Configuring Intelligent Reflecting Surface with Performance Guarantees: Blind Beamforming

This work gives a blind beamforming strategy for intelligent reflecting surface (IRS), aiming to boost the received signal-to-noise ratio (SNR) by coordinating phase shifts across reflective elements in the absence of channel information. While the existing methods of IRS beamforming typically first estimate channels and then optimize phase shifts, we propose a conditional sample mean based statistical approach that explores the wireless environment via random sampling without performing any channel estimation. Remarkably, the new method just requires a polynomial number of random samples to yield an SNR boost that is quadratic in the number of reflective elements, whereas the standard random-max sampling algorithm can only achieve a linear boost under the same condition. Moreover, we gain additional insight into blind beamforming by interpreting it as a least squares problem. Field tests demonstrate the significant advantages of the proposed blind beamforming algorithm over the benchmark algorithms in enhancing wireless transmission.Comment: 16 pages, 15 figure

A Linear Time Algorithm for the Optimal Discrete IRS Beamforming

It remains an open problem to find the optimal configuration of phase shifts under the discrete constraint for intelligent reflecting surface (IRS) in polynomial time. The above problem is widely believed to be difficult because it is not linked to any known combinatorial problems that can be solved efficiently. The branch-and-bound algorithms and the approximation algorithms constitute the best results in this area. Nevertheless, this work shows that the global optimum can actually be reached in linear time in terms of the number of reflective elements (REs) of IRS. The main idea is to geometrically interpret the discrete beamforming problem as choosing the optimal point on the unit circle. Although the number of possible combinations of phase shifts grows exponentially with the number of REs, it turns out that there are merely a linear number of points on the unit circle to consider. Furthermore, the proposed algorithm can be viewed as a novel approach to a special case of the discrete quadratic program (QP).Comment: 5 page

10H‐3,6‐Diazaphenothiazines triggered the mitochondrial‐dependent and cell death receptor‐dependent apoptosis pathways and further increased the chemosensitivity of MCF‐7 breast cancer cells via inhibition of AKT1 pathways

Breast cancer is one of the leading causes of death in cancer categories, followed by lung, colorectal, and ovarian among the female gender across the world. 10H-3,6-diazaphenothiazine (PTZ) is a thiazine derivative compound that exhibits many pharmacological activities. Herein, we proceed to investigate the pharmacological activities of PTZ toward breast cancer MCF-7 cells as a representative in vitro breast cancer cell model. The PTZ exhibited a proliferation inhibition (IC50 = 0.895 µM) toward MCF-7 cells. Further, cell cycle analysis illustrated that the S-phase checkpoint was activated to achieve proliferation inhibition. In vitro cytotoxicity test on three normal cell lines (HEK293 normal kidney cells, MCF-10A normal breast cells, and H9C2 normal heart cells) demonstrated that PTZ was more potent toward cancer cells. Increase in the levels of reactive oxygen species results in polarization of mitochondrial membrane potential (ΔΨm), together with suppression of mitochondrial thioredoxin reductase enzymatic activity suggested that PTZ induced oxidative damages toward mitochondria and contributed to improved drug efficacy toward treatment. The RT2 PCR Profiler Array (human apoptosis pathways) proved that PTZ induced cell death via mitochondria-dependent and cell death receptor-dependent pathways, through a series of modulation of caspases, and the respective morphology of apoptosis was observed. Mechanistic studies of apoptosis suggested that PTZ inhibited AKT1 pathways resulting in enhanced drug efficacy despite it preventing invasion of cancer cells. These results showed the effectiveness of PTZ in initiation of apoptosis, programmed cell death, toward highly chemoresistant MCF-7 cells, thus suggesting its potential as a chemotherapeutic drug

Ferritinophagy and ferroptosis in the management of metabolic diseases

Ferroptosis is a form of regulated cell death modality associated with disturbed iron-homeostasis and unrestricted lipid peroxidation. Ample evidence has depicted an essential role for ferroptosis as either the cause or consequence for human diseases, denoting the likely therapeutic promises for targeting ferroptosis in the preservation of human health. Ferritinophagy, a selective form of autophagy, contributes to the initiation of ferroptosis through degradation of ferritin, which triggers labile iron overload (IO), lipid peroxidation, membrane damage, and cell death. In this review, we will delineate the role of ferritinophagy in ferroptosis, and its underlying regulatory mechanisms, to unveil the therapeutic value of ferritinophagy as a target in the combat of ferroptosis to manage metabolic diseases.Peer reviewe

Pooled Sequencing Analysis of Geese (Anser cygnoides) Reveals Genomic Variations Associated With Feather Color

During the domestication of the goose a change in its feather color took place, however, the molecular mechanisms responsible for this change are not completely understood. Here, we performed whole-genome resequencing on three pooled samples of geese (feral and domestic geese), with two distinct feather colors, to identify genes that might regulate feather color. We identified around 8 million SNPs within each of the three pools and validated allele frequencies for a subset of these SNPs using PCR and Sanger sequencing. Several genomic regions with signatures of differential selection were found when we compared the gray and white feather color populations using the FST and Hp approaches. When we combined previous functional studies with our genomic analyses we identified 26 genes (KITLG, MITF, TYRO3, KIT, AP3B1, SMARCA2, ROR2, CSNK1G3, CCDC112, VAMP7, SLC16A2, LOC106047519, RLIM, KIAA2022, ST8SIA4, LOC106044163, TRPM6, TICAM2, LOC106038556, LOC106038575, LOC106038574, LOC106038594, LOC106038573, LOC106038604, LOC106047489, and LOC106047492) that potentially regulate feather color in geese. These results substantially expand the catalog of potential feather color regulators in geese and provide a basis for further studies on domestication and avian feather coloration

The Impact of Migration on Farm Performance : Evidence from Rice Farmers in China

Developing economies face challenges in improving the overall performance of farms. An essential challenge could be a substantial shift in the agricultural labor force to off-farm sectors during the process of economic transition. This paper estimates the causal impact of migration on the economic and environmental performance of rice farms, measured using technical efficiency and fertilizer use efficiency. A stochastic frontier analysis, based on the survey data collected in four regions of China, is applied, finding an average technical efficiency of 0.92, while the average fertilizer use efficiency is only 0.22. The results of propensity score matching suggest that migration has a marginally negative impact on both technical efficiency and fertilizer use efficiency of their rice production, while the impact is amplified for farmers who participated in migration more intensively. This would imply that the government policy on the migration of rural households might also need to consider this impact

The Effect of School Quality on House Prices: Evidence from Shanghai, China

Understanding the housing price premium of high-quality education could be important for improving our knowledge on the formation of housing prices and potential consequences of educational resources misallocation. This paper estimates the housing price premium of high-quality primary schools in Shanghai, China. Applying the hedonic price and paired difference models with a boundary fixed effect to the house resale transaction data from January to October 2019, the study found that the housing price premium of high-quality primary school was approximately 15.6%. Moreover, the price premium of small houses was larger than that of large houses. The results suggest that high-quality education has a significant capitalization effect on housing values. This implies that the policy of restricting one student to have a seat in only one particular school within the zoning area would lead to greater education inequality and future policies should consider this effect

Rural household migration in China – the roles of actual and perceived tenure security

Migration can make an important contribution to rural poverty reduction and overall productivity growth, but it may be limited by prevailing rural land tenure arrangements. Since 1998, the Chinese government has implemented a number of land tenure reforms with the aim of improving the tenure security and the transferability of land. Although these reforms enhanced legal tenure security, it is not clear to what extent they remove existing land tenure bottlenecks in migration. Both actual tenure security, i.e. local implementation of laws that warrant tenure security, and household perceptions of tenure security are likely to play a role. In this paper we examine the impacts of actual and perceived tenure security on rural household migration in China, taking into account the degree of development of land rental markets. We argue that actual and perceived tenure security can have both positive and negative effects on migration decisions and that the presence of land rental markets may modify these effects. A two-step control function approach that controls for endogeneity of tenure security perceptions is applied to household and village-level data collected in Jiangsu, Jiangxi, Liaoning provinces and Chongqing municipality. We find that both actual and perceived tenure security affect migration, but the impact of perceived tenure security measured by land reallocation expectations is much stronger and is positive, whereas the independent impact of actual tenure security is negative. Households perceiving a lower risk of losing land when one or more members migrate are more inclined to migrate, independent of the availability of land rental markets in their villages. Actual tenure security, as measured by absence of land reallocations and possession of land certificates, has an independent negative effect on migration only in villages with underdeveloped land rental markets.</p