Closed-Loop Multi-Objective Optimization for Cu-Sb-S Photo-Electrocatalytic Materials' Discovery.

Copper antimony sulfides are regarded as promising catalysts for photo-electrochemical water splitting because of their earth abundance and broad light absorption. The unique photoactivity of copper antimony sulfides is dependent on their various crystalline structures and atomic compositions. Here, a closed-loop workflow is built, which explores Cu-Sb-S compositional space to optimize its photo-electrocatalytic hydrogen evolution from water, by integrating a high-throughput robotic platform, characterization techniques, and machine learning (ML) optimization workflow. The multi-objective optimization model discovers optimum experimental conditions after only nine cycles of integrated experiments-machine learning loop. Photocurrent testing at 0 V versus reversible hydrogen electrode (RHE) confirms the expected correlation between the materials' properties and photocurrent. An optimum photocurrent of -186 µA cm-2 is observed on Cu-Sb-S in the ratio of 9:45:46 in the form of single-layer coating on F-doped SnO2 (FTO) glass with a corresponding bandgap of 1.85 eV and 63.2% Cu1+ /Cu species content. The targeted intelligent search reveals a nonobvious CuSbS composition that exhibits 2.3 times greater activity than baseline results from random sampling.

A fresh look at propriospinal interneurons plasticity and intraspinal circuits remodeling after spinal cord injury.

Spinal cord injury (SCI) disrupts communication between the brain-derived descending commands and the intraspinal circuits, the central pattern generator (CPG), that execute movements. Dynamic changes in the interaction of the brain-spinal cord as well as in structure-function relationships play a vital role in the determination of neurological function restoration. These changes also have important clinical implications for the treatment of patients with SCI. After SCI, at both brain and spinal cord levels, detour circuits formation and neuronal plasticity have been linked to functional improvement under the condition of spontaneous recovery as well as electrical stimulation- and rehabilitative training-assisted recovery. The principles governing neural circuit remodeling and the neuronal subtypes specifically involved during the recovery from SCI are largely unknown. In the present review, we focus on how multi-level neural circuits are reconstructed after SCI. We highlight some new studies using rodent and zebrafish SCI models that describe how the intraspinal detour circuits are reconstructed and the important roles of spinal excitatory interneurons.

Performance and application of new inorganic retarding sealing material suitable for multi-scale fractures.

Gas extraction is an important way to solve coal mine gas in China. At present, the development of new and more efficient gas sealing materials is an urgent problem in China's coal mining industry. In order to improve the gas extraction efficiency and promote the development and utilization of coalbed methane, we developed a new inorganic slow setting material which used bentonite as main material. We added two kinds of organic modified materials and two kinds of inorganic modified materials to optimize the sealing performance, and analyzed the viscosity, sealing and particle size changes after modification. The rheological properties and diffusion properties of sealing materials was studied. Meanwhile, field experiments were carried out to verify that it has more efficient sealing performance than traditional cement materials and could improves the efficiency of gas drainage and reduces mine gas disaster accidents.

Intermittent water supply and self-rated health in rural China's karst region.

Introduction: With rapid economic and social development, surging demand for domestic water, and the increasing shortage of water resources, the applications of intermittent water supply systems have become more common in rural China and other developing countries. The accompanying hygiene risks require our more attention. Methods: Based on the Grossman model, this paper conducted an IV-Oprobit model to investigate whether and how intermittent water supply affect rural residents' self-rated health status. Our data came from "China Karst Rural Economic Survey (CKRS)", which covers 8 provinces and 641 villages in rural China's karst region. Results and discussion: We found that: (1) Intermittent water supply has adverse effects on the self-rated health status of rural residents. Compared with the rural residents under continuous water supply, the probability of "fair" health status under intermittent water supply significantly increases by 18.2%, while the probability of "excellent" significantly reduces by 58.8%. (2) Residents' water storage behavior and sanitary water habit are important mechanisms for intermittent water supply to affect residents' self-rated health status; (3) Intermittent water supply has a greater impact on the self-rated health of females and the groups with lower education levels. The results of our study have the following policy implications: relevant departments should make a rational plan about water supply methods and improve related supporting measures; we should strengthen health education for rural residents on water behavior to standardize their water storage and sanitary water behavior; government should enhance the pertinence of policy implementation and favor specific measures to specific populations.

Strengthening Mechanism for the Mechanical Properties of Cement-Based Materials after Internal Nano-SiO2 Production.

This study focuses on overcoming the agglomeration issue of nano-SiO2 powder in cement, facilitating the strengthening mechanism of cement-based materials. A nano-SiO2 precursor solution (NSPS) was added to cement-based materials to replace nano-SiO2 powder. The influencing laws of the alkalinity and dosage of the NSPS on the mechanical properties of cement were investigated. Further, the strengthening mechanism of the mechanical properties of cement-based materials after internal nano-SiO2 production was analysed. The results show that (1) when the alkalinity of the precursor solution is a weak acid (pH = 6), the compressive strength of cement-based materials after internal nano-SiO2 production is 25%~36% higher than that of pure cement-based materials and 16%~22% higher than that of cement-based materials with silica fume; (2) when the solid content of SiO2 in the current displacement solution is about 0.16% of the cement mass, the compressive strength of the prepared cement-based material is the highest. With the continuous increase in the solid content of SiO2 in the precursor solution, the compressive strength of cement-based materials after internal nano-SiO2 production decreases but is always greater than the compressive strength of the cement-based material mixed with nano-SiO2 micro powder. According to a microstructural analysis, nano-SiO2 particles that precipitate from the precursor solution can facilitate the hydration process of cement and enrich the gel products formed on the cement particle surface. In addition, new network structures among cement particles are formed, and precipitated nano-SiO2 particles fill in the spaces among these cement particles as crystal nuclei to connect the cement particles more tightly and compact the cement-based materials. This reinforces the mechanical properties of cement-based materials.

De novo establishment of circuit modules restores locomotion after spinal cord injury in adult zebrafish.

Mechanisms underlying spontaneous locomotor recovery after spinal cord injury (SCI) remain unclear. Using adult zebrafish with complete SCI, we show that V2a interneurons regrow their axon to bridge the lesioned spinal segments in a subclass-specific and chronological order. Early after SCI, reestablishment of a unitary high-rhythm locomotor circuit is driven merely by axon-regrown fast V2a interneurons. Later, the reestablished intraspinal de novo circuit is organized into a modular design by axon-regrown fast and slow V2a interneurons rostral to the lesion, selectively driving caudal fast V2a/motor neurons and slow V2a/motor neurons, respectively. This orderly circuitry reestablishment determines the stepwise restoration of locomotor repertoire and recapitulates developmental processes. This progress can be interrupted by ablation of calretinin, a fast module-related protein, and accelerated by physical training. These findings suggest that promotion of axon regrowth of propriospinal V2a interneurons and establishment of de novo intraspinal circuits underpin the effectiveness of physical training in patients after SCI.

An injury-induced serotonergic neuron subpopulation contributes to axon regrowth and function restoration after spinal cord injury in zebrafish.

Spinal cord injury (SCI) interrupts long-projecting descending spinal neurons and disrupts the spinal central pattern generator (CPG) that controls locomotion. The intrinsic mechanisms underlying re-wiring of spinal neural circuits and recovery of locomotion after SCI are unclear. Zebrafish shows axonal regeneration and functional recovery after SCI making it a robust model to study mechanisms of regeneration. Here, we use a two-cut SCI model to investigate whether recovery of locomotion can occur independently of supraspinal connections. Using this injury model, we show that injury induces the localization of a specialized group of intraspinal serotonergic neurons (ISNs), with distinctive molecular and cellular properties, at the injury site. This subpopulation of ISNs have hyperactive terminal varicosities constantly releasing serotonin activating 5-HT1B receptors, resulting in axonal regrowth of spinal interneurons. Axon regrowth of excitatory interneurons is more pronounced compared to inhibitory interneurons. Knock-out of htr1b prevents axon regrowth of spinal excitatory interneurons, negatively affecting coordination of rostral-caudal body movements and restoration of locomotor function. On the other hand, treatment with 5-HT1B receptor agonizts promotes functional recovery following SCI. In summary, our data show an intraspinal mechanism where a subpopulation of ISNs stimulates axonal regrowth resulting in improved recovery of locomotor functions following SCI in zebrafish.

MoS2 /Polymer Heterostructures Enabling Stable Resistive Switching and Multistate Randomness.

Resistive random-access memories (ReRAMs) based on transition metal dichalcogenide layers are promising physical sources for random number generation (RNG). However, most ReRAM devices undergo performance degradation from cycle to cycle, which makes preserving a normal probability distribution during operation a challenging task. Here, ReRAM devices with excellent stability are reported by using a MoS2 /polymer heterostructure as active layer. The stability enhancement manifests in outstanding cumulative probabilities for both high- and low-resistivity states of the memory cells. Moreover, the intrinsic values of the high-resistivity state are found to be an excellent source of randomness as suggested by a Chi-square test. It is demonstrated that one of these cells alone can generate ten distinct random states, in contrast to the four conventional binary cells that would be required for an equivalent number of states. This work unravels a scalable interface engineering process for the production of high-performance ReRAM devices, and sheds light on their promising application as reliable RNGs for enhanced cybersecurity in the big data era.

Performance Comparison of N95 and P100 Filtering Facepiece Respirators with Presence of Artificial Leakage.

OBJECTIVES: National Institute for Occupational Safety and Health-approved P100 filtering facepiece respirators (FFRs) have a higher filter efficiency compared to the N95 filters. However, the former typically produce higher flow resistance (Rf). Consequently, when faceseal leakage is present, the proportion of leakage airflow for P100 FFRs may exceed that of N95s, resulting in a higher total inward leakage (TIL) of the P100. METHODS: In this manikin-based study, the performance of two pairs of N95 and P100 FFRs (N95-A versus P100-A; N95-B versus P100-B) were compared under five sealing conditions (fully sealed and partially sealed with one, two, or three leaks of 0.8-mm, and one 2-mm leak). Sodium chloride particles (CMD ~45 nm) were used as the challenge aerosol. Respirators were tested under three constant flows (15, 50, and 85 L/min) and three cyclic flows (mean inspiratory flow = 15, 50, and 85 L/min). Both filter penetration (Pfilter) and TIL were determined. The Rf under constant flows was recorded. Based on Pfilter, TIL, and Rf, the quality factor (qf) was calculated to compare the overall performance of N95 and P100 FFRs. RESULTS: For a fully sealed condition, the Pfilter was much lower for the P100 FFRs than for the N95 FFRs. When small leaks were inserted (0.8-mm and 2 × 0.8-mm), the TIL was higher for the P100 FFRs than for the N95 FFRs under the lowest tested flow (15 L/min), while for greater leaks (3 × 0.8-mm and 2-mm), the TIL of the P100 FFRs was always higher regardless of the flow. The Rf of P100 FFRs was measured twice as high as the N95. The qf values were also found higher for the N95 FFRs than for the P100 FFRs regardless of leak size and breathing flow. CONCLUSIONS: With the presence of artificial leakage, a P100 FFR with high-flow-resistance may not be as protective as a low-flow-resistance N95 FFR. This finding suggests that future efforts should be directed to reducing the breathing resistance when designing P100 FFRs.

Group-velocity-locked vector soliton molecules in fiber lasers.

Physics phenomena of multi-soliton complexes have enriched the life of dissipative solitons in fiber lasers. By developing a birefringence-enhanced fiber laser, we report the first experimental observation of group-velocity-locked vector soliton (GVLVS) molecules. The birefringence-enhanced fiber laser facilitates the generation of GVLVSs, where the two orthogonally polarized components are coupled together to form a multi-soliton complex. Moreover, the interaction of repulsive and attractive forces between multiple pulses binds the particle-like GVLVSs together in time domain to further form compound multi-soliton complexes, namely GVLVS molecules. By adopting the polarization-resolved measurement, we show that the two orthogonally polarized components of the GVLVS molecules are both soliton molecules supported by the strongly modulated spectral fringes and the double-humped intensity profiles. Additionally, GVLVS molecules with various soliton separations are also observed by adjusting the pump power and the polarization controller.

M-OTDR sensing system based on 3D encoded microstructures.

In this work, a quasi-distributed sensing scheme named as microstructured OTDR (M-OTDR) by introducing ultra-weak microstructures along the fiber is proposed. Owing to its relative higher reflectivity compared with the backscattered coefficient in fiber and three dimensional (3D) i.e. wavelength/frequency/time encoded property, the M-OTDR system exhibits the superiorities of high signal to noise ratio (SNR), high spatial resolution of millimeter level and high multiplexing capacity up to several ten thousands theoretically. A proof-of-concept system consisting of 64 sensing units is constructed to demonstrate the feasibility and sensing performance. With the help of the demodulation method based on 3D analysis and spectrum reconstruction of the signal light, quasi-distributed temperature sensing with a spatial resolution of 20 cm as well as a measurement resolution of 0.1 °C is realized.

Cardiac resynchronization therapy reduces T-wave alternans in patients with heart failure.

AIMS: T-wave alternans (TWA) represents myocardial instability. The present study was to determine the impact of cardiac resynchronization therapy (CRT) on TWA and left ventricular ejection fraction (LVEF) in heart failure patients. METHODS AND RESULTS: T-wave alternans was analysed using a spectral method in 27 CRT-ICD patients. Ambulatory device electrograms were collected and LVEF and New York Heart Association (NYHA) classification were assessed at baseline prior to CRT and 3 months following CRT. Patients were followed for 6 months to monitor cardiac events. Spectral TWA of device electrograms was measured during AAI and CRT pacing tests. Each pacing mode had the up-titration pacing rate from 90 to 105 b.p.m. with 90 s for each pacing rate. At baseline, 20 (76.9%) patients had TWA during AAI pacing tests and 13 (50%) during CRT pacing tests (P = 0.044 between two pacing modes). Following 3-month CRT, TWA was identified in 11 patients (45.8%) during AAI pacing tests (a 31.1% reduction from the baseline value, P = 0.023) and 7 patients (28%) during CRT pacing tests (a 22% reduction, P = 0.108). Six of seven patients who had cardiac events had TWA (three patients had arrhythmic events, two died of heart failure, one received heart transplant). Overall, LVEF improved from 27.3 ± 5.8 to 35.9 ± 10.5% (P < 0.001) and NYHA classification improved from 2.8 ± 0.6 to 1.6 ± 0.6 after 3-month CRT (P < 0.001). CONCLUSION: In heart failure patients who receive a CRT-ICD, CRT reduces TWA that is associated to cardiac events, suggesting that CRT promotes clinically significant reverse electrical and mechanical remodelling.

Study of optical parameters of polystyrene spheres in dense aqueous suspensions.

We investigated the dependence of the scattering and absorption coefficients of particles in dense suspensions by the low-coherence fiber optic dynamic light scattering (FODLS) technique. The estimated particle size was used to calculate the scattering coefficient of particles suspended in dense suspensions. The path-length resolved intensity distributions of light backscattered from absorbing dense suspensions were investigated experimentally. The absorption coefficient can be obtained by applying the measured path-length resolved intensity distributions to the modified Lambert-Beer law. As a result, the low-coherence FODLS technique can simultaneously measure the scattering and absorption coefficients of particles in absorbing dense suspensions, and the scattering and absorption coefficients are independent of each other in dense suspensions in the low-scattering regime of 2l(d) < 10ℓ*.

Effect of transarterial pulsed perfusion with heated saline on tumor vascular permeability in a rabbit VX2 liver tumor model.

PURPOSE: To evaluate the effect of transarterial pulsed perfusion with 60 °C saline on vascular permeability of tumor tissue, as well as its hepatic and renal toxicity, in a rabbit VX2 liver model. MATERIALS AND METHODS: VX2 carcinomas were grown in rabbit livers, forty male New Zealand white tumor-bearing rabbits were randomly divided into four groups, followed by transarterial perfusion with 37 °C saline 60 ml (n=10) (control 1 group), transarterial pulsed perfusion with 37 °C saline 60 ml (n=10) (control 2 group), transarterial continuous perfusion with 60 °C saline 60 ml (n=10) (TCP group), transarterial pulsed perfusion with 60 °C saline 60 ml (n=10) (TPP group), the duration of time for tumor tissues in the range 43-45 °C of the treated groups was measured with needle thermometer during perfusion. Vascular permeability was assessed using the extravasation of Evans blue (EB) dye in the tumor or normal liver tissues of the four groups separately, the tumor or normal liver tissues of the four groups were estimated by histopathologic examination, and hepatic and renal toxicity was evaluated by means of blood biochemical analysis. The vascular endothelial cells in the tumor were observed by transmission electron microscopy (TEM). RESULTS: The duration of time for tumor tissues in the range 43-45 °C of TPP group showed significantly longer than that of TCP group (12.3±3.3 min vs. 5.7±2.5 min) (P<0.01). After perfusion, the EB content of tumor tissue in TPP group showed significantly higher than that in TCP group (15.21±0.94 µg/100 mg vs. 10.71±0.84 µg/100 mg) (P<0.01), and also showed significantly higher than that in the two control group (3.42±0.87 µg/100 mg, 3.57±0.64 µg/100 mg) (P<0.01). Blood chemical analysis indicating there was an increase (P<0.05) in the serum ALT, AST levels in the two heated perfusion groups at 1, 2, 4, 8 h after infusion when compared to that in the two control group, but there was no significant difference in the serum ALT, AST levels among the four groups at 24 h after perfusion (P>0.05), and there was no significant difference in the serum BUN, Cr levels among the four groups at 1, 2, 4, 8, 24 h after perfusion. Observed by hematoxylin and eosin staining, there were no obvious signs of tissue destruction in liver tissue and tumor tissue. TEM indicating the endothelial cell gap was broadened and the endothelial cells' microvillus was decreased after heated perfusion. CONCLUSIONS: The vascular permeability of the rabbit VX2 tumor was significantly increased after transarterial pulsed perfusion with 60°C saline without significant increase in hepatic and renal toxicity.

Potent HIV fusion inhibitors against Enfuvirtide-resistant HIV-1 strains.

T20 (generic name: Enfuvirtide, brand name: Fuzeon) is the only FDA-approved HIV fusion inhibitor that is being used for treatment of HIV/AIDS patients who have failed to respond to current antiretroviral drugs. However, it rapidly induces drug resistance in vitro and in vivo. On the basis of the structural and functional information of anti-HIV peptides from a previous study, we designed an HIV fusion inhibitor named CP32M, a 32-mer synthetic peptide that is highly effective in inhibiting infection by a wide range of primary HIV-1 isolates from multiple genotypes with R5- or dual-tropic (R5X4) phenotype, including a group O virus (BCF02) that is resistant to T20 and C34 (another anti-HIV peptide). Strikingly, CP32M is exceptionally potent (at low picomolar level) against infection by a panel of HIV-1 mutants highly resistant to T20 and C34. These findings suggest that CP32M can be further developed as an antiviral therapeutic against multidrug resistant HIV-1.

Identification of a critical motif for the human immunodeficiency virus type 1 (HIV-1) gp41 core structure: implications for designing novel anti-HIV fusion inhibitors.

Human immunodeficiency virus type 1 (HIV-1) entry into the host cell involves a cascade of events and currently represents one of most attractive targets in the search for new antiviral drugs. The fusion-active gp41 core structure is a stable six-helix bundle (6-HB) folded by its trimeric N-terminal heptad repeat (NHR) and C-terminal heptad repeat (CHR). Peptides derived from the CHR region of HIV-1 gp41 are potent fusion inhibitors that target the NHR to block viral and cellular membrane fusion in a dominant negative fashion. However, all CHR peptides reported to date are derived primarily from residues 628 to 673 of gp41; little attention has been paid to the upstream sequence of the pocket binding domain (PBD) in the CHR. Here, we have identified a motif ((621)QIWNNMT(627)) located at the upstream region of the gp41 CHR, immediately adjacent to the PBD ((628)WMEWEREI(635)). Biophysical characterization demonstrated that this motif is critical for the stabilization of the gp41 6-HB core. The peptide CP621-652, containing the (621)QIWNNMT(627) motif, was able to interact with T21, a counterpart peptide derived from the NHR, to form a typical 6-HB structure with a high thermostability (thermal unfolding transition [T(m)] value of 82 degrees C). In contrast, the 6-HB formed by the peptides N36 and C34, which has been considered to be a core structure of the fusion-active gp41, had a T(m) of 64 degrees C. Different from T-20 (brand name Fuseon), which is the first and only HIV-1 fusion inhibitor approved for clinical use, CP621-652 could efficiently block 6-HB formation in a dose-dependent manner. Significantly, CP621-652 had potent inhibitory activity against HIV-1-mediated cell-cell fusion and infection, especially against T-20- and C34-resistant virus. Therefore, our works provide important information for understanding the core structure of the fusion-active gp41 and for designing novel anti-HIV peptides.