Evaluation of radiation dose to the lens in interventional cardiology physicians before and after dose limit regulation changes.

In response to the International Commission on Radiological Protection (ICRP), which lowered the lens equivalent dose limit, Japan lowered the lens dose limit from 150 mSv/year to 100 mSv/5 years and 50 mSv/year, with this new rule taking effect on April 1, 2021. DOSIRIS® is a dosimeter that can accurately measure lens dose. Herein, we investigated lens dose in interventional cardiology physicians one year before and after the reduction of the lens dose limit using a neck dosimeter and lens dosimeter measurements. With an increase in the number of cases, both personal dose equivalent at 0.07 mm [Hp(0.07), neck dosimeter] and personal dose equivalent at 3 mm depth [Hp(3), lens dosimeter] increased for most of the physicians. The Hp(3) of the lens considering the shielding effect of the Pb glasses using lens dosimeter exceeded 20 mSv/year for two of the 14 physicians. Protection from radiation dose will become even more important in the future, as these two physicians may experience radiation dose exceeding 100 mSv/5 years. The average dose per procedure increased, but not significantly. There was a strong correlation between the neck dosimeter and lens dosimeter scores, although there was no significant change before and after the lens dose limit was lowered. This correlation was particularly strong for physicians who primarily treated patients. As such, it is possible to infer accurate lens doses from neck doses in physicians who primarily perform diagnostics. However, it is desirable to use a dosimeter that can directly measure Hp(3) because of the high lens dose.

Quantile regression for longitudinal data with values below the limit of detection and time-dependent covariates-application to modeling carbon nanotube and nanofiber exposures.

BACKGROUND: In studies of occupational health, longitudinal environmental exposure, and biomonitoring data are often subject to right skewing and left censoring, in which measurements fall below the limit of detection (LOD). To address right-skewed data, it is common practice to log-transform the data and model the geometric mean, assuming a log-normal distribution. However, if the transformed data do not follow a known distribution, modeling the mean of exposure may result in bias and reduce efficiency. In addition, when examining longitudinal data, it is possible that certain covariates may vary over time. OBJECTIVE: To develop predictive quantile regression models to resolve the issues of left censoring and time-dependent covariates and to quantitatively evaluate if previous and current covariates can predict current and/or future exposure levels. METHODS: To address these gaps, we suggested incorporating different substitution approaches into quantile regression and utilizing a method for selecting a working type of time dependency for covariates. RESULTS: In a simulation study, we demonstrated that, under different types of time-dependent covariates, the approach of multiple random value imputation outperformed the other approaches. We also applied our methods to a carbon nanotube and nanofiber exposure study. The dependent variables are the left-censored mass of elemental carbon at both the respirable and inhalable aerosol size fractions. In this study, we identified some potential time-dependent covariates with respect to worker-level determinants and job tasks. CONCLUSION: Time dependency for covariates is rarely accounted for when analyzing longitudinal environmental exposure and biomonitoring data with values less than the LOD through predictive modeling. Mistreating the time-dependency as time-independency will lead to an efficiency loss of regression parameter estimation. Therefore, we addressed time-varying covariates in longitudinal exposure and biomonitoring data with left-censored measurements and illustrated an entire conditional distribution through different quantiles.

An activatable NIR turn-on fluorescent probe for copper (II) ion and live cell imaging.

Herein we have reported a fluorescent probe (MB-M) based on MB derivative for Cu2+ ions detection. The probe was well characterized by 1H NMR, 13C NMR and HR-MS spectrum. Probe MB-M showed naked-eyes recognition to Cu2+ as color change from colorless to indigo. The probe exhibited promising features such as high fluorescence and UV-vis selectivity, fast response (5 mint), workable at pH 2-7, and low limit of detection (LOD = 0.33 µM). Probe MB-M was also used for Cu2+ ions imaging in HepG-2 cells and detection in daily life (Test Strip and lake water). Moreover, non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis were used to study the interaction between MB-M and Cu2+ ions. By examining the electronic characteristics of the complex using natural bond orbital (NBO), electron density difference (EDD), and frontier molecular orbital (FMO) analysis, the sensitivity of MB-M towards Cu2+ ions were investigated. The results illustrated that the interactions between MB-M and Cu2+ ions involved chemisorption.

The LOD paradox: When lower isn't always better in biosensor research and development.

Biosensor research has long focused on achieving the lowest possible Limits of Detection (LOD), driving significant advances in sensitivity and opening up new possibilities in analysis. However, this intense focus on low LODs may not always meet the practical needs or suit the actual uses of these devices. While technological improvements are impressive, they can sometimes overlook important factors such as detection range, ease of use, and market readiness, which are vital for biosensors to be effective in real-world applications. This review advocates for a balanced approach to biosensor development, emphasizing the need to align technological advancements with practical utility. We delve into various applications, including the detection of cancer biomarkers, pathology-related biomarkers, and illicit drugs, illustrating the critical role of LOD within these contexts. By considering clinical needs and broader design aspects like cost-effectiveness, sustainability, and regulatory compliance, we argue that integrating technical progress with practicality will enhance the impact of biosensors. Such an approach ensures that biosensors are not only technically sound but also widely useable and beneficial in real-world applications. Addressing the diverse analytical parameters alongside user expectations and market demands will likely maximize the real-world impact of biosensors.

Comparison of EV characterization by commercial high-sensitivity flow cytometers and a custom single-molecule flow cytometer.

High-sensitivity flow cytometers have been developed for multi-parameter characterization of single extracellular vesicles (EVs), but performance varies among instruments and calibration methods. Here we compare the characterization of identical (split) EV samples derived from human colorectal cancer (DiFi) cells by three high-sensitivity flow cytometers, two commercial instruments, CytoFLEX/CellStream, and a custom single-molecule flow cytometer (SMFC). DiFi EVs were stained with the membrane dye di-8-ANEPPS and with PE-conjugated anti-EGFR or anti-tetraspanin (CD9/CD63/CD81) antibodies for estimation of EV size and surface protein copy numbers. The limits of detection (LODs) for immunofluorescence and vesicle size based on calibration using cross-calibrated, hard-dyed beads were ∼10 PE/∼80 nm EV diameter for CytoFLEX and ∼10 PEs/∼67 nm for CellStream. For the SMFC, the LOD for immunofluorescence was 1 PE and ≤ 35 nm for size. The population of EVs detected by each system (di-8-ANEPPS+/PE+ particles) differed widely depending on the LOD of the system; for example, CellStream/CytoFLEX detected only 5.7% and 1.5% of the tetraspanin-labelled EVs detected by SMFC, respectively, and median EV diameter and antibody copy numbers were much larger for CellStream/CytoFLEX than for SMFC as measured and validated using super-resolution/single-molecule TIRF microscopy. To obtain a dataset representing a common EV population analysed by all three platforms, we filtered out SMFC and CellStream measurements for EVs below the CytoFLEX LODs as determined by bead calibration (10 PE/80 nm). The inter-platform agreement using this filtered dataset was significantly better than for the unfiltered dataset, but even better concordance between results was obtained by applying higher cutoffs (21 PE/120 nm) determined by threshold analysis using the SMFC data. The results demonstrate the impact of specifying LODs to define the EV population analysed on inter-instrument reproducibility in EV flow cytometry studies, and the utility of threshold analysis of SMFC data for providing semi-quantitative LOD values for other flow cytometers.

A potential toxicological risk assessment of heavy metals and pesticides in irrigated rice cultivars near industrial areas of Dhaka, Bangladesh.

Rice intake represents a significant pathway through which humans accumulate heavy metals. This study presents a comprehensive analysis of heavy metal and pesticide contamination in rice cultivars irrigated with industrial wastewater near Dhaka, Bangladesh, a region heavily influenced by industrial activities. This study employed a unique methodology that not only quantified the concentrations of heavy metals and pesticide residues in rice grains but also extended to evaluating the physicochemical properties of rice stems, husks, soil, and irrigation water. The findings revealed alarmingly high levels of heavy metals such as lead, cadmium, chromium, nickel, and mercury in the soil and irrigation water, with concentrations in some cases exceeding the World Health Organization safety thresholds by 2 to 15 times. Notably, the rice grains also exhibited significant contamination, including substantial amounts of diazinon and fenitrothion pesticides, exceeding the established safety limits. The study employed hazard quotients (HQs) and cancer risk (CR) assessments to evaluate the potential health risks associated with the consumption of contaminated rice. The results indicated HQ values were greater than 1 for rice grains across the sampled fields, suggesting a considerable non-carcinogenic health risk, particularly from lead exposure, which was found at levels twice the standard limit in all the sampling fields. Moreover, the CR values for As, Pb, Cd, Co, and Mn highlighted a significant carcinogenic risk in several instances.

Detection and quantification of Brucella abortus DNA in water buffaloes (bubalus bubalis) using droplet digital polymerase chain reaction.

Brucellosis represents a major public health concern worldwide. Human transmission is mainly due to the consumption of unpasteurized milk and dairy products of infected animals. The gold standard for the diagnosis of Brucella spp in ruminants is the bacterial isolation, but it is time-consuming. Polymerase Chain Reaction (PCR) is a quicker and more sensitive technique than bacterial culture. Droplet digital PCR (ddPCR) is a novel molecular assay showing high sensitivity in samples with low amount of DNA and lower susceptibility to amplification inhibitors. Present study aimed to develop a ddPCR protocol for the detection of Brucella abortus in buffalo tissue samples. The protocol was validated using proficiency test samples for Brucella spp by real time qPCR. Furthermore, 599 tissue samples were examined. Among reference materials, qPCR and ddPCR demonstrated same performance and were able to detect up to 225 CFU/mL. Among field samples, ddPCR showed higher sensitivity (100%), specificity and accuracy of 93.4% and 94.15%, respectively. ddPCR could be considered a promising technique to detect B. abortus in veterinary specimens, frequently characterized by low amount of bacteria, high diversity in matrices and species and poor storage conditions.

Nested PCR effective to detect low viral loads of SARS-CoV-2 in animal samples.

SARS-CoV-2 emerged from an animal source and was then transmitted to humans, causing the COVID-19 pandemic. Since a wide range of animals are susceptible to SARS-CoV-2 infection, the zoonotic potential of SARS-CoV-2 increases with every new animal infected. The molecular gold standard assay for SARS-CoV-2 detection is real-time RT-PCR, where the Ct obtained is proportional to the amount of nucleic acid and can be a semi-quantitative measure of the viral load. However, since the use of real-time RT-PCR assays in animal samples is low due to the high costs, the use of validated nested PCR assays will help to monitor large-scale animal samplings, by reducing the costs of detection. In the present study, 140 samples from dogs and cats (15 SARS-CoV-2-positive samples with Ct values from 27 to 33, and 125 negative samples), previously analyzed by real-time RT-PCR, were analyzed by nested PCR. To increase the number of positive samples to determine the sensitivity of the assay, 40 human samples obtained during COVID-19 diagnosis in 2020 were included. The specificity of the primers was analyzed against samples positive to canine coronavirus (CCV) and feline infectious peritonitis virus (FIPV). To calculate the limit of detection (LoD) of the nested PCR, the viral load was estimated extrapolating the Ct value obtained by real-time RT-PCR. The Ct values obtained were considered as semi-quantitative and were able to distinguish between high, moderate and low viral loads. The Kappa value or "agreement" between assays and reliability of the nested PCR were also determined. Eleven of the animal samples analyzed by nested PCR targeting the N gene were detected as positive, while 129 were detected as negative to the virus, with Ct values ranging between17 and 31.5. All the samples from humans analyzed by nested PCR were positive. These results indicate that the assay has a sensitivity of near 95 % and a specificity of 100 %. No unspecific reactions analyzed by nested PCR were observed with the samples positive to CCV and FIPV. The samples detected as positive to SARS-CoV-2 by nested PCR were those that presented a Ct between17 and 31.5. The LoD of the nested PCR was estimated close to 50 copies/µL of viral load, corresponding with a Ct of 31.5. The Kappa value between assays was excellent (k = 0.829). The results obtained demonstrate that nested PCR is useful to detect SARS-CoV-2 low viral loads at a lower cost than with real-time RT-PCR.

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope.

The Boltzmann Tyranny, set by thermionic statistics, dictates the lower limit of switching slope (SS) of a MOSFET to be 60 mV/dec, the fundamental barrier for low-dissipative electronics. The large SS leads to nonscalable voltage, significant leakage, and power consumption, particularly at short channels, making transistor scaling an intimidating challenge. In recent decades, an array of steep-slope transistors has been proposed; none is close to an ideal switch with ultimately abrupt switching (SS ∼ 0 mV/dec) between the binary logic states. We demonstrated an all-2D-materials van-der-Waals-heterostructure (vdW)-based FET that exhibits ultrasteep switching (0.33 mV/dec), a large on/off current ratio (∼107), and an ultralow off current (∼0.1 pA). The "Subthreshold-Free" operation achieved by the collective behavior of functional materials enables FET switching directly from the OFF-state to the ON-state with entirely eliminated subthreshold region, behaving as the ideal logic switch. Two-inch wafer-scale device fabrication is demonstrated. Boosted by device innovation and emerging materials, the research presents an advancement in achieving the "beyond-Boltzmann" transistors, overcoming one of the CMOS electronics' most infamous technology barriers that have plagued the research community for decades.

The heat is on: Thermoregulatory and evaporative cooling patterns of desert-dwelling bats.

For small endotherms inhabiting desert ecosystems, defending body temperatures (Tb) is challenging as they contend with extremely high ambient temperatures (Ta) and limited standing water. In the arid zone, bats may thermoconform whereby Tb varies with Ta, or may evaporatively cool themselves to maintain Tb < Ta. We used an integrative approach that combined both temperature telemetry and flow through respirometry to investigate the ecological and physiological strategies of lesser long-eared bats (Nyctophilus geoffroyi) in Australia's arid zone. We predicted individuals would exhibit desert-adapted thermoregulatory patterns (i.e., thermoconform to prioritise water conservation), and that females would be more conservative with their water reserves for evaporative cooling compared to males. Temperature telemetry data indicated that free-ranging N. geoffroyi were heterothermic (Tskin = 18.9-44.9 °C) during summer and thermoconformed over a wide range of temperatures, likely to conserve water and energy during the day. Experimentally, at high Tas, females maintained significantly lower Tb and resting metabolic rates, despite lower evaporative water loss (EWL) rates compared to males. Females only increased EWL at experimental Ta = 42.5 °C, significantly higher than males (40.7 °C), and higher than any bat species yet recorded. During the hottest day of this study, our estimates suggest the water required for evaporative cooling ranged from 18.3% (females) and 25.5% (males) of body mass. However, if we extrapolate these results to a recent heatwave these values increase to 36.5% and 47.3%, which are likely beyond lethal limits. It appears this population is under selective pressures to conserve water reserves and that these pressures are more pronounced in females than males. Bats in arid ecosystems are threatened by both current and future heatwaves and we recommend future conservation efforts focus on protecting current roost trees and creating artificial standing water sites near vulnerable populations.

Rapid Drug Susceptibility Testing to Preserve Antibiotics.

Antibiotic resistance is a global challenge likely to cost trillions of dollars in excess costs in the health system and more importantly, millions of lives every year. A major driver of resistance is the absence of susceptibility testing at the time a healthcare worker needs to prescribe an antimicrobial. The effect is that many prescriptions are unintentionally wasted and expose mutable organisms to antibiotics increasing the risk of resistance emerging. Often simplistic solutions are applied to this growing issue, such as a naïve drive to increase the speed of drug susceptibility testing. This puts a spotlight on a technological solution and there is a multiplicity of such candidate DST tests in development. Yet, if we do not define the necessary information and the speed at which it needs to be available in the clinical decision-making progress as well as the necessary integration into clinical pathways, then little progress will be made. In this chapter, we place the technological challenge in a clinical and systems context. Further, we will review the landscape of some promising technologies that are emerging and attempt to place them in the clinic where they will have to succeed.

Longitudinal changes in cardiovascular disease-related proteins in welders.

OBJECTIVE: Occupational exposure to welding fumes is linked to a higher risk of cardiovascular disease; however, the threshold exposure level is unknown. Here, we aimed to identify changes in proteins associated with cardiovascular disease in relation to exposure to welding fumes. METHODS: Data were obtained from two timepoints six years apart for 338 non-smoking men (171 welders, 167 controls); of these, 174 (78 welders, 96 controls) had measurements available at both timepoints. Exposure was measured as personal respirable dust (adjusted for personal protective equipment), welding years, and cumulative exposure. Proximity extension assays were used to measure a panel of 92 proteins involved in cardiovascular processes in serum samples. Linear mixed models were used for longitudinal analysis. The biological functions and diseases related to the identified proteins were explored using the Ingenuity Pathway Analysis software. RESULTS: At both timepoints, the median respirable dust exposure was 0.7 mg/m3 for the welders. Seven proteins were differentially abundant between the welders and controls and increased incrementally with respirable dust: FGF23, CEACAM8, CD40L, PGF, CXCL1, CD84, and HO1. CD84 was significant after adjusting for multiple comparisons. These proteins have been linked to disorders of blood pressure, damage related to clogged blood vessels, and chronic inflammatory disorders. CONCLUSION: Exposure to mild steel welding fumes below current occupational exposure limits for respirable particles and welding fumes in Europe and the US (1-5 mg/m3) was associated with changes in the abundance of proteins related to cardiovascular disease. Further research should evaluate the utility of these proteins as prospective biomarkers of occupational cardiovascular disease.

Double-Sided Bonding Process Enables X-ray Flat Panel Detectors.

Metal halide perovskites have demonstrated superior sensitivity, lower detection limits, stability, and exceptional photoelectric properties in comparison to existing commercially available X-ray detector materials, showing their potential for shaping the next generation of X-ray detectors. Nevertheless, significant challenges persist in the seamless integration of these materials into pixelated array sensors for large-area X-ray direct detection imaging. In this article, we propose a strategy for fabricating large-scale array devices using a double-sided bonding process. The approach involves depositing a wet film on the surface of a thin-film transistor substrate to establish a robust bond between the substrate and δ-CsPbI3 wafer via van der Waals force, thereby facilitating area-array imaging. Additionally, the freestanding polycrystalline δ-CsPbI3 wafer demonstrated a competitive ultralow detection limit of 3.46 nGyair s-1 under 50 kVP X-ray irradiation, and the δ-CsPbI3 wafer still maintains a stable signal output (signal current drift is 3.5 × 10-5 pA cm-1 s-1 V-1) under the accumulated radiation dose of 234.9 mGyair. This strategy provides a novel perspective for the industrial production of large-area X-ray flat panel detectors utilizing perovskites and their derivatives.

Lead-Free Bismuth-Based Perovskite X-ray Detector with High Sensitivity and Low Detection Limit.

Bismuth-based halide perovskites have shown great potential for direct X-ray detection, attributable to their nontoxicity and advantages in detection sensitivity and spatial resolution. However, the practical application of such materials still faces the critical challenge of combining both high sensitivity and low detection limits. Here, we report a new type of zero-dimensional (0D) perovskite (HIS)BiI5 (1, where HIS2+ = histamine) with high sensitivity and a low detection limit. Structurally, the strong N-H···I hydrogen bonds between HIS2+ cations and inorganic frameworks enhance the rigidity of the structure and diminish the intermolecular distance between adjacent inorganic [Bi2I10]4- dimers. By virtue of such structural merits, single crystal 1 exhibits excellent physical properties perpendicular to both the (001) and (010) faces. Perpendicular to the (010) face, 1 exhibited a high electrical resistivity (2.31 × 1011 Ω cm) and a large carrier mobility-lifetime product (µτ) (2.81 × 10-4 cm2 V-1) under X-ray illumination. Benefiting from these superior physical properties, it demonstrates an excellent X-ray detection capability with a sensitivity of approximately 103 µC Gyair-1 cm-2 and a detection limit of 36 nGyair s-1 in both directions perpendicular to the (001) and (010) crystal faces. These results provide a promising candidate material for the development of new, lead-free, high-performance X-ray detectors.

Biological invasion with a porous medium type diffusion in a heterogeneous space.

The knowledge of traveling wave solutions is the main tool in the study of wave propagation. However, in a spatially heterogeneous environment, traveling wave solutions do not exist, and a different approach is needed. In this paper, we study the generation and the propagation of hyperbolic scale singular limits of a KPP-type reaction-diffusion equation when the carrying capacity is spatially heterogeneous and the diffusion is of a porous medium equation type. We show that the interface propagation speed varies according to the carrying capacity.

Fully Printed Negative-Capacitance Field-Effect Transistors with Ultralow Subthreshold Swing and High Inverter Signal Gain.

The switching of conventional field-effect transistors (FETs) is limited by the Boltzmann barrier of thermionic emission, which prevents the realization of low-power electronics. In order to overcome this limitation, among others, unconventional device geometry with a ferroelectric/dielectric insulator stack has been proposed to demonstrate stable negative-capacitance behavior. Here, the switching of the ferroelectric layer behaves like a step-up amplifier and results in a body factor less than 1. This implies a larger change in the semiconductor surface potential compared to the applied gate voltage variation. The transistors with such ferroelectric/dielectric stack are known as negative-capacitance field-effect transistors (nc-FETs), and can demonstrate a subthreshold slope lower than the Boltzmann's limit (60 mV/decade). While nc-FETs have typically been realized with high-vacuum-deposition processes, here we show fully printed nc-FETs with amorphous indium-gallium-zinc oxide (a-IGZO) as the semiconductor material, Al2O3 as the dielectric, and poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) as the polymer ferroelectric. The printed nc-FETs demonstrate an extremely low subthreshold slope of ∼2.3 mV/decade at room temperature, which remains below the Boltzmann's limit for over 5 orders of magnitude of drain currents. Furthermore, the unipolar depletion-load-type inverters fabricated using n-type nc-FETs have demonstrated an extraordinary signal gain of 2691.

Data on the saturation behaviour of the 63-90 µm quartz from the Carpathian Basin.

This dataset offers valuable insights into the luminescence saturation behaviour of 63-90 µm quartz grains sourced from the Carpathian Basin, as examined under controlled laboratory conditions. Its significance lies not only in shedding light on the luminescence properties specific to this region but also in facilitating comparative analyses with quartz samples from other geographic areas. Moreover, the dataset contributes novel findings to the ongoing investigations concerning the upper dating limit of quartz grains, which holds implications for refining luminescence dating methodologies. Grounded in the framework of several previous studies which underscore the challenges associated with utilizing quartz from certain regions for precise dose measurements, the dataset addresses the crucial aspect of setting upper dose limits for accurate luminescence dating. Consequently, the study conducts a series of tests to assess the proximity of natural sensitivity-corrected luminescence signals to laboratory saturation levels, particularly focusing on quartz samples from the Kisiljevo loess-palaeosol sequence. The dataset includes data from OSL saturation experiments conducted on sample 23019, along with associated calculations encompassing all 19 collected samples. This comprehensive dataset serves as a valuable resource for researchers and practitioners engaged in luminescence dating studies, offering detailed insights into saturation behaviours and dose-response characteristics of quartz grains from the Carpathian Basin. Beyond its immediate research implications, the dataset holds significant potential for reuse in various contexts. Researchers exploring luminescence properties of geological materials, particularly quartz grains, can leverage this dataset to compare saturation behaviours across different regions, thus enriching our understanding of luminescence dating methodologies on a broader scale. Additionally, the dataset could inform future studies on refining dose limits and calibration protocols, ultimately enhancing the accuracy and reliability of luminescence dating techniques. In summary, this dataset not only advances our understanding of luminescence saturation behaviours in quartz grains from the Carpathian Basin but also fosters collaborative research efforts aimed at refining luminescence dating methodologies and addressing broader questions in geochronology and palaeoenvironmental studies.

Metal-Organic Framework-Derived Au-Doped In2O3 Nanotubes for Monitoring CO at the ppb Level.

Achieving selective detection of ppb-level CO is important for air quality testing at industrial sites to ensure personal safety. Noble metal doping enhances charge transfer, which in turn reduces the detection limit of metal oxide gas sensors. In this work, metal-organic framework-derived Au-doped In2O3 nanotubes with high electrical conductivity are synthesized by pyrolysis of the Au-doped metal-organic framework (In-MIL-68) as a template. Gas-sensing experiments reveal that the detection limit of 0.2% Au-doped In2O3 nanotubes (0.2% Au, mass fraction) is as low as 750 ppb. Meanwhile, the sensing material shows a response value of 18.2 to 50 ppm of CO at 240 °C, which is about 2.8 times higher than that of pure In2O3. Meanwhile, the response and recovery times are short (37 s/86 s). The gas-sensing mechanism of CO is uncovered by in situ DRIFTS through the reaction intermediates. In addition, first-principles calculations suggest that Au doping of In2O3 significantly enhances its adsorption energy for CO and improves the electron transfer properties. This study reveals a novel synthesis pathway for Au-doped In2O3 nanotubular structures and their potential application in low concentration CO detection.

Nonrelativistic Limit of Generalized MIT Bag Models and Spectral Inequalities.

For a family of self-adjoint Dirac operators - i c ( α · ∇ ) + c 2 2 subject to generalized MIT bag boundary conditions on domains in R 3 , it is shown that the nonrelativistic limit in the norm resolvent sense is the Dirichlet Laplacian. This allows to transfer spectral geometry results for Dirichlet Laplacians to Dirac operators for large c.

Nano-Photonic Crystal D-Shaped Fiber Devices for Label-Free Biosensing at the Attomolar Limit of Detection.

Maintaining both high sensitivity and large figure of merit (FoM) is crucial in regard to the performance of optical devices, particularly when they are intended for use as biosensors with extremely low limit of detection (LoD). Here, a stack of nano-assembled layers in the form of 1D photonic crystal, deposited on D-shaped single-mode fibers, is created to meet these criteria, resulting in the generation of Bloch surface wave resonances. The increase in the contrast between high and low refractive index (RI) nano-layers, along with the reduction of losses, enables not only to achieve high sensitivity, but also a narrowed resonance bandwidth, leading to a significant enhancement in the FoM. Preliminary testing for bulk RI sensitivity is carried out, and the effect of an additional nano-layer that mimics a biological layer where binding interactions occur is also considered. Finally, the biosensing capability is assessed by detecting immunoglobulin G in serum at very low concentrations, and a record LoD of 70 aM is achieved. An optical fiber biosensor that is capable of attaining extraordinarily low LoD in the attomolar range is not only a remarkable technical outcome, but can also be envisaged as a powerful tool for early diagnosis of diseases.