NanoSIMS analysis of water content in bridgmanite at the micron scale: An experimental approach to probe water in Earth’s deep mantle

Water, in trace amounts, can greatly alter chemical and physical properties of mantle minerals and exert primary control on Earth’s dynamics. Quantifying how water is retained and distributed in Earth’s deep interior is essential to our understanding of Earth’s origin and evolution. While directly sampling Earth’s deep interior remains challenging, the experimental technique using laser-heated diamond anvil cell (LH-DAC) is likely the only method available to synthesize and recover analog specimens throughout Earth’s lower mantle conditions. The recovered samples, however, are typically of micron sizes and require high spatial resolution to analyze their water abundance. Here we use nano-scale secondary ion mass spectrometry (NanoSIMS) to characterize water content in bridgmanite, the most abundant mineral in Earth’s lower mantle. We have established two working standards of natural orthopyroxene that are likely suitable for calibrating water concentration in bridgmanite, i.e., A119(H2O) = 99 ± 13 μg/g (1SD) and A158(H2O) = 293 ± 23 μg/g (1SD). We find that matrix effect among orthopyroxene, olivine, and glass is less than 10%, while that between orthopyroxene and clinopyroxene can be up to 20%. Using our calibration, a bridgmanite synthesized by LH-DAC at 33 ± 1 GPa and 3,690 ± 120 K is measured to contain 1,099 ± 14 μg/g water, with partition coefficient of water between bridgmanite and silicate melt ∼0.025, providing the first measurement at such condition. Applying the unique analytical capability of NanoSIMS to minute samples recovered from LH-DAC opens a new window to probe water and other volatiles in Earth’s deep mantle

Resistance-based logic aptamer sensor for CCRF-CEM and Ramos cells integrated on microfluidic chip

A logic aptamer sensor platform was developed for intelligent detection of two types of cancer cells based on the interdigital Au-line microarray (IAuLM) chip. The signal of resistance change caused by capturing of target cells with the aptamers modified on IAuLM is easy to be measured with a commercially available multimeter. By coupling logic operation design, the intelligent diagnostics for multiple kinds of cancer cells could be made. Target cells in blood samples were successfully detected by this chip, indicating that this method can be employed for the early diagnose of cancer and holds promising potential in point of care testing and clinical applications. Keywords: Logic gates, Interdigital Au-line microarray, Cancer cells, Aptamer, Resistanc

Efficacy and safety of total parathyroidectomy with autotransplantation vs. subtotal parathyroidectomy for secondary hyperparathyroidism: A retrospective study

Background: No consensus has been reached on the best surgical approach for secondary hyperparathyroidism (SHPT). We evaluated the short-term and long-term efficacy and safety of total parathyroidectomy with autotransplantation (TPTX + AT) and subtotal parathyroidectomy (SPTX). Methods: We retrospectively analyzed the data of 140 patients undergoing TPTX + AT and 64 undergoing SPTX between 2010 and 2021 in Second Affiliated Hospital of Soochow University, and carried out follow-up. We compared the differences in symptoms, serological examinations, complications and mortality between the two methods, and explored the independent risk factors of secondary hyperparathyroidism recurrence. Results: In short time after surgery, serum intact parathyroid hormone and calcium level was lower in TPTX + AT group than that in SPTX group (both P < 0.05). Severe hypocalcemia was more common in TPTX group (P = 0.003). The recurrent rate was 17.1% for TPTX + AT and 34.4% for SPTX (P = 0.006). There was no statistical difference in all-cause mortality, cardiovascular events, cardiovascular mortality between the two methods. Higher preoperative serum phosphorus level (HR: 1.929 95% CI 1.045–3.563, P = 0.011) and the SPTX surgical method (HR: 2.309, 95% CI 1.276–4.176, P = 0.006) were found to be independent risk factors for SHPT recurrence. Conclusions: Compared with SPTX, TPTX + AT is more effective in reducing the recurrent risk of SHPT without increasing the risk of all-cause mortality and cardiovascular events

A novel chopping current protection circuit for intrinsically safe power supply

For problems that traditional chopping current protection circuit had small cut-off current value and poor anti load impact ability, and needed additional recovery circuit or manual circuit after over-current fault, a novel chopping current protection circuit for intrinsically safe power supply was designed. The circuit adopts double parallel control structure, so as to improve reliability. The circuit can chop circuit rapidly under condition of load over flowing, and put into operation fast after fault with adjusted input point. Meanwhile, the circuit has low power consumption part, so as to reduce power loss under condition of light load or no-load. The experimental results show that the circuit can recover automatically after over-current fault with low load effect and strong load capacity

Pressure-Transient Performances of Fractured Horizontal Wells in the Compartmentalized Heterogeneous Unconventional Reservoirs

In order to investigate pressure performance of multiple fractured horizontal wells (MFHWs) penetrating heterogeneous unconventional reservoir and avoid the high computational cost of numerical simulation, a semi-analytical model for MFHWs combining Green function solution and boundary element method has been obtained, where the reservoir is divided into different homogeneous substructures and coupled at interface boundaries by plane source function in a closed rectangular parallelepiped. Hydraulic fractures are assumed uniform flux and dual porosity model is used for natural fractures system. Then the model is validated by compared with analytical solution of MFHWs in a homogeneous reservoir and trilinear flow model, which shows that this model can achieve high accuracy even with a small interface discretization number, and it can consider the radial flow around each hydraulic fractures. Finally, the pressure responses with heterogeneous parameters of reservoirs are discussed including heterogeneous permeability, non-uniform block-length and fracture half-length distribution as well as dual porosity parameters like elastic storage ratio and crossflow ratio

Leakage Analysis and Hazardous Boundary Determination of Buried Gas Pipeline Considering Underground Adjacent Confined Space

Urban underground construction projects are intertwined vertically and horizontally, and adjacent confined spaces such as water supply and drainage pipelines, side ditches and underground canals may exist near buried gas pipelines. Once the buried gas pipeline leaks, the gas will diffuse into the confined space through the soil and even enter the residential room by the confined space, which brings serious potential safety hazards. In this paper, the underground adjacent confined space hazardous boundary (HB) of underground gas pipeline leakage was defined, the distribution properties of gas leakage diffusion flow field were analyzed by numerical simulation and the distribution law of gas entering the confined space was studied. Using the least-squares method and multiple regression theory, the gas concentration prediction model in the adjacent confined space of buried gas pipeline leakage was established, the HB calculation model was further deduced, and the HB drawing board was drawn. The results showed that in the initial stages, the internal and external pressure and velocity distribution of the pipeline near the leakage hole were unstable, reaching a stable state after 60 s, and then the reverse flow occurred in the pipeline downstream of the leak hole. Reducing the minimum construction distance between the buried gas pipeline and the confined space improved the gas distribution concentration in the confined space. When the minimum construction distance increased from 3 m to 9 m, the gas concentration distribution decreased from 90.21% to 0.88%. Meanwhile, increasing the pipeline pressure and leakage diameter enhanced the gas concentration distribution in the confined space. The HB calculation model and HB drawing board realize the rapid determination of the HB between buried gas pipeline and confined space and offer a more reasonable basis for the design of gas pipeline safe distance in urban underground engineering construction

G‑quadruplex-Based Fluorescent Assay of S1 Nuclease Activity and K⁺

Endonuclease plays an important role in many biological processes, and an assay of endonuclease activity is of great significance. However, traditional methods for the assay of endonuclease activity have undesirable limitations, such as high cost, DNA-consuming and laboriousness. In the present work, a G-quadruplex-based, fluorescent assay of endonuclease activity has been developed with protoporphyrin IX (PPIX) as a signal reporter. S1 nuclease, a single strand DNA (ssDNA)-specific endonuclease, is employed as model system. In the “on” state, G-quadruplex DNA can greatly enhance the fluorescence of PPIX. However, if S1 nuclease could cleave G-quadruplex DNA into small fragments, there would be no formation of G-quadruplexes, accompanied by low emission response of PPIX. This fluorescent discrimination before or after digestion by nuclease can be used to monitor the activity of S1 nuclease. This assay is simple in design and offers a convenient protocol for homogeneous, rapid and high-throughput detection. In addition, the proposed strategy avoids complicated covalent modifications or chemical labeling, and thus offers advantages of simplicity and cost efficiency. More importantly, K⁺ is found to well inhibit the activity of S1 nuclease when using certain G-quadruplex DNA as substrate, and thus this system is further used for turn-on detection of K⁺. S1 nuclease is critical in the detection of K⁺ since it helps to reduce the background signal

Spatial–Temporal Patterns of Carbon Sequestration Benefits and Identification of County-Level Compensation Orders in Beijing–Tianjin–Hebei Ecosystems

The role of ecosystems in sequestering carbon is becoming increasingly important as China’s “dual-carbon” strategy and the construction of an ecological civilisation continue to be promoted and implemented. The rapid economic development of the Beijing–Tianjin–Hebei region is accompanied by the problem of excessive carbon emissions. Focusing on enhancing the carbon sequestration benefits of ecosystems and coordinating regional development, this paper adopts the model construction method, spatial correlation analysis, and centre of gravity migration analysis to study the spatial and temporal patterns of ecosystems’ carbon sequestration benefits in the counties of Beijing–Tianjin–Hebei, spatial and spatial aggregation, the pattern of centre of gravity migration, and the sequence of county compensation differentials in the period from 2000 to 2020. The results show (1) the carbon account of the Beijing–Tianjin–Hebei region before the revision shows an overall distribution pattern of “low in the north and high in the south”. However, it is important to take into account the differences in the regional area, regional population, and regional GDP and the fact that the analysis of the amount of ecological compensation does not mechanically take into account the absolute magnitude of each value but rather takes into account all the values and then makes a trade-off for the difference in the value of the difference in the background. The spatial distribution of corrected carbon accounts is more even. (2) The high–high aggregation area of ecological compensation from 2000 to 2020 is mainly distributed in a dozen counties, such as Lulong County and Luan County in the eastern part of the Beijing–Tianjin–Hebei region, while the low–low aggregation area is mainly concentrated in counties such as Weichang County and Longhua County in the western and northern parts of the country, and the scope has a tendency to expand. (3) The centre of gravity of the ecological compensation amount moves roughly within the range of 116°17′30″ E–116°30′30″ E, 38°40′ N–38°50′ N, and the overall change rule of northwest to southeast migration is observed, with reciprocal movement in some years. (4) The top 15 lists of eco-compensation pay areas and payment areas have basically remained stable, with only some internal sorting changes, and the overall amount of payment areas is larger than that of payee areas, with sufficient surplus funds to ensure the smooth implementation of eco-compensation work at the county level in Beijing–Tianjin–Hebei. The findings of this paper are important for coordinating the integrated development of Beijing–Tianjin–Hebei and, at the same time, contributing positively to the realisation of China’s carbon peaking and carbon neutrality goals