated the market of portable electronics and electric vehicles owing to their high energy density and long-term cyclability. However, if applying LIBs for large-scale energy storage scenarios, such as regulating the output of electricity generated by sustainable energy in the future age of carbon neutrality, the current electrochemistry of LIBs based on Li-ion interaction/deinteraction between a transition-metal oxide cathode and graphite anode will suffer from problems of scarce natural resources (e.g., Li, Co, and Ni) and high energy consumption/CO2 emission involved in the production of electrodes. Similarly, other commercial batteries such as lead-acid batteries and nickel-metal hydride batteries are also plagued by these issues.In contrast, organic electrode materials, especially carbonyl materials, exhibit advantages of abundant resources, renewability, high capacity, environmental friendliness, and structural designability and have shown great promise for various rechargeable batteries in recent years. However, organic carbonyl electrode materials generally exhibit unsatisfactory cycling stability and rate performance, which are highly dependent on the electrolyte and interfacial chemistry. Appropriate electrolytes and a stable electrode/electrolyte interface would be beneficial for preventing the dissolution of organic carbonyl electrode materials and/or their redox intermediates in electrolytes and promoting fast ion transport between the electrode and electrolyte. In this regard, designing an appropriate electrolyte and constructing a stable electrode/electrolyte interface are the keys to enhancing the comprehensive performance of organic carbonyl electrode materials.In this Account, on the basis of our progress and related works from other groups in the past decade, we afford an overview of understanding the effects of electrolyte and interfacial chemistry on the electrochemical performance of organic carbonyl electrode materials. We will start by briefly introducing the basic properties, working mechanisms, and issues of organic carbonyl electrode materials. Then, the implications of electrolyte and electrode/electrolyte interfacial chemistry on electrochemical performance will be summarized and highlighted through discussing the performance of organic carbonyl electrodes in different types of electrolytes (organic liquid and aqueous and solid-state electrolytes). Meanwhile, the design principles of electrolytes and interfacial chemistry for organic carbonyl electrodes are also discussed. A representative example is that organic carbonyl electrode materials often exhibit better electrochemical performance in ether-based electrolytes than in ester-based electrolytes, which could be mainly attributed to the stable and robust solid electrolyte interphase (SEI) formed on carbonyl electrodes in the ether-based electrolyte. This example demonstrates the importance of investigating the electrode/electrolyte interfacial chemistry of organic carbonyl electrode materials. Finally, future perspectives on designing appropriate electrolytes and understanding electrode/electrolyte interfacial chemistry will also be discussed. It is meaningful to thoroughly reveal the dynamic evolution of the electrode/electrolyte interface during discharge/charge processes and evaluate the compatibility between electrolytes and organic carbonyl electrode materials under practical conditions using limited quantities of electrolytes and high areal-specific-capacity electrodes in the future. This Account could attract more attention to electrolytes and the electrode/electrolyte interfacial chemistry of organic carbonyl electrode materials and finally promote their future commercial applications.

Diagnostic performance of metagenomic next-generation sequencing for the detection of pathogens in cerebrospinal fluid in pediatric patients with central nervous system infection: a systematic review and meta-analysis

BackgroundDetecting pathogens in pediatric central nervous system infection (CNSI) is still a major challenge in medicine. In addition to conventional diagnostic patterns, metagenomic next-generation sequencing (mNGS) shows great potential in pathogen detection. Therefore, we systematically evaluated the diagnostic performance of mNGS in cerebrospinal fluid (CSF) in pediatric patients with CNSI.MethodsRelated literature was searched in the Web of Science, PubMed, Embase, and Cochrane Library. We screened the literature and extracted the data according to the selection criteria. The quality of included studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool and the certainty of the evidence was measured by the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) score system. Then, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd’s ratio (DOR), and area under the curve (AUC) of the summary receiver operating characteristic curve (sROC) were estimated in Stata Software and MetaDisc. Subgroup analyses were performed to investigate the potential factors that influence the diagnostic performance.ResultsA total of 10 studies were included in the meta-analysis. The combined sensitivity was 0.68 (95% confidence interval [CI]: 0.59 to 0.76, I2 = 66.77%, p < 0.001), and the combined specificity was 0.89 (95% CI: 0.80 to 0.95, I2 = 83.37%, p < 0.001). The AUC of sROC was 0.85 (95% CI, 0.81 to 0.87). The quality level of evidence elevated by the GRADE score system was low.ConclusionsCurrent evidence shows that mNGS presents a good diagnostic performance in pediatric CNSI. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.

Drinking Water Plan for Narsinghpur District

Water is the most important commodity of this large ecological system. Looking to the scarcity/ rareness and importance of pure water, water is an intrusive and the most important factor for the genesis of all the living organism, flora and fauna. All lives are dependent on water. It is the priceless gift of nature and is present in a very limited quantity. Its use should be judicious considering the national development and conservation for future. Looking to the current data total water available from precipitation the country is about 4000 Billon cubic meter. The availability from surface water and replenishable ground water is 1869 BCM. Out of this only 60% of this available water i.e. 1122 BCM (Surface Water 690 BCM and Ground water 432 BCM) can be used and may be considered as available water resource of the country. One more point to be noted is that water is not available uniformly at all places and at all time. In India more then 50% of Urban and Industrial water supply, more than 85% of rural drinking water supply and more than 50% irrigation requirement is dependent on Ground water. In many parts of the country water is being taken out more rapidly from the water wearing formations as compared to the natural refilling which is called the ground water recharge. Water table in these places is falling constanty. Increasing rate of population growth and pressure of development are mainly responsible for this situation. For enhancing productivity and taking cash crops are resulting high tapping of the groundwater everywhere as well as in Madhya Pradesh also. Therefore water resource utilization of an area should be planned keeping in view the availability and demand. Such a planning is presented in this paper for Narsinghpur district of Madhya Pradesh.

Sodium Chloride Induced pH and Temperature Responsive Biocompatible Hydrogel of Choline Oleate for Transdermal Drug Delivery of Doxorubicin

AbstractNanodrug carriers have various biological and pharmaceutical applications, and among all the transdermal drug delivery is fascinating, specifically for localized medication therapy to a specific diseased organ or limited diseased area of the body, such as breast cancer cells or carcinoma cells. This way the efficacy of drug can be enhanced and its side effect to other healthy organs can be reduced to great extent. To ameliorate the limitations of traditional polymeric drug delivery systems, such as limited quantity and heterogeneity of the loaded drug, we developed a NaCl induced biocompatible gel of wormlike micelles of surface active ionic liquid (SAIL) i. e. choline oleate ([Ch][Ol]). Apart from the pH and temperature responsive mechanical properties, the designed gel also show good skin permeability, biocompatibility, adhesive qualities, stretchability, and viscoelasticity. The gel was tested for encapsulation of anticancer drug doxorubicin (DOX) and its transdermal delivery at pH=7.4 and pH=5.2. This system exhibits tremendous transdermal permeability of DOX and selective release more amount of the drug at 5.2 pH. Hence for localised and targeted delivery of an anticancer drug, this system can be proven to be suitable.

УРАЛО-КУЗБАССКАЯ УГОЛЬНО-МЕТАЛЛУРГИЧЕСКАЯ БАЗА В УСЛОВИЯХ ВЕЛИКОЙ ОТЕЧЕСТВЕННОЙ ВОЙНЫ

The article is devoted to the history of functioning of the metallurgical base of the Ural-Kuzbass during the Great Patriotic War. The author explains the mutual dependence of both regions. The ferrous metallurgy of the Urals and Kuzbass was able to dramatically increase the production of armaments by the second half of 1942. Before the war, local industry did not produce weapons or produced them in limited quantities. The sharp increase in military production was ensured by the reorientation of the region’s metallurgy towards the production of alloy steels and armour metal. The shortage of rolling stock forced to transfer limited transport resources in favour of coking needs for the Urals metallurgy. The Urals power industry had to give up Kuzbass and Karaganda coals and switch to local low-calorific fuel. The author analyses monthly plans for the production of armour plate at the USSR metallurgical plants and the production of tanks. He concludes that the Ural-Kuzbass industry played a leading role in the production of armour and tanks. The industrial and resource potential of the Ural-Kuzbass was limited. Therefore, the success was achieved by redistributing materials in favour of military production to the detriment of the development of civilian industry. This led to the depletion of the production base of the Ural-Kuzbass industry during the war period, but made it possible to establish mass production of a large number of armaments in a short period.

Heavy Metal Toxicity in Human Beings

The escalation of industrial activities over the past century has significantly heightened human exposure to heavy metals, posing grave threat to the health as well as the environment. Cadmium, mercury, and lead are few of the many heavy metals. They are prevalent pollutants and are absorbed, retained, and accumulated within the human body. On the basis of the absorbed dosage, exposure route, and duration, the range of the toxicity fluctuate. While these metals are essential in limited quantities, excessive exposure can lead to severe health complications and disorders. This review examines the mechanisms and adverse effects of cadmium, mercury, and lead on human health when present in exceedingly large amounts.

A mini-review on non-enzymatic electrochemical biosensing techniques for creatinine determination

The escalation of industrial activities over the past century has significantly heightened human exposure to heavy metals, posing grave threat to the health as well as the environment. Cadmium, mercury, and lead are few of the many heavy metals. They are prevalent pollutants and are absorbed, retained, and accumulated within the human body. On the basis of the absorbed dosage, exposure route, and duration, the range of the toxicity fluctuate. While these metals are essential in limited quantities, excessive exposure can lead to severe health complications and disorders. This review examines the mechanisms and adverse effects of cadmium, mercury, and lead on human health when present in exceedingly large amounts.

Electrochemical sensing of B-complex vitamins: current challenges and future prospects with microfluidic integration.

Vitamins are crucial micronutrients found in limited quantities in food, living organisms, and soil. Since most vitamins are not produced within the human body, a lack of these essential nutrients can result in various physiological disorders. Analyzing vitamins typically involves costly, time-consuming methods, requiring skilled personnel, automated equipment, and dedicated laboratory setups. The pressing need is for the development of efficient, portable, and user-friendly detection techniques that are cost-effective, addressing the challenges associated with traditional analytical approaches. In recent years, electrochemical sensors and electrochemical microfluidic devices have garnered prominence owing to their remarkable sensitivity, quick analysis, cost-effectiveness, and facile fabrication procedures. Electrochemical sensing and microfluidics are two distinct fields that are often integrated to create powerful and versatile sensing devices. The connection between them leverages the advantages of both fields to create highly efficient, miniaturized, and portable analytical systems. This interdisciplinary approach has led to the development of innovative devices with broad applications in various scientific, medical, and environmental domains. This review begins by outlining the importance of vitamins in human nutrition and health and emphasizing the need for precise and reliable sensing techniques. Owing to the limited literature available on electrochemical detection of vitamin B complexes, this review offers an in-depth analysis of modern electrochemical sensing of water-soluble vitamins, focusing on B1, B2, B6, B9, and B12. The challenges faced by researchers are addressed, including selectivity, sensitivity, interference, matrix effects, and calibration, while also exploring promising prospects such as nanomaterial integration, miniaturization, microfluidics-based IoTs, and innovative sensor designs.

Heme o Isolation and Analysis Using Heme o Synthase Heterologously Expressed in Escherichia coli.

Heme o is an Fe-porphyrin involved in the majority of aerobic respiration pathways found in all three domains of life. In eukaryotes and most aerobic prokaryotes, heme o functions solely as the precursor for the synthesis of heme a, a necessary cofactor for most heme-copper terminal oxidases. In some prokaryotes, such as Escherichia coli (E. coli), heme o can serve as a cofactor for heme-copper oxidases instead of heme a. Given its role as a key substrate or cofactor, purified heme o promises to be a valuable resource for the study of heme-copper oxidase assembly and activity. However, commercially available heme o is sold in limited quantities at a relatively high cost (compared to the prototypical heme b), making the use of heme o purchased from suppliers unfeasible for such studies. In this chapter, we present step-by-step methods both for heme o isolation from E. coli overexpressing heme o synthase and for HPLC analysis of cellular hemes (i.e., heme o and heme b).

Certification and long-term stability monitoring of low-content folic acid and 5-methyltetrahydrofolate in human plasma certified reference material by isotope dilution ultra-high performance liquid chromatography/tandem mass spectrometry.

A reliable measurement of blood folate levels is necessary in the clinical field to prevent serious diseases such as cognitive impairment and neural tube defects. Herein, the certification of the low-content folic acid (FA) and 5-methyltetrahydrofolate (5-Me-THF) in human plasma certified reference material (KRISS CRM 111-01-018) was performed. A human plasma pool obtained from the Korean Red Cross was used as a CRM candidate. The certification of the human plasma CRM was performed by isotope dilution ultra-performance liquid chromatography/tandem mass spectrometry. Two-dimensional liquid chromatography was employed to confirm the validity of the analytical method for FA due to the susceptibility of FA to matrix effects because of its limited quantity. The CRM stability was evaluated at -20 °C for 2 months and at -70 °C for up to 12 months to determine the certified value of the CRM. The certified value of the CRM was (84.6 ± 4.3) ng kg-1 and (5.80 ± 0.47) μg kg-1 for FA and 5-Me-THF, respectively. The homogeneity of the CRM was 1.64% and 3.10% for FA and 5-Me-THF, respectively. Further long-term stability assessments were conducted, indicating that the CRM remains valid for at least 58 months at -70 °C for FA and 48 months for 5-Me-THF. Compared to other blood-based CRMs, this CRM has lower folate levels, making it helpful in establishing analytical methods for a broader range of folate levels.

Laser-induced graphene-based digital microfluidics (gDMF): a versatile platform with sub-one-dollar cost.

Digital microfluidics (DMF), is an emerging liquid-handling technology, that shows promising potential in various biological and biomedical applications. However, the fabrication of conventional DMF chips is usually complicated, time-consuming, and costly, which seriously limits their widespread applications, especially in the field of point-of-care testing (POCT). Although the paper- or film-based DMF devices can offer an inexpensive and convenient alternative, they still suffer from the planar addressing structure, and thus, limited electrode quantity. To address the above issues, we herein describe the development of a laser-induced graphene (LIG) based digital microfluidics chip (gDMF). It can be easily made (within 10 min, under ambient conditions, without the need of costly materials or cleanroom-based techniques) by a computer-controlled laser scribing process. Moreover, both the planar addressing DMF (pgDMF) and vertical addressing DMF (vgDMF) can be readily achieved, with the latter offering the potential of a higher electrode density. Also, both of them have an impressively low cost of below $1 ($0.85 for pgDMF, $0.59 for vgDMF). Experiments also show that both pgDMF and vgDMF have a comparable performance to conventional DMF devices, with a colorimetric assay performed on vgDMF as proof-of-concept to demonstrate their applicability. Given the simple fabrication, low cost, full function, and the ease of modifying the electrode pattern for various applications, it is reasonably expect that the proposed gDMF may offer an alternative choice as a versatile platform for POCT.