Bioinspired Dielectric Nanocomposites with High Charge-Discharge Efficiency Enabled by Superspreading-Induced Alignment of Nanosheets.

High-performance dielectric nanocomposites are promising candidates for thin-film dielectric capacitors for high-power pulse devices. However, the existing nanocomposites suffer from low charge-discharge efficiency (η), which results in severe generation and accumulation of Joule heat and subsequently the failure of the devices. In this work, we report nacre-inspired dielectric nanocomposites with outstanding η, which are enabled by superspreading shear flow-induced highly aligned two-dimensional (2D) nanofillers. Taking boron nitride nanosheets (BNNS) as an example, the highly aligned BNNS in the poly(vinylidene fluoride) (PVDF)-based nanocomposites contributes to a highly efficient Coulomb blockade effect for the injected charge carriers. Therefore, the bioinspired nanocomposites with highly aligned BNNS show significantly reduced dielectric loss (tan δ) (63.3%) and improved η (144.8%), compared to the ones with partially aligned nanosheets fabricated by solution casting. Furthermore, the optimized loading content of BNNS is as low as 3.6 wt %. The resulting nanocomposites exhibit reduced tan δ (0.018) and enhanced Eb (687 kV/mm), η (71%), and Ue (16.74 J/cm3). Our work demonstrates that the realization of high alignment of 2D nanofillers enabled by the superspreading shear flow is a promising way for the development of high-performance dielectric nanocomposites.

Concurrent Enhancement of Breakdown Strength and Dielectric Constant in Poly(vinylidene Fluoride) Film with High Energy Storage Density by Ultraviolet Irradiation.

Polyvinylidene fluoride (PVDF) film with high energy storage density has exhibited great potential for applications in modern electronics, particle accelerators, and pulsed lasers. Typically, dielectric/ferroelectric properties of PVDF film have been tailored for energy storage through stretching, annealing, and defect modification. Here, PVDF films were prepared by the solution casting method followed by an ultraviolet (UV) irradiation process, with special emphasis on how such treatment influences their dielectric and energy storage properties. Upon UV irradiation, the dielectric constant and breakdown strength of the PVDF film were enhanced simultaneously. A high energy density of 18.6 J/cm3, along with a charge-discharge efficiency of 81% at 600 MV/m, was achieved in PVDF after exposure to UV for 15 min. This work may provide a simple and yet effective route to enhance energy storage density of PVDF-based polymers.

Modeling and Durability Behavior of Erosion-Corrosion of Sand Control Screens in Deepwater Gas Wells.

Deepwater gas wells usually have high production rates, which result in high-speed sand movement along with the gas flow and acid components such as CO2 in the gas flow. The erosion and corrosion effect intensifies the damage to sand screens and can further lead to sand control failures, which endanger the safety of production operations. In this paper, using a differential rotation device to simulate erosion, corrosion, and erosion-corrosion, experiments observing the impacts of several factors on sand screens were carried out. The factors include CO2 partial pressure, temperature, flow velocity, sand content, and sand particle size. Their impacts on erosion, corrosion, and erosion-corrosion rate are inspected independently, and the sensitivity of factors to the erosion-corrosion rate of a sand screen was determined using the range method. Traditional erosion models involving flow rate, sand content, and sand grain size and traditional corrosion models involving CO2 partial pressure and temperature are taken as references, and an erosion-corrosion coupled model of sand screens is established based on the experimental results using the multivariate regression analysis. With critical damage thickness taken as the failure criterion of a sand screen, a prediction method for sand screen failure is formed and is applied to the case study of the S deepwater gas field. The results show that under the experimental conditions, the screen loss rate due to erosion-corrosion is significantly higher than that of erosion only or corrosion only and is even higher than the sum of both. The erosion-corrosion rate increases with the increase of CO2 partial pressure, temperature, flow velocity, sand content, and sand particle size. It has an exponential relationship with the negative reciprocal of temperature, a linear relationship with the partial pressure of CO2, and power fitting relationships with flow velocity, sand content, and sand particle size. The ranking of sensitivities to the erosion-corrosion rate of high-quality screens is as follows: sand content > flow velocity > temperature > sand particle size > CO2 partial pressure. The error between the predicted results by the proposed model and the experimental results is in the range of 0.44-9.47%. The erosion-corrosion rate of sand screens in each production well of the S gas field is in the range of 0.0111-0.0521 mm/a, while the durability of the screens is 14-68 years. The erosion-corrosion rate model of a sand screen and the prediction method for sand screen failure proposed in this paper provide theoretical support to the durability evaluation of sand screen in deepwater gas wells, which is of great significance for ensuring the safe and efficient development of offshore oil and gas resources.

QTL Mapping of Adult-Plant Resistance to Leaf and Stripe Rust in Wheat Cross SW 8588/Thatcher using the Wheat 55K SNP Array.

Wheat leaf rust (caused by Puccinia triticina) and stripe rust (caused by Puccinia striiformis f. sp. tritici) cause large production losses in many regions of the world. The objective of this study was to identify quantitative trait loci (QTL) for resistance to leaf rust and stripe rust in a recombinant inbred line population derived from a cross between wheat cultivars SW 8588 and Thatcher. The population and parents were genotyped with the Wheat 55K SNP Array and SSR markers and phenotyped for leaf rust severity at Zhoukou in Henan Province and Baoding in Hebei Province. Stripe rust responses were also evaluated at Chengdu in Sichuan Province, and at Baoding. Seven and six QTL were detected for resistance to leaf rust and stripe rust, respectively. Four QTL on chromosomes 1BL, 2AS, 5AL, and 7BL conferred resistance to both rusts. The QTL on 1BL and 2AS were identified as Lr46/Yr29 and Lr37/Yr17, respectively. QLr.hebau-2DS from Thatcher, identified as Lr22b that was previously thought to be ineffective in China, contributed a large effect for leaf rust resistance. QLr.hebau-5AL/QYr.hebau-5AL, QLr.hebau-3BL, QLr.hebau-6DS, QYr.hebau-4BS, and QYr.hebau-6DS are likely to be new QTL, but require further validation. Kompetitive allele-specific PCR (KASP) markers for QLr.hebau-2DS and QLr.hebau-5AL/QYr.hebau-5AL were successfully developed and validated in a diverse wheat panel from Sichuan Province, indicating their usefulness under different genetic backgrounds. These QTL and their closely linked SNP and SSR markers will be useful for fine mapping, candidate gene discovery, and marker-assisted selection in breeding for durable resistance to both leaf and stripe rusts.

Pubertal administration of antiserum against nerve growth factor regresses renal vascular remodeling in spontaneously hypertensive rats.

To investigate the role of nerve growth factor (NGF) in the development of hypertensive renal vascular remodeling, antiserum against NGF (anti-NGF) or vehicle was injected at 3 weeks of age in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats (n = 9 for each treatment in each strain). Flow-pressure (F-P) and pressure-glomerular filtration rate (P-GFR) relationships at vasodilated perfused kidneys were determined at 10 weeks of age. In the vehicle rats, blood pressure, renal noradrenaline content, the gradient of F-P (minimal vascular resistance at pre- and post-glomerular vasculature) and the X-intercept of P-GFR (preglomerular : postglomerular vascular resistance ratio) were greater in SHR than in WKY rats, although the gradient of P-GFR (glomerular filtration capacity) did not differ significantly between the strains. Blood pressure and renal noradrenaline content were lower in SHR receiving anti-NGF than in SHR receiving vehicle, although such difference was not observed in WKY rats. The gradient of F-P was less but the gradient of P-GFR was greater in SHR receiving anti-NGF compared with SHR receiving vehicle, although the similar differences did not occur in WKY rats. Blood pressure and renal noradrenaline content remained greater in SHR treated with anti-NGF compared with WKY rats treated with vehicle; however, the gradient of F-P did not differ significantly between them. Contrary, anti-NGF did not affect the X-intercept of P-GFR in either strain. In conclusion, NGF could contribute to the genesis of renal vascular remodeling, at least in part, through modification of renal sympathetic activity and blood pressure in SHR.

Imbalance of renal production between 5-hydroxytryptamine and dopamine in patients with essential hypertension complicated by microalbuminuria.

BACKGROUND: In the kidney, 5-hydroxytryptamine (5-HT) and dopamine (DA) are formed by the same enzyme, l-aromatic amino acid decarboxylase, but act on renal function and glomerular structure in an opposite direction. The present study was designed to explore whether rates of renal production of 5-HT relative to that of DA are altered in patients with essential hypertension and microalbuminuria. METHODS: We measured urinary levels of 5-HT and DA, reflecting renal production of 5-HT and DA as well as 24-hour ambulatory blood pressure and urinary albumin excretion in 82 consecutive untreated, essential hypertensives without overt proteinuria. RESULTS: Urinary 5-HT excretion and the ratio of urinary 5-HT to DA were significantly higher in 22 patients with microalbuminuria than in the remaining patients with normoalbuminuria, although urinary DA levels did not differ between the groups. The 24-hour systolic and diastolic blood pressures were also higher in the microalbuminuric group than in the normoalbuminuric group. Multiple regression analysis revealed that urinary 5-HT excretion and 24-hour systolic blood pressure were independently associated with urinary albumin excretion. Furthermore, urinary 5-HT excretion was positively correlated with creatinine clearance as well as blood pressure but tended to be negatively correlated with fractional excretion of sodium. CONCLUSIONS: Renal production of 5-HT is enhanced compared with that of DA in essential hypertensives with microalbuminuria. This imbalance may contribute to the genesis of hypertensive glomerular damage.

[Effect of health education intervention in schools of Yanrui Town, Yushan County].

OBJECTIVE: To evaluate the effect of a new mode of health education in schools. METHODS: In the Zhaiqian Primary School, Yanrui Town, Yushan County in a hilly schistosomiasis endemic area, a new mode of health education intervention, i. e. "rewards and punishment + advise others by using one's experience + teachers' participation" was carried out, and the knowledge, attitude and practice of schistosomiasis prevention of the pupils, and the schistosome infection rates of the pupils were investigated and the results were analyzed and compared before and after the intervention. RESULTS: Among 204 pupils investigated, the awareness rate of schistosomiasis prevention knowledge increased from 26.47% before the intervention to 86.76% and 99.51% one and two years after the intervention, respectively; the rate of correct attitude increased from 17.04% to 73.04% and 100%, respectively; the rate of the infested water contact decreased from 83.33% to 26.96% and 0, respectively; the schistosome infection rate decreased from 2.94% to 0.49% and 0, respectively. CONCLUSION: The health education of schistosomiasis prevention in schools is necessary, and the new mode of health education, "rewards and punishment + advise others by using one's experience + teachers' participation" is effective in the prevention from schistosome infection in pupils.

[Case of distal renal tubular acidosis complicated with renal diabetes insipidus, showing aggravation of symptoms with occurrence of diabetes mellitus].

We report herein a 27-year-old male case of inherited distal renal tubular acidosis complicated with renal diabetes insipidus, the symptoms of which were aggravated by the occurrence of diabetes mellitus. At 2 months after birth, he was diagnosed as having inherited distal renal tubular acidosis and thereafter supplementation of both potassium and alkali was started to treat his hypokalemia and metabolic acidosis. At the age of 4 years, calcification of the bilateral renal medulla was detected by computed tomography. Subsequently his urinary volume gradually increased and polyuria of approximately 4 L/day persisted. At the age of 27 years, he became fond of sugar-sweetened drinks and also often forgot to take the medicine. He was admitted to our hospital due to polyuria of more than 10 L day, muscle weakness and gait disturbance. Laboratory tests disclosed worsening of both hypokalemia and metabolic acidosis in addition to severe hyperglycemia. It seemed likely that occurrence of diabetes mellitus and cessation of medications can induce osmotic diuresis and aggravate hypokalemia and metabolic acidosis. Consequently, severe dehydration, hypokalemia-induced damage of his urinary concentration ability and enhancement of the renin angiotensin system occurred and thereby possibly worsened his hypokalemia and metabolic acidosis. As normalization of hyperglycemia and metabolic acidosis might have exacerbated hypokalemia further, dehydration and hypokalemia were treated first. Following intensive treatment, these abnormalities were improved, but polyuria persisted. Elevated plasma antidiuretic hormone (12.0 pg/mL) and deficit of renal responses to antidiuretic hormone suggested that the polyuria was attributable to the preexisting renal diabetes insipidus possibly caused by bilateral renal medulla calcification. Thiazide diuretic or nonsteroidal anti-inflammatory drugs were not effective for the treatment of diabetes insipidus in the present case.

[Autopsy case of Henoch-Schönlein purpura nephritis complicated with intestinal cytomegalovirus infection].

A 55-year-old man was admitted to our hospital because of arthralgia, purpura, abdominal pain, melena and leg edema. Laboratory findings showed an increased serum creatinine level (2.4 mg/dL), hematuria and massive proteinuria (10.7 g/day). Renal biopsy revealed diffuse endocapillary proliferation and focal mesangial proliferation with IgA deposition predominantly in the glomerular capillary walls. Based on these findings, he was diagnosed as having Henoch-Schönlein purpura nephritis and steroid therapy was started. Following steroid therapy, his nephrotic state remained unchanged, although his renal function improved concomitantly with the disappearance of arthralgia, purpura and abdominal symptoms. Therefore, cyclosporine was added to the steroid therapy to enhance immunosuppression. However, melena recurred and anemia progressed. Endoscopy revealed multiple ulcers in the duodenum and jejunum, and clipping was performed at some bleeding sites. However, he died of hemorrhagic shock. The autopsy revealed that hemorrhagic lesions having cytomegalovirus infection spread widely in the stomach, duodenum and jejunum. Recurrence of gastrointestinal bleeding during the treatment of Henoch-Schönlein purpura nephritis is usually due to severe vasculitis or steroid ulcer. However, in patients receiving strong immunosuppressive therapy, cytomegalovirus infection needs to be considered as cause of gastrointestinal bleeding.