Simultaneous information and power transfer over the wireless channels potentially offers great convenience to mobile users. Yet practical receiver designs impose technical constraints on its ...hardware realization, as practical circuits for harvesting energy from radio signals are not yet able to decode the carried information directly. To make theoretical progress, we propose a general receiver operation, namely, dynamic power splitting (DPS), which splits the received signal with adjustable power ratio for energy harvesting and information decoding, separately. Three special cases of DPS, namely, time switching (TS), static power splitting (SPS) and on-off power splitting (OPS) are investigated. The TS and SPS schemes can be treated as special cases of OPS. Moreover, we propose two types of practical receiver architectures, namely, separated versus integrated information and energy receivers. The integrated receiver integrates the front-end components of the separated receiver, thus achieving a smaller form factor. The rate-energy tradeoff for the two architectures are characterized by a so-called rate-energy (R-E) region. The optimal transmission strategy is derived to achieve different rate-energy tradeoffs. With receiver circuit power consumption taken into account, it is shown that the OPS scheme is optimal for both receivers. For the ideal case when the receiver circuit does not consume power, the SPS scheme is optimal for both receivers. In addition, we study the performance for the two types of receivers under a realistic system setup that employs practical modulation. Our results provide useful insights to the optimal practical receiver design for simultaneous wireless information and power transfer (SWIPT).
Antimicrobial resistance is now widely regarded as a global public health threat. A growing number of studies suggest that antibiotic resistance is higher in China than in most western countries. ...Despite the current official regulation prohibiting pharmacies from the unrestricted selling of antibiotics, there is little sign of declining consumer demand. China now ranks as the second largest consumer of antibiotics in the world, after India. Drawing on published historical data, unpublished archival documents, and recently collected oral interviews, this paper provides a historical overview of antibiotic use and abuse in the People's Republic of China (PRC) from the second half of the 20th century to the present. It demonstrates how the political demand for health improvement, along with the state-sponsored popularization of allopathic medicine, on the one hand, and the lack of access to adequate medical care for the majority of the population, as well as the existing culture of self-medication, on the other hand, are working in tandem to create antibiotic dependency in China. In addition, the privatization and marketization of biomedicine and health care in post-Mao China have helped to build a new and ever-thriving network of production, distribution, and marketing of antibiotics, which has often proven difficult for the authorities to monitor. At the same time, increased purchasing power and easier accessibility created by this new network of production, distribution, and marketing have further contributed to the prevalence of antibiotic overuse in the late 20th and early 21st centuries.
In this paper, we study the optimal design for simultaneous wireless information and power transfer (SWIPT) in downlink multiuser orthogonal frequency division multiplexing (OFDM) systems, where the ...users harvest energy and decode information using the same signals received from a fixed access point (AP). For information transmission, we consider two types of multiple access schemes, namely, time division multiple access (TDMA) and orthogonal frequency division multiple access (OFDMA). At the receiver side, due to the practical limitation that circuits for harvesting energy from radio signals are not yet able to decode the carried information directly, each user applies either time switching (TS) or power splitting (PS) to coordinate the energy harvesting (EH) and information decoding (ID) processes. For the TDMA-based information transmission, we employ TS at the receivers; for the OFDMA-based information transmission, we employ PS at the receivers. Under the above two scenarios, we address the problem of maximizing the weighted sum-rate over all users by varying the time/frequency power allocation and either TS or PS ratio, subject to a minimum harvested energy constraint on each user as well as a peak and/or total transmission power constraint. For the TS scheme, by an appropriate variable transformation the problem is reformulated as a convex problem, for which the optimal power allocation and TS ratio are obtained by the Lagrange duality method. For the PS scheme, we propose an iterative algorithm to optimize the power allocation, subcarrier (SC) allocation and the PS ratio for each user. The performances of the two schemes are compared numerically as well as analytically for the special case of single-user setup. It is revealed that the peak power constraint imposed on each OFDM SC as well as the number of users in the system play key roles in the rate-energy performance comparison by the two proposed schemes.
•Hot spring waters from shallow reservoirs are mostly of Ca-SO4 or Ca-HCO3 type.•Hot spring waters from deep reservoirs are mostly of Na-HCO3 type.•Hot springs with a deeper circulation depth have ...higher TDS.•Various mixing ratios indicate the heterogeneity of faults and different reservoirs.•Li/Cl ratios show that geothermal waters have three different reservoir sources.
Hot springs in fault zones play a critical role in studying the structural effects on the evolution of geothermal systems. The northern Red River Fault Zone lies in the western part of Yunnan, southwest China, with hot springs ranging from low-medium to high temperatures. From 2013 to 2019, thirty water samples were collected to analyze hydrochemical characteristics and structural effects. The hydrochemical compositions of hot springs mainly come from the weathering or dissolution of the carbonate, evaporite, and silicate minerals, and the cation exchange. High contents of F and Si in the hot springs of high temperature enhance water–rock interactions. For hot springs along faults, there is a positive correlation between TDS and circulation depth. Li/Cl ratios show that geothermal waters have three reservoir sources of different depths. Hot spring waters from shallower reservoirs are mainly Ca-SO4 or Ca-HCO3 type, and those from deeper reservoirs are Na-HCO3 type. Hydrochemical compositions of the hot springs are controlled by faults in terms of circulation depth and geothermal reservoirs. Hot spring waters are mixed, with the proportions of cold water ranging from 60% to 90%. The hot springs with varying mixing ratios may indicate the heterogeneity of fault networks and different reservoir sources. This study underlines the hydrochemical evolution of geothermal water along faults, with key implications for the understanding and exploitation of geothermal systems in the fault zone and similar regions.
► The one step hydrothermal method with ammonia used in this manuscript can reduce graphene oxide (GO) and anchor ZnO nanostuctures to reduced graphene oxide (RGO) sheets synchronously. ► The ...morphology of ZnO in ZnO–RGO can be changed by adjusting mass ratio between Zn(NO3)2·6H2O and GO used for preparation of ZnO–RGO. ► The ZnO–RGO can hinder the recombination of photo electrons and holes to enhance the photocatalytic degradation of methylene blue.
Hydrothermal method was utilized to prepare reduced graphene oxide (RGO) and fabricate ZnO–RGO hybrid (ZnO–RGO) with zinc nitrate hexahydrate and graphene oxide (GO) as raw materials under pH value of 11 adjusted by ammonia water. During the process of reduction of GO, hydrothermal condition with ammonia provided thermal and chemical factors to synthesize RGO. The retained functional groups on RGO planes played an important role in anchoring ZnO to RGO, which was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy and photoluminescence spectra. The various mass ratios of zinc nitrate hexahydrate to GO used to prepare ZnO–RGO impacted significantly on the morphology of ZnO nanostructures such as nanoparticles and nanorods. And, the RGO sheets wrapped ZnO nanoparticles and nanorods very tightly. After the emission of photo electrons from ZnO, RGO in ZnO–RGO can effectively transfer the photo electrons to exhibit a high performance and reproducibility in photocatalytic degradation toward methylene blue (MB) absorbed on the surface of RGO through π–π conjugation.
Sodium dual‐ion batteries (Na‐DIBs) have attracted increasing attention due to their high operative voltages and low‐cost raw materials. However, the practical applications of Na‐DIBs are still ...hindered by the issues, such as low capacity and poor Coulombic efficiency, which is highly correlated with the compatibility between electrode and electrolyte but rarely investigated. Herein, fluoroethylene carbonate (FEC) is introduced into the electrolyte to regulate cation/anion solvation structure and the stability of cathode/anode‐electrolyte interphase of Na‐DIBs. The FEC modulates the environment of PF6− solvation sheath and facilitates the interaction of PF6− on graphite. In addition, the NaF‐rich interphase caused by the preferential decomposition of FEC effectively inhibits side reactions and pulverization of anodes with the electrolyte. Consequently, Sb||graphite full cells in FEC‐containing electrolyte achieve an improved capacity, cycling stability and Coulombic efficiency. This work elucidates the underlying mechanism of bifunctional FEC and provides an alternative strategy of building high‐performance dual ion batteries.
With the addition of FEC, a robust electrode‐electrolyte interphase formed on the surface of Sb anode and graphite cathode, inhibiting the pulverization of Sb and the expansion of graphite. The formation of FEC‐rich anions solvation structure facilitates the insertion of PF6−, which significantly improves the reversible capacity. Thus, guaranteeing the greatly enhanced performance of high voltage and power density Sb||graphite dual‐ion batteries.
We approach the continuous‐time mean–variance portfolio selection with reinforcement learning (RL). The problem is to achieve the best trade‐off between exploration and exploitation, and is ...formulated as an entropy‐regularized, relaxed stochastic control problem. We prove that the optimal feedback policy for this problem must be Gaussian, with time‐decaying variance. We then prove a policy improvement theorem, based on which we devise an implementable RL algorithm. We find that our algorithm and its variant outperform both traditional and deep neural network based algorithms in our simulation and empirical studies.
Background and Aims
Endoscopic radiofrequency ablation (RFA) is an emerging technique for the palliation of inoperable malignant biliary strictures (MBSs). We aimed to systemically investigate the ...long‐term outcome of RFA in a large cohort of patients.
Methods
We recruited 883 patients with various MBSs who underwent endoscopic interventions at two large‐volume centers; 124 patients underwent RFA and stenting, whereas 759 underwent stenting alone. To overcome selection bias, we performed 1:4 propensity score matching (PSM). The main outcome was overall survival (OS).
Results
Following PSM, patients in the RFA group showed significantly longer OS (9.5 months; 95% CI: 7.7‐11.3 months) than those in the stenting alone group (6.1 months; 95% CI: 5.6‐6.6 months; P < .001). In stratified analyses, the improved OS was only demonstrated in the subgroup of extrahepatic cholangiocarcinoma (11.3 months 95% CI: 10.2‐12.4 vs 6.9 months 95% CI: 6.0‐7.8; P < .001), but not in the subgroups of gallbladder cancer, hepatocellular carcinoma, intrahepatic cholangiocarcinoma, pancreatic cancer, and other metastatic cancers (all P > .05). The survival benefits were noted only in the patients with non‐metastatic cholangiocarcinoma (11.5 vs 7.4 months, P < .001).
Conclusions
The survival benefits of endoscopic RFA appear to be limited to patients with extrahepatic cholangiocarcinoma without distant metastasis.
HighlightXia and colleagues investigated the outcomes of endoscopic interventions in a large cohort of 883 patients with inoperable malignant biliary strictures using propensity score matching. Compared with stenting alone, additional endobiliary radiofrequency ablation improved overall survival; however, the survival benefit was limited to patients with extrahepatic cholangiocarcinoma without distant metastasis.
This study aimed to determine the mutational spectrum of familial Parkinson's disease and sporadic early-onset Parkinson's disease (sEOPD) in a mainland Chinese population and the clinical features ...of mutation carriers. We performed multiplex ligation-dependent probe amplification assays and whole-exome sequencing for 1676 unrelated patients with Parkinson's disease in a mainland Chinese population, including 192 probands from families with autosomal-recessive Parkinson's disease, 242 probands from families with autosomal-dominant Parkinson's disease, and 1242 sEOPD patients (age at onset ≤ 50). According to standards and guidelines from the American College of Medical Genetics and Genomics, pathogenic/likely pathogenic variants in 23 known Parkinson's disease-associated genes occurred more frequently in the autosomal-recessive Parkinson's disease cohort (65 of 192, 33.85%) than in the autosomal-dominant Parkinson's disease cohort (10 of 242, 4.13%) and the sEOPD cohort (57 of 1242, 4.59%), which leads to an overall molecular diagnostic yield of 7.88% (132 of 1676). We found that PRKN was the most frequently mutated gene (n = 83, 4.95%) and present the first evidence of an SNCA duplication and LRRK2 p.N1437D variant in mainland China. In addition, several novel pathogenic/likely pathogenic variants including LRRK2 (p.V1447M and p.Y1645S), ATP13A2 (p.R735X and p.A819D), FBXO7 (p.G67E), LRP10 (c.322dupC/p.G109Rfs*51) and TMEM230 (c.429delT/p.P144Qfs*2) were identified in our cohort. Furthermore, the age at onset of the 132 probands with genetic diagnoses (median, 31.5 years) was about 14.5 years earlier than that of patients without molecular diagnoses (i.e. non-carriers, median 46.0 years). Specifically, the age at onset of Parkinson's disease patients with pathogenic/likely pathogenic variants in ATP13A2, PLA2G6, PRKN, or PINK1 was significantly lower than that of non-carriers, while the age at onset of carriers with other gene pathogenic/likely pathogenic variants was similar to that of non-carriers. The clinical spectrum of Parkinson's disease-associated gene carriers in this mainland Chinese population was similar to that of other populations. We also detected 61 probands with GBA possibly pathogenic variants (3.64%) and 59 probands with GBA p.L444P (3.52%). These results shed insight into the genetic spectrum and clinical manifestations of Parkinson's disease in mainland China and expand the existing repertoire of pathogenic or likely pathogenic variants involved in known Parkinson's disease-associated genes. Our data highlight the importance of genetic testing in Parkinson's disease patients with age at onset < 40 years, especially in those from families with a recessive inheritance pattern, who may benefit from early diagnosis and treatment.
In littoral zones where fresh groundwater discharges into the sea, a vertical difference in hydraulic head always exists within the fresh-water zone, i.e., the Dupuit assumption is not satisfied. The ...hydraulic head difference may affect the sharp interface and needs to be taken into account when position of the interface is determined. Examination of the equilibrium status of a point on the interface reveals that the location of the interface in a homogeneous and isotropic coastal unconfined aquifer can be determined based on the fresh-water head and the salt-water head at one point on the sharp interface. Considering a linear increase or decrease in the hydraulic head within the fresh-water zone, a method for estimating the position of the sharp interface is described on the basis of the fresh hydraulic heads at two arbitrary points in the fresh-water zone and the salt hydraulic head at one arbitrary point in the salt-water zone in the same vertical straight line in the littoral zone. The method using corresponding pressures at the points is also given. The Ghyben-Herzberg model is a specific case of the method. This method requires three nearest observation wells, two revealing the fresh-water zone and one tapping the deeper salt-water zone, or three transducers installed in one well, two in the fresh-water zone and one in the deeper salt-water zone. The Observations of piezometric heads in the northwest Beihai coast in China are used to illustrate the application of the method to determine the position of the sharp interface, which ranges from 32.56 to 49.15 m under the mean sea level during the specific observation period.
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