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863 result(s) for "acetic acid detection"
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A Polyvinylpyrrolidone Nanofibrous Sensor Doubly Decorated with Mesoporous Graphene to Selectively Detect Acetic Acid Vapors
An original approach has been proposed for designing a nanofibrous (NF) layer using UV-cured polyvinylpyrrolidone (PVP) as a matrix, incorporating mesoporous graphene carbon (MGC) nanopowder both inside and outside the fibers, creating a sandwich-like structure. This architecture is intended to selectively adsorb and detect acetic acid vapors, which are known to cause health issues in exposed workers. The nanocomposite MGC-PVP-NFs layer was fabricated through electrospinning deposition onto interdigitated microelectrodes (IDEs) and stabilized under UV–light irradiation. To enhance the adhesion of MGC onto the surface of the nanocomposite polymeric fibers, the layer was dipped in a suspension of polyethyleneimine (PEI) and MGC. The resulting structure demonstrated promising electrical and sensing properties, including rapid responses, high sensitivity, good linearity, reversibility, repeatability, and selectivity towards acetic acid vapors. Initial testing was conducted in a laboratory using a bench electrometer, followed by validation in a portable sensing device based on consumer electronic components (by ARDUINO®). This portable system was designed to provide a compact, cost-effective solution with high sensing capabilities. Under room temperature and ambient air conditions, both laboratory and portable tests exhibited favorable linear responses, with detection limits of 0.16 and 1 ppm, respectively.
Thermal ablation versus cryotherapy or loop excision to treat women positive for cervical precancer on visual inspection with acetic acid test: pilot phase of a randomised controlled trial
Cryotherapy is standard practice for treating patients with cervical precancer in see-and-treat programmes in low-income and middle-income countries (LMICs). Because of logistical difficulties with cryotherapy (eg, the necessity, costs, and supply chain difficulties of refrigerant gas; equipment failure; and treatment duration >10 min), a battery-operated thermal ablator that is lightweight and portable has been developed. We aimed to compare thermal ablation using the new device with cryotherapy. We report the pilot phase of a randomised controlled trial in routine screen-and-treat clinics providing cervical screening using visual inspection with acetic acid (VIA) in Lusaka, Zambia. We recruited non-pregnant women, aged 25 years or older, who were eligible for ablative therapy. We randomly assigned participants (1:1:1) to thermal ablation, cryotherapy, or large loop excision of the transformation zone (LLETZ), using computer-generated allocation. The randomisation was concealed but the nurses providing treatment and the participants were unmasked. Thermal ablation was achieved using the Liger thermal ablator (using 1–5 overlapping applications of the probe heated to 100°C, each application lasting for 40 s), cryotherapy was carried out using the double-freeze technique (freeze for 3 min, thaw for 5 min, and freeze again for 3 min), and LLETZ (using a large loop driven by an electro-surgical unit to excise the transformation zone) was done under local anaesthesia. The primary endpoint was treatment success, defined as either human papillomavirus (HPV) type-specific clearance among participants who were positive for the same HPV type at baseline, or a negative VIA test at 6-month follow-up, if the baseline HPV test was negative. Per protocol analyses were done. Enrolment for the full trial is ongoing. Here, we present findings from a prespecified pilot phase of the full trial. The final analysis of the full trial will assess non-inferiority of the groups for the primary efficacy endpoint. The study is registered with ClinicalTrials.gov, number NCT02956239. Between Aug 2, 2017, and Jan 15, 2019, 750 participants were randomly assigned (250 per group). 206 (84%) participants in the cryotherapy group, 197 (81%) in the thermal ablation group, and 204 (84%) in the LLETZ group attended the 6-month follow-up examination. Treatment success was reported in 120 (60%) of 200 participants in the cryotherapy group, 123 (64%) of 192 in the thermal ablation group, and 134 (67%) of 199 in the LLETZ group (p=0·31). Few participants complained of moderate to severe pain in any group immediately after the procedure (six [2%] of 250 in the cryotherapy group, four [2%] of 250 in the thermal ablation group, and five [2%] of 250 in the LLETZ group) and 2 weeks after the procedure (one [<1%] of 241 in the cryotherapy group, none of 242 in the thermal ablation group, and two [<1%] of 237 in the LLETZ group). None of the participants reported any complication requiring medical consultation or admission to hospital. Results from this pilot study preliminarily suggest that thermal ablation has similar treatment success to cryotherapy, without the practical disadvantages of providing cryotherapy in an LMIC. However, the study was not powered to establish the similarity between the techniques, and results from the ongoing randomised controlled trial are need to confirm these results. US National Institutes of Health.
The IARC Perspective on Cervical Cancer Screening
This article reviews recent evidence from the International Agency for Research on Cancer on the best methods of screening for cervical cancer, including by means of conventional cytology, visual inspection with acetic acid, human papillomavirus (HPV) nucleic acid testing, and combinations of these tests. HPV nucleic acid testing was superior whether used alone or in combination with other methods.
Sulfonation of IAA in Urtica eliminates its DR5 auxin activity
Key message N -Sulfonated IAA was discovered as a novel auxin metabolite in Urtica where it is biosynthesized de novo utilizing inorganic sulfate. It showed no auxin activity in DR5::GUS assay, implying possible inactivation/storage mechanism. A novel auxin derivative, N -sulfoindole-3-acetic acid (IAA- N -SO 3 H, SIAA), was discovered in stinging nettle ( Urtica dioica ) among 116 sulfonated metabolites putatively identified by a semi-targeted UHPLC–QqTOF-MS analysis of 23 plant/algae/fungi species. These sulfometabolites were detected based on the presence of a neutral loss of sulfur trioxide, as indicated by the m/z difference of 79.9568 Da in the MS 2 spectra. The structure of newly discovered SIAA was confirmed by synthesizing its standard and comparing retention time, m/z and MS 2 spectrum with those of SIAA found in Urtica . To study its natural occurrence, 73 species in total were further analyzed by UHPLC–QqTOF-MS or targeted UHPLC–MS/MS method with a limit of detection of 244 fmol/g dry weight. However, SIAA was only detected in Urtica at a concentration of 13.906 ± 9.603 nmol/g dry weight. Its concentration was > 30 times higher than that of indole-3-acetic acid (IAA), and the SIAA/IAA ratio was further increased under different light conditions, especially in continuous blue light. In addition to SIAA, structurally similar metabolites, N -sulfoindole-3-lactic acid, 4-(sulfooxy)phenyllactic acid and 4-(sulfooxy)phenylacetic acid, were detected in Urtica for the first time. SIAA was biosynthesized from inorganic sulfate in seedlings, as confirmed by the incorporation of exogenous 34 S-ammonium sulfate (1 mM and 10 mM). SIAA exhibited no auxin activity, as demonstrated by both the Arabidopsis DR5::GUS assay and the Arabidopsis phenotype analysis. Sulfonation of IAA may therefore be a mechanism for IAA deactivation and/or storage in Urtica , similar to sulfonation of the jasmonates in Arabidopsis .
Analysis of cellulose synthesis in a high-producing acetic acid bacterium Komagataeibacter hansenii
Bacterial cellulose (BC) represents a renewable biomaterial with unique properties promising for biotechnology and biomedicine. Komagataeibacter hansenii ATCC 53,582 is a well-characterized high-yield producer of BC used in the industry. Its genome encodes three distinct cellulose synthases (CS), bcsAB1, bcsAB2, and bcsAB3, which together with genes for accessory proteins are organized in operons of different complexity. The genetic foundation of its high cellulose-producing phenotype was investigated by constructing chromosomal in-frame deletions of the CSs and of two predicted regulatory diguanylate cyclases (DGC), dgcA and dgcB. Proteomic characterization suggested that BcsAB1 was the decisive CS because of its high expression and its exclusive contribution to the formation of microcrystalline cellulose. BcsAB2 showed a lower expression level but contributes significantly to the tensile strength of BC and alters fiber diameter significantly as judged by scanning electron microscopy. Nevertheless, no distinct extracellular polymeric substance (EPS) from this operon was identified after static cultivation. Although transcription of bcsAB3 was observed, expression of the protein was below the detection limit of proteome analysis. Alike BcsAB2, deletion of BcsAB3 resulted in a visible reduction of the cellulose fiber diameter. The high abundance of BcsD and the accessory proteins CmcAx, CcpAx, and BglxA emphasizes their importance for the proper formation of the cellulosic network. Characterization of deletion mutants lacking the DGC genes dgcA and dgcB suggests a new regulatory mechanism of cellulose synthesis and cell motility in K. hansenii ATCC 53,582. Our findings form the basis for rational tailoring of the characteristics of BC.Key points• BcsAB1 induces formation of microcrystalline cellulose fibers.• Modifications by BcsAB2 and BcsAB3 alter diameter of cellulose fibers.• Complex regulatory network of DGCs on cellulose pellicle formation and motility.
Multi‐Peak Redox Strategy for Ultrasensitive Adsorptive Stripping Voltammetric Detection of 5‐Hydroxyindole Acetic Acid on a Thermally Oxidized Graphite Felt
The precise determination of 5‐hydroxyindole acetic acid (5‐HIAA), an essential biomarker for neuroendocrine tumors and neurological diseases, is of paramount importance. Herein, we develop a sensitive electrochemical sensor based on an oxidized graphite felt (OGF) electrode, functionalized with oxygen‐containing groups via facile thermal oxidation. The synergistic integration of these moieties with the inherent 3D porous structure facilitates hydrogen‐bonding interactions, enabling efficient capture of a crucial oxidative intermediate of 5‐HIAA: its cationic free radical. This unique molecular recognition mechanism generates a distinctive six‐peak voltammetric signature in cyclic voltammetry, providing deeper insights into the complex oxidation pathway of 5‐HIAA. Utilizing adsorptive stripping square wave voltammetry, the OGF sensor achieves a wide linear range of 0.35–26.5 μmol/L and a low limit of detection of 0.094 μmol/L (S/N = 3). The enhanced analytical performance is directly linked to the superior intermediate‐trapping capability of OGF, highlighting its potential for reliable biosensing applications. The six‐peak voltammetric signature in cyclic voltammetry of 5‐HIAA on the surface of thermally oxidized graphite felt electrode is clearly observed..
Hydrotropism in the primary roots of maize
• Recent studies mainly in Arabidopsis have renewed interest and discussion in some of the key issues in hydrotropism of roots, such as the site of water sensing and the involvement of auxin. We examined hydrotropism in maize (Zea mays) primary roots. • We determined the site of water sensing along the root using a nonintrusive method. Kinematic analysis was conducted to investigate spatial root elongation during hydrotropic response. Indole-3-acetic acid (IAA) and other hormones were quantified using LC–MS/MS. The transcriptome was analyzed using RNA sequencing. • Main results: The very tip of the root is the most sensitive to the hydrostimulant. Hydrotropic bending involves coordinated adjustment of spatial cell elongation and cell flux. IAA redistribution occurred in maize roots, preceding hydrotropic bending. The redistribution is caused by a reduction of IAA content on the side facing a hydrostimulant, resulting in a higher IAA content on the dry side. Transcriptomic analysis of the elongation zone prior to bending identified IAA response and lignin synthesis/wall cross-linking as some of the key processes occurring during the early stages of hydrotropic response. • We conclude that maize roots differ from Arabidopsis in the location of hydrostimulant sensing and the involvement of IAA redistribution.
Irrigating Acetic Acid Solution During Colonoscopy for the Detection of Sessile Serrated Neoplasia: A Randomized Controlled Trial
BackgroundMisdiagnosed sessile serrated lesions (SSLs) are important precursors for interval colorectal cancers.AimsWe investigated the usage of acetic acid (AA) solution for improving the detection of SSLs in the right colon in a randomized controlled trial.MethodsA tandem observation of the right colon was performed in 412 consecutive patients. A first inspection was performed under white light high-definition endoscopy. In the AA group, a low concentration vinegar solution (AA: 0.005%) irrigated by a water pump in the right colon was compared with a plain solution of normal saline (NS) in the diagnostic yield of SSLs during the second inspection. Secondary outcomes in overall polyp detection were measured.ResultsQualitative comparisons showed significant differences in the detection rates of all polyps except adenomas, with remarkable improvement in the demonstration of advanced (> 20 mm), SSLs, and hyperplastic polyps during the second inspection of the right colon using the AA solution. Significant improvement was also noted in the AA group, as far as the mean number of polyps/patient detected, not only in SSLs (AA group: 0.14 vs. NS group: 0.01, P < 0.001), but also in all histological types and all size-categories in the right colon. Small (≤ 9 mm) polyps were detected at a higher rate in the sigmoid colon expanding the effect of the method in the rest of the colon.ConclusionAA-assisted colonoscopy led to a significant increase in SSLs detection rate in the right colon in a safe, quick, and effective manner.
Disposable stainless steel working electrodes for sensitive and simultaneous detection of indole-3-acetic acid and salicylic acid in Arabidopsis thaliana leaves under biotic stresses
The detection of phytohormones in real time has attracted increasing attention because of their critical roles in regulating the development and signaling of plants, especially in defense against biotic stresses. Herein, stainless steel sheet electrodes modified with carbon cement were coupled with paper-based analysis devices for direct and simultaneous detection of salicylic acid (SA) and indole-3-acetic acid (IAA) in plants. We demonstrated that the excellent conductivity of stainless steel sheet electrodes enabled us to simultaneously differentiate IAA and SA at a level of 10 nM. With our approach, the content of IAA and SA in Arabidopsis thaliana leaves infected or not infected with Pst DC3000 could be rapidly quantified at the same time. Our experimental results on differentiation of IAA and SA at different time points showed that there were antagonistic interactions between the IAA and SA after infection of Arabidopsis leaves with Pst DC3000. By offering a cost-effective approach for rapid and sensitive detection of IAA and SA, this study suggests that electrochemical detection can be used in the study and development of precision agriculture technology.
Integrated cervical cancer screening in Mayuge District Uganda (ASPIRE Mayuge): a pragmatic sequential cluster randomized trial protocol
Background Cervical cancer is almost entirely preventable through vaccination and screening, yet remains one of the ‘gravest threats to women’s lives’ according to the World Health Organization. Specific high-risk subtypes of human papillomavirus (HR-HPV) are well-established as the primary cause of cervical cancer. Uganda has one of the highest cervical cancer incidence rates in the world (54.8 per 100,000) as a result of limited screening access and infrastructure. The integration of a self-collected cervical cancer screening program using HPV testing within existing community-based primary health care services could increase access to screening and reduce cervical cancer rates among Ugandan women. Methods Using a pragmatic, sequential, cluster randomized trial design; we will compare the effectiveness of two cervical cancer screening models for self-collected HPV testing: 1) community health worker recruitment (door-to-door); and 2) community health meetings. In Mayuge district, Uganda, 31 villages are randomized to one of two treatment arms. Due to the nature of this trial, blinding is not possible. Women are eligible to participate if they have no previous history of hysterectomy or treatment for cervical cancer or pre-cancer and are aged 25–49 years old. All participants receive an integrated package of cervical cancer screening and education. Samples are tested for HPV using GeneXpert point of care testing. All women who test positive for HR-HPV types are referred to a designated health centre for follow-up inspection by Visual Inspection with Acetic acid (VIA) and treatment with thermal ablation. The primary outcome for the trial is the number of women who attend follow-up for VIA screening at a designated Health Centre after a positive HR-HPV test out of all women screened per arm. Secondary outcomes include: cervical cancer screening knowledge; patient-reported experience measures for self-collected cervical cancer screening; and HPV incidence. Discussion Results from this study will inform the national scale-up of cervical cancer screening in Uganda, aligning with the World Health Organization’s target of achieving cervical cancer elimination through the pillar of increased HPV screening coverage. Trial registration ISRCTN , ISRCTN12767014. Registered 14 May 2019, https://doi.org/10.1186/ISRCTN12767014; clinicaltrials.gov , NCT04000503; Registered 27 June 2019, https://clinicaltrials.gov/ct2/show/NCT04000503 Protocol version January 8, 2020, version 1.