Nanoelectrochemistry reveals how soluble Aß42 oligomers alter vesicular storage and release of glutamate.

Glutamate (Glu) is the major excitatory transmitter in the nervous system. Impairment of its vesicular release by ß-amyloid (Aß) oligomers is thought to participate in pathological processes leading to Alzheimer's disease. However, it remains unclear whether soluble Aß42 oligomers affect intravesicular amounts of Glu or their release in the brain, or both. Measurements made in this work on single Glu varicosities with an amperometric nanowire Glu biosensor revealed that soluble Aß42 oligomers first caused a dramatic increase in vesicular Glu storage and stimulation-induced release, accompanied by a high level of parallel spontaneous exocytosis, ultimately resulting in the depletion of intravesicular Glu content and greatly reduced release. Molecular biology tools and mouse models of Aß amyloidosis have further established that the transient hyperexcitation observed during the primary pathological stage is mediated by an altered behavior of VGLUT1 responsible for transporting Glu into synaptic vesicles. Thereafter, an overexpression of Vps10p-tail-interactor-1a, a protein that maintains spontaneous release of neurotransmitters by selective interaction with t-SNAREs, resulted in a depletion of intravesicular Glu content, triggering advanced-stage neuronal malfunction. These findings are expected to open perspectives for remediating Aß42-induced neuronal hyperactivity and neuronal degeneration.

Calibration-free, high-precision, and robust terahertz ultrafast metasurfaces for monitoring gastric cancers.

Optical sensors, with great potential to convert invisible bioanalytical response into readable information, have been envisioned as a powerful platform for biological analysis and early diagnosis of diseases. However, the current extraction of sensing data is basically processed via a series of complicated and time-consuming calibrations between samples and reference, which inevitably introduce extra measurement errors and potentially annihilate small intrinsic responses. Here, we have proposed and experimentally demonstrated a calibration-free sensor for achieving high-precision biosensing detection, based on an optically controlled terahertz (THz) ultrafast metasurface. Photoexcitation of the silicon bridge enables the resonant frequency shifting from 1.385 to 0.825 THz and reaches the maximal phase variation up to 50° at 1.11 THz. The typical environmental measurement errors are completely eliminated in theory by normalizing the Fourier-transformed transmission spectra between ultrashort time delays of 37 ps, resulting in an extremely robust sensing device for monitoring the cancerous process of gastric cells. We believe that our calibration-free sensors with high precision and robust advantages can extend their implementation to study ultrafast biological dynamics and may inspire considerable innovations in the field of medical devices with nondestructive detection.

Parental methylome reprogramming in human uniparental blastocysts reveals germline memory transition.

Uniparental embryos derived from only the mother (gynogenetic [GG]) or the father (androgenetic [AG]) are unique models for studying genomic imprinting and parental contributions to embryonic development. Human parthenogenetic embryos can be obtained following artificial activation of unfertilized oocytes, but the production of AG embryos by injection of two sperm into one denucleated oocyte leads to an extra centriole, resulting in multipolar spindles, abnormal cell division, and developmental defects. Here, we improved androgenote production by transferring the male pronucleus from one zygote into another haploid androgenote to prevent extra centrioles and successfully generated human diploid AG embryos capable of developing into blastocysts with an identifiable inner cell mass (ICM) and trophectoderm (TE). The GG embryos were also generated. The zygotic genome was successfully activated in both the AG and GG embryos. DNA methylome analysis showed that the GG blastocysts partially retain the oocyte transcription-dependent methylation pattern, whereas the AG blastocyst methylome showed more extensive demethylation. The methylation states of most known imprinted differentially methylated regions (DMRs) were recapitulated in the AG and GG blastocysts. Novel candidate imprinted DMRs were also identified. The production of uniparental human embryos followed by transcriptome and methylome analysis is valuable for identifying parental contributions and epigenome memory transitions during early human development.

Experimental Demonstration of Controllable PT and Anti-PT Coupling in a Non-Hermitian Metamaterial.

Non-Hermiticity has recently emerged as a rapidly developing field due to its exotic characteristics related to open systems, where the dissipation plays a critical role. In the presence of balanced energy gain and loss with environment, the system exhibits parity-time (PT) symmetry, meanwhile as the conjugate counterpart, anti-PT symmetry can be achieved with dissipative coupling within the system. Here, we demonstrate the coherence of complex dissipative coupling can control the transition between PT and anti-PT symmetry in an electromagnetic metamaterial. Notably, the achievement of the anti-PT symmetric phase is independent of variations in dissipation. Furthermore, we observe phase transitions as the system crosses exceptional points in both anti-PT and PT symmetric metamaterial configurations, achieved by manipulating the frequency and dissipation of resonators. This work provides a promising metamaterial design for broader exploration of non-Hermitian physics and practical application with a controllable Hamiltonian.

Mechanical Strain Induces and Increases Vesicular Release Monitored by Microfabricated Stretchable Electrodes.

Exocytosis involving the fusion of intracellular vesicles with cell membrane, is thought to be modulated by the mechanical cues in the microenvironment. Single-cell electrochemistry can offer unique information about the quantification and kinetics of exocytotic events; however, the effects of mechanical force on vesicular release have been poorly explored. Herein, we developed a stretchable microelectrode with excellent electrochemical stability under mechanical deformation by microfabrication of functionalized poly(3,4-ethylenedioxythiophene) conductive ink, which achieved real-time quantitation of strain-induced vesicular exocytosis from a single cell for the first time. We found that mechanical strain could cause calcium influx via the activation of Piezo1 channels in chromaffin cell, initiating the vesicular exocytosis process. Interestingly, mechanical strain increases the amount of catecholamines released by accelerating the opening and prolonging the closing of fusion pore during exocytosis. This work is expected to provide revealing insights into the regulatory effects of mechanical stimuli on vesicular exocytosis.

In vivo flow cytometry reveals an anti-metastatic effect of Rujifang in triple-negative breast cancer.

Breast cancer is the most common cancer, and triple-negative breast cancer (TNBC) has the highest metastasis and mortality rate among all breast cancer subtypes. Rujifang is a traditional Chinese medicine formula with many years of clinical application in breast cancer treatment. Here, we aim to investigate the effects of Rujifang on circulating tumor cell (CTC) dynamics and the tumor microenvironment in a ZsGreen/luciferase double-labeled TNBC orthotopic model. We report that the number of CTCs monitored by in vivo flow cytometry (IVFC) strongly correlates with disease progression. Rujifang treatment decreased the number of CTCs and suppressed the distant metastasis of TNBC. Moreover, immunofluorescence analysis revealed that Rujifang treatment could affect the tumor microenvironment by downregulating Kindlin-1, which has been reported to promote metastasis of TNBC. Our study provides evidence of the anti-metastatic effect of Rujifang against TNBC in an animal model using fluorescent cell lines. The results suggest the potential therapeutic value of Rujifang as an anti-metastatic drug, however, further clinical trials are needed to validate these findings in humans.

Effective protection: the embryonic development and clinical outcomes of emergency vitrification of 1246 oocytes and Day 0-Day 5 embryos in a natural disaster.

STUDY QUESTION: Can emergency vitrification protect embryos and oocytes during natural disasters or other events that prevent normal practice to achieve satisfactory embryonic development and clinical outcomes at a later time? SUMMARY ANSWER: Emergency vitrification of oocytes and Day 0-Day 5 (D0-D5) embryos during disasters is a safe and effective protective measure. WHAT IS KNOWN ALREADY: When some destructive events such as floods, earthquakes, tsunamis, and other accidents occur, emergency vitrification in embryo laboratories to protect human embryos, oocytes, and sperm is one of the important measures of an IVF emergency plan. However, there are few detailed reports on emergency vitrification in a state of disaster, especially about oocytes and D0 zygotes. Therefore, the effectiveness and safety of emergency vitrification of oocytes and D0-D5 embryos in disaster states are still unclear. STUDY DESIGN, SIZE, DURATION: A retrospective study was made in the Reproductive Medicine Center of the First Affiliated Hospital of Zhengzhou University from January 2018 to November 2022. The record rainstorms in Zhengzhou, China, caused severe flooding, traffic disruptions, and power outages. From 17:30, 20 July 2021 to 17:30, 21 July 2021, 1246 oocytes and D0-D5 embryos of 155 patients were vitrified whilst the laboratory had only an emergency power supply. PARTICIPANTS/MATERIALS, SETTING, METHODS: As of 21 December 2021, 1149 emergency vitrified oocytes and D0-D5 embryos of 124 patients underwent frozen-thawed embryo transfer (FET). They were divided into the following four groups according to the days of embryo culture in vitro: oocyte group, Day 0-Day 1 (D0-D1) group, Day 2-Day 3 (D2-D3) group, and Day 4-Day 5 (D4-D5) group. Control groups for each were selected from fresh cycle patients who underwent IVF/ICSI from January 2018 to October 2021. Control and emergency vitrification patients were matched on criteria that included age, fertilization method, days of embryonic development, and number and grade of transferred embryos. A total of 493 control patients were randomly selected from the eligible patients and matched with the emergency vitrification groups in a ratio of 4:1. The results of assisted reproduction and follow-up of pregnancy were analyzed. The embryonic development, clinical outcomes, and birth outcomes in each group were statistically analyzed. MAIN RESULTS AND THE ROLE OF CHANCE: A significant difference was observed in fertilization rate (81% versus 72%, P = 0.022) between the oocyte group and the control group. Significant differences were also observed in the monozygotic twin pregnancy rate (10% versus 0%, P = 0.038) and ectopic pregnancy rate (5% versus 0%, P = 0.039) between the D0-D1 group and the control group. No significant differences (P > 0.05) were observed between vitrified oocytes/D0-D1 embryos/D2-D3 embryos and the control group on the number of high-quality embryos (3.17 ± 3.00 versus 3.84 ± 3.01, P = 0.346; 5.04 ± 3.66 versus 4.56 ± 2.87, P = 0.346; 4.85 ± 5.36 versus 5.04 ± 4.64, P = 0.839), the number of usable blastocysts (1.22 ± 1.78 versus 1.21 ± 2.03, P = 0.981; 2.16 ± 2.26 versus 1.55 ± 2.08, P = 0.090; 2.82 ± 3.23 versus 2.58 ± 3.32, P = 0.706), clinical pregnancy rate (56% versus 57%, P = 0.915; 55% versus 55%, P = 1.000; 40% versus 50%, P = 0.488), miscarriage rate (30% versus 15%, P = 0.496; 5% versus 11%, P = 0.678; 17% versus 20%, P = 1.000), and live birth rate (39% versus 49%, P = 0.460; 53% versus 50%, P = 0.772; 33% versus 40%, P = 0.635). No significant differences (P > 0.05) were observed between the D4-D5 group and the control group on clinical pregnancy rate (40% versus 55%, P = 0.645), miscarriage rate (0% versus 18%, P = 1.000), and live birth rate (40% versus 45%, P = 1.000). LIMITATIONS, REASONS FOR CAUTION: The retrospective study design is a limitation. The timing and extent of natural disasters are unpredictable, so the sample size of vitrified oocytes, zygotes, and embryos is beyond experimental control. WIDER IMPLICATIONS OF THE FINDINGS: This study is the first study analyzing embryonic development, clinical outcomes, and birth outcomes of large samples of oocytes, D0 zygotes, and D1-D5 embryos after emergency vitrification under the disaster conditions. The results show that emergency vitrification is a safe and effective protective measure applicable to oocytes and D0-D5 embryos. The embryology laboratories need to be equipped with an emergency uninterrupted power supply capable of delivering for 6-8 h at full load. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (grant 81871206). The authors declare that they have no conflicts of interest. All authors have completed the ICMJE Disclosure form. TRIAL REGISTRATION NUMBER: N/A.

Random projection ensemble classification with high-dimensional time series.

Multivariate time-series (MTS) data are prevalent in diverse domains and often high dimensional. We propose new random projection ensemble classifiers with high-dimensional MTS. The method first applies dimension reduction in the time domain via randomly projecting the time-series variables into some low-dimensional space, followed by measuring the disparity via some novel base classifier between the data and the candidate generating processes in the projected space. Our contributions are twofold: (i) We derive optimal weighted majority voting schemes for pooling information from the base classifiers for multiclass classification and (ii) we introduce new base frequency-domain classifiers based on Whittle likelihood (WL), Kullback-Leibler (KL) divergence, eigen-distance (ED), and Chernoff (CH) divergence. Both simulations for binary and multiclass problems, and an Electroencephalogram (EEG) application demonstrate the efficacy of the proposed methods in constructing accurate classifiers with high-dimensional MTS.

Development of Child-Friendly Lisdexamfetamine Chewable Tablets Using Ion Exchange Resin as a Taste-Masking Carrier Based on the Concept of Quality by Design (QbD).

Taste masking is critical to improving the compliance of pediatric oral dosage forms. However, it is challenging for extremely bitter lisdexamfetamine dimesylate (LDX) with a long half-life and given in large dose. The present study aims to develop an immediate-release, taste-masked lisdexamfetamine chewable tablet. Lisdexamfetamine-resin complexes (LRCs) were prepared using the batch method. The molecular mechanism of taste masking was explored by PXRD, PLM, STA, and FT-IR. The results showed that taste masking was attributed to the ionic interaction between drug and the resin. The ion exchange process conformed to first-order kinetics. The rate-limiting step of drug release was the diffusion of ions inside the particles, and the concentration of H+ was the key factor for immediate release. The masking efficiency of the prepared LRCs in saliva exceeded 96%, and the drug could be completely released within 15 min in aqueous HCl (pH 1.2). Furthermore, the SeDeM expert system was used for the first time to comprehensively study the powder properties of LRCs and to quickly visualize their defects (compressibility, lubricity/stability, and lubricity/dosage). The selection of excipients was targeted rather than traditional screening, thus obtaining a robust chewable tablet formulation suitable for direct compression. Finally, the difference between chewable tablets containing LRCs and chewable tablets containing lisdexamfetamine dimesylate was compared by in vitro dissolution test, electronic tongue, and disintegration test. In conclusion, an immediate-released, child-friendly lisdexamfetamine chewable tablets without bitterness was successfully developed by the QbD approach, using the SeDeM system, which may help in further development of chewable tablets.

[Chromosomal aneuploidy and pregnancy outcomes for D5/D6 blastocysts from patients undergoing PGT-A treatment].

OBJECTIVE: To compare the prevalence of chromosomal aneuploidies and pregnancy outcomes of D5 and D6 blastocysts subjected to preimplantation genetic testing for aneuploidy (PGT-A). METHODS: Clinical and laboratory data of 268 couples who underwent PGT-A at the Reproductive Center of the First Affiliated Hospital of Zhengzhou University from September 2018 to September 2020 were collected. The prevalence of chromosomal aneuploidies and pregnancy outcomes of D5/D6 biopsied blastocysts were compared. RESULTS: Compared with D6 blastocysts, the euploidy rate of D5 blastocysts was significantly higher (49.1% vs. 41.1%, P = 0.001 1), whilst their aneuploidy rate was significantly lower (50.9% vs. 58.9%, P = 0.001 1). The rate of numerical abnormalities of D6 blastocysts was significantly higher than that of D5 blastocysts (27.9% vs. 20.2%, P = 0.000 5). For patients under 35 years old, the euploidy rate of D5 blastocysts was significantly higher than that of D6 blastocysts (53.8% vs. 44.3%, P = 0.001), whilst the numerical abnormality rate was significantly lower (16.3% vs. 23.9%, P = 0.001). For both D5 and D6 blastocysts, the euploidy rates for patients <= 35 were significantly higher than those for > 35. The elder group had the lowest rates for aneuploidies and live births. Compared with those receiving D6 blastocysts transplantation, the pregnancy rate, implantation rate and live birth rate for those receiving thawed D5 blastocysts transplantation were significantly higher (60.2% vs.37.0%, P = 0.000 3; 59.1% vs.37.0%, P = 0.000 6; 47.7% vs. 28.3%, P = 0.002). CONCLUSION: For patients undergoing PGT-A, the chromosomal euploidy rate for D5 blastocysts is higher than that for D6 blastocysts, and the clinical outcome of D5 blastocysts with normal signal is better than that of D6 blastocysts. Elder patients have a higher rate of aneuploidies.

Homeostasis inside Single Activated Phagolysosomes: Quantitative and Selective Measurements of Submillisecond Dynamics of Reactive Oxygen and Nitrogen Species Production with a Nanoelectrochemical Sensor.

Reactive oxygen and nitrogen species (ROS/RNS) are generated by macrophages inside their phagolysosomes. This production is essential for phagocytosis of damaged cells and pathogens, i.e., protecting the organism and maintaining immune homeostasis. The ability to quantitatively and individually monitor the four primary ROS/RNS (ONOO-, H2O2, NO, and NO2-) with submillisecond resolution is clearly warranted to elucidate the still unclear mechanisms of their rapid generation and to track their concentration variations over time inside phagolysosomes, in particular, to document the origin of ROS/RNS homeostasis during phagocytosis. A novel nanowire electrode has been specifically developed for this purpose. It consisted of wrapping a SiC nanowire with a mat of 3 nm platinum nanoparticles whose high electrocatalytic performances allow the characterization and individual measurements of each of the four primary ROS/RNS. This allowed, for the first time, a quantitative, selective, and statistically robust determination of the individual amounts of ROS/RNS present in single dormant phagolysosomes. Additionally, the submillisecond resolution of the nanosensor allowed confirmation and measurement of the rapid ability of phagolysosomes to differentially mobilize their enzyme pools of NADPH oxidases and inducible nitric oxide synthases to finely regulate their homeostasis. This reveals an essential key to immune responses and immunotherapies and rationalizes its biomolecular origin.

Monitoring radiofrequency therapy-induced tumor cell dissemination by in vivo flow cytometry.

Clinical and experimental findings have disclosed a high recurrence rate after radiofrequency ablation (RFA), which might be due to the dissemination of malignant cells into the vasculature during ablation. Here, we apply in vivo flow cytometry (IVFC) to monitor circulating tumor cells (CTCs) while performing ablation in a real-time and noninvasive way in an orthotopic model of prostate cancer. We report that CTCs are dramatically increased during RFA. The CTCs induced by ablation eventually translate into enhanced distant metastasis and reduced survival as compared to resection. Immunofluorescence analysis reveals that RFA significantly increases the infiltration of tumor-associated macrophages (TAMs) in the lung. Our study thus suggests that the ablative procedure of prostate tumors causes immediate tumor cell dissemination and increases distant metastasis.

Lower chromosomal abnormality frequencies in miscarried conceptuses from frozen blastocyst transfers in ART.

STUDY QUESTION: Are blastocyst culture and cryopreservation in ART associated with chromosomal abnormalities in miscarried products of conception (POC)? SUMMARY ANSWER: Frozen blastocyst transfer in women aged 35 years or older and frozen embryo transfer (ET) (including both cleavage-stage embryo and blastocyst) in women aged <35 years are associated with decreased frequencies of embryonic chromosomal abnormalities in miscarried POC. WHAT IS KNOWN ALREADY: Blastocyst culture and embryo cryopreservation have been previously associated with favorable ART treatment outcomes and widely applied in clinical practice. However, the association between these embryo manipulation procedures and embryonic chromosomal abnormalities has not been evaluated to the best of our knowledge. STUDY DESIGN, SIZE, DURATION: This retrospective study included a total of 720 patients who underwent IVF/ICSI, and the retained POC were obtained. A single-nucleotide polymorphism (SNP)-based chromosomal microarray analysis (CMA) of all miscarried conceptuses was performed. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study was based on the Clinical Reproductive Medicine Management System/Electronic Medical Record Cohort Database (CCRM/EMRCD) at our center. In total, 720 miscarried POCs were collected from patients undergoing ART (including fresh cleavage-stage ET, fresh blastocyst transfer, frozen cleavage-stage ET and frozen blastocyst transfer), and the incidences and profiles of cytogenetic abnormalities in the miscarried conceptuses were measured via SNP-based CMA. MAIN RESULTS AND THE ROLE OF CHANCE: The chromosomal abnormality rate in POC varied from 33.7% to 66.7% among the different ET strategies. In the patients aged ≥35 years, frozen blastocyst transfer was significantly associated with a lower incidence of chromosomal aberrations in the POCs (adjusted odds ratio (aOR): 0.171 (95% CI: 0.040-0.738); P = 0.018) than fresh blastocyst transfer. In the patients aged <35 years, frozen ET was significantly associated with a lower incidence of chromosomal aberrations than fresh ET in both cleavage-stage ET cycles and blastocyst transfers cycles (aOR: 0.545 (0.338-0.879), P = 0.013; and aOR: 0.357 (0.175-0.730), P = 0.005, respectively). Trisomy was the most frequent abnormal embryonic karyotype in the different ET strategies, and its frequency significantly differed among strategies (P < 0.05). LIMITATIONS, REASONS FOR CAUTION: This study was retrospectively designed, and we cannot draw any definite conclusions from our results regarding the adequate safety of embryo cryopreservation in ongoing pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is the first study assessing the associations of ET strategies with the probability of miscarriage associated with embryonic chromosomal abnormalities. However, the underlying mechanism of these associations is unknown; this study may promote research concerning ET strategies and promote comprehensive consultations and recommendations for patients. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Natural Science Foundation of China (Grant No.81571409), Science and Technology Research Project of Henan (Grant No. 172102310009) and Medical Science and Technology Research Project of Henan (Grant No. 201701005). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

In Vivo Flow Cytometry.

In vivo flow cytometry (IVFC) was first designed to detect circulating cells in a mouse ear. It allows real-time monitoring of cells in peripheral blood with no need to draw blood. The IVFC field has made great progress during the last decade with the development of fluorescence, photoacoustic, and multiphoton microscopy. Moreover, the application of IVFC is no longer restricted to circulating cells. IVFC based on fluorescence and photoacoustic are most widely applied in biomedical research. Methods based on fluorescence are often used for object monitoring in superficial vessels, while methods based on photoacoustics have an advantage of label-free monitoring in deep vessels. In this chapter, we introduce technical points and key applications of IVFC. We focus on the principles, labeling strategies, sensitivity, and biomedical applications of the technology. In addition, we summarize this chapter and discuss important research directions of IVFC in the future.

The Study of Dynamic Modeling and Multivariable Feedback Control for Flexible Manipulators with Friction Effect and Terminal Load.

The flexible manipulato is widely used in the aerospace industry and various other special fields. Control accuracy is affected by the flexibility, joint friction, and terminal load. Therefore, this paper establishes a robot dynamics model under the coupling effect of flexibility, friction, and terminal load, and analyzes and studies its control. First of all, taking the structure of the central rigid body, the flexible beam, and load as the research object, the dynamic model of a flexible manipulator with terminal load is established by using the hypothesis mode and the Lagrange method. Based on the balance principle of the force and moment, the friction under the influence of flexibility and load is recalculated, and the dynamic model of the manipulator is further improved. Secondly, the coupled dynamic system is decomposed and the controller is designed by the multivariable feedback controller. Finally, using MATLAB as the simulation platform, the feasibility of dynamic simulation is verified through simulation comparison. The results show that the vibration amplitude can be reduced with the increase of friction coefficient. As the load increases, the vibration can increase further. The trajectory tracking and vibration suppression of the manipulator are effective under the control method of multi-feedback moment calculation. The research is of great significance to the control of flexible robots under the influence of multiple factors.

Effect of Packaging Materials and the Leached Iron on the Stability of Butorphanol Tartrate Injection.

The aim of this study was to investigate the effect of various parameters on the stability of butorphanol tartrate injection and to screen the optimal packaging material. The effect of the headspace oxygen levels, ampoule color, manufacturer, and size on the stability of butorphanol tartrate formulation were evaluated. The headspace oxygen levels controlled by nitrogen purging were found to be particularly effective in improving stability of the butorphanol formulation, especially below 2%. Although it is a photolabile drug, butorphanol tartrate was getting degraded at much higher extent in amber color ampoules in comparison to clear ampoules. The degradation by oxidation was found to be a free radical-mediated process catalyzed by the presence of iron ions leached from the amber ampoules. The ampoule manufacturers also had a significant effect on the stability of butorphanol. Two-milliliter ampoules provided a better stability of the butorphanol tartrate injection than 1mL ampoules as 2-mL ampoules had the lower headspace oxygen level at the same level of oxygen content. The oxidation mechanism of the butorphanol tartrate injection was investigated under various conditions, which include iron powder spiking, removal of excipients, exposure to oxygen/nitrogen, exposure to stainless steel and at different pH. Iron powder spiking, presence of citric acid, exposure to oxygen, exposure to stainless steel, and high pH accelerated the oxidative degradation. The effect of oxygen, iron ion and citric acid is in agreement with a metal-catalyzed oxidation mechanism called Udenfriend reaction. Based on the formulation test results, limiting headspace oxygen level, ampoule color, manufacturer, size, controlling iron ion contamination, and pH are recommended for formulation development. In conclusion, it can be suggested that this study can lead to a better understanding of the degradation mechanism of butorphanol tartrate; hence, it would contribute to the development of butorphanol tartrate injection with improved stability. Virous packaging materials have different effects on the stability of butorphanol tartrate injection, and the leached iron of packaging ampoules and stainless steel can trigger Udenfriend reaction with butorphanol tartrate and citric acid (CA), which lead to the oxydative degradation of butorphanol tartrate injection.

[Nucleosides-based identification model for Fritillariae Cirrhosae Bulbus].

A high performance liquid chromatography( HPLC) method was established for the fast,and precise determination of ten nucleosides in Fritillariae Cirrhosae Bulbus and its counterfeits. Then multivariate statistical analyses,such as clustering analysis,principal component analysis( PCA),and Fisher' s linear discriminant analysis( LDA),were conducted to establish a discriminant function model for an integrated analysis. The results indicated that data acquisition time of a single sample was shortened within 16 min by the HPLC method. In the range of 5-1 000 mg·kg~(-1),the mass concentrations of all nucleosides exhibited good linear relationships with the corresponding peak areas( R2> 0. 999). The spiked recoveries were in the range of 93. 83%-108. 9% with RSDs of0. 12%-1. 3%( n = 5). The limit of quantitation( LOQ) was 0. 98-4. 13 mg·kg~(-1). As revealed by the clustering analysis,Fritillariae Cirrhosae Bulbus and the counterfeits could be discriminated into two clusters based on the content of nucleosides. Fisher's LDA could achieve this discrimination,while PCA dimension reduction failed. The accuracy of the discriminant function model established on the screened characteristic indicators reached 97. 5%. The present study proposed a new identification method of Fritillariae Cirrhosae Bulbus with one-dimensional indicators,which is simple,accurate,and reliable. It can provide a scientific basis for further optimizing the identification techniques for Fritillariae Cirrhosae Bulbus and inspiration for quality control strategy development of Chinese medicinal materials.

Quantitative Nano-amperometric Measurement of Intravesicular Glutamate Content and its Sub-Quantal Release by Living Neurons.

Quantitative measurements of intravesicular glutamate (Glu) and of transient exocytotic release contents directly from individual living neurons are highly desired for understanding the mechanisms (full or sub-quantal release?) of synaptic transmission and plasticity. However, this could not be achieved so far due to the lack of adequate experimental strategies relying on selective and sensitive Glu nanosensors. Herein, we introduce a novel electrochemical Glu nanobiosensor based on a single SiC nanowire that can selectively measure in real-time Glu fluxes released via exocytosis by large Glu vesicles (ca. 125 nm diameter) present in single hippocampal axonal varicosities as well as their intravesicular content before exocytosis. These measurements revealed a sub-quantal release mode in living hippocampal neurons, viz., only ca. one third to one half of intravesicular Glu molecules are released by individual vesicles during exocytotic events. Importantly, this fraction remained practically the same when hippocampal neurons were pretreated with L-Glu-precursor L-glutamine, while it significantly increased after zinc treatment, although in both cases the intravesicular contents were drastically affected.

EIA metamaterials based on hybrid metal/dielectric structures with dark-mode-enhanced absorption.

Metamaterial analogue of electromagnetically induced absorption (EIA) has promising applications in spectroscopy and sensing. Here we propose an EIA metamaterial based on hybrid metal/dielectric structures, which are composed of a metallic wire and a dielectric block, and investigate the EIA-like effect by simulations, experiments, and the two-oscillator model. An EIA-like effect emerges in virtue of the near-field coupling between metallic wire and dielectric block, and the dielectric block exhibiting magnetic dipolar resonance makes a major contribution to the resonance absorption. The magnetic flux through the dielectric block engendered by the near filed of the metallic wire determines the coupling between dielectric block and metallic wire. With the variation of the separation between dielectric block and metallic wire, the EIA-like effect is preserved and does not convert into the EIT-like effect although the coupling and consequently the absorbance are altered. Based on the two-oscillator model, the absorption spectrum of the EIA metamaterial is quantitatively analyzed and the parameters of the oscillator system are retrieved.

Process for (S)-Ketamine and (S)-Norketamine via Resolution Combined with Racemization.

A concise, recyclable, and efficient process is presented for the preparation of (S)-ketamine (esketamine, (S)-1a) via classic resolution combined with the recycling of the undesired isomer. With commercially available ketone 2 as the starting material, this procedure features three steps including (1) an unique hydroxylation-ring expansion rearrangement, (2) mild amination via methanesulfonate, and (3) chiral separation using L-(+)-tartaric acid. The three simple steps are all performed in mild conditions and (S)-1a tartrate is obtained in 99.5% ee without recrystallization. Subsequently, racemization of the unwanted (R)-1a remained in resolution mother liquor was performed in the presence of a Lewis acid in quantitative yield with >99.0% chemical purity. This original and economical process afforded esketamine in 67.4% (28.9% without racemization) overall yield with two times recycling of the mother liquor without column purification. In addition, this procedure can also be applied to the preparation of (S)-norketamine, which is a safer potential antidepressant.