Elimination of Chlorella using peracetic acid activated by dielectric barrier discharge plasma: Mechanism and cell deactivation process.

Excessive proliferation of algae in water depletes dissolved oxygen, resulting in the demise of aquatic life and environmental damage. This study delves into the effectiveness of the dielectric barrier discharge (DBD) plasma activated peracetic acid (PAA) system in deactivating Chlorella. Within 15 min, the algae removal effectiveness reached 89 % under ideal trial conditions. DBD plasma activation of PAA augmented the concentration of reactive species such as ·OH, 1O2, and organic radicals (RO·) in the solution, which are involved in the process of cell inactivation. Reactive oxygen species (ROS) within Chlorella cells continued to rise as a result of treatment-induced damage to the morphological structure and cell membrane of the organism. DNA and chlorophyll-a (Chl-a), were oxidized and destroyed by these invasive active compounds. This study presents an efficient advanced oxidation method to destroy algal cells and adds an alternative strategy for algal control in areas where eutrophication occurs.

Exploiting synthetic biology platforms for enhanced biosynthesis of natural products in Yarrowia lipolytica.

With the rapid development of synthetic biology, researchers can design, modify, or even synthesize microorganisms de novo, and microorganisms endowed with unnatural functions can be considered "artificial life" and facilitate the development of functional products. Based on this concept, researchers can solve critical problems related to the insufficient supply of natural products, such as low yields, long production cycles, and cumbersome procedures. Due to its superior performance and unique physiological and biochemical characteristics, Yarrowia lipolytica is a favorable chassis cell used for green biomanufacturing by numerous researchers. This paper mainly reviews the development of synthetic biology techniques for Y. lipolytica and summarizes the recent research progress on the synthesis of natural products in Y. lipolytica. This review will promote the continued innovative development of Y. lipolytica by providing theoretical guidance for research on the biosynthesis of natural products.

Polymer Implantable Electrode Foundry: A shared resource for manufacturing polymer-based microelectrodes for neural interfaces.

Large scale monitoring of neural activity at the single unit level can be achieved via electrophysiological recording using implanted microelectrodes. While neuroscience researchers have widely employed chronically implanted electrode-based interfaces for this purpose, a commonly encountered limitation is loss of highly resolved signals arising from immunological response over time. Next generation electrode-based interfaces improve longitudinal signal quality using the strategy of stabilizing the device-tissue interface with microelectrode arrays constructed from soft and flexible polymer materials. The limited availability of such polymer microelectrode arrays has restricted access to a small number of researchers able to build their own custom devices or who have developed specific collaborations with engineering researchers who can produce them. Here, a new technology resource model is introduced that seeks to widely increase access to polymer microelectrode arrays by the neuroscience research community. The Polymer Implantable Electrode (PIE) Foundry provides custom and standardized polymer microelectrode arrays as well as training and guidance on best-practices for implantation and chronic experiments.

Dyslexia-related loci are significantly associated with language and literacy in Chinese-English bilingual Hong Kong Chinese twins.

A recent genome-wide association study on dyslexia in 51,800 affected European adults and 1,087,070 controls detected 42 genome-wide significant single nucleotide variants (SNPs). The association between rs2624839 in SEMA3F and reading fluency was replicated in a Chinese cohort. This study explores the genetic overlap between Chinese and English word reading, vocabulary knowledge and spelling, and aims at replicating the association in a unique cohort of bilingual (Chinese-English) Hong Kong Chinese twins. Our result showed an almost complete genetic overlap in vocabulary knowledge (r2 = 0.995), and some genetic overlaps in word reading and spelling (r2 = 0.846, 0.687) across the languages. To investigate the region near rs2624839, we tested proxy SNPs (rs1005678, rs12632110 and rs12494414) at the population level (n = 305-308) and the within-twin level (n = 342-344 [171-172 twin pairs]). All the three SNPs showed significant associations with quantitative Chinese and English vocabulary knowledge (p < 0.05). The strongest association after multiple testing correction was between rs12494414 and English vocabulary knowledge at the within-twin level (p = 0.004). There was a trend of associations with word reading and spelling in English but not in Chinese. Our result suggested that the region near rs2624839 is one of the common genetic factors across English and Chinese vocabulary knowledge and unique factors of English word reading and English spelling in bilingual Chinese twins. A larger sample size is required to validate our findings. Further studies on the relationship between variable expression of SEMA3F, which is important to neurodevelopment, and language and literacy are encouraged.

Imaging the Self-Healing Dynamics of Single-Nanoparticle Electron Transfer Event Regulated by Local Electron Insertion.

The self-healing properties of nanomaterials to resist electron beam damage are of great concern, which is inspiring to improve the stability and electron transfer efficiency of nanoelectronic devices especially in an abnormal environment. However, the influence of electron beam insertion on the electron transfer efficiency of single nanoentities at a heterogeneous electrochemical interface is still in debate, which is a concern for the development of in situ liquid cell transmission electron microscopy of the next generation. Herein, we employ an electro-optical imaging technique and directly visualize the controllable recovery of electron transfer ability for single Prussian blue nanoparticle (PBNP) after electron beam insertion with different electron doses. While eliminating e-beam damage by decreasing charge accumulation, the precise control of electron insertion behaviors induces a lossless chemical reduction mechanism for metal ions on the framework structure of PBNP, which leads to static imbalance and temporarily blocks the electron transfer channels. A subsequent charge rebalance process at a sub-nanoparticle level driven by electrochemical cycling controllably rebuilds the ion migration channels on the outer layer of single PBNP to repair the electron transfer path, which is confirmed by single-nanoparticle spectral characterizations. This work provides a generic methodology to study the electron-particle interplay and mechanism of electrode materials for eliminating the heterogeneity of electrochemical activity down to a sub-nanoparticle level.

An in-depth insight into the simultaneous oxidation of sulfamethoxazole and reduction of Cr (VI) by one system of water film DBD plasma: The interaction effect, role of active species, and their dominant to pathways.

This study aims to deeply investigate the simultaneous elimination of sulfamethoxazole (SMZ) and Cr (VI) through one system of water film dielectric barrier discharge (WFDBD) plasma. The interaction effect of SMZ degradation and Cr (VI) reduction and dominant effect of active species were highlighted. Results showed that the oxidation of SMZ and the reduction of Cr (VI) directly promote each other. When the concentration of Cr (VI) raised from 0 to 2 mg L-1, the degradation rate of SMZ enhanced from 75.6% to 88.6%, respectively. Similarly, when the concentration of SMZ improved from 0 to 15 mg L-1, the removal efficiency of Cr (VI) improved from 70.8% to 84.3%, respectively. ·OH, 1O2 and ·O2- play crical roles for SMZ degradation, and e-, ·O2-, ·H and H2O2 dominated to the Cr (VI) reduction. The variations of pH, conductivity and TOC during the removal process were also explored. The removal process was studied by UV-vis spectroscopy and a three-dimensional excitation-emission matrix. Based on DFT calculation and LC-MS analysis, free radicals dominated SMZ degradation pathways in the WFDBD plasma system were clarified. Besides, the influence of Cr (VI) on SMZ degradation pathway was clarified. The ecotoxicity of SMZ and the toxicity of Cr (VI) into Cr (III) were greatly reduced. This study provides a significant reference value for the application and mechanism of plasma simultaneous removal of organic pollutants and heavy metals in wastewater.

Loss of p53 enhances the tumor-initiating potential and drug resistance of clonogenic multiple myeloma cells.

Tumor relapse and drug resistance are major factors that limit the curability of multiple myeloma (MM). New regimens have improved overall MM survival rates, but patients with high-risk features continue to have inferior outcomes. Chromosome 17p13 deletion (del17p) that includes the loss of the TP53 gene is a high-risk cytogenetic abnormality and is associated with poor clinical outcomes owing to relatively short remissions and the development of pan-drug resistant disease. Increased relapse rates suggest that del17p enhances clonogenic growth, and we found that the loss of p53 increased both the frequency and drug resistance of tumor-initiating MM cells (TICs). Subsequent RNA sequencing (RNA-seq) studies demonstrated significant activation of the Notch signaling pathway and upregulation of inhibitor of DNA binding (ID1/ID2) genes in p53-knock out (p53-KO) cells. We found that the loss of ID1 or HES-1 expression or treatment with a gamma-secretase inhibitor (GSI) significantly decreased the clonogenic growth of p53-KO but not p53 wild-type cells. GSI treatment in a small set of MM specimens also reduced the clonogenic growth in del17p samples but not in non-del17p samples. This effect was specific as overexpression of the Notch intracellular domain (NICD) rescued the effects of GSI treatment. Our study demonstrates that the Notch signaling and ID1 expression are required for TIC expansion in p53-KO MM cells. These findings also suggest that GSI may be specifically active in patients with p53 mutant MM.

A C-shaped miniaturized coil for transcranial magnetic stimulation in rodents.

Objective.Transcranial magnetic stimulation (TMS) is a non-invasive technique widely used for neuromodulation. Animal models are essential for investigating the underlying mechanisms of TMS. However, the lack of miniaturized coils hinders the TMS studies in small animals, since most commercial coils are designed for humans and thus incapable of focal stimulation in small animals. Furthermore, it is difficult to perform electrophysiological recordings at the TMS focal point using conventional coils.Approach.We designed, fabricated, and tested a novel miniaturized TMS coil (4-by-7 mm) that consisted of a C-shaped iron powder core and insulated copper wires (30 turns). The resulting magnetic and electric fields were characterized with experimental measurements and finite element modeling. The efficacy of this coil in neuromodulation was validated with electrophysiological recordings of single-unit activities (SUAs), somatosensory evoked potentials (SSEPs), and motor evoked potentials (MEPs) in rats (n= 32) following repetitive TMS (rTMS; 3 min, 10 Hz).Main results.This coil could generate a maximum magnetic field of 460 mT and an electric field of 7.2 V m-1in the rat brain according to our simulations. With subthreshold rTMS focally delivered over the sensorimotor cortex, mean firing rates of primary somatosensory and motor cortical neurons significantly increased (154±5% and 160±9% from the baseline level, respectively); MEP and SSEP amplitude significantly increased (136±9%) and decreased (74±4%), respectively.Significance.This miniaturized C-shaped coil enabled focal TMS and concurrent electrophysiological recording/stimulation at the TMS focal point. It provided a useful tool to investigate the neural responses and underlying mechanisms of TMS in small animal models. Using this paradigm, we for the first time observed distinct modulatory effects on SUAs, SSEPs, and MEPs with the same rTMS protocol in anesthetized rats. These results suggested that multiple neurobiological mechanisms in the sensorimotor pathways were differentially modulated by rTMS.

A simple synthesis method of microsphere immunochromatographic test strip for time-resolved luminescence detection of folic acid.

Folic acid (FA) is an ingredient that must be added to infant milk powder to avoid potential defects. Rapid, sensitive and reliable detection methods are needed to determined FA addition levels. Thus, this study established a microsphere immunochromatographic test strip for time-resolved luminescence detection (TRLM-ICTS) based on carboxyl-functionalized time-resolved luminescent microspheres (Eu-TRLMs) prepared by a one-step method as fluorescent markers for the immediate quantitative detection of FA in milk powder. Eu-TRLMs prepared by the one-step method showed good dispersion, high stability and strong fluorescence intensity, which is improving the sensitivity of TRLM-ICTS. In the performance evaluation of TRLM-ICTS, the detection limit was 0.487 ng mL-1, the recovery rate was 97.3-105 %, and the actual sample detection results were in line with those of UPLC-MS/MS. TRLM-ICTS has the advantages of rapid, high sensitivity and strong specificity and could as a practical quantitative detection method for the detection of FA in milk powder.

Making a case for endovascular approaches for neural recording and stimulation.

There are many electrode types for recording and stimulating neural tissue, most of which necessitate direct contact with the target tissue. These electrodes range from large, scalp electrodes which are used to non-invasively record averaged, low frequency electrical signals from large areas/volumes of the brain, to penetrating microelectrodes which are implanted directly into neural tissue and interface with one or a few neurons. With the exception of scalp electrodes (which provide very low-resolution recordings), each of these electrodes requires a highly invasive, open brain surgical procedure for implantation, which is accompanied by significant risk to the patient. To mitigate this risk, a minimally invasive endovascular approach can be used. Several types of endovascular electrodes have been developed to be delivered into the blood vessels in the brain via a standard catheterization procedure. In this review, the existing body of research on the development and application of endovascular electrodes is presented. The capabilities of each of these endovascular electrodes is compared to commonly used direct-contact electrodes to demonstrate the relative efficacy of the devices. Potential clinical applications of endovascular recording and stimulation and the advantages of endovascular versus direct-contact approaches are presented.

Subthreshold repetitive transcranial magnetic stimulation suppresses ketamine-induced poly population spikes in rat sensorimotor cortex.

Cortical oscillations within or across brain regions play fundamental roles in sensory, motor, and memory functions. It can be altered by neuromodulations such as repetitive transcranial magnetic stimulation (rTMS) and pharmacological manipulations such as ketamine. However, the neurobiological basis of the effects of rTMS and ketamine, as well as their interactions, on cortical oscillations is not understood. In this study, we developed and applied a rodent model that enabled simultaneous rTMS treatment, pharmacological manipulations, and invasive electrophysiological recordings, which is difficult in humans. Specifically, a miniaturized C-shaped coil was designed and fabricated to deliver focal subthreshold rTMS above the primary somatosensory (S1) and motor (M1) cortex in rats. Multi-electrode arrays (MEA) were implanted to record local field potentials (LFPs) and single unit activities. A novel form of synchronized activities, poly population spikes (PPS), was discovered as the biomarker of ketamine in LFPs. Brief subthreshold rTMS effectively and reversibly suppressed PPS while increasing the firing rates of single unit activities. These results suggest that ketamine and rTMS have convergent but opposing effects on cortical oscillations and circuits. This highly robust phenomenon has important implications to understanding the neurobiological mechanisms of rTMS and ketamine as well as developing new therapeutic strategies involving both neuromodulation and pharmacological agents.

Four-Component Cyclization of Naphthol/Thionaphthol/Naphthylamine, Formaldehyde, and DBU in Water.

A practical and environmentally benign cascade multicomponent condensation of naphthol/thionaphthol/naphthylamine, formaldehyde, and DBU in water without any catalysts has been achieved. A wide variety of dihydrooxazine, dihydrothiazine, and tetrahydrobenzoquinazoline derivatives N-substituted with a tether bearing a caprolactam unit were afforded in moderate to good yields. The advantages of being cost-effective, metal-free, and easily handled and the use of water as medium made this protocol conform with the principle of green synthesis.

Acute in vivo Recording with a Generic Parylene Microelectrode Array Implanted with Dip-coating Method into the Rat Brain.

Flexible polymer-based microelectrode arrays (MEAs) can reduce tissue inflammation and foreign body response and greatly prolong the lifetime of neural implants. However, standard and customized polymer devices are only accessible to limited groups. To better promote the development and application of polymer MEAs, we have launched the Polymer Implantable Electrode (PIE) Foundry and developed a 64-channel Parylene C-based MEA with generic electrodes layout that can be used to record from both cortical and sub-cortical regions in rodents. In addition, a practical dip-coating protocol for the insertion of the flexible standard Parylene MEA is developed.

Directly Imaging Dynamic Electronic Coupling during Electrochemical Oxidation of Single Silver Nanoparticles.

The electronic coupling between a metal electrode and single nano-entities is of unfading significance which impacts the heterogeneous electron transfer. Herein, we demonstrated a simple optical technique for directly imaging the transient interfacial electronic coupling events during electrochemical oxidation of single Ag nanoparticles on Au electrode. The electronic coupling brings out a dramatic dip behavior of bright field imaging traces, and is conductive to cross the energy barrier of oxidation for single silver nanoparticles. This dip behavior is further verified by in situ vis-transmission spectroscopy, and the heterogeneity of the Au-Ag electronic coupling down to single-nanoparticle level is uncovered by unifying the morphology and size of individual silver nanoparticles. These results suggest the interfacial electronic coupling facilitates electron transfer of single nanoparticles, and provide important insight into understanding detailed mechanism of nanoelectrochemistry.

Problems of the Grid Size Selection in Differential Box-Counting (DBC) Methods and an Improvement Strategy.

The differential box-counting (DBC) method is useful for determining the fractal dimension of grayscale images. It is simple to learn and implement and has been extensively utilized. However, this approach has several problems, such as over- or undercounting the number of boxes due to inappropriate parameter choices, limiting the calculation accuracy. Many studies have been conducted to increase the algorithm's computational accuracy by improving the calculating parameters of the differential box-counting method. The grid size is a crucial parameter for the DBC method. Generally, there are two typical ways for selecting the grid size in relevant studies: consecutive integer and divisors of image size. However, both methods for grid size selection are problematic. The consecutive integer method cannot partition the image entirely and will result in the undercounting of boxes; the divisors of image size can partition the image completely. However, this method uses fewer grid sizes to compute fractal dimensions and has a relatively huge distance error (DE). To address the shortcomings of the above-mentioned two approaches, this research presents an improved grid size selection strategy. The improved method enhances computational accuracy by computing the discarded image edge areas in the consecutive integer method, allowing the original image information to be used as thoroughly as the divisor strategy. Based on fractional Brownian motion (FBM), Brodatz, and Aerials image sets, the accuracy of the three grid size selection techniques (consecutive integer method, divisors of image size method, and the improved algorithm) to compute the fractal dimension is then compared. The results reveal that, compared to the two prior techniques, the revised algorithm described in this study minimizes the distance error and increases the accuracy of the fractal dimension computation.

Determining the depth of surface charging layer of single Prussian blue nanoparticles with pseudocapacitive behaviors.

Understanding the hybrid charge-storage mechanisms of pseudocapacitive nanomaterials holds promising keys to further improve the performance of energy storage devices. Based on the dependence of the light scattering intensity of single Prussian blue nanoparticles (PBNPs) on their oxidation state during sinusoidal potential modulation at varying frequencies, we present an electro-optical microscopic imaging approach to optically acquire the Faradaic electrochemical impedance spectroscopy (oEIS) of single PBNPs. Here we reveal typical pseudocapacitive behavior with hybrid charge-storage mechanisms depending on the modulation frequency. In the low-frequency range, the optical amplitude is inversely proportional to the square root of the frequency (∆I ∝ f-0.5; diffusion-limited process), while in the high-frequency range, it is inversely proportional to the frequency (∆I ∝ f-1; surface charging process). Because the geometry of single cuboid-shaped PBNPs can be precisely determined by scanning electron microscopy and atomic force microscopy, oEIS of single PBNPs allows the determination of the depth of the surface charging layer, revealing it to be ~2 unit cells regardless of the nanoparticle size.

Cu(II)-Catalyzed C-H Amidation/Cyclization of Azomethine Imines with Dioxazolones via Acyl Nitrenes: A Direct Access to Diverse 1,2,4-Triazole Derivatives.

We report a Cu(II)-catalyzed C-H amidation/cyclization of azomethine imines with dioxazolones as acyl nitrene transfer reagents under additive- and ligand-free conditions. An array of 1,2,4-triazolo[1,5-a]pyridine derivatives were afforded in moderate to good yields with excellent functional group tolerance. In addition, scale-up reaction and photoluminescence properties were discussed.

Low Intensity Repetitive Transcranial Magnetic Stimulation Modulates Spontaneous Spiking Activities in Rat Cortex.

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique for neuromodulation. Even at low intensities, rTMS can alter the structure and function of neural circuits; yet the underlying mechanism remains unclear. Here we report a new experimental paradigm for studying the effect of low intensity rTMS (LI-rTMS) on single neuron spiking activities in the sensorimotor cortex of anesthetized rats. We designed, built, and tested a miniaturized TMS coil for use on small animals such as rats. The induced electric field in different 3D locations was measured along different directions using a dipole probe. A maximum electric field strength of 2.3 V/m was achieved. LI-rTMS (10 Hz, 3 min) was delivered to the rat primary motor and somatosensory cortices. Single-unit activities were recorded before and after LI-rTMS. Results showed that LI-rTMS increased the spontaneous firing rates of primary motor and somatosensory cortical neurons. Diverse modulatory patterns were observed in different neurons. These results indicated the feasibility of using miniaturized coil in rodents as an experimental platform for evaluating the effect of LI-rTMS on the brain and developing therapeutic strategies for treating neurological disorders.

Tracking the optical mass centroid of single electroactive nanoparticles reveals the electrochemically inactive zone.

The inevitable microstructural defects, including cracks, grain boundaries and cavities, make a portion of the material inaccessible to electrons and ions, becoming the incentives for electrochemically inactive zones in single entity. Herein, we introduced dark field microscopy to study the variation of scattering spectrum and optical mass centroid (OMC) of single Prussian blue nanoparticles during electrochemical reaction. The "dark zone" embedded in a single electroactive nanoparticle resulted in the incomplete reaction, and consequently led to the misalignment of OMC for different electrochemical intermediate states. We further revealed the dark zones such as lattice defects in the same entity, which were externally manifested as the fixed pathway for OMC for the migration of potassium ions. This method opens up enormous potentiality to optically access the heterogeneous intraparticle dark zones, with implications for evaluating the crystallinity and electrochemical recyclability of single electroactive nano-objects.

Stimulation and Recording of the Hippocampus Using the Same Pt-Ir Coated Microelectrodes.

Same-electrode stimulation and recording with high spatial resolution, signal quality, and power efficiency is highly desirable in neuroscience and neural engineering. High spatial resolution and signal-to-noise ratio is necessary for obtaining unitary activities and delivering focal stimulations. Power efficiency is critical for battery-operated implantable neural interfaces. This study demonstrates the capability of recording single units as well as evoked potentials in response to a wide range of electrochemically safe stimulation pulses through high-resolution microelectrodes coated with co-deposition of Pt-Ir. It also compares signal-to-noise ratio, single unit activity, and power efficiencies between Pt-Ir coated and uncoated microelectrodes. To enable stimulation and recording with the same microelectrodes, microelectrode arrays were treated with electrodeposited platinum-iridium coating (EPIC) and tested in the CA1 cell body layer of rat hippocampi. The electrodes' ability to (1) inject a large range of electrochemically reversable stimulation pulses to the tissue, and (2) record evoked potentials and single unit activities were quantitively assessed over an acute time period. Compared to uncoated electrodes, EPIC electrodes recorded signals with higher signal-to-noise ratios (coated: 9.77 ± 1.95 dB; uncoated: 1.95 ± 0.40 dB) and generated lower voltages (coated: 100 mV; uncoated: 650 mV) for a given stimulus (5 µA). The improved performance corresponded to lower energy consumptions and electrochemically safe stimulation above 5 µA (>0.38 mC/cm2), which enabled elicitation of field excitatory post synaptic potentials and population spikes. Spontaneous single unit activities were also modulated by varying stimulation intensities and monitored through the same electrodes. This work represents an example of stimulation and recording single unit activities from the same microelectrode, which provides a powerful tool for monitoring and manipulating neural circuits at the single neuron level.