Effects of single unilaterally impacted mesiodens on maxillary central incisors: A 3D quantitative assessment based on cone-beam computed tomography.

BACKGROUND: Mesiodens usually lead to the malposition and abnormal morphology of maxillary central incisors. AIM: To evaluate the detrimental effects of single unilaterally impacted mesiodens on the three-dimensional positions and morphology of the maxillary central incisor using cone-beam computed tomographic (CBCT) examinations. DESIGN: A total of 321 patients aged 5-17 years with single unilaterally impacted mesiodens were included and divided into two groups: mixed dentition group (5-10 years) and early permanent dentition group (11-17 years). CBCT data for these patients were retrospectively analyzed to compare the inclination, rotation, angulation, and morphology of maxillary central incisors between the affected and contralateral control sides. The morphology, orientation, and spatial location of mesiodens were also assessed. RESULTS: Central incisors on the affected side showed significant palatal crown inclination, shorter root, shorter tooth, and greater crown-to-root ratio in both groups, whereas significant mesial crown angulation was only observed in the mixed dentition group. CONCLUSION: Impacted mesiodentes result in the displacement and impaired root development of central incisors, strongly suggesting timely clinical management of these abnormal teeth, such as the early removal of mesiodens and orthodontic treatments.

Fully automated deep learning model for detecting proximity of mandibular third molar root to inferior alveolar canal using panoramic radiographs.

OBJECTIVE: This study endeavored to develop a novel, fully automated deep-learning model to determine the topographic relationship between mandibular third molar (MM3) roots and the inferior alveolar canal (IAC) using panoramic radiographs (PRs). STUDY DESIGN: A total of 1570 eligible subjects with MM3s who had paired PR and cone beam computed tomography (CBCT) from January 2019 to December 2020 were retrospectively collected and randomly grouped into training (80%), validation (10%), and testing (10%) cohorts. The spatial relationship of MM3/IAC was assessed by CBCT and set as the ground truth. MM3-IACnet, a modified deep learning network based on YOLOv5 (You only look once), was trained to detect MM3/IAC proximity using PR. Its diagnostic performance was further compared with dentists, AlexNet, GoogleNet, VGG-16, ResNet-50, and YOLOv5 in another independent cohort with 100 high-risk MM3 defined as root overlapping with IAC on PR. RESULTS: The MM3-IACnet performed best in predicting the MM3/IAC proximity, as evidenced by the highest accuracy (0.885), precision (0.899), area under the curve value (0.95), and minimal time-spending compared with other models. Moreover, our MM3-IACnet outperformed other models in MM3/IAC risk prediction in high-risk cases. CONCLUSION: MM3-IACnet model can assist clinicians in MM3s risk assessment and treatment planning by detecting MM3/IAC topographic relationship using PR.

Impact of shale gas wastewater discharge on the trace elements of the receiving river in the Sichuan Basin, China.

The potential contamination of shale gas wastewater generated from hydraulic fracturing to water resources is of growing concern, yet minimum attention has been paid to the impact of shale gas wastewater on the trace elements of the receiving waters. In this study, we analyzed the levels of 50 trace elements of a river that receives effluent from a shale gas wastewater treatment facility in the Sichuan Basin, China. Sixteen trace elements were detected in the surface water sample from the effluent discharge site, all of which were of higher concentrations than the upstream background level. Among the 16 shale gas wastewater-related elements, Sr, Ba, and Li were of elevated levels in the downstream water samples (24.9-44.2%, 5.0-8.0 times, and 17.8-22.8 times higher than the upstream background level, respectively). Shale gas wastewater effluent may be related to the accumulation of Sr, Ba, Li, and Cs in riverbed sediments near and/or downstream of the effluent discharge site and may lead to elevated pollution level of Sr and Li in downstream sediments. The ecological risk of the riverbed sediments was of medium to high level, with Cd contributing to the most risk, while shale gas wastewater-related elements are of low potential risk throughout the river. Our results suggested that shale gas wastewater effluent discharge had limited impacts on the trace elements of the receiving river within two years.

Simple and active magnetic-field stabilization for cold atom experiments.

Cold atom experiments usually need a controllable and low-noise bias magnetic field to provide a quantization axis. Most labs need home-made stabilization of the field according to the actual setup, as commercially available power supply cannot directly satisfy their requirements. Here, by measuring the field fluctuations and active feedback modulating current supply of the applied magnetic field, we successfully demonstrate a field of 10.58 G with a stability to the level of 2.8 × 10-7 in a duration of 5 min. The root mean square noise is reduced to 0.05 mG, compared to the noise of 1.3 mG without stabilization. The coherence time of the magnetic-field sensitive transition between the rubidium ground states F=1,mF=-1 and 1,0, as measured by Rabi oscillation, is extended to 19.2 ms from the unstabilized value of 1.3 ms. This result is long enough for most experiments on quantum simulation and precision measurement. As our system has no passive magnetic shielding and additional compensation coils, it is highly simple and compact to provide the stable magnetic field and would be adapted to various applications with cold atoms.

Detection and Quantitation of Adulterated Paprika Samples Using Second-Order HPLC-FLD Fingerprints and Chemometrics.

Paprika is a widely consumed spice in the world and its authentication has gained interest considering the increase in adulteration cases in recent years. In this study, second-order fingerprints acquired by liquid chromatography with fluorescence detection (HPLC-FLD) were first used to detect and quantify adulteration levels of Chinese paprika samples. Six different adulteration cases, involving paprika production region, cultivar, or both, were investigated by pairs. Two strategies were employed to reduce the data matrices: (1) chromatographic fingerprints collected at specific wavelengths and (2) fusion of the mean data profiles in both spectral and time dimensions. Afterward, the fingerprint data with different data orders were analyzed using partial least squares (PLS) and n-way partial least squares (N-PLS) regression models, respectively. For most adulteration cases, N-PLS based on second-order fingerprints provided the overall best quantitation results with cross-validation and prediction errors lower than 2.27% and 20.28%, respectively, for external validation sets with 15-85% adulteration levels. To conclude, second-order HPLC-FLD fingerprints coupled with chemometrics can be a promising screening technique to assess paprika quality and authenticity in the control and prevention of food frauds.

Testing Real Quantum Theory in an Optical Quantum Network.

Quantum theory is commonly formulated in complex Hilbert spaces. However, the question of whether complex numbers need to be given a fundamental role in the theory has been debated since its pioneering days. Recently it has been shown that tests in the spirit of a Bell inequality can reveal quantum predictions in entanglement swapping scenarios that cannot be modeled by the natural real-number analog of standard quantum theory. Here, we tailor such tests for implementation in state-of-the-art photonic systems. We experimentally demonstrate quantum correlations in a network of three parties and two independent EPR sources that violate the constraints of real quantum theory by over 4.5 standard deviations, hence disproving real quantum theory as a universal physical theory.

Bimodal Fluorescence/Magnetic Resonance Molecular Probes with Extended Spin Lifetimes.

Bimodal molecular probes combining nuclear magnetic resonance (NMR) and fluorescence have been widely studied in basic science, as well as clinical research. The investigation of spin phenomena holds promise to broaden the scope of available probes allowing deeper insights into physiological processes. Herein, a class of molecules with a bimodal character with respect to fluorescence and nuclear spin singlet states is introduced. Singlet states are NMR silent but can be probed indirectly. Symmetric, perdeuterated molecules, in which the singlet states can be populated by vanishingly small electron-mediated couplings (below 1 Hz) are reported. The lifetimes of these states are an order of magnitude longer than the longitudinal relaxation times and up to four minutes at 7 T. Moreover, these molecules show either aggregation induced emission (AIE) or aggregation caused quenching (ACQ) with respect to their fluorescence. In the latter case, the existence of excited dimers, which are proposed to use in a switchable manner in combination with the quenching of nuclear spin singlet states, is observed.

Parahydrogen-Induced Polarization in Hydrogenation Reactions Mediated by a Metal-Free Catalyst.

We report nuclear spin hyperpolarization of various alkenes achieved in alkyne hydrogenations with parahydrogen over a metal-free hydroborane catalyst (HCAT). Being an intramolecular frustrated Lewis pair aminoborane, HCAT utilizes a non-pairwise mechanism of H2 transfer to alkynes that normally prevents parahydrogen-induced polarization (PHIP) from being observed. Nevertheless, the specific spin dynamics in catalytic intermediates leads to the hyperpolarization of predominantly one hydrogen in alkene. PHIP enabled the detection of important HCAT-alkyne-H2 intermediates through substantial 1 H, 11 B and 15 N signal enhancement and allowed advanced characterization of the catalytic process.

Exotic nuclear spin behavior in dendritic macromolecules.

Dendrimers are a class of branched, highly symmetric macromolecules that have been shown to be useful for a vast number of different applications. Potential uses as fluorescence sensors, in catalysis and perhaps most importantly in medical applications as drug delivery systems or cytotoxica have been proposed. Herein we report on an exotic behaviour of the nuclear spins in a dendritic macromolecule in the presence of different paramagnetic ions. We show that the stability of the long lived nuclear singlet state, is affected by the presence of Cu(II), whereas other ions did not have any influence at all. This effect could not be observed in the case of a simple tripeptide, in which the nuclear singlet stability was influenced by all investigated paramagnetic ions, a potentially useful effect in the development of Cu(II) selective probes. By adding a fluorescent marker to our molecule we could show that the nuclear singlet multimer (NUSIMER) is taken up by living cells. Furthermore we were able to show that nuclear singlet state NMR can be used to investigate the NUSIMER in the presence of living cells, showing that an application in in vivo NMR can be feasible.

Cavity-Enhanced Atom-Photon Entanglement with Subsecond Lifetime.

A cold atomic ensemble suits well for optical quantum memories, and its entanglement with a single photon forms the building block for quantum networks that give promise for many revolutionary applications. Efficiency and lifetime are among the most important figures of merit for a memory. In this Letter, we report the realization of entanglement between an atomic ensemble and a single photon with subsecond lifetime and high efficiency. We engineer dual control modes in a ring cavity to create entanglement and make use of three-dimensional optical lattice to prolong memory lifetime. The memory efficiency is 38% for 0.1 s storage. We verify the atom-photon entanglement after 1 s storage by testing the Bell inequality with a result of S=2.36±0.14.

E-cadherin Plays a Role in Hepatitis B Virus Entry Through Affecting Glycosylated Sodium-Taurocholate Cotransporting Polypeptide Distribution.

Hepatitis B virus (HBV) infection is a major cause of chronic liver disease and hepatocellular carcinoma. Current antiviral therapy does not effectively eradicate HBV and further investigations into the mechanisms of viral infection are needed to enable the development of new therapeutic agents. The sodium-taurocholate cotransporting polypeptide (NTCP) has been identified as a functional receptor for HBV entry in liver cells. However, the NTCP receptor is not sufficient for entry and other membrane proteins contribute to modulate HBV entry. This study seeks to understand how the NTCP functions in HBV entry. Herein we show that knockdown of the cell-cell adhesion molecule, E-cadherin significantly reduced infection by HBV particles and entry by HBV pseudoparticles in infected liver cells and cell lines. The glycosylated NTCP localizes to the plasma membrane through interaction with E- cadherin, which increases interaction with the preS1 portion of the Large HBV surface antigen. Our study contributes novel insights that advance knowledge of HBV infection at the level of host cell binding and viral entry.

Nuclear Spin Singlet States in Photoactive Molecules: From Fluorescence/NMR Bimodality to a Bimolecular Switch for Spin Singlet States.

Nuclear spin singlet states are silent states in nuclear magnetic resonance (NMR). However, they can be probed indirectly and offer great potential for the development of contrast agents for magnetic resonance imaging (MRI). Introduced here are two novel concepts: Firstly, the bimodal NMR/fluorescence properties of 13 C2 -tetraphenylethylene. It possesses a long-lived singlet state in organic solvents, and it shortens upon the addition of water. This simultaneously increases the aggregation-induced emission (AIE) of the molecule, resulting in a substantial enhancement of fluorescence. Secondly, introduced is a bimolecular switch for singlet states based on 3-2 H-coumarin containing an isolated proton. Upon UV-light exposure, a dimer forms, leading to a coupling between two previously isolated protons. A nuclear spin singlet state can now be populated. Excitation with a wavelength of 254 nm results in partial ring cleavage of the molecule back to its monomer.

Magnetic-enhanced modulation transfer spectroscopy and laser locking for 87Rb repump transition.

Locking of a laser frequency to an atomic or molecular resonance line is a key technique in applications of laser spectroscopy and atomic metrology. Modulation transfer spectroscopy (MTS) provides an accurate and stable laser locking method which has been widely used. Normally, the frequency of the MTS signal would drift due to Zeeman shift of the atomic levels and rigorous shielding of stray magnetic field around the vapor cell is required for the accuracy and stability of laser locking. Here on the contrary, by applying a transverse bias magnetic field, we report for the first time observation of a magnetic-enhanced MTS signal on the transition of 87Rb D2-line Fg = 1→ Fe = 0 (close to the repump transition of Fg = 1→ Fe = 2), with signal to noise ratio larger than 100:1. The error signal is immune to the external magnetic fluctuation. Compared to the ordinary MTS scheme, it provides a robust and accurate laser locking approach with more stable long-term performance. This technique can be conveniently applied in areas of laser frequency stabilization, laser manipulation of atoms and precision measurement.

Development of a near-infrared fluorescent sensor with a large Stokes shift for sensing pyrophosphate in living cells and animals.

The detection of pyrophosphate (PPi) in living systems has attracted considerable attention in recent years due to its biological significance. While many fluorescent PPi sensors were developed with emission changes in the visible region, near-infrared (NIR) fluorescent sensors for PPi are rather scarce. In this paper, a dicyanomethylene-benzopyran (DCMB) based phenol-bridged dinuclear Zn(II)-DPA (DPA: dipicolylamine) complex was prepared, which was found to be a promising NIR fluorescent sensor for PPi. This sensor features a remarkable large Stokes shift (>150 nm) and shows colorimetric and NIR fluorescence changes for PPi with high selectivity and sensitivity in 100% aqueous solution. The detection limit of this sensor for PPi was determined to be as low as 42 nM. In addition, this sensor exhibits low cytotoxicity and can be conveniently employed for bioimaging PPi in living cells and animals, indicating it has great potential for in vitro and in vivo detection of PPi.

Pulsed Magnetic Resonance to Signal-Enhance Metabolites within Seconds by utilizing para-Hydrogen.

Diseases such as Alzheimer's and cancer have been linked to metabolic dysfunctions, and further understanding of metabolic pathways raises hope to develop cures for such diseases. To broaden the knowledge of metabolisms in vitro and in vivo, methods are desirable for direct probing of metabolic function. Here, we are introducing a pulsed nuclear magnetic resonance (NMR) approach to generate hyperpolarized metabolites within seconds, which act as metabolism probes. Hyperpolarization represents a magnetic resonance technique to enhance signals by over 10 000-fold. We accomplished an efficient metabolite hyperpolarization by developing an isotopic labeling strategy for generating precursors containing a favorable nuclear spin system to add para-hydrogen and convert its two-spin longitudinal order into enhanced metabolite signals. The transfer is performed by an invented NMR experiment and 20 000-fold signal enhancements are achieved. Our technique provides a fast way of generating hyperpolarized metabolites by using para-hydrogen directly in a high magnetic field without the need for field cycling.

Detection and differentiation of Cys, Hcy and GSH mixtures by 19F NMR probe.

Simultaneous detection and differentiation of biomolecules is of significance in biological research. Biothiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play an important role in regulating the vital functions of living organisms. However, existing methods for simultaneous detection and differentiation of Cys, Hcy, and GSH are still challenging because of their similarity in structure and chemical properties. Herein we report a probe that simultaneously detects and discriminates between mixtures of Cys, Hcy and GSH using 19F nuclear magnetic resonance (NMR). This 19F NMR probe responds rapidly to biothiols through the Michael addition reaction and subsequent intramolecular cyclization reaction allowing differentiation between Cys, Hcy and GSH through 19F NMR chemical shift. We demonstrate that this 19F NMR probe is a powerful method for analysis of complex mixtures.

Hyperpolarized 129 Xe Magnetic Resonance Imaging Sensor for H2 S.

A new magnetic resonance imaging (MRI) molecular sensor for hydrogen sulfide detection and imaging using the nuclear spin resonance of hyperpolarized 129 Xe is developed. The designed MRI sensor employs cryptophane for NMR sensing, together with an azide group serving as a reaction site. It demonstrates a "proof-of-concept" that a fluorescent H2 S probe can be linked to a xenon-binding cryptophane and thereby converted into an MRI probe, which could provide a very generalizable template.

Hong-Ou-Mandel Interference between Two Deterministic Collective Excitations in an Atomic Ensemble.

We demonstrate deterministic generation of two distinct collective excitations in one atomic ensemble, and we realize the Hong-Ou-Mandel interference between them. Using Rydberg blockade we create single collective excitations in two different Zeeman levels, and we use stimulated Raman transitions to perform a beam-splitter operation between the excited atomic modes. By converting the atomic excitations into photons, the two-excitation interference is measured by photon coincidence detection with a visibility of 0.89(6). The Hong-Ou-Mandel interference witnesses an entangled NOON state of the collective atomic excitations, and we demonstrate its two times enhanced sensitivity to a magnetic field compared with a single excitation. Our work implements a minimal instance of boson sampling and paves the way for further multimode and multiexcitation studies with collective excitations of atomic ensembles.

[NaHS inhibits A549 cell injury induced by lipopolysaccharide].

OBJECTIVE: To observe the effect of NaHS on lipopolysaccharide (LPS)-induced injury of A549 lung cancer cells and explore the possible mechanisms. METHODS: A549 cells were divided into 4 groups: control group, 10 µg/mL LPS treated group, 10 µmol/L NaHS treated group and the group treated with 10 µg/mL LPS plus 10 µmol/L NaHS. After treatment for 24 hours, C-reactive protein (CRP) content in culture solution was measured by ELISA, and the cell viability was detected by MTT assay and lactate dehydrogenase (LDH) assay. Transepithelial electrical resistance (TER) was evaluated by EVOM resistance meter, and the expression and distribution of zonula occludens-1 (ZO-1) protein was examined by immunofluorescence cytochemistry. RESULTS: There were no significant differences in CRP content, TER, cell viability, the expression and distribution of ZO-1 between the control group and the NaHS group. Compared with the control group, CRP content distinctly increased, TER, cell viability and ZO-1 expression markedly decreased, and ZO-1 distribution was disrupted in the LPS group. Compared with the LPS group, CRP level was distinctly reduced, TER, cell viability and ZO-1 expression were raised, and the disrupted ZO-1 distribution was partly reversed in the LPS plus NaHS treated group. CONCLUSION: NaHS can inhibit A549 cell injury induced by LPS via increasing cell viability, TER and the expression of ZO-1 as well as decreasing CRP level.

Biothiol Xenon MRI Sensor Based on Thiol-Addition Reaction.

Biothiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play an important role in regulating the vital functions of living organisms. Knowledge of their biodistribution in real-time could help diagnose a variety of conditions. However, existing methods of biothiol detection are invasive and require assays. Herein we report a molecular biosensor for biothiol detection using the nuclear spin resonance of (129)Xe. The (129)Xe biosensor consists of a cryptophane cage encapsulating a xenon atom and an acrylate group. The latter serves as a reactive site to covalently bond biothiols through a thiol-addition reaction. The biosensor enables discrimination of Cys from Hcy and GSH through the chemical shift and average reaction rate. This biosensor can be detected at a concentration of 10 µM in a single scan and it has been applied to detect biothiols in bovine serum solution. Our results indicate that this biosensor is a promising tool for the real-time imaging of biothiol distributions.