High Sensitivity Research Articles

"How well do we know our patients?": Further validation of a complexity rating scale for HIV.

Despite advances in the management and treatment of HIV, identifying risks for disengagement are essential to maximize positive outcomes. The current study investigated the validity of the Clinical Complexity Rating Scale for HIV (CCRS-HIV), a risk-prediction tool, by assessing agreement between patient and clinician scores of patient complexity. 207 patients completed the patient version of the CCRS-HIV (CCRS-HIVP), and six Attending Medical Officers (AMOs) caring for those individuals completed the original clinician version (CCRS-HIVC). Kappa statistics, sensitivity and specificity were used to assess patient-clinician agreement. Patient-clinician agreement was highest for problematic crystal methamphetamine use (86%), polypharmacy (84%) and other physical health concerns (67%). Cut-offs of 40 and 45 for the total CCRS-HIV score were identified as most appropriate, with high sensitivity (79.31% and 76.0% respectively). Overall agreement between the clinician and patient complexity scores was high. These findings provide further evidence of the validity of the scale. The study demonstrates that the unique role of AMOs at the center contributes to them knowing their patients well, allowing them to manage and refer when required for interdisciplinary care which likely contributes to their ongoing engagement in care and may account for the high level of agreement.

MSIGen: An Open-Source Python Package for Processing and Visualizing Mass Spectrometry Imaging Data.

Mass spectrometry imaging (MSI) provides information about the spatial localization of molecules in complex samples with high sensitivity and molecular selectivity. Although point-wise data acquisition, in which mass spectra are acquired at predefined points in a grid pattern, is common in MSI, several MSI techniques use line-wise data acquisition. In line-wise mode, the imaged surface is continuously sampled along consecutive parallel lines and MSI data are acquired as a collection of line scans across the sample. Furthermore, aside from the standard imaging mode in which full mass spectra are acquired, other acquisition modes have been developed to enhance molecular specificity, enable separation of isobaric and isomeric species, and improve sensitivity to facilitate the imaging of low abundance species. These methods, including MS/MS-MSI in both MS2 and MS3 modes, multiple-reaction monitoring (MRM)-MSI, and ion mobility spectrometry (IMS)-MSI have all demonstrated their capabilities, but their broader implementation is limited by the existing MSI analysis software. Here, we present MSIGen, an open-source Python package for the visualization of MSI experiments performed in line-wise acquisition mode containing MS1, MS2, MRM, and IMS data, which is available at https://github.com/LabLaskin/MSIGen. The package supports multiple vendor-specific and open-source data formats and contains tools for targeted extraction of ion images, normalization, and exportation as images, arrays, or publication-style images. MSIGen offers multiple interfaces, allowing for accessibility and easy integration with other workflows. Considering its support for a wide variety of MSI imaging modes and vendor formats, MSIGen is a valuable tool for the visualization and analysis of MSI data.

Specific imaging of CD8 + T-Cell dynamics with a nanobody radiotracer against human CD8β.

While immunotherapy has revolutionized the oncology field, variations in therapy responsiveness limit the broad applicability of these therapies. Diagnostic imaging of immune cell, and specifically CD8+ T cell, dynamics could allow early patient stratification and result in improved therapy efficacy and safety. In this study, we report the development of a nanobody-based immunotracer for non-invasive SPECT and PET imaging of human CD8+ T-cell dynamics. Nanobodies targeting human CD8β were generated by llama immunizations and subsequent biopanning. The lead anti-human CD8β nanobody was characterized on binding, specificity, stability and toxicity. The lead nanobody was labeled with technetium-99m, gallium-68 and copper-64 for non-invasive imaging of human T-cell lymphomas and CD8+ T cells in human CD8 transgenic mice and non-human primates by SPECT/CT or PET/CT. Repeated imaging of CD8+ T cells in MC38 tumor-bearing mice allowed visualization of CD8+ T-cell dynamics. The nanobody-based immunotracer showed high affinity and specific binding to human CD8 without unwanted immune activation. CD8+ T cells were non-invasively visualized by SPECT and PET imaging in naïve and tumor-bearing mice and in naïve non-human primates with high sensitivity. The nanobody-based immunotracer showed enhanced specificity for CD8+ T cells and/or faster in vivo pharmacokinetics compared to previous human CD8-targeting immunotracers, allowing us to follow human CD8+ T-cell dynamics already at early timepoints. This study describes the development of a more specific human CD8+ T-cell-targeting immunotracer, allowing follow-up of immunotherapy responses by non-invasive imaging of human CD8+ T-cell dynamics.

Fabrication of Nanobioengineered Interfaces Utilizing Quaternary Nanocomposite for Highly Efficient and Selective Electrochemical Biosensing of Urea.

Nanobioengineered interfaces have gained attention owing to their small size and high surface area-to-volume ratio for utilization as a platform for highly selective and sensitive biosensing applications owing to the integration of biological molecules with engineered nanomaterials/nanocomposites. In this work, a novel Ag-complex, [(PPh3)2Ag(SCOf)]-based quaternary Ag-S-Zn-O nanocomposites (NCs), was synthesized through an environmentally-friendly process. The results revealed the formation of the NCs with an average crystallite size and particle size of 36.08 and 40.22 nm, respectively. In addition, this is the first study to utilize such NCs synthesized via a single-source precursor method, offering enhanced sensor performance due to their unique structural properties. Further, these NCs were used to fabricate a urease (Ur)/Ag-S-Zn-O NCs/ITO nanobioengineered electrode for precise and sensitive electrochemical biosensing of urea. The interfacial kinetic studies revealed quasi-reversible processes with high electron transfer rates and linear current responses, indicating efficient reaction dynamics. A high diffusion coefficient and low surface concentration suggested a fast diffusion-controlled process, affirming the electrode's potential for rapid and sensitive urea detection. The biosensor demonstrated notable sensing properties such as high sensitivity (12.56 μA mM-1 cm-2) and a low detection limit (0.54 mM). The fabricated bioelectrode was highly selective and reproducible and demonstrated stability for up to 60 days. These results validate the potential of this nanobioengineered interface for next-generation biosensing applications, paving the way for advanced point-of-care diagnostics and real-time health monitoring.

Piecewise modified Prandtl-Ishlinskii model for precise nano-positioning

Piezoelectric ceramic, an indispensable micro-nano actuator, has advantages of small size, high sensitivity and strong controllability, which is widely applied in various fields like micro-nano processing, medicine, chemistry and materials. However, its nonlinear and asymmetric hysteresis features directly affect its positioning accuracy. The classical and generalized Prandtl-Ishlinskii models with linear symmetry operators are commonly used to deal with these issues, but they still face difficulties in asymmetric systems. Therefore, a piecewise modified Prandtl-Ishlinskii (PMPI) model is proposed to compensate nonlinear and asymmetric hysteresis in this paper. The new nonlinear operator and piecewise nonlinear envelope function are introduced into the PMPI model. Independent right and left parts are adopted to describe hysteresis increasing and decreasing stages, while the threshold and weight vectors correspond to them. Weight vectors are extended and a new diagonal matrix is constructed for avoiding excessive parameters and computation. Simulations and experiments are shown that the PMPI model has good compensation performance and effectiveness, which has better fitting, higher accuracy, fewer parameters and computation, and can be well applied to the precise nano-positioning systems with less nonlinear and asymmetric errors.

Feasibility study of computed high b-value diffusion-weighted magnetic resonance imaging for pediatric posterior fossa tumors.

To evaluate the diagnostic efficacy of computed diffusion-weighted imaging (DWI) in pediatric posterior fossa tumors generated using high b-values. We retrospectively performed our study on 32 pediatric patients who had undergone brain magnetic resonance imaging for a posterior fossa tumor between January 2016 and January 2022. The DWIs were evaluated for each patient by two blinded radiologists. The computed DWI (cDWI) was mathematically derived using a mono-exponential model from images with b = 0 and 1,000 s/mm2 and high b-values of 1,500, 2,000, 3,000, and 5,000 s/mm2. The posterior fossa tumors were divided into two groups, low grade and high grade, and the tumor/thalamus signal intensity (SI) ratios were compared. The Mann-Whitney U test and receiver operating characteristic (ROC) curves were used to compare the diagnostic performance of the acquired DWI (DWI1000), apparent diffusion coefficient (ADC)1000 maps, and cDWI (cDWI1500, cDWI2000, cDWI3000, and cDWI5000). The comparison of the two tumor groups revealed that the tumor/thalamus SI ratio on the DWI1000 and cDWI (cDWI1500, cDWI2000, cDWI3000, and cDWI5000) was statistically significantly higher in high-grade tumors (P < 0.001). In the ROC curve analysis, higher sensitivity and specificity were detected in the cDWI1500, cDWI2000, cDWI3000, and ADC1000 maps (100%, 90.90%) compared with the DWI1000 (80%, 81.80%). cDWI3000 had the highest area under the curve (AUC) value compared with other parameters (AUC: 0.976). cDWI generated using high b-values was successful in differentiating between low-grade and high-grade posterior fossa tumors without increasing imaging time. cDWI created using high b-values can provide additional information about tumor grade in pediatric posterior fossa tumors without requiring additional imaging time.

Overlooked Trace Molecules in Organic Aerosol Revealed by Gas Chromatography-Orbitrap Mass Spectrometry.

Molecular characterization of organic aerosol (OA) is crucial for understanding its sources and atmospheric processes. However, the chemical components of OA remain not well constrained. This study used gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap MS) and GC-Quadrupole MS (GC-qMS) to investigate the organic composition in PM2.5 from Xi'an, Northwest China. GC-Orbitrap MS identified 335 organic tracers, including overlooked isomers and low-concentration molecules, approximately 1.6 times more than GC-qMS. The "molecular corridor" assessment shows the superior capability of GC-Orbitrap MS in identifying an expansive range of compounds with higher volatility and oxidation states, such as furanoses/pyranoses, di/hydroxy/ketonic acids, di/poly alcohols, aldehydes/ketones, and amines/amides. Seasonal variations in OA composition reflect diverse sources: increased di/poly alcohols in winter are derived from indoor emissions, furanoses/pyranoses and heterocyclics in spring and summer might be from biogenic emissions and secondary formation, and amides in autumn are probably from biomass burning. Integrating partial least squares discriminant analysis (PLS-DA) and potential source contribution function (PSCF) models, the source similarities and differences are further elucidated, highlighting the role of local emissions and transport from southern cities. This study offers new insights into the OA composition aided by the high mass resolution and sensitivity of GC-Orbitrap MS.

Rational Design of A-Site Cation for High Performance Lead-Free Perovskite X-Ray Detectors.

Design of hypotoxic lead-free perovskites, e.g. Bismuth(Bi)-based perovskites, is much beneficial for commercialization of perovskite X-ray detectors due to their strong radiation absorption. Nevertheless, the design principles governing the selection of A-site cations for achieving high-performance X-ray detectors remain elusive. Here, seven molecules (methylamine MA, amine NH3, dimethylbiguanide DGA, phenylethylamine PEA, 4-fluorophenethylamine p-FPEA, 1,3-propanediamine PDA, and 1,4-butanediamine BDA) and calculated their dipole moments and interaction strength with metal halide (BiI3) are selected. The first-principles calculations and related spectroscopy measurements confirm that organic molecules (DGA) with large dipole moments can have strong interactions with perovskite octahedron and improve the carrier transport between the organic and inorganic clusters. Consequently, zero-dimensional single crystal (SC) (DGA)BiI5∙H2O is synthesized. The (DGA)BiI5∙H2O SCs demonstrate an exceptional carrier mobility-lifetime product of 6.55×10-3cm2V-1, resulting in the high sensitivity of 5879.4µCGyair -1cm-2, featuring a low detection limit (4.7nGyairs-1) and remarkable X-ray irradiation stability even after 100 days of aging at a high electric field (100Vmm-1). Furthermore, the (DGA)BiI5∙H2O SCs for imaging, achieving a notable spatial resolution of 5.5lpmm-1 are applied. This investigation establishes a pathway for systematically screening A-site cations to design low-dimensional SCs for high-performance X-ray detection.

Efficient, specific and direct detection of double-stranded DNA targets using Cas12f1 nucleases and engineered guide RNAs

To address the limitations of the CRISPR/Cas12f1 system in clinical diagnostics, which require the complex preparation of single-stranded DNA (ssDNA) or in vitro transcripts (RNA), we developed a fluorescent biosensor named PDTCTR (PAM-dependent dsDNA Target-activated Cas12f1 Trans Reporter). This innovative biosensor integrates Recombinase Polymerase Amplification (RPA) with the Cas12f_ge4.1 system, facilitating the direct detection of double-stranded DNA (dsDNA). PDTCTR represents a significant leap forward, exhibiting a detection sensitivity that is a hundredfold greater than the original Cas12f1 system. It demonstrates the capability to detect Mycoplasma pneumoniae (M. pneumoniae) and Hepatitis B virus (HBV) with excellent sensitivity of 10 copies per microliter (16.8 attomolar) and distinguishes single nucleotide variations (SNVs) with high precision, including the EGFR (L858R) mutations prevalent in non-small cell lung cancer (NSCLC). Clinical evaluations of PDTCTR have demonstrated its high sensitivity and specificity, with rates ranging from 93%∼100% and 100%, respectively, highlighting its potential to revolutionize diagnostic approaches for infectious diseases and cancer-related SNVs.This research underscores the substantial advancements in CRISPR technology for clinical diagnostics and its promising future in early disease detection and personalized medicine.

Carbon‐Based Biosensor in Point of Care Setting

AbstractIn medical diagnosis, detecting disease biomarkers at ultra‐low concentrations is vital. Point‐of‐care (POC) diagnostics require rapid detection, live monitoring, high sensitivity, low detection threshold, and cost‐effectiveness. Carbon‐based nanomaterials (CBNs) are promising due to their large surface‐to‐volume ratio, conductivity, biocompatibility, and stability, making them ideal for biosensors. Recent advancements in CBN applications, including biosensing, drug delivery, and cancer therapy, highlight their potential in enhancing detection sensitivity and specificity. Electrochemical sensors and biosensor platforms using carbon nanocomposites are pivotal in diagnostics. This review explores the current state and future challenges of CBN integration in POC settings, envisioning a transformative impact on healthcare diagnostics and therapeutics.

Efficacy and outcomes of bempedoic acid versus placebo in patients with hypercholesterolemia: an updated systematic review and meta-analysis of randomized controlled trials.

Bempedoic acid (BA) has shown varied efficacy in managing hyperlipidemia. We conducted the most extensive up-to-date meta-analysis, the first to include recent studies by Nissen et al., which boast the largest sample size. Literature search was done on Medline, EMBASE, and Cochrane Library. The primary endpoint was a change in low-density lipoprotein-cholesterol (LDL-C) levels, while secondary endpoints encompassed changes in lipid parameters, clinical endpoints, and safety endpoints. The least-square mean (LSM) percent change was utilized for lipid changes, with statistical significance set at P < 0.05. This analysis included 12 randomized control trials with 22,249 participants. BA exhibited a substantial reduction in LDL-C levels [LSM % change, -24.34; 95% confidence interval (CI), -27.80 to -20.88; P < 0.0001], total cholesterol levels (LSM % change, -16.62; 95% CI, -21.70 to -11.54; P < 0.00001) and high-density lipoprotein-cholesterol (HDL-C) levels (LSM % change, -4.22; 95% CI, -5.51 to -2.92; P < 0.00001) compared to the placebo. BA significantly lowers LDL-C, total cholesterol, HDL-C, non-HDL-C, high sensitivity C reactive protein, and apolipoprotein levels.

Bismuth Oxyiodide as a Highly Efficient Room Temperature NOx Gas Sensor: Role of Surface Orientations on Sensing Performance

In the pursuit of developing fast and reliable gas sensors, a new ternary oxide semiconductor, a bismuth oxyiodide (BiOI)-based sensing material, has been reported with desirable adsorption energy, short recovery time, and high sensitivity and selectivity for detecting nitrogen oxide mixtures (NOx, typically NO and NO2). The structural, electronic, and transport properties of both (001) and (012) planes of BiOI surfaces upon the adsorption of six environmentally relevant gases (NO, NO2, SO2, SO3, O2, and H2O) are systematically explored using a combination of density functional theory (DFT) and non-equilibrium Green’s function (NEGF) methods. The results indicate that BiOI (001) exhibits weak interaction with these gases, with the highest adsorption energy observed for NO. In contrast, the BiOI (012) surface shows enhanced adsorption stability for these gases, particularly acceptable strong adsorption to NO2, indicating its promising capability for detecting these gases with high specificity. Moreover, it demonstrates the most intense chemisorption for SO3, suggesting it to be a reliable SO3 adsorbent/cleaner. The obtained transport characteristics, including current-voltage (I-V) and resistance-voltage (R-V) curves, further highlight the higher selectivity of the BiOI (001) device towards NO and the BiOI (012) device towards NO2 against the other gases. Furthermore, the transmission spectra analyses reveal that the BiOI-based sensor can electrically discriminate the target gas molecules from other considered gas molecules. Besides, the practical application possibilities of both orientations are explored by estimating their recovery time, and the results show that the BiOI sensor has excellent recovery times at room temperature (NO/BiOI (001) = 0.158 ns, and NO2/BiOI (012) = 3.89 s), highlighting its potential as an ideal reversible gas-sensing material for detecting NOx gases.

Horseradish peroxidase enzyme/graphene oxide based electrochemical biosensor for detection of glutathione

Glutathione (GSH) is a tripeptide composed of three amino acids: cysteine, glycine, and glutamate. It is essential to many different living things as an antioxidant. Glutathione serves as a key biomarker and its detection is crucial for studying its levels in living bodies, providing insights into various diseases. In this work, we present the use of a highly sensitive electrochemical sensor to detect glutathione utilizing a graphene oxide modified Indium Tin Oxide (ITO) electrode immobilized with the enzyme horseradish peroxidase (HRP). The modified electrode was further characterized by Fourier transform infrared spectroscopy (FTIR) and spectrum showed that HRP was successfully immobilized onto GO. The electrochemical behavior of the modified ito was examined by cyclic voltammetry. Cyclic voltammetry demonstrated HRP/GO/ITO electrode has better electrocatalytic activity than bare ito in the oxidation of GSH in acetate buffer solution. The electrochemical sensor had a 1μM detection limit and a linear range of 10μM to 50 μM. The HRP/GO/ITO electrode resulted improved electrocatalytic properties, long-term stability, good repeatability and high sensitivity, and, along with a quick response to detect GSH. Additionally, GSH concentration in real sample was measured using the HRP/GO/ITO modified electrode.

Fabrication of Graphene-based Ammonia Sensors: A Review

Abstract: Graphene gas sensors have gained much scientific interest due to their high sensitivity, selectivity, and fast detection of various gases. This article summarizes the research progress of graphene gas sensors for detecting ammonia gas at room temperature. Firstly, the performance and development trends of the graphene/semiconductor Schottky diode sensor are discussed. Secondly, manufacturing methods and the latest developments in graphene field-effect transistor sensors are reviewed. Finally, the basic challenges and latest efforts of functional ammonia gas sensors are studied. The discussion delves into each sensor type's detection principles and performance indicators, including selectivity, stability, measurement range, response time, recovery time, and relative humidity. A comparative analysis is conducted to highlight the progress achieved in research, elucidating the advantages, disadvantages, and potential solutions associated with various sensors. As a result, the paper concludes by exploring the future development prospects of graphene-based ammonia sensors.

Deep learning-assisted flexible piezoresistive sensor with liquid-phase reduced metal electrodes for fitness movement recognition and correction

Flexibility and wearability in electronic devices gain prominence with the rise of national fitness campaigns. Among them, piezoresistive sensors stand out for their ability to accurately monitor health signals due to their high sensitivity. However, conventional metal nanoparticle ink electrodes face issues like peeling, chemical instability, and substrate limitations. This study introduces a novel method for fabricating high-performance flexible piezoresistive sensors using liquid-phase reduced metal electrodes. Integration of porous polydimethylsiloxane (PDMS) substrates with highly conductive interdigital silver electrodes (1.6 × 10−6 Ω·m) addresses conventional electrode shortcomings, offering permeability, flexibility, and outstanding conductivity. Incorporation of a graphene (GR)/carbon nanotube (CNT)/Ecoflex composite enhances sensor piezoresistive sensing capabilities, with features including high sensitivity (3.57 KPa−1), rapid response time (58 ms/72 ms), and excellent cycle stability (>10000 cycles). The sensor finds utility in various applications, including human physiological signal monitoring, pressure array recognition, and handwriting recognition. Additionally, with deep learning techniques, the system achieves accurate recognition (99.25 %) and correction (98.75 %) of diverse fitness movements, aiming to promote safer exercise practices, enhance training efficiency, and advance intelligent wearable fitness devices.

SERS and electrochemical dual-mode detection of miRNA-141 by using single Au@Ag nanowire as a new platform.

As biomarkers of cancer, the accurate and sensitive detection of microRNAs is of great significance. Therefore, we proposed a surface-enhanced Raman scattering (SERS)/electrochemical (EC) dual-mode nanosensor for sensitively detecting miRNA-141. The nanosensor uses Au@Ag nanowires as a novel SERS/EC sensing platform, which has the advantages of good biocompatibility, fast response, and high sensitivity. The dual-mode nanosensor can not only effectively overcome the problem of insufficient reliability of single signal, but also realize the amplification and stable output of the detection signal, to ensure the reliability and repeatability of miRNA detection. With this sensing strategy, the target miRNA-141 can be detected over a wide linear range (100 fM to 50 nM) (LOD of 18.4 fM for SERS and 16.0 fM for electrochemical methods). In addition, the process shows good selectivity and can distinguish miRNA-141 from other interfering miRNAs. The actual analysis of human serum samples also proves that our strategy has good reliability, repeatability, and has broad application prospects in the field of analysis and detection.

MicroLOCK: Highly stable microgel biosensor using locked nucleic acids as bioreceptors for sensitive and selective detection of let-7a

Chemically modified oligonucleotides can solve biosensing issues for the development of capture probes, antisense, CRISPR/Cas, and siRNA, by enhancing their duplex-forming ability, their stability against enzymatic degradation, and their specificity for targets with high sequence similarity as microRNA families. However, the use of modified oligonucleotides such as locked nucleic acids (LNA) for biosensors is still limited by hurdles in design and from performances on the material interface. Here we developed a fluorogenic biosensor for non-coding RNAs, represented by polymeric PEG microgels conjugated with molecular beacons (MB) modified with locked nucleic acids (MicroLOCK). By 3D modeling and computational analysis, we designed molecular beacons (MB) inserting spot-on LNAs for high specificity among targets with high sequence similarity (95%). MicroLOCK can reversibly detect microRNA targets in a tiny amount of biological sample (2μL) at 25°C with a higher sensitivity (LOD 1.3fM) without any reverse transcription or amplification. MicroLOCK can hybridize the target with fast kinetic (about 30min), high duplex stability without interferences from the polymer interface, showing high signal-to-noise ratio (up to S/N=7.3). MicroLOCK also demonstrated excellent resistance to highly nuclease-rich environments, in real samples. These findings represent a great breakthrough for using the LNA in developing low-cost biosensing approaches and can be applied not only for nucleic acids and protein detection but also for real-time imaging and quantitative assessment of gene targeting both in vitro and in vivo.

Current Trends and Challenges in Explosives Detection using Nanotechnology

Objective: This article highlights the applications of nanotechnology in the detection of explosives. Evidence acquisition: The increasing rise in terrorist acts throughout the globe has brought attention to the significance of locating hidden bombs and motivated new propelled breakthroughs to ensure public safety. Recognizing explosives and closely related-threatening combinations has already risen to the top of the priority list for contemporary national security and counterterrorism applications. Sensors based on nanotechnology have a fair probability of fulfilling all the criteria needed to be a practical solution for explosive trace detection. Results: Nanowire/nanotube, nanomechanical devices, and electronic noses are three nanosensor technologies that have the most potential to develop into commercially viable technology platforms for the detection of trace explosives. Certain functionalized nanoparticles can exhibit different behaviors as a result of unique interactions with nitroaromatics. Semiconducting singlewalled carbon nanotubes (SWCNT) have been used as wearable chemical sensors. Conclusion: In this paper, the potential of nanosensors has been exposed that can be used to build a sensor system with high selectivity and sensitivity and appropriate platforms for signal transduction for the detection of explosives.

Quantitative reevaluation of the function of Karez using remote sensing technology

The water delivery capacity of Karez is gradually declining, and it is possible that such a traditional water supply systems might be completely replaced by modern water conservancy projects. To determine whether these ancient water conservancy projects have a future, we conducted a study in a typical research area of Xinjiang Province, China. Using remote sensing technology, in situ surveying, and the analytic hierarchy process, we evaluated Karez in terms of water delivery capacity, water intake convenience, and capability to maintaining the ecological stability of the surrounding area. The derived results are as follows. (1) During 2005–2020, the length of 14 Karez systems in the study area decreased; however, the calculated water access convenience degree (C) indicated that Karez are more convenient for water intake compared with modern transmission channels, i.e., Ckarez = 0.68 and Cchannel = 0.51. (2) The mean annual runoff of the Karez system was 69.38 × 106 m3, similar to that of the modern water transmission channels in the area (73.49 × 106 m3). (3) Change in ecological sensitivity occurred mostly in regions where Karez systems have disappeared, with increase of 70.69 % and 14.51 % in high and medium sensitivity areas, respectively, and decline of 21.53 % and 9.74 % in low-sensitivity and non-sensitivity areas. Our research shows that Karez have considerable water delivery capacity, and that their existence is beneficial to maintaining the stability of the surrounding ecology. The Karez system can be considered a template for harmonious coexistence between humans and nature.

Selective Determination of Acetaminophen in Presence of Ascorbic Acid at Poly (p-Methoxyphenol) Electrode

In the present work, we discuss the modification of a gold electrode with p-methoxyphenol and its application as a sensor for acetaminophen (ACP) in a phosphate buffer solution (pH = 7.4). The modified electrode was subsequently employed to determine acetaminophen in the presence of ascorbic acid (AA) using differential pulse voltammetry (DPV). The peak positions and relative sensitivity of ACP/AA were influenced by the potential window used during polymerization. For polymerization between 0 and 1.0 V, the peak potentials recorded in the phosphate buffer solution (pH = 7.4) were 488 mV for ACP and 280 mV vs. Ag/AgCl for AA. Furthermore, the effects of pH and electrolyte type on the linearity range and detection limit were investigated. The high selectivity and sensitivity for ACP were attributed to charge discrimination and analyte accumulation. The detection limit for the 3σ-test was determined to be 0.2 nM. This study highlights the potential of the modified gold electrode for selective and sensitive detection of acetaminophen, even in the presence of interfering substances such as ascorbic acid. The optimization of polymerization conditions and the comprehensive analysis of pH and electrolyte effects contribute to the electrode's superior performance.