Highly Durable Bidirectional Rotary Triboelectric Nanogenerator with a Self-Lubricating Texture and Self-Adapting Contact Synergy for Wearable Applications.

Sliding-freestanding triboelectric nanogenerators (SF-TENGs) are desirable for application in wearable power sources; however, improving their durability is the primary challenge. Meanwhile, few studies focus on enhancing the service life of tribo-materials, especially from an anti-friction perspective during dry operation. Herein, for the first time, a surface-textured film with self-lubricating property is introduced into the SF-TENG as a tribo-material, which is obtained by the self-assembly of hollow SiO2 microspheres (HSMs) close to a polydimethylsiloxane (PDMS) surface under vacuum conditions. The PDMS/HSMs film with micro-bump topography simultaneously reduces the dynamic coefficient of friction from 1.403 to 0.195 and increases the electrical output of SF-TENG by an order of magnitude. Subsequently, a textured film and self-adapting contact synergized bidirectional rotary TENG (TAB-TENG) is developed, and the superiorities of the soft flat rotator with bidirectional reciprocating rotation are systematically investigated. The obtained TAB-TENG exhibits a remarkable output stability and an outstanding mechanical durability over 350 000 cycles. Furthermore, a smart foot system for stepping energy harvesting and wireless walking states monitoring is realized. This study proposes a pioneering strategy for extending the lifetime of SF-TENGs and advances it toward practical wearable applications.

Flame Retardancy and Mechanical Properties of Melt-Spun PA66 Fibers Prepared by End-Group Blocking Technology.

Preparing flame-retardant polyamide 66 (PA66) fibers through melt spinning remains one of the biggest challenges nowadays. In this work, dipentaerythritol (Di-PE), an eco-friendly flame retardant, was blended into PA66 to prepare PA66/Di-PE composites and fibers. It was confirmed that Di-PE could significantly improve the flame-retardant properties of PA66 by blocking the terminal carboxyl groups, which was conducive to the formation of a continuous and compact char layer and the reduced production of combustible gas. The combustion results of the composites showed that the limiting oxygen index (LOI) increased from 23.5% to 29.4%, and underwriter laboratories 94 (UL-94) passed the V-0 grade. The peak of heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) decreased by 47.3%, 47.8%, and 44.8%, respectively, for the PA66/6 wt% Di-PE composite compared to those recorded for pure PA66. More importantly, the PA66/Di-PE composites possessed excellent spinnability. The prepared fibers still had good mechanical properties (tensile strength: 5.7 ± 0.2 cN/dtex), while maintaining good flame-retardant properties (LOI: 28.6%). This study provides an outstanding industrial production strategy for fabricating flame-retardant PA66 plastics and fibers.

Effects of Alternating Magnetic Fields on the OER of Heterogeneous Core-Shell Structured NiFe2O4@(Ni, Fe)S/P.

Composition optimization, structural design, and introduction of external magnetic fields into the catalytic process can remarkably improve the oxygen evolution reaction (OER) performance of a catalyst. NiFe2O4@(Ni, Fe)S/P materials with a heterogeneous core-shell structure were prepared by the sulfide/phosphorus method based on spinel-structured NiFe2O4 nanomicrospheres. After the sulfide/phosphorus treatment, not only the intrinsic activity of the material and the active surface area were increased but also the charge transfer resistance was reduced due to the internal electric field. The overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm-2 (iR correction), Tafel slope, and charge transfer resistance were 261 mV, 42 mV dec-1, and 3.163 Ω, respectively. With an alternating magnetic field, the overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm-2 (without iR correction) declined by 45.5% from 323 mV (0 mT) to 176 mV (4.320 mT). Such enhancement of performance is primarily accounted for the enrichment of the reactive ion OH- on the electrode surface induced by the inductive electric potential derived from the Faraday induction effect of the AMF. This condition increased the electrode potential and thus the charge transfer rate on the one hand and weakened the diffusion of the active substance from the electrolyte to the electrode surface on the other hand. The OER process was dominantly controlled by the charge transfer process under low current conditions. A fast charge transfer rate boosted the OER performance of the catalyst. At high currents, diffusion exerted a significant effect on the OER process and low OH- diffusion rates would lead to a decrease in the OER performance of the catalyst.

Mechanical design of brush coating technology for the alignment of one-dimension nanomaterials.

Widespread approaches to fabricate surfaces with aligned nanostructured topographies have been stimulated by opportunities to enhance interface performance by combing physical and chemical effects, in which brush-coating technology (BCT) is a cost-effective and feasible method for aligned film and large-scale production. Here, we reported a BCT process to realize the alignment of various 1D nanostructures through mechanical design that provides a more precise and higher shear force. By regulating the viscosity of dispersion, shear force is proved to be 24 and 20.3 times larger (when the volume ratio of water and glycerol is 1:3) according to the theoretical calculation and ANSYS simulating calculation results respectively, which plays a vital role in brush coating process. The universality was demonstrated by the alignment of one-dimension nanomaterials with different diameters, including silver nanowires (~80 nm), molybdenum trioxide nanobelts (~150 nm), vanadium pentoxide nanobelts (~150 nm) and bismuth sulfide nanobelts (~200 nm), et al., which in consequence have different alignment ratios. Meanwhile, anisotropic and flexible electrical conductors (the resistance anisotropic ratio was 2) and thermoelectric films (Seebeck coefficient was calculated to be 56.7 µV/K) were demonstrated.

Hemorrhagic pure sensory strokes in the thalamus and striatocapsular area: causes, clinical features and long-term outcome.

BACKGROUND: Although there have been sporadic reports of patients with hemorrhagic pure sensory strokes (HPSS) in the thalamus and striatocapsular areas, the causes, clinical featuring and long-term outcome have not been adequately investigated. METHODS: We recruited 7 consecutive patients without hemiparetic stroke who had HPSS in the thalamic and striatocapsular areas. A CT scan was performed to verify brain imaging patterns, and their causes, clinical featuring and long-term outcome were observed. RESULTS: We studied 7 patients who had HPSS in the thalamic and striatocapsular areas as seen in CT scans. The 7 patients had hypertension, and small hemorrhages were found in the thalamus of 2 patients and in the posterior quarter of the posterior limb of the internal capsule in 4 patients; only 1 patient had a microhemorrhage in the thalamus. The volume of the hemorrhages ranged from 0.3 to 6.3 ml, with a mean of 2.3 ± 1.9 ml. Three patients showed a decreased sense of spinothalamic modality, and position and vibration senses were spared. Four patients showed a sensory deficit of both spinothalamic and medial lemniscal type. The outcomes were excellent and without post-stroke pain in all patients. CONCLUSION: HPSS in the thalamus and striatocapsular area are usually small hemorrhages or microhemorrhages from rupturing of the microvessels or the branches of small vessels. HPSS only have an impact on the adjacent sensory nucleus or pathway, and have a good outcome without post-stroke pain.

In-Situ Polymerization of High-Molecular Weight Nylon 66 Modified Clay Nanocomposites with Low Apparent Viscosity.

High-molecular weight nylon 66/modified clay (Mclay) nanocomposites with a low apparent viscosity were prepared by in-situ polymerization and post solid-state polycondensation. Thermogravimetric analysis and X-ray diffraction patterns of the Mclay revealed that cetyltrimethyl ammonium bromide successfully inserted into the interlayers of the clay. Scanning electron microscope images of the cross sections showed that the Mclay was well-dispersed in the nylon 66 matrix. The effects of clay on the mechanical, rheological, and thermal properties of the nanocomposites were investigated using an Instron 5969 machine, a capillary rheometer, and a differential scanning calorimeter. The results indicated that the incorporation of a very small amount of Mclay considerably decreased the shear viscosity of the nanocomposites and increased the melt index, acting as a viscosity reducer. More importantly, the mechanical properties and spinnability of the nylon 66/Mclay nanocomposites were not affected by the viscosity reducer.

Metabolic Syndrome Is a Strong Risk Factor for Minor Ischemic Stroke and Subsequent Vascular Events.

BACKGROUND: Minor ischemic stroke (MIS) represents a major global public health problem worldwide due to high incidence. The aim of this study was to investigate whether metabolic syndrome (MetS) is a strong risk for MIS and subsequent vascular events (SVE). METHODS: A retrospective cohort study was performed examining symptomatic MIS in a Chinese neurologic outpatient population aged over 25 years without history of stroke. MetS was defined using the International Diabetes Federation criteria. MIS was diagnosed by magnetic resonance imaging-diffusion weighted images or fluid-attenuated inversion recovery. RESULTS: Of 1361 outpatients, a total of 753 (55.3%) patients were diagnosed with MIS; of them, 80% had a score of 0 using the MIS had a 0 score on the National Institutes of Health Stroke Scale. Among these, 303 (40.2%) individuals with MIS were diagnosed with MetS. Diagnosed of MIS with MetS significantly correlated with abdominal obesity (30.7% v.s 18.0%), hypertension (91.1% v.s 81.6%), increased blood glucose (6.9±2.4 v.s 5.0±0.4), dyslipidemia (78.2% v.s 48.2%), and SVE (50.5% v.s 11.3%) when compared with the controls group. On adjusted analysis, the risk of SVE was also significantly associated with three additional MetS criterion (RR,9.0; 95% CI, 5.677-14.46). Using Cox proportional analysis, risk of SVE in patient with MIS was significantly associated with MetS (RR, 3.3; 95% CI, 1.799-6.210), older age (RR, 1.0; 95% CI, 1.001-1.048), and high blood glucose (RR,1.1; 95%CI, 1.007-1.187). CONCLUSIONS: The MetS is a strong risk factor for MIS, and patients presenting with MIS and MetS are at a high risk of SVE. Further studies are required to determine the improvement of Mets prevention in the reduction of MIS and SVE.

Transient and persistent symptoms in patients with lacunar infarction: results from a prospective cohort study.

BACKGROUND: The transient symptoms with lacunar infarction (TSI) and persistent symptoms with lacunar infarction (PSI) are the most common forms of symptomatic lacunar infarction (LI). The aim of this study was to compare the differences in TSI and PSI of symptomatic LI. METHODS: A prospective cohort study was conducted in the neurologic outpatients of the tertiary teaching hospital in Northern China between February 2011 and February 2012. The TSI and PSI in participants aged 35 years or over were assessed. Patients were followed up and their outcomes were compared. RESULTS: Of the 453 symptomatic outpatients, 251 patients with LI were diagnosed by magnetic resonance imaging. Approximately 77.3% (194/251) of the patients with LI at this time had TSI. and the remaining 23.7% had PSI. After the adjusted odds ratios, only middle age (risk ratio [RR], 1.1; 95% confidence interval [CI], 1.157-1.189), lower National Institutes of Health Stroke Scale score (RR, 20.6; 95% CI, 6.705-13.31), smaller lacunae on brain images (RR, 2.9; 95% CI, 1.960-4.245), and LI frequently in the anterior circulation territory (RR, 0.2; 95% CI, 0.079-0.721) were independently associated with TSI. During a mean follow-up of 6 months, survival rate was significantly higher among patients with TSI than among those with PSI (log rank, 6.9; P=0.010); estimated unadjusted incidence of vascular subsequent events (30.9% vs 54.4%, P=0.001) was significantly lower in TSI than in PSI. CONCLUSION: The TSI has a higher prevalence and is associated with a lower risk of vascular subsequent events and death than PSI. The implications of these findings for TSI and PSI may require different interventions.

Early prediction and outcome of septic encephalopathy in acute stroke patients with nosocomial coma.

BACKGROUND: Septic encephalopathy (SE) is the most common acute encephalopathy in ICU; however, little attention has been focused on risk of SE in the course of acute stroke. Our aim is to investigate the early prediction and outcome of SE in stroke patients with nosocomial coma (NC). METHODS: A retrospective cohort study was conducted in an ICU of the tertiary teaching hospital in China from January 2006 to December 2009. Ninety-four acute stroke patients with NC were grouped according to with or without SE. Risk factors for patients with SE were compared with those without SE by univariate and multivariate analysis. RESULTS: Of 94 stroke patients with NC, 46 (49%) had NC with SE and 48 (51%) had NC without SE. The onset-to-NC time was significant later in stroke patients with SE than those without SE (P < 0.01). There was a significant difference in body temperature, heart rate, respiratory rate, white blood cell (WBC), systolic blood pressure (SBP), diastolic blood pressure (DBP), systemic inflammatory response syndrome (SIRS), acute respiratory failure, septic shock, hypernatremia, and sequential organ failure assessment (SOFA) score between the SE and non-SE group (P < 0.05). On a repeat head imaging, vasogenic edema (P = 0.023) and subcortical white matter lesions (P = 0.011) were significantly higher in patients with SE than those without SE, while hematoma growth (P = 0.000), infarction progress (P = 0.003), and recurrent subarachnoid hemorrhage (SAH) (P = 0.011) were significantly lower in patients with SE than those without SE. Patients with SE had higher adjusted rates of fever ≥ 39 °C (odds ratio (OR): 2.753; 95% confidence interval (CI): 1.116 - 6.794; P = 0.028) and SIRS ≥ 3 items (OR: 6.459; 95% CI: 2.050 - 20.351; P = 0.001). The 30-day mortality in stroke patients with SE was higher than those without SE (76.1% vs. 45.8%, P = 0.003). CONCLUSION: High fever and severe SIRS are two early predictors of stroke patients with SE, and survival rates were worse in stroke patients with SE than those without SE.

The biomass and aboveground net primary productivity of Schima superba-Castanopsis carlesii forests in east China.

The biomass and productivity of Schima superba-Castanopsis carlesii forests in Tiantong, Zhejiang Province, were determined using overlapping quadrants and stem analyses. The total community biomass was (225.3+/-30.1) t hm(-2), of which the aboveground parts accounted for 72.0% and the underground parts accounted for 28.0%. About 87.2% of biomass existed in the tree layer. The resprouting biomass was small, of which over 95.0% occurred in the shrub layer. The productivity of the aboveground parts of the community was (386.8+/-98.9) g m(-2)a(-1), in which more than 96.0% was present at the tree level. The trunk's contribution to productivity was the greatest, while that of leaves was the smallest. In China, the community biomass of subtropical evergreen broadleaved forests differs significantly with the age of the forest. The community biomass of the 52-year-old S. superba-C. carlesii forests in this study was lower than the average biomass of subtropical evergreen broadleaved forests in China, and was lower than the biomass of other subtropical evergreen broadleaved forests elsewhere in the world. Moreover, its productivity was lower than the model estimate, indicating that without disturbance, this community has great developmental potential in terms of community biomass and productivity.

[Protective effect of Na2SeO3 against cerebral ischemia-reperfusion injury to the hippocampal neurons in rats].

OBJECTIVE: To investigate the protective effects of selenium on rat hippocampal neurons against ischemia-reperfusion (IR) injury. METHODS: Thirty-two rats were randomly divided into sham-operated group, IR group and selenium-treated group, and in the latter two groups, cerebral IR injury was induced by middle cerebral artery occlusion; Na2SeO3 treatment was administer in selenium-treated group. At 14 days after reperfusion, the brain tissues were harvested from the rats and hippocampal neuron injuries were observed by TUNEL and Methylene Blue staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and nerve growth factor (NGF) in the hippocampal tissues were measured by ELISA. RESULTS: Compared with IR group, the rats in selenium-treated group showed no significant increase in the expression of m-NGF (P>0.05), but pro-NGF expression was significantly increased (P<0.05) in the hippocampal tissue. Na2SeO3 treatment significantly inhibited the expressions of TNF-α and IL-1ß and decreased the apoptosis of hippocampal neurons following cerebral IR injury (P<0.05). CONCLUSION: Selenium produces antiapoptotic effect to protect the hippocampal neurons following cerebral IR injury possibly not by increasing the level of m-NGF but by decreasing the expressions of the inflammatory factors.

[Age structure and growth characteristic of Castanopsis fargesii population].

In this paper, the age structure and growth characteristics of Castanopsis fargesii population in a shade-tolerant broadleaved evergreen forest were studied, aimed to understand more about the regeneration patterns and dynamics of this population. The results showed that the age structure of C. fargesii population was of sporadic type, with two death peaks of a 30-year gap. This population had a good plasticity in growth to light condition. Because there were no significant differences in light condition under the canopy in vertical, the saplings came into their first suppression period when they were 5-8 years old, with a height growth rate less than 0. 1 m x a(-1) lasting for 10 years. The beginning time of the first growth suppression period was by the end of the first death peak of the population, and the ending time of the first growth suppression period was at the beginning of the second death peak of the population, demonstrating that growth characteristic was the key factor affecting the age structure of C. fargesii.