Strain Engineering of Unconventional Crystal-Phase Noble Metal Nanocatalysts.

The crystal phase, alongside the composition, morphology, architecture, facet, size, and dimensionality, has been recognized as a critical factor influencing the properties of noble metal nanomaterials in various applications. In particular, unconventional crystal phases can potentially enable fascinating properties in noble metal nanomaterials. Recent years have witnessed notable advances in the phase engineering of nanomaterials (PEN). Within the accessible strategies for phase engineering, the effect of strain cannot be ignored because strain can act not only as the driving force of phase transition but also as the origin of the diverse physicochemical properties of the unconventional crystal phase. In this review, we highlight the development of unconventional crystal-phase noble metal nanomaterials within strain engineering. We begin with a short introduction of the unconventional crystal phase and strain effect in noble metal nanomaterials. Next, the correlations of the structure and performance of strain-engineered unconventional crystal-phase noble metal nanomaterials in electrocatalysis are highlighted, as well as the phase transitions of noble metal nanomaterials induced by the strain effect. Lastly, the challenges and opportunities within this rapidly developing field (i.e., the strain engineering of unconventional crystal-phase noble metal nanocatalysts) are discussed.

Mechanism of Thermoelectric Performance Enhancement in CaMg2 Bi2 -Based Materials with Different Cation Site Doping.

Chemical bonds determine electron and phonon transport in solids. Tailoring chemical bonding in thermoelectric materials causes desirable or compromise thermoelectric transport properties. In this work, taking an example of CaMg2 Bi2 with covalent and ionic bonds, density functional theory calculations uncover that element Zn, respectively, replacing Ca and Mg sites cause the weakness of ionic and covalent bonding. Electrically, Zn doping at both Ca and Mg sites increases carrier concentration, while the former leads to higher carrier concentration than that of the latter because of its lower vacancy formation energy. Both doping types increase density-of-state effective mass but their mechanisms are different. The Zn doping Ca site induces resonance level in valence band and Zn doping Mg site promotes orbital alignment. Thermally, point defect and the change of phonon dispersion introduced by doping result in pronounced reduction of lattice thermal conductivity. Finally, combining with the further increase of carrier concentration caused by Na doping and the modulation of band structure and the decrease of lattice thermal conductivity caused by Ba doping, a high figure-of-merit ZT of 1.1 at 823 K in Zn doping Ca sample is realized, which is competitive in 1-2-2 Zintl phase thermoelectric systems.

Effects of acupoints-based TENS combined with tDCS on spasticity and motor function in ischemic stroke with spastic hemiplegia: study protocol for a randomized controlled trial.

Background: Spastic hemiplegia following ischemic strokes seriously impedes the recovery of motor function posing a vast rehabilitation challenge. As the uncertain effects of recommended conventional treatments such as botulinum toxin injections on active functional improvement and potential adverse effects cannot be bypassed, there is an increasing need in alternative, more effective and safer modalities. Acupoints-based transcutaneous electrical nerve stimulation (Acu-TENS) and transcranial direct current stimulation (tDCS) are effective non-invasive modalities for stroke rehabilitation, particularly showing anti-spastic effect and functional improvements as well. However, the optimal stimulation frequency of Acu-TENS and whether combination of Acu-TENS and tDCS exert synergistic effect remain to be investigated. Objective: To evaluate the effects of Acu-TENS combined with tDCS on spasticity and motor function in ischemic stroke patients with spastic hemiplegia and screen the optimal frequency of Acu-TENS. Methods: A total of 90 post-ischemic stroke patients with spastic hemiplegia will be intervened for 4 weeks and followed up for 4 weeks. They will be randomly assigned to three groups including two observation groups and a standard care control group in a 1:1:1 ratio. All patients will receive standard care and regular rehabilitation accordingly. In addition, the two observation groups will receive 12 sessions of Acu-TENS at 20 Hz or 100 Hz for 30 min combined with 1 mA tDCS for 20 min, three times a week, for 4 weeks. The primary outcome is the change in total modified Ashworth scale (MAS) score from baseline to week 4. Secondary outcomes include changes in surface electromyography (SEMG), Fugl-Meyer Motor Function Scale, Modified Barthel Index (MBI), and 10-meter walk test from baseline to week 4. MAS score will also be measured after 4 weeks of follow-up. Adverse events throughout the study will be recorded. Discussion: This trial will evaluate, for the first time, the therapeutic potentials and safety of Acu-TENS combined with tDCS on spasticity and motor function in stroke patients. It will provide evidence for frequency-dependent anti-spastic effect of Acu-TENS, and a reference for rated parameter setting of new mixed transcutaneous and transcranial stimulation system for stroke rehabilitation, thereby promoting proactive healthcare consequently. Trial registration: Chinese Clinical Trials Register ChiCTR2200067186.

Electrophysiological mechanisms of motion-style scalp acupuncture for treating poststroke spasticity in rats. / è¿åŠ¨å¤´é’ˆæ³•æŠ—å’ä¸­åŽç—‰æŒ›æ•ˆåº”çš„ç”µç”Ÿç†æœºåˆ¶ç ”ç©¶.

OBJECTIVES: To observe the effect of motion-style scalp acupuncture (MSSA) on H-reflex in rats with post-stroke spasticity (PSS), so as to explore the electrophysiological mechanisms of MSSA against spasticity. METHODS: A total of 36 male SD rats were randomly divided into sham operation, model and MSSA groups, with 12 rats in each group. The stroke model was established by occlusion of the middle cerebral artery. After modeling, rats in the MSSA group were treated by scalp acupuncture (manipulated every 15 min, 200 r/min) at ipsilesional "parietal and temporal anterior oblique line" (MS6) for a total of 30 min, the treadmill training (10 m/min) was applied during the needling retention, once daily for consecutive 7 days. The neurological deficits, muscle tone and motor function were assessed by Zea Longa score, modified modified Ashworth scale (MMAS) score and screen test score before and after treatment, respectively. The H-reflex of spastic muscle was recorded by electrophysiological recordings and the frequency dependent depression (FDD) of H-reflex was also recorded. The cerebral infarction volume was evaluated by TTC staining. RESULTS: Compared with the sham operation group, the Zea longa score, MMAS score, cerebral infarction volume, motion threshold, Hmax/Mmax ratio and FDD of H-reflex were significantly increased (P<0.01), while the screen test score was significantly decreased (P<0.01) in the model group. Intriguingly, compared with the model group, the above results were all reversed (P<0.01) in the MSSA group. CONCLUSIONS: MSSA could exert satisfactory anti-spastic effects in rats with PSS, the underlying mechanism may be related to the improvement of nerve function injury, the reduction of spastic muscle movement threshold, Hmax/Mmax ratio and H-reflex FDD.

Nocturnal Bladder Function and Sleep in the Children with Refractory Nocturnal Enuresis: A Prospective Study.

OBJECTIVE: To prospectively investigate the nocturnal bladder function and sleep in children with refractory primary monosymptomatic nocturnal enuresis (RPMNE). MATERIALS AND METHODS: Fifty-three children diagnosed with RPMNE and 30 controls who had upper urinary tract abnormality but without any voiding problems were included in the study. RPMNE patients underwent a standardized investigation protocol, including the Pittsburgh Sleep Quality Index (PSQI) questionnaire, a 7-day bladder diary, and the simultaneous ambulatory urodynamic monitoring and polysomnography (PSG); controls were evaluated using the PSQI questionnaire and PSG. RESULTS: The children with RPMNE were subdivided into the nocturnal detrusor overactivity (NDO) case group and the non-NDO case group. The children in the NDO case group had a higher percentage of total sleep time in light sleep and a lower percentage in the N3 sleep stage than those in the non-NDO case group and control group (P <.05). The cortical arousal index and PSQI scores of both RPMNE subgroups were higher compared to the control group (P <.05). The incidences of reduced nocturnal bladder capacity (NBC) in the NDO case group were higher than in the non-NDO case group (P <.05). The frequency of involuntary detrusor contractions during sleep was positively correlated with cortical arousal index in the NDO case group (r = 0.811, P <.0001). CONCLUSION: In addition to the reduced NBC, the RPMNE is related to abnormal NDO, increased light sleep period, and cortical arousal dysfunction. Moreover, there is a certain correlation between the abnormal degrees of NDO and cortical arousal dysfunction.

Combining Chitosan, Stearic Acid, and (Cu-, Zn-) MOFs to Prepare Robust Superhydrophobic Coatings with Biomedical Multifunctionalities.

There is an urgent need to develop a series of multifunctional materials with good biocompatibility, high mechanical strength, hemostatic properties, antiadhesion, and anti-infection for applications in wound care. However, successfully developing multifunctional materials is challenging. In this study, two superhydrophobic composite coatings with good biocompatibility, high mechanical strength, strong antifouling and blood repellency, fast hemostasis, and good antibacterial activity are prepared on cotton fabric surface by simple, green, and low-cost one-step dip-coating technology. The results discussed in the manuscript reveals that the two superhydrophobic composite coatings can maintain good mechanical stability, strong water repellency, and durability under various types of mechanical damage, high-temperature treatment, and long-term strong light irradiation. The coatings also exhibit good repellency to various solid pollutants, highly viscous liquid pollutants, and blood. In vitro and in vivo hemostatic experiments show that both composite coatings have good hemostatic and anticlot adhesion properties. More importantly, this superhydrophobic coating prevents bacterial adhesion and growth and released Cu2+ and Zn2+ ions and chitosan to achieve bactericidal properties, thereby protecting injured skin from bacterial infection. The two superhydrophobic coatings enhance the antifouling, antiadhesion, hemostatic, and antibacterial functions of blood-repellent dressings and therefore have broad application prospects in medical and textile fields.

Biofeedback physical regulation of hypertension based on acupoints: A clinical trial.

BACKGROUND: Hypertension is a predominant risk factor for cardiovascular disease and has imposed a global disease burden. Poor medication compliance is the major obstacle to antihypertensive drug therapy, and negative mood status is also detrimental to blood pressure (BP) management. While transcutaneous electrical acupoint stimulation (TEAS), as an electrical stimulation modality for biofeedback physical regulation based on acupoints, offers a such nondrug alternative option that is noninvasive, safe, and effective with high adherence. However, the optimal stimulation parameters of TEAS for hypertension remain unclear, especially the frequency, which needs further exploration. OBJECTIVE: The study aims to investigate the efficacy of TEAS for hypertension, and to screen the optimal electrical stimulation frequency. METHODS: This is an 8-week, randomized, controlled pilot trial with 3 parallel groups. In a ratio of 1:1:1, 120 patients with stage 1 hypertension will be divided into the TEAS-2Hz group, TEAS-10Hz group, or usual care group. All patients will receive the usual care for hypertension including lifestyle education, etc. Additionally, the 2 TEAS groups will receive 12 sessions of TEAS interventions at 2 Hz or 10 Hz, 3 times weekly for 30 minutes each, with 4 weeks of follow-up. The main outcome will be the change from baseline to week 4 in systolic BP among the groups. Secondary outcomes consist of changes in diastolic BP, mean arterial pressure, heart rate, heart rate variability, medication adherence, and quality of life. The safety outcomes will be any adverse event during the treatment. DISCUSSION: As a pre-study for the next large clinical trial of TEAS for hypertension, this study will offer references for optimized frequency of biofeedback electrical devices and promote more consciousness of the benefits of body-mind holistic regulation of BP, thereby achieving proactive and overall process management of BP.

Development of a Facile Lysosome-Targeting Nitric Oxide Fluorescent Probe Based on a Novel Reaction Mechanism.

As a ubiquitous signal molecule in biosystems, nitric oxide (NO) plays an important role in many physiological and pathological processes. Therefore, it is of great significance to detect NO in organisms for the study of related diseases. Currently, a variety of NO fluorescent probes have been developed based on several types of reaction mechanisms. However, due to the inherent disadvantages of these reactions, like potential interference by biologically related species, there is a great need to develop NO probes based on the new reactions. Herein, we report our discovery of the unprecedented reaction between a widely used fluorophore of 4-(dicyanomethylene)-2-methyl-6-(p-(dimethylamino)styryl)-4H-pyran (DCM) and NO under mild conditions with fluorescence changes. By the analysis of the structure of the product, we proved that DCM undergoes a particular nitration process and proposed a mechanism for fluorescence changes due to the interruption of the intramolecular charge transfer (ICT) process of DCM by the nitrated product of DCM-NO2. Based on the understanding of this specific reaction, we then easily constructed our lysosomal-localized NO fluorescent probe LysoNO-DCM by linking DCM and a morpholine group, a lysosomal-targeting functional group. LysoNO-DCM exhibits excellent selectivity, sensitivity, pH stability, and outstanding lysosome localization ability with Pearson's colocalization coefficient of up to 0.92 and is successfully applied to the imaging of exogenous and endogenous NO in cells and zebrafish. Our studies expand design methods for NO fluorescence probes based on the novel reaction mechanism and will benefit the studies of this signaling molecule.

The factors affecting neurogenesis after stroke and the role of acupuncture.

Stroke induces a state of neuroplasticity in the central nervous system, which can lead to neurogenesis phenomena such as axonal growth and synapse formation, thus affecting stroke outcomes. The brain has a limited ability to repair ischemic damage and requires a favorable microenvironment. Acupuncture is considered a feasible and effective neural regulation strategy to improve functional recovery following stroke via the benign modulation of neuroplasticity. Therefore, we summarized the current research progress on the key factors and signaling pathways affecting neurogenesis, and we also briefly reviewed the research progress of acupuncture to improve functional recovery after stroke by promoting neurogenesis. This study aims to provide new therapeutic perspectives and strategies for the recovery of motor function after stroke based on neurogenesis.

Targeting macrophagic 17ß-HSD7 by fenretinide for the treatment of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and macrophage polarization plays an important role in its pathogenesis. However, which molecule regulates macrophage polarization in NAFLD remains unclear. Herein, we showed NAFLD mice exhibited increased 17ß-hydroxysteroid dehydrogenase type 7 (17ß-HSD7) expression in hepatic macrophages concomitantly with elevated M1 polarization. Single-cell RNA sequencing on hepatic non-parenchymal cells isolated from wild-type littermates and macrophage-17ß-HSD7 knockout mice fed with high fat diet (HFD) for 6 weeks revealed that lipid metabolism pathways were notably changed. Furthermore, 17ß-HSD7 deficiency in macrophages attenuated HFD-induced hepatic steatosis, insulin resistance and liver injury. Mechanistically, 17ß-HSD7 triggered NLRP3 inflammasome activation by increasing free cholesterol content, thereby promoting M1 polarization of macrophages and the secretion of pro-inflammatory cytokines. In addition, to help demonstrate that 17ß-HSD7 is a potential drug target for NAFLD, fenretinide was screened out from an FDA-approved drug library based on its 17ß-HSD7 dehydrogenase inhibitory activity. Fenretinide dose-dependently abrogated macrophage polarization and pro-inflammatory cytokines production, and subsequently inhibited fat deposition in hepatocytes co-cultured with macrophages. In conclusion, our findings suggest that blockade of 17ß-HSD7 signaling by fenretinide would be a drug repurposing strategy for NAFLD treatment.

Efficacy and Safety of Sacral Neuromodulation by Converting Constant Frequency Stimulation Into Variable Frequency Stimulation in Patients With Detrusor Overactivity and Impaired Contractility: A Single-Center Prospective Study.

OBJECTIVES: In patients with detrusor overactivity with impaired contractility (DOIC), it is difficult to relieve abnormal lower urinary tract symptoms during both storage and voiding using sacral neuromodulation (SNM) with constant frequency stimulation (CFS). We sought to evaluate the efficacy and safety of SNM using variable frequency stimulation (VFS) in patients with DOIC by comparing it with outcomes of SNM with CFS. MATERIALS AND METHODS: Between September 2020 and May 2021, we prospectively enrolled 20 patients with DOIC, confirmed on urodynamic examination, and administered SNM with VFS. The patients were followed up and required to maintain voiding diaries and record scale scores of overactive bladder symptoms, psychology and quality of life, uroflowmetry, ultrasonic postvoid residual urine, and adverse events at baseline and during the CFS and VFS phases. RESULTS: The average testing phase was 26.3 ± 4.1 days. Compared with baseline values, overactive bladder symptom, psychologic health questionnaire, and quality of life scores, in addition to voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic postvoid residual (PVR) decreased significantly during both the CFS and VFS phases (p < 0.05). The average voided volume, functional bladder capacity, and maximum urine flow rate significantly increased during the CFS and VFS phases (p < 0.05). In the VFS phase, voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic PVR further decreased (p < 0.05), whereas functional bladder capacity, maximum urine flow rate, quality of life score, overactive bladder symptom score, and psychologic health questionnaire score further improved compared with results obtained in the CFS phase (p < 0.05). In the VFS phase, the success rate of further improvement of symptoms was 85.0%, and no new complications were noted. CONCLUSIONS: SNM that converts CFS into VFS may be an effective treatment option for patients with DOIC, exhibiting no increase in adverse events.

Video-urodynamics efficacy of sacral neuromodulation for neurogenic bladder guided by three-dimensional imaging CT and C-arm fluoroscopy: a single-center prospective study.

To assess the efficacy of sacral neuromodulation (SNM) for neurogenic bladder (NB), guided by intraoperative three-dimensional imaging of sacral computed tomography (CT) and mobile C-arm fluoroscopy through video-urodynamics examination. We enrolled 52 patients with NB who underwent conservative treatment with poor results between September 2019 and June 2021 and prospectively underwent SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy. Video-urodynamics examination, voiding diary, quality of life questionnaire, overactive bladder symptom scale (OABSS) scoring, and bowel dysfunction exam were completed and recorded at baseline, at SNM testing, and at 6-month follow-up phases. Finally, we calculated the conversion rate from period I to period II, as well as the treatment efficiency and the occurrence of adverse events during the testing and follow-up phases. The testing phase of 52 NB patients was 18-60 days, with an average of (29.3 ± 8.0) days. Overall, 38 patients underwent SNM permanent electrode implantation, whose follow-up phase was 3-25 months, with an average of (11.9 ± 6.1) months. Compared with baseline, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased significantly in the testing phase. The daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased significantly in the testing phase. Besides, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased further from the testing to follow-up phase. Daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased further from testing to follow-up. At baseline, 10 ureteral units had vesicoureteral reflux (VUR), and 9 of them improved in the testing phase. Besides, there was 1 unit that further improved to no reflux during the follow-up phase. At baseline, 10 patients had detrusor overactivity (DO), and 8 of them improved in the testing phase. Besides, 1 patient's symptoms further improved during the follow-up phase. At baseline, there were 35 patients with detrusor-bladder neck dyssynergia (DBND); 14 (40.0%) of them disappeared during the testing phase. Among 13 cases who had DBND in the testing phase, 6 (46.2%) disappeared during the follow-up phase. Of the 47 patients with detrusor-external sphincter dyssynergia (DESD) at baseline, 8 (17.0%) disappeared during the testing phase. Among 26 cases who had DESD in the testing phase, 6 (23.1%) disappeared during the follow-up phase. The effective rate of this study was 88.5% (46/52), and the conversion rate from phase I to phase II was 73.1% (38/52). Additionally, the efficacy in a short-term follow-up was stable. SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy is an effective and safe treatment option for NB in short time follow-up. It would be well improved in the bladder storage function, sphincter synergetic function and emptying efficiency by video-urodynamics examination in this study.Trial registration: Chinese Clinical Trial Registry. ChiCTR2100050290. Registered August 25 2021. http://www.chictr.org.cn/index.aspx .

Hybrid Transition-Metal Oxide and Nitride@N-Doped Reduced Graphene Oxide Electrodes for High-Performance, Flexible, and All-Solid-State Supercapacitors.

Nanoscale composites for high-performance electrodes employed in flexible, all-solid-state supercapacitors are being developed. A series of binder-free composites, each consisting of a transition bimetal oxide, a metal oxide, and a metal nitride grown on N-doped reduced graphene oxide (rGO)-wrapped nickel foam are obtained by using a universal strategy. Three different transition metals, Co, Mo, and Fe, are separately compounded with nickel ions, which originate from the nickel foam, to form three composites, NiCoO2 @Co3 O4 @Co2 N, NiMoO4 @MoO3 @Mo2 N, and NiFe2 O4 @Fe3 O4 @Fe2 N, respectively. These as-prepared active materials have similar regular variation patterns in their properties, including better conductivity and battery-mimicking pseudocapacitance, which result in their high whole-electrode capacitance performance [2598.3 F g-1 (39.85 F cm-2 ), 3472.6 F g-1 (41.43 F cm-2 ) and 1907.5 F g-1 (3.41 F cm-2 ) for the composites incorporating Co, Mo, and Fe, respectively]. The as-assembled flexible, all-solid-state NiCoO2 @Co3 O4 @Co2 N//KOH/PVA//NiCoO2 @Co3 O4 @Co2 N device can be easily bent and exhibits high energy density and power density of 92.8 Wh kg-1 and 1670.4 W kg-1 , respectively. The universality of this design strategy could allow it to be employed in producing hybrid materials for high-performance energy-storage devices.

New Way to Synthesize Robust and Porous Ni1-xFex Layered Double Hydroxide for Efficient Electrocatalytic Oxygen Evolution.

Traditional catalysts are usually synthesized by sputtering, electrochemical deposition, or hydrothermal methods, and they also need to be combined with substrates to obtain the working electrodes. Here we introduce a new route to produce an efficient catalyst for oxygen evolution reaction (OER) that is made by ball milling and sintering. By using Se as a grinding aid, the bulk electrode Ni1-xFexSe1.15 is obtained with high porosity and robust mechanical strength after sintering. Active Ni1-xFex layered double hydroxide (LDH) nanosheets are subsequently produced on the surface of the Ni1-xFexSe1.15 by in situ electrochemical oxidation. Compared with traditional synthesis methods, the new process displays superior advantages, such as producing an electrode that is substrate-free and exhibits robust mechanical strength as well as being cost-effective for mass production. Additionally, V- and Mn-doped Ni0.75Fe0.25-LDH exhibit comparable and competent OER performance in 1 M KOH solution. Ni0.71V0.04Fe0.25-LDH achieves current densities of 100 and 1000 mA cm-2 at overpotentials of 244 and 300 mV, respectively. This work demonstrates a promising way to synthesize highly efficient and robust electrocatalysts for water oxidation.

Improving the Thermoelectric Properties of the Half-Heusler Compound VCoSb by Vanadium Vacancy.

The effects of V vacancy on the thermoelectric performance of the half-Heusler compound VCoSb have been investigated in this study. A certain amount of CoSb secondary phase is generated in the VCoSb matrix when the content of V vacancy is more than 0.1 at%. According to the results, a ZT value of 0.6, together with a power factor of 29 µW cm-1 K-2 at 873 K, were achieved for the nonstoichiometric sample V0.9CoSb. This proved that moderate V vacancy could improve the thermoelectric (TE) properties of VCoSb. The noticeable improvements are mainly owing to the incremental Seebeck coefficient, which may benefit from the optimized carrier concentration. However, too much V vacancy will result in more CoSb impurity and deteriorate the TE performances of VCoSb owing to the increased thermal conductivity.

Electrochemical Performance of Free-Standing and Flexible Graphene and TiO2 Composites with Different Conductive Polymers as Electrodes for Supercapacitors.

The advantage of using composite electrode materials for energy storage is, to a large extent, the synergistic role of their components. Our work focuses on the investigation of the interactions of each phase, exploring the patterns found with the change of materials to provide theoretical or experimental foundations for future study. Here, conductive polymers (CPs), including polyaniline (PANi), polypyrrole (PPy), and polythiophene (PTh), as well as reduced graphene oxide (rGO), and TiO2 with the different crystalline phases of anatase and rutile were applied to form a series of free-standing and flexible binary or ternary composite electrodes. The electrochemical behaviors of these composite electrodes are presented. The results indicate that the synergistic improvement in electrochemical performance is due to the incorporation of the different components. CPs significantly increase the current density of these composite films and contribute their pseudocapacitance to improve the specific capacitance, but lead to a decline in cycle stability. After introducing TiO2 , both the specific capacitance and the cycle-stability of rGO-TiO2 -CP were synergistically improved. A CP can magnify the pseudocapacitance behavior of any of the TiO2 crystalline phases, and interactions vary with the specific CP and the specific TiO2 crystalline phase employed. The synergistic effects of the as-prepared composites were theoretically predicted and explored.

Improved Thermoelectric Performance of Tellurium by Alloying with a Small Concentration of Selenium to Decrease Lattice Thermal Conductivity.

Phonon scattering through alloying is a highly effective way to reduce lattice thermal conductivity due to the mass difference between the host and alloyed atoms and strains caused by the different atoms. In this work we investigate the thermoelectric properties of Te between 323 and 623 K. By varying the alloying concentration of Se, a minimum lattice thermal conductivity was achieved with ∼10% (by stoichiometry) alloying of Te by Se. Additionally, Sb has been used as a dopant to increase the carrier concentration of the system. With reduced lattice thermal conductivity by Se alloying and increased carrier concentration by Sb doping, the room-temperature figure of merit ( ZT) increased by 60%, leading to an average ZT of ∼0.8 in Te0.88Se0.10Sb0.02, which corresponds to an engineering figure of merit ( ZT)eng ∼ 0.5 between 323 and 623 K and an efficiency of ∼8% in the same temperature range. The results indicate that the combination of Se alloying and Sb doping is successful in improving the thermoelectric properties of Te.

The Effects of Excess Co on the Phase Composition and Thermoelectric Properties of Half-Heusler NbCoSb.

NbCoSb with nominal 19 valence electrons, and is supposed to be metallic, has recently been reported to also exhibit the thermoelectric properties of a heavily doped n-type semiconductor. In this study, we prepared Co-rich NbCo1+xSb samples (x = 0, 0.2, 0.3, 0.4, 0.5), and their phase compositions, microstructures and thermoelectric properties were investigated. The Seebeck coefficient increased a great deal with increasing x, due to decreasing carrier concentration, and the total thermal conductivity reduced mainly because of declining κe. Finally, a peak thermoelectric figure of merit, ZT, was about 0.46 for NbCo1.3Sb at 973 K. This enhancement was mainly attributed to the reduction of electric thermal conductivity and the increase of Seebeck coefficient. The excess Co had effects on the carrier concentration, deformation potential Edef and DOS effective mass m*. Adding an excessive amount of Co leads to a very high Edef, which was detrimental for transport characteristics.

Bio-derived three-dimensional hierarchical carbon-graphene-TiO2 as electrode for supercapacitors.

This paper reports a novel loofah-derived hierarchical scaffold to obtain three-dimensional biocarbon-graphene-TiO2 (BC-G-TiO2) composite materials as electrodes for supercapacitors. The loofah scaffold was first loaded with G and TiO2 by immersing, squeezing, and loosening into the mixed solution of graphene oxide and titania, and then carbonized at 900 °C to form the BC-G-TiO2 composite. The synergistic effects of the naturally hierarchical biocarbon structure, graphene, and TiO2 nanoparticles on the electrochemical properties are analyzed. The biocarbon provides a high interconnection and an easy accessibility surface for the electrolyte. Graphene bridged the BC and TiO2 nanoparticles, improved the conductivity of the BC-G-TiO2 composite, and increased the electron transfer efficiency. TiO2 nanoparticles also contributed to the pesudocapacitance and electrochemical stability.

The Formation Mechanism and Corrosion Resistance of a Composite Phosphate Conversion Film on AM60 Alloy.

Magnesium alloy AM60 has high duc and toughness, which is expected to increase in demand for automotive applications. However, it is too active, and coatings have been extensively studied to prevent corrosion. In this work, a Ba-containing composite phosphate film has been prepared on the surface of AM60. The composition and formation mechanism of the film have been investigated using a scanning electronic microscope equipped with energy dispersive X-ray spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, and X-ray diffractometry tests. The corrosion resistance of the film has been measured by electrochemical and immersion tests. The results show that the deposition film has fully covered the substrate but there are some micro-cracks. The structure of the film is complex, and consists of MgHPO4·3H2O, MnHPO4·2.25H2O, BaHPO4·3H2O, BaMg2(PO4)2, Mg3(PO4)2·22H2O, Ca3(PO4)2·xH2O, and some amorphous phases. The composite phosphate film has better anticorrosion performance than the AM60 and can protect the bare alloy from corrosion for more than 12 h in 0.6 M NaCl.