Analytical Probe Research Articles

Curcumin-Derived (3-Aminopropyl)trimethoxysilane-Functionalized Carbon Quantum Dots: A Fluorometric and Colorimetric Nanoprobe for Picric Acid Detection, Antioxidant Activity, and Liposome Encapsulation.

Creating an analytical probe to track extremely mutagenic picric acid (PA) is essential for human health and the environment. Here, we developed a straightforward and quick fluorescence analytical method utilizing 3-aminopropyltrimethoxysilane (3-APTMS)-functionalized curcumin carbon quantum dots (CQDs) for the fast and selective detection of PA. Solvothermal carbonization and functionalization of curcumin with 3-APTMS were used to create multifunctional CQDs, which were then characterized using UV-vis spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD), ζ-potential, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Our CQDs, as synthesized with an average diameter of 3.4 nm, exhibited excitation-dependent emission behavior, demonstrating 63.85% yield, 1.59% quantum yield, and fluorescence lifetime decay broader than a single exponential. The addition of picric acid significantly reduced the fluorescence (FL) emission intensity of CQDs and caused a noticeable color shift in visible as well as UV light. Throughout the 0.1-2.5 μM range, the calibration curve of the suggested assay demonstrated favorable linearity between quenched FL emission intensity and PA concentration, with the lowest detection limit of 88.96 nM. The CQD shows antioxidant activity at low concentrations (<0.07 mg/mL), measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (colorimetry and electrochemically). Further, we encapsulated our CQDs in the liposome to make it biocompatible for cell imaging for future study. The results indicate the efficacy of CQDs as a nanoprobe for the selective detection of PA, retaining a few of the primary properties of natural curcumin-like antioxidant activity while having significantly higher bioavailability and water solubility; they can be used as a modifier in semiconductors for photocatalytic application and can also be a promising fluorescence probe in cell imaging.

Colorimetric quantification of vancomycin by highly active nitroxyl radical compounds.

Nitroxyl radicals, represented by 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO), are highly stable organic free radicals with unique properties and are used as functional molecules in various fields. However, TEMPO had low reactivity and sometimes did not provide enough response. Therefore, highly active nitroxyl radical compounds have been developed in which bicyclo and tricyclo structures stabilize the radicals. In this study, we found that nortropine N-oxyl (NNO), a type of highly active nitroxyl radical, can oxidize the 2,2'-dihydroxybiphenyl structure under physiological conditions, and succeeded in the colorimetric quantification of vancomycin containing 2,2'-dihydroxybiphenyl moieties in the molecular structure. The reaction took only a few minutes to complete and could be confirmed with the naked eye, with a quantitative range of 10-100μM. High-performance analytical probes are expected to be developed that use highly active nitroxyl radical derivatives to replace TEMPO derivatives.

Unexpected thermal aging effect on brittle fracture and elemental segregation in modern dissimilar metal weld

A full-scale dissimilar metal weld safe-end mock-up, precisely replicating a critical component of a modern nuclear power plant, was investigated. The brittle fracture behavior, carbide evolution and nanoscale elemental segregation in the heat-affected zone (HAZ) of low alloy steel (LAS) were analyzed under both post-weld heat-treated and thermally-aged conditions (400 °C for 15,000 h, equivalent to 90 years of operation) using analytical electron microscopy and atom probe tomography. The observed increase in grain boundary (GB) decohesion and intergranular cracking on the fracture surface and the decrease of fracture toughness are primarily attributed to P and Mn segregation to GBs and the coarsening of carbides upon long-term thermal aging. The direct observations of significant elemental segregation to GBs and the consequent reduction in fracture toughness in the HAZ are unexpected for modern low-phosphorus LASs, highlighting potential concerns for evaluating the structural integrity of modern nuclear power plants.

Rational Design of an Activatable Near-Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection.

Rational and effective design of a universal near-infrared (NIR) light-absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging-guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4-hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)-recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS-Fe-CE and NBS-C-Fe-CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging-guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.

Rational Design of an Activatable Near‐Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection

Rational and effective design of a universal near‐infrared (NIR) light‐absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging‐guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4‐hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)‐recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS‐Fe‐CE and NBS‐C‐Fe‐CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging‐guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.

Highly fluorescent nitrogen doped carbon dots as analytical probe for sensitive detection of curcumin through smartphone integrated 3D-printed platform: A new horizon in food safety

COVID-19 pandemic has significantly influenced the dietary habits of humans, emphasizing the incorporation of natural ingredients to enhance immunity towards viral and bacterial infections. Curcumin (Cur), a widely used traditional medicine in various Asian countries and a natural coloring agent, has gained popularity, leading to surge in its usage specially in post COVID-19 era. This surge has led to increased scrutiny of the potential side effects of excessive Cur use, with recent reports suggesting it may result in inactivation of DNA and reduce adenosine triphosphate levels, leading to health risks. In this work, we synthesized highly fluorescent nitrogen-doped carbon dots with a photoluminescence quantum yield of 72.9 % for the sensitive and selective detection of Cur. The developed fluorescent probe exhibits excellent sensory response towards Cur within a concentration range of 0.081–51.45 µM, achieving an ultra-low detection limit of 15.91 nM. The sensor was successfully tested on real food samples like ginger powder, turmeric powder, and curry powder, demonstrating good recovery rates. To assess the practicality of the sensor system, we developed a 3D-printed smartphone-integrated device platform for curcumin detection through fluorescence image analysis. This developed platform exhibited promising results, achieving a limit of detection (LoD) of 132.28 nM across a curcumin concentration range of 0.13–54.00 µM. This device platform holds significant potential for the development of efficient sensors for real-time detection of Cur in food samples.

Dominik Tatarka and His Journalist Dimension

The study focuses on the Slovak writer Dominik Tatarka and his aspect of journalism. Although he is primarily a personality who belongs to the artistic-literary space, he was also heavily involved as a journalist at one time. However, the recognition of this journalistic line remains in the background, while it had a societal impact and was a serious testimony of the writer’s turbulent opinion development, turns, and attitudes. The writer radically succumbed to the communist regime at some point in his life, but after realizing the destruction that the totalitarian regime was perpetrating, he subsequently radically moved away from these positions and became its loud critic. Naturally, these positions of opinion are also copied by his journalistic activity, the reflection of which, as we have already stated, remains somewhat in the background. The study therefore has the ambition to eliminate this deficit at least partially. Based on the research of collected journalistic texts and analytical probe into their semantic space, our goal is to make available the hitherto undisclosed semantic dimensions of his journalistic communications, put them in relationships and context and thus expand the portfolio of information about this distinctive, at that time key figure of the Slovak cultural space. With regard to the limited spatial possibilities of the contribution, we focus on Tatarka's journalistic activities in the period of the second half of the 1940s to approximately the first half of the 1950s. This is the period in which he manifested himself most strongly as a journalist and his activities in this direction took on serious social dimensions.The study aims to expand the scope of information about this prominent Slovak social and cultural figure and to contribute to a more comprehensive understanding of him. Keywords: writer, journalist, communist regime, newspaper article, journalism, print media

Falcon Probe: A High-Pressure and Robust Sampling Interface for Coupling Lossless Liquid Chromatography Injection with In Situ Nanoliter-Scale Sample Pretreatment.

With the increasing demand for trace sample analysis, injecting trace samples into liquid chromatography-mass spectrometry (LC-MS) systems with minimal loss has become a major challenge. Herein, we describe an in situ LC-MS analytical probe, the Falcon probe, which integrates multiple functions of high-pressure sample injection without sample loss, high-efficiency LC separation, and electrospray. The main body of the Falcon probe is made of stainless steel and fabricated by the computer numerical control (CNC) technique, which has ultrahigh mechanical strength. By coupling a nanoliter-scale droplet reactor made of polyether ether ketone (PEEK) material, the Falcon probe-based LC-MS system was capable of operating at mobile-phase pressures up to 800 bar, which is comparable to those of conventional ultraperformance liquid chromatography (UPLC) systems. Using the probe pressing microamount in situ (PPMI) injection approach, the Falcon probe-based LC-MS system showed high separation efficiency and good repeatability with relative standard deviations (RSDs) of retention time and peak area of 1.8% and 9.9%, respectively, in peptide mixture analysis (n = 6). We applied this system to the analysis of a trace amount of 200 pg of HeLa protein digest and successfully identified an average of 766 protein groups (n = 5). By combining in situ sample pretreatment at the nanoliter range, we further applied the present system in single-cell proteomic analysis, and 241 protein groups were identified in single 293 cells, which preliminarily demonstrated its potential in the analysis of trace amounts of samples with complex compositions.

Analytical probe for reliable sensing of metformin using cannon ball flower derived fluorescent CDs

Analytical probe for reliable sensing of metformin using cannon ball flower derived fluorescent CDs

Analysis of the ion collection model in the ExB probe

An ExB probe is a pass-band velocity filter for an ion beam. The ExB probe measurement is related to the ion velocity distribution function (IVDF); however, the finite pass-band filter window size leads to differences in the true IVDF and measured ExB probe spectrum. We derive for the first time an analytical ExB probe transmittancy matrix and use it to examine differences in the IVDF and the probe spectrum. The probe spectra are compared to a synthetically defined test IVDF to study how probe geometry and ion species affect the differences. It is found that the difference in the probe spectrum and the true IVDF is dependent on the ion species, and the deviation is larger for heavier ions. The peak velocity of the spectrum was shifted by up to 13%, and the velocity spread was broadened by up to 276%. The relative ion species fraction is calculated from the probe spectra by two different methods and compared to the true fraction. Using the approach of this work, direct integration of the spectrum resulted in a 2% difference, while a more common approach from literature overestimated one ion species by 184%.

An Ideological Critical Discourse Analytical Research Probe into The Bold Language Use in Women’s Freedom March in Pakistan

An Ideological Critical Discourse Analytical Research Probe into The Bold Language Use in Women’s Freedom March in Pakistan

Determination of glyphosate using electrochemical aptamer-based label-free voltammetric biosensing platform

Glyphosate is currently the most frequently used herbicide in the agricultural industry. Due to its widespread usage, there are concerns about its potential toxicity when it contaminates water, soil, and agricultural products. In this study, a simple aptamer-based biosensor was developed to detect glyphosate. The electrode surfaces were modified by reducing diazonium salts during electrodeposition and forming carboxylic acid groups. The immobilization of aminoated glyphosate aptamers on the electrode surface was then carried out using a carbodiimide reaction between the amino and carboxylic acid groups. The electrochemical cell circuit was completed using an analyte and redox probe solution on the electrode surface. Cyclic voltammetry, differential pulse, and electrochemical impedance spectroscopy techniques were then explored to investigate their potential as biosensors. Upon exposure to glyphosate, the spatial conformation of the specific aptamer used is altered, which generates an electrochemical response that can be quantified. Glyphosate could be quantified using voltammetry in the 1 to 5000 nM range, with a 0.67 nM detection limit. Furthermore, the constructed aptasensor demonstrated significant selectivity for glyphosate in the presence of interfering substances like glycine, dimethoate, and alanine. This biosensor has considerable potential for evaluating glyphosate in actual samples because of its simple design, high sensitivity, and rapid functionality. Moreover, developing a simple, cost-effective, and portable device for field applications may be possible.

The quantum corrected Schwarzschild black hole with a linear-quadratic GUP: a comprehensive evaluation

In this manuscript, we delve into an analytic and numerical probe of shadow with different accretion models, quasinormal modes, Hawking radiation, and gravitational lensing to study observational impacts of quantum effect introduced through linear-quadratic GUP(LQG). Our investigation reveals that the shadows of LQG-modified black holes are smaller and brighter than Schwarzschild black holes. To examine the impact of the quantum correction on the quasinormal mode, linear-quadratic GUP-modified black holes are explored under scalar andelectromagnetic field perturbation. Here, linear-quadratic GUP isused to capture quantum corrections. It is observed that theincorporation of quantum correction by linear-quadratic GUP altersthe singularity structure of the black hole. To compute thequasinormal modes of this linear-quadratic GUP-inspiredquantum-corrected black holes, we compute the effective potentialgenerated under the perturbation of scalar and electromagneticfield, and then we use the sixth-order WKB approach in conjunctionwith the appropriate numerical analysis. We find that the greybody factor decreases with the GUP parameter α implying that the probability of transmission decreases with the GUP parameter. The total power emitted by LQG modified black hole is found to be greater than that emitted by Schwarzschild black hole. Finally, we study weak gravitational lensing and make a comparison with quadratic GUP and linear GUP-modified black holes.

Fabrication of two-dimensional fluorescent stanene oxide nanosheets for the detection of cortisone in biofluids

The current work provides a new approach for the fabrication of two-dimensional blue fluorescent guanidine acetic acid templated stanene oxide nanosheets (GAA-SnO2 NSs) for selective determination of cortisone. The GAA-SnO2 NSs displayed blue fluorescence with a quantum yield of 21.16 %. Under excitation wavelength of 370 nm, the GAA-SnO2 NSs responded to cortisone by exhibiting noticeably decrease in the emission peak at 454 nm. The introduction of cortisone to GAA-SnO2 NSs significantly altered fluorescence emission, leading to achieve desirable linear relationship between the intensity ratio (I0/I) and the concentration (0.5–10 μM). The detection limit was found to be 41.74 nM for cortisone. The GAA-SnO2 NSs were decorated on paper for the development of embedded analytical probe for cortisone detection. Furthermore, the method was successfully demonstrated to assay cortisone in biofluid (plasma and urine) samples with good recoveries.

Johann Ulrich Surgantʼs Manuale curatorum predicandi as a product of medieval intellectual heritage in Basel libraries

Manuale curatorum predicandi – the treatise on the art of preaching written by Basel scholar Johann Ulrich Surgant in 1502 – is usually classified as a humanist and nearly proto-reformation work. The paper disputes this classification; it provides several analytical textual probes to show the deep dependence of the Manuale curatorum on the older scholastic tradition. Following on from former research, a few relatively well-known high and late medieval artes praedicandi are identified as the main sources of Surgantʼs writing. Moreover, the study aims to trace specific manuscripts or early prints in Basel libraries, which could have been directly used by the author-compiler.

Early events during the aggregation of Aβ16-22-derived switch-peptides tracked using Protein Charge Transfer Spectra

BackgroundUnderstanding Aβ aggregation and inhibiting it at early stages is of utmost importance in treating Alzheimer's and other related amyloidogenic diseases. However, majority of the techniques to study Aβ aggregation mainly target the late stages; while those used to monitor early stages are either expensive, use extrinsic dyes, or do not provide information on molecular level interactions. Here, we investigate the early events of Aβ16-22(KLVFFAE) aggregation using Aβ16-22 derived switch-peptides (SwPs) through a novel label-free approach employing Protein Charge Transfer Spectra (ProCharTS). ResultsWhen pH is increased from 2 to 7.2, the Aβ-derived switch peptides undergo controlled self-assembly, where the initial random coil peptides convert into β-sheet. We leveraged the intrinsic absorbance/luminescence arising from ProCharTS among growing peptide oligomers to observe the aggregation kinetics in real-time. In comparison to monomer, the lysine and glutamate headgroups in the peptide oligomer are expected to come in proximity enhancing ProCharTS intensity due to photoinduced electron transfer. With a combination of Aβ-derived switch-peptides and ProCharTS, we obtained structural insights on the early stages of Aβ-derived SwP aggregation in four unique peptides. Increase in scatter corrected ProCharTS absorbance (250–500 nm) and luminescence (320–720 nm) along with decreased mean luminescence lifetime (2.3–0.8 ns) characterize the initial stages of aggregation monitored for 1–96 h depending on the peptide. We correlated the results with Circular Dichroism (CD), 8-anilino-1-naphthalenesulfonic acid (ANS) and Thioflavin T (ThT) measurements. SignificanceWe demonstrate ProCharTS as an intrinsic analytical probe with following advantages over other conventional methods to track aggregation: it is a label-free probe; it's intensity can be measured using a UV–Vis spectrophotometer; it is more sensitive in detecting the early molecular events in aggregation compared to ANS and ThT; and it can provide information on specific contacts made between charged headgroups of Lysine/Glutamate in the oligomer.

PEGylated AIEgens for dual sensing of ATP and H2S and cancer cells photodynamic therapy

Fluorescent sensors have been widely applied for biosensing, but probes for both multiple analytes sensing and photodynamic therapy (PDT) effect are less reported. In this article, we reported three AIE-based probes anchored with different mass-weight polyethylene glycol (PEG) tails, i.e., TPE-PEG160, TPE-PEG350, and TPE-PEG750, for both adenosine-5′-triphosphate (ATP) and hydrogen sulfide (H2S) detection and also cancer cells photodynamic therapy. TPE-PEGns (n = 160, 350 and 750) contain the tetraphenylethylene-based fluorophore core, the pyridinium and amide anion binding sites, the H2S cleavable disulfide bond, and the hydrophilic PEG chain. They exhibit a good amphiphilic property and can self-assemble nona-aggregation with a moderated red emission in an aqueous solution. Importantly, the size of aggregation, photophysical property, sensing ability and photosensitivity of these amphiphilic probes can be controlled by tuning the PEG chain length. Moreover, the selected probe TPE-PEG160 has been successfully used to detect environmental H2S and image ATP levels in living cells, and TPE-PEG750 has been used for photodynamic therapy of tumor cells under light irradiation.

A possible production area of Chinese faience? Reference to beads decorating coffins from Shijia Yucun site, Gansu Province

AbstractShijia Yucun site is a northwestern settlement from the Zhou period (1046–221 BCE). Faience beads used as a personal ornament and coffin decoration are notable among plenty of funerary objects. Thirteen faience objects are determined using analytical electron probe micro‐analysis (EPMA) and scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM–EDS). The information on their provenance indicates that the types of faience beads around bodies include the mixed‐alkali faience from Europe or the Eurasian Steppe, the soda‐enriched faience from West Asia, and the local products rich in potash. However, faience samples adorning coffins are all local products, and the quality is rougher compared to the faience decorating the body. This unique feature is hardly found in other tombs of Zhou elites. As faience was a precious personal ornament in other stronger polities, it was already available as a general coffin decoration in such a small‐economy feudal state, so faience samples decorating coffins were not likely to be precious gifts from other elites. It is reasonable to assume that faience beads adorning coffins might have been made near the ruins. This investigation is significant to reveal the cultural exchange in the western frontier of the Zhou realm that dates back to the power decline of the Western Zhou period and highlight a possible high‐potash faience production area.

EFFECT ON INCLINED STRETCHING PLATE UNDER SLIP CONDITION DUE TO NON-NEWTONIAN FLUID IN POROUS MEDIUM FOR MAGNETOHYDRODYNAMIC FLOW OF UNSTEADY NATURE

An analytical probe is executed for evaluating the impact of unsteady flow pertaining to non-Newtonian fluid of magnetohydrodynamic nature on a stretching inclined porous plate, built in porous medium. Electrically conducting unsteady flow facing applied magnetic force with applied slip condition are the other factors utilized for the study of convective heat transfer. For converting governing equations to nonlinear differential equations, the similarity transformation method has been deployed. MATLAB was also used. Ordinary differential equations were solved numerically with the help of the Newton iterative method as well as the shooting method. Results for velocity and temperature were derived for a wide range of unsteady and other parameters including magnetic, source/sink, Grashof number, Prandtl number, Deborah number, and angle of inclination. Graphs and tables were used for compiling and computing values of skin friction and heat transfer rate. Results derived in the present analysis have been compared to those available in the previous literature, and parity has been formed to ascertain the accuracy of the current analytical exercise.

Ceramic Filters Coated with Green Ag-Nanoparticles for Drinking Water Treatment in Rural Households of Nigeria.

A ceramic water filter (CWF) coated with plant-based nanoparticles was used as household water purifier in a rural community. Silver nanoparticles (AgNPs) were produced from the stem bark of Bridelia ferruginea plant, and their efficacy to enhance the physical, chemical, and microbial quality of raw stream water sample was determined using analytical probes and pour-plate techniques, respectively. The pH of the filtered water sample ranged 7.6 to 8.1, which is within the WHO permissible limit for drinking water, and the electrical conductivity values were also reduced from 110 to 70 µS/cm. The CWF coated with AgNPs (CWF-AgNPs) removed Klebsiella pnuemoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Entamoeba histolytica from the stream water sample. The highest percentage of coliform reduction in the CWF and CWF-AgNPs were 93.18% and 99.64%, respectively. The raw data showed that the CWF-NPs enhanced the quality of the stream water. The surface and internal structure of the CWF-AgNPs can be modified by varying the concentration of the composite materials, so as to determine the most effective combination. The improved CWF-AgNPs will enhance achieving United Nations Sustainable Development Goal #6, which focuses on clean water and sanitation.