Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics

The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment. However, the need for high heat transfer rates in thermal harvesting systems is a longstanding obstacle for their practical application. In this work, we construct thermally conductive networks in Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(Zr95Ti5)1−yO3 (lead magnesium niobate–lead antimony–manganese–lead zirconate titanate: PMN–PMS–PZT) ceramics to improve heat transfer and enhance their ferroelectric properties by use of a thermally conductive AlN additive dispersed in the ceramic matrix. The ferroelectric properties, pyroelectric coefficient and thermal conductivity of the PMN–PMS–PZT: AlN composite materials are influenced by the AlN content as a result of the formation of random bridges or thermally conductive networks for phonon transfer in the ceramic matrix, thereby leading to high heat transfer. For a PMN–PMS–PZT composite with a 0.2 wt% AlN content, the ferroelectric properties, pyroelectric coefficient and thermal conductivity are shown to be enhanced owing to the improved crystallinity and density, and the relative permittivity is also reduced, which results in optimized pyroelectric figure of merits. This combination of materials property enhancements is shown to be beneficial for high performance pyroelectric materials in devices for energy harvesting applications

Hexagonal boron nitride nanosheets doped pyroelectric ceramic composite for high-performance thermal energy harvesting

Recently, recycling energy from wasted heat with pyroelectric materials has received significant attention. However, pyroelectric energy harvesters generally suffer from a low energy efficiency due to the low rates of heat transfer. Here, we report high-performance thermal energy harvesting using novel hybrid pyroelectric ceramics with greatly improved heat transfer and rate of temperature changes. This is achieved by evenly dispersing 0.1 wt% hexagonal boron nitride (hBN) nanosheets into a Pb[(Mn 1/3 Nb 2/3 ) 1/2 (Mn 1/3 Sb 2/3 ) 1/2 ] 0.04 (Zr 0.95 Ti 0.05 ) 0.96 O 3 (lead magnesium niobate-lead antimony-manganese-lead zirconate titanate: PMN-PMS-PZT) ceramic matrix. Due to the vibrations of whole chain and phonon scattering, heat transfer through the hybrid crystalline chain is more efficient than that of unfilled PMN-PMS-PZT. It is demonstrated that the harvested power was increased by up to 65.6%. This work paved an efficient and cost-effective way to largely improve the traditional pyroelectric ceramic for thermal energy harvesting. </p

Multiplexed Serum Biomarkers for the Detection of Lung Cancer

AbstractCurrently, there is no available biomarker for lung cancer diagnosis. Here we recruited 844 lung cancer patients and 620 healthy participants from six hospitals. A total of four serum proteins was identified and subsequently assessed in the training and validation cohorts. The concentrations of four serum proteins were found to be significantly higher in lung cancer patients compared with healthy participants. The area under the curve (AUC) for the 4-biomarker were 0.86 in the training cohort, and 0.87 in the validation cohort. The classification improved to a corrected AUC of 0.90 and 0.89 respectively following addition of sex, age and smoking status. Similar results were observed for early-stage lung cancer. Remarkably, in a blinded test with a suspicious pulmonary nodule, the adjusted prediction model correctly discriminated the patients with 86.96% sensitivity and 98.25% specificity. These results demonstrated the 4-biomarker panel improved lung cancer prediction beyond that of known risk factors. Moreover, the biomarkers were valuable in differentiating benign nodules which will remain indolent from those that are likely to progress and therefore might serve as an adjuvant diagnosis tool for LDCT scanning

Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics

The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment.</p

Effect of Zr/Ti ratio on microstructure and electrical properties of pyroelectric ceramics for energy harvesting applications

In this paper, Pb[(MnxNb1-x)1/2(MnxSb1-x)1/2]y(ZrzTi1-z)1-yO3 (lead magnesium niobate-lead antimony-manganese-lead zirconate titanate: PMnN-PMS-PZT) ceramics with three different Zi/Ti compositions of 95/5 (Zr95), 85/15 (Zr85) and (Zr85 + Zr95) were successfully fabricated and characterized. The effect of Zr/Ti ratio on the microstructure and electric properties were studied in detail. The pyroelectric coefficient of Zr95 ceramic was 5957 μC/m2K which was more than 2–3 times higher than other reported pyroelectric ceramics. The effect on pyroelectric energy harvesting was systemically investigated via a variation of Zr/Ti compositions in the ceramics, which was directly evaluated by the output power acquired from the data acquisition system. The output power was 25.7 μW, 4.8 μW and 14.2 μW at a composition ratio of Zr95, Zr85 and Zr85 + Zr95, respectively under identical conditions. Among the three Zi/Ti compositions, the best pyroelectric and ferroelectric properties were achieved with Zr95, which indicated that the pyroelectric energy harvesting can be efficiently optimized by the appropriate control of phase structure.</p

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

A Study on the Effect of Dynamic Photovoltaic Shading Devices on Energy Consumption and Daylighting of an Office Building

Photovoltaic shading devices (PVSDs) have the dual function of providing shade and generating electricity, which can reduce building energy consumption and improve indoor daylighting levels. This study adopts a parametric performance design method and establishes a one-click simulation process by using the Grasshopper platform and Ladybugtools. The research focuses on the effect of dynamic PVSDs on daylighting and energy consumption in an office building in Qingdao. The optimal configuration of PVSDs for each month under three dynamic strategies (rotation, sliding, and hybrid) is determined here. Additionally, different control strategies and fixed PVSDs are compared to clarify the impact of various control strategies on daylighting and energy consumption. The findings reveal that, compared to no shading, dynamic PVSDs in the rotation strategy, sliding strategy, and hybrid strategy can achieve energy savings of 32.13%, 47.22%, and 50.38%, respectively. They can also increase the annual average UDI by 1.39%, 2.8%, and 3.1%, respectively. Dynamic PVSDs can significantly reduce the energy consumption of office buildings in Qingdao while improving indoor daylighting levels. A flexible control strategy that adapts to climate change can significantly improve building performance. This research can provide theoretical, methodological, and data support for the application of the PVSD in cold-climate regions in China