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In order to explore the effects of continuous RESET operations and continuous SET operations on the endurance characteristic of phase change memory (PCM), the endurance characteristics of PCM at different ratios of RESET-SET times are studied based on a 4Mbit PCM chip. The variation of resistance distributions of PCM after continuous RESET and continuous SET operations are measured. The endurance characteristics of PCM in RESET-only and SET-only operations are compared with the typical endurance characteristic. Besides, the causes and repair methods of failure are also discussed. Moreover, the endurance characteristics of PCM at 8 different RESET-SET ratios are compared. The research results show that continuous RESET operation has little effect on the endurance characteristic of PCM, and the endurance characteristic of PCM in the RESET-only mode is on the same order as the typical endurance characteristic. However, the continuous SET operation has a significantly destructive effect on the endurance characteristic of PCM, and the endurance characteristic of PCM in the SET-only mode is 2 orders of magnitude lower than the typical endurance characteristic. The failure process of PCM caused by continuous RESET operation is irreversible while the failure process of PCM caused by continuous SET operation can be repaired by intermittent RESET operation.

BackgroundSynchrotron radiation confocal micro X-ray fluorescence (confocal μ-SRXRF) micro-probe is a three dimensional analytical method for detecting chemical elements with depth resolution. It can be used to obtain the chemical element information at different depths of samples in situ, which is suitable in the fields of life and environmental sciences.PurposeThis study aims to apply the confocal μ-SRXRF device and in-situ cryogenic device, developed at the hard X-ray micro-focusing beamline (BL15U1) of Shanghai Synchrotron Radiation Facility (SSRF), to analyze the in vivo chemical elemental imaging of biological samples.MethodsConfocal μ-SRXRF was based on K-B mirrors and polycapillary X-ray optics. The foci of the polycapillary X-ray optics and the incident X-ray beam were coincident by continuous scanning and position modification. The confocal μ-SRXRF was used for in-situ XRF imaging analysis of Arabidopsis thaliana seeds and Daphnia magna, and compared with that of conventional μ-SRXRF. The confocal volume was submerged at different depths within the samples to obtain the depth-dependent information. In addition, an in-situ cryogenic device was used to keep Daphnia magna under the cryogenic environment.ResultsThe spatial distributions of chemical elements for in vivo biological samples were directly obtained by confocal μ-SRXRF, without slicing or drying. The specific distribution of chemical elements in plant tissues or organs is more accurately obtained while the absorption and distribution characteristics of chemical elements in organisms are observed more carefully.ConclusionsConfocal μ-SRXRF can be used to directly and effectively analyze the spatial distribution of chemical elements within biological samples. Meanwhile, it can be expanded to analyze the heat-sensitive biological samples and chemical elements by equipping with in-situ cryogenic device, providing a powerful in-situ characterization technique for the life and environment research.

Secondary hyperparathyroidism (SHPT) is one of the common complications of end-stage renal disease-uremia, and is mainly manifested as parathyroid hyperplasia and abnormal secretion of parathyroid hormone (PTH). To investigate the value and advantages of contrast-enhanced ultrasound (CEUS) in evaluating the survival of autografts after parathyroidectomy + parathyroid autotransplantation. In this study, 125 patients with renal failure due to polycystic kidney disease, chronic nephritis, diabetic nephropathy, lupus nephritis, and atherosclerotic nephropathy were enrolled as the participants and each of them had 4 secondary hyperactive parathyroid glands and underwent parathyroid autotransplantation. One parathyroid gland was taken from each patient and equally divided into 4 parts and placed in the subcutaneous fat of one forearm for transplantation. CEUS was performed 14 days after the transplantation to observe the micro blood supply of the graft and assess the survival and secretory function of the transplanted parathyroid. The grafts were divided into the partial survival group and the total survival group based on the enhancement characteristics. The survival of the grafts was determined by comparing the parathyroid hormone level in bilateral elbow cephalic veins 1 month after surgery. Among the 125 patients, 112 had linear or punctate enhancement of 2–4 parathyroid glands 14 days after surgery, and 13 patients had linear or punctate enhancement of 0–1 parathyroid gland. There were statistically significant differences in the perfusion pattern, enhancement uniformity, and parathyroid hormone levels in the cephalic veins at the elbow on both the graft and non-graft sides among all groups (P< 0.05). Compared to the detection of the difference in the parathyroid hormone level in the cephalic vein of bilateral elbows 1 month after surgery, CEUS can reflect the parathyroid survival after transplantation more quickly and accurately 2 weeks later, and provide a more rapid and agile non-invasive clinical diagnosis method. [ABSTRACT FROM AUTHOR]

We conducted a joint anion photoelectron spectroscopy and theoretical investigation on hybrid lanthanum-copper oxides clusters, LaCu2On−/0 (n=4, 5). The experimental vertical detachment energies of LaCu2O4− and LaCu2O5− are determined to be 3.70 and 3.79 eV, respectively. Theoretical calculations show that the most stable structures of LaCu2O4,5− are mainly composed of LaCu2O3 six-membered ring, with an additional O atom or O2 unit interacting with the La atom. In LaCu2O4−, covalent interaction is presented between the external O atom and the LaCu2O3 six-membered ring. As for LaCu2O5− anion, a weak interaction dominated by inductive force is presented between the external O2 unit and the LaCu2O3 six-membered ring. [ABSTRACT FROM AUTHOR]

Prostanoids are endogenous lipid bioactive mediators that play essential roles in physiological processes such as glucocorticoid secretion. Here, it is found that the thromboxane (Tx)A2 receptor (TP) is highly expressed in the adrenal cortex of mice. Both global and adrenocortical‐specific deletion of the TP receptor lead to increased adiposity in mice by elevating corticosterone synthesis. Mechanistically, the TP receptor deletion increases the phosphorylation of steroidogenic acute regulatory protein (StAR) and corticosterone synthesis in adrenal cortical cells by suppressing p‐p38‐mediated phosphorylation of 14‐3‐3γ adapter protein at S71. The activation of the p38 in the adrenal cortical cells by forced expression of the MKK6EE gene attenuates hypercortisolism in TP‐deficient mice. These observations suggest that the TxA2/TP signaling regulates adrenal corticosterone homeostasis independent of the hypothalamic–pituitary–adrenal axis and the TP receptor may serve as a promising therapeutic target for hypercortisolism. [ABSTRACT FROM AUTHOR]

Crop mapping using satellite imagery is crucial for agriculture applications. However, a fundamental challenge that hinders crop mapping progress is the scarcity of samples. The latest foundation model, Segment Anything Model (SAM), provides an opportunity to address this issue, yet few studies have been conducted in this area. This study investigated the parcel segmentation performance of SAM on commonly used medium-resolution satellite imagery (i.e., Sentinel-2 and Landsat-8) and proposed a novel automated sample generation framework based on SAM. The framework comprises three steps. First, an image optimization automatically selects high-quality images as the inputs for SAM. Then, potential samples are generated based on the masks produced by SAM. Finally, the potential samples are subsequently subjected to a sample cleaning procedure to acquire the most reliable samples. Experiments were conducted in Henan Province, China, and southern Ontario, Canada, using six proven effective classifiers. The effectiveness of our method is demonstrated through the combination of field-survey-collected samples and differently proportioned generated samples. Our results indicated that directly using SAM for parcel segmentation remains challenging, unless the parcels are large, regular in shape, and have distinct color differences from surroundings. Additionally, the proposed approach significantly improved the performance of classifiers and alleviated the sample scarcity problem. Compared to classifiers trained only by field-survey-collected samples, our method resulted in an average improvement of 16% and 78.5% in Henan and Ontario, respectively. The random forest achieved relatively good performance, with weighted-average F1 of 0.97 and 0.996 obtained using Sentinel-2 imagery in the two study areas, respectively. Our study contributes insights into solutions for sample scarcity in crop mapping and highlights the promising application of foundation models like SAM. [ABSTRACT FROM AUTHOR]

In multichannel retailing, consumers may experience products in physical stores and eventually purchase online, which is referred to as showrooming behaviour. In this study, we investigate a manufacturer's online channel strategy in the presence of showrooming behaviour in a supply chain composed of a manufacturer and a physical retailer. Our results exhibit the following major findings. First, adding an online channel regardless of a direct or an indirect online channel (i.e. owned by the manufacturer or an independent online retailer) will not always benefit the manufacturer but introducing a direct online channel will always hurt the physical retailer. Second, when introducing an indirect online channel, the manufacturer will decrease the wholesale price to regulate the effect of showrooming behaviour. Interestingly, if the market size of distant consumers is relatively large, the showrooming behaviour can benefit both the manufacturer and the physical retailer when an indirect online channel is introduced. [ABSTRACT FROM AUTHOR]

The efficient ethanol electrosynthesis from CO2 is challenging with low selectivity at high CO2 electrolysis rates, due to the competition with H2 and other reduction products. Copper‐based bimetallic electrocatalysts are potential candidates for the CO2‐to‐ethanol conversion, but the secondary metal has mainly been focused on active components (such as Ag, Sn) for CO2 electroreduction, which also promote selectivity of ethylene or other reduction products rather than ethanol. Limited attention has been given to alkali‐earth metals due to their inherently active chemical property. Herein, we rationally synthesized a (111) facet‐oriented nano Cu2Mg (designated as Cu2Mg(111)) intermetallic compound with high‐density ordered Cu3‐Mg sites. The in situ Raman spectroscopy and density function theory calculations revealed that the Cu3−δ $_{^{\rm{{\rm \delta} }} }$ −‐Mg−δ $_{^{\rm{{\rm \delta} }} }$ + active sites allowed to increase *CO surface coverage, decrease reaction energy for *CO−CO coupling, and stabilize *CHCHOH intermediates, thus promoting the ethanol formation pathway. The Cu2Mg(111) catalyst exhibited a high FEC2H5OH of 76.2±4.8 % at 600 mA⋅cm−2, and a peak value of |jC2H5OH| of 720±34 mA⋅cm−2, almost 4 times of that using conventional Cu2Mg with (311) facets, comparable to the best reported values for the CO2‐to‐ethanol electroreduction. [ABSTRACT FROM AUTHOR]