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Postsynthetic modification (PSM) of the metal-organic framework (MOF) has been demonstrated to be an effective strategy to enhance performance. In this particular work, the anion framework

Ultrahigh-Q chiroptical resonance metasurfaces based on merging bound states in the continuum (BICs) are investigated and numerically demonstrated. The destruction of C2 symmetry results in the leakage of BICs into quasi-BICs, and a chiral quasi-BIC is obtained by oblique incidence or continuous destruction of the mirror symmetry of the structure. Due to the significant topological properties of merging BICs, the Q factor (over 2 × 105) of the chiral resonance peak obtained is much higher than that of the previous work. Moreover, the proposed structure is easy to fabricate because no additional out-of-plane asymmetry is introduced. The proposed scheme is of importance in chiral biosensing applications.

Transition metal dichalcogenides (TMDs) have attracted wide attention due to their quasi-two-dimensional layered structure and exotic properties. Plenty of efforts have been done to modulate the interlayer stacking manner for novel states. However, as an equally important element in shaping the unique properties of TMDs, the effect of intralayer interaction is rarely revealed. Here, we report a particular case of pressure-tuned re-arrangement of intralayer atoms in distorted 1T-NbTe2, which was demonstrated to be a new type of structural phase transition in TMDs. The structural transition occurs in the pressure range of 16-20 GPa, resulting in a transformation of Nb atomic arrangement from the trimeric to dimeric structure, accompanied by a dramatic collapse of unit cell volume and lattice parameters. Simultaneously, a charge density wave (CDW) was also found to collapse during the phase transition. The strong increase in the critical fluctuations of CDW induces a significant decline in the electronic correlation and a change of charge carrier type from hole to electron in NbTe2. Our finding reveals a new mechanism of structure evolution and expands the field of pressure-induced phase transition.

We report a novel method to synthesize bulk grain-size gradient polycrystalline Ni by AGG. By periodical sintering in the large volume press (LVP), AGG repeatedly occurs, resulting in exceptionally large grains on the sample surface, but the inner grains are still small. The formation of grain-size gradient profile is attributed to the uneven plastic deformation caused by compression in the LVP. Besides, the gradient structure can be achievable with uniformity by employing tungsten with a high shear modulus into the sample assembly. This work would guide us to design bulk heterogeneous gradient nanostructured materials with both excellent strength and ductility. The uniform grained gradient structure obtained with the improved LVP assembly. (a) The improved LVP assembly with W tablet used between Ni sample and outer Mo-capsule; (b) Inverse pole figure mapping characterization of uniform grain-size gradient structure comprised of smaller grains.

A series of covalent organic frameworks substituted with azo groups (AzoCOFs) have been synthesized via imine condensation. The obtained frameworks show crystallinity and high stability. More importantly, the AzoCOFs exhibit exceptionally high ideal adsorption solution theory (IAST) selectivity in adsorption of C2H2 (35-2891) over CH4 at 273 K and 1 bar, owing to the favorable interactions between azo groups and acetylene molecules. The dependence of the gas adsorption property on pore size and polarity of the frameworks was also studied. The triethylene glycol substituted Tg-AzoCOF shows the highest C2H2/CH4 selectivity (IAST selectivity of 2891), which represents the highest reported for all porous materials. The AzoCOFs also exhibit high IAST adsorption selectivity of C2H4/CH4 (11-20), C2H6/CH4 (15-22), and CO2/CH4 (12-37), which is comparable with most porous materials, thus showing their great potential in gas separation applications.

Indium telluride (In

This paper presents tables of key thermoelectric properties, which define thermoelectric conversion efficiency, for a wide range of inorganic materials. The twelve families of materials included in these tables are primarily selected on the basis of well established, internationally-recognized performance and promise for current and future applications: tellurides, skutterudites, half Heuslers, Zintls, Mg-Sb antimonides, clathrates, FeGa3-type materials, actinides and lanthanides, oxides, sulfides, selenides, silicides, borides and carbides. As thermoelectric properties vary with temperature, data are presented at room temperature to enable ready comparison, and also at a higher temperature appropriate to peak performance. An individual table of data and commentary are provided for each family of materials plus source references for all the data., National Science Foundation; UK Engineering and Physical Sciences Research Council (EPSRC)

Dense and submicron-sized polycrystalline β-Si3N4 bulk samples with average grain size of 263 ± 68 nm have been synthesized using micron-sized α-Si3N4 powder (2 μm) as the starting material by simultaneously tuning the pressure and temperature conditions. The measured Vickers hardness HV of the submicron-sized polycrystalline β-Si3N4 could reach up to about 20 GPa, approaching the upper limit of the single crystal β-Si3N4. The measured fracture toughness KIC of the polycrystalline β-Si3N4 has been enhanced from 3.0 to 4.1 MPa m1/2, as much as 36%, while without sacrificing the hardness. This study demonstrates that using micron-sized powder as the starting material to synthesize submicron-sized polycrystalline bulks by phase transformation under extreme pressure conditions is an efficient pathway to break through the old paradigm—the higher the fracture toughness of a material, the lower the hardness.

Both the air quality index (AQI) and indicatory air pollutants of Anqing, Hefei, and Suzhou near central China from 2017 to 2019, and the impact of COVID-19 epidemic prevention and control actions on air quality were investigated. The combined data for the three cities from 2017 to 2019 indicated that the lowest AQI (averaged 78.1) occurred in the summer season, for which the AQI proportions for classes I, II, III, IV, V, and VI were 25.6%, 49.9%, 21.9%, 2.7%, 0%, and 0%, respectively. The highest (AQI average of 112.6) was in winter, for which the proportions were 7.4%, 39.5%, 33.3%, 12.5%, 7.2%, and 0.1%, respectively. PM2.5, PM10, and NO2 in order were the most important indicatory air pollutants for AQI classes IV, V, and VI, which all prevailed in winter and spring, while O3 was the indicatory air pollutant that occurred most in summer. The COVID-19 event, which triggered global attention, broke out at the end of 2019. This study also investigated and compared the air quality levels in the three cities from January to March 2017–2019 with those in 2020. The results showed that during February 2020, in the three cities, the average ambient air concentrations of PM2.5, PM10, SO2, CO, and NO2 were 41.9 µg m–3, 50.1 µg m–3, 2.18 ppb, 0.48 ppm, and 8.97 ppb, and were 46.5%, 48.9%, 52.5%, 36.2%, and 52.8%, respectively, lower than those in the same month in 2017–2019, respectively. However, the O3 average concentration (80.6 ppb) did not show significant fluctuations and even slightly increased by 3.6%. This is because a lower concentration of NO2 resulted in constraints on the reaction of NO + O3, so the O3 level could not be effectively further reduced. In addition, this study also analyzed and compared the five highest daily AQIs from February 2017–2019 with those of 2020 for the three cities. The mean AQI for the 5 days with the highest daily AQI (averaged 122.6) in February 2020 was 45.1% lower than that for February 2017–2019 (averaging 223.2), and the indicatory air pollutant was always PM2.5, which decreased by 46.7% (from 173.6 to 92.6 µg m–3). It is clear that during the COVID-19 epidemic prevention and control action periods, the air quality near central China improved significantly.

The hydrogen evolution reaction (HER) is one of the most effective and sustainable ways to produce hydrogen gas as an alternative clean fuel. The rate of this electrocatalytic reaction is highly dependent on the properties (dispersity and stability) of electrocatalysts. Herein, we developed well-dispersed and highly stable platinum nanoparticles (PtNPs) supported on a covalent organic framework (COF-bpyTPP), which exhibit excellent catalytic activities toward HER as well as the hydride reduction reaction. The nanoparticles have an average size of 2.95 nm and show superior catalytic performance compared to the commercially available Pt/C under the same alkaline conditions, producing 13 times more hydrogen with a far more positive onset potential (−0.13 V vs. −0.63 V) and ca. 100% faradaic efficiency. The reaction rate of the hydride reduction of 4-nitrophenol was also 10 times faster in the case of PtNPs@COF compared to the commercial Pt/C under the same loading and conditions. More importantly, the PtNPs@COF are highly stable under the aqueous reactions conditions and can be reused without showing noticeable aggregation and activity degradation.

In early 2020, the COVID-19 epidemic spread globally. This study investigated the air quality of three cities in Hubei Province, Wuhan, Jingmen, and Enshi, central China, from January to March 2017–2020 to analyze the impact of the epidemic prevention and control actions on air quality. The results indicated that in the three cities, during February 2020, when the epidemic prevention and control actions were taken, the average concentrations of atmospheric PM2.5, PM10, SO2, CO, and NO2 in the three cities were 46.1 µg m–3, 50.8 µg m–3, 2.56 ppb, 0.60 ppm, and 6.70 ppb, and were 30.1%, 40.5%, 33.4%, 27.9%, and 61.4% lower than the levels in February 2017–2019, respectively. However, the average O3 concentration (23.1, 32.4, and 40.2 ppb) in 2020 did not show a significant decrease, and even increased by 12.7%, 14.3%, and 11.6% in January, February, and March, respectively. This is because a lower concentration of NO2 resulted in constraints on the NO + O3 reaction, and the O3 could not be effectively further depleted. In addition, the average air quality index (AQI) for the three cities in January, February, and March 2020 were 32.2%, 27.7%, and 14.9% lower than the levels in 2017–2019, respectively. Based on the AQIs for the three cities, the combined proportions of Class I and Class Ⅱ in January, February, and March 2020 increased by 27.9%, 24.8%, and 4.3%, respectively, while the combined proportion of AQI Classes III, IV, V, and VI was reduced from 34.8% to 15.8%. In addition, in the first three months of 2020, the indicatory air pollutants in the three cities for the AQIs were predominant in the following order: PM2.5 (72.0%), O3 (16.4%), PM10 (8.3%), NO2 (2.9%), and CO (0.4%). This study provides useful information for establishing a scientific air pollution control strategy and is a valuable reference for future research on improving urban air quality.

This study investigated the AQI (air quality index) and atmospheric pollutants including PM2.5, PM10, CO, SO2, NO2 and O3 in Chongqing, Luzhou and Chengdu from 2017 to 2019. In addition, the impacts of the COVID-19 event on the air quality in the three cities in 2020 were compared and discussed. For the combined AQIs for the three cities, in spring, the daily AQIs ranged between 25 and 182 and averaged 72.1. In summer, the daily AQIs ranged between 24 and 206 and averaged 77.5. In autumn, the daily AQIs ranged between 22 and 170 and averaged 61.1, and in winter, the daily AQIs ranged between 28 and 375 and averaged 99.6. The distributions of the six AQI classes in spring were 3%, 94%, 3%, 0%, 0%, and 0%; in summer, they were 11%, 74%, 15%, 0%, 0% and 0%; in autumn, they were 29%, 70%, 1%, 0%, 0%, and 0%, and in winter, they were 1%, 52%, 44%, 3%, 0%, and 0%, respectively. The average AQIs, in order, were Chengdu (85.4) > Chongqing (73.8) > Luzhou (73.2). Both the highest AQIs and PM2.5 (as the major indicatory air pollutant) occurred mainly in the low temperature season (January, December, and February), while O3 was the main air pollutant in June and August when the weather was hot. In February 2020, during the epidemic prevention and control actions taken in response to COVID-19 for the three cities, the combined AQIs for the top five days with the highest AQIs in February 2020 was 79.4, which was 23.6% lower than that from 2017–2019 (AQI = 100.7), and the average concentrations of PM2.5, PM10, SO2, CO, and NO2 were 89.4 µg m–3, 106 µg m–3, 2.31 ppb, 0.72 ppm, and 12.3 ppb, respectively, and were 17.9%, 30.8%, 83.8%, 19.8%, and 62.1%, lower than those in February 2017–2019. However, the average O3 concentration (31.8 ppb) in February 2020 rather than decreasing, increased by 6.2%. This is because a lower NO2 concentration hindered the NO + O3 reaction and led to increase O3 concentration in the ambient air.

The COVID-19 epidemic discovered and reported at the end of December 2019 and began spreading rapidly around the world. The impact of the COVID-19 event on the trip intensity, AQI (air quality index), and air pollutants, including PM2.5, PM10, SO2, CO, NO2, and O3 in Shenzhen, Guangzhou, and Foshan (the so-called ‘three cities’) from January 12 to March 27, in 2019 and 2020, are compared and discussed. In 2020, the combined trip intensity in the three cities ranged between 0.73 and 5.54 and averaged 2.57, which was 28.4% lower than that in 2019. In terms of the combined AQIs for the three cities, from January 12 to March 26, 2020, the daily AQIs ranged between 21.0 and 121.3 and averaged 56.4, which was 16.0% lower than that in 2019. The average AQIs in order were Guangzhou (57.5) > Foshan (54.1) > Shenzhen (44.1). In 2019, the distribution proportions of the six AQI classes were 45.2%, 50.4%, 4.40%, 0%, 0%, and 0%, respectively, while those in 2020 were 62.7%, 37.3%, 0%, 0%, 0% and 0%, respectively. For the combined data for the three cities, on the top five days with the highest AQIs during the epidemic period, the average concentrations of PM2.5, PM10, SO2, CO, NO2, and O3 were 76.4 μg m–3, 113.4 μg m–3, 5.14 ppb, 0.88 ppm, 36.5 ppb and 55.5 ppb, which were 55.2%, 49.4%, 55.1%, 30.0%, 45.1% and 15.5% lower than those during the non-epidemic period (from January 12 to March 27, 2017–2019). The above results revealed that the comprehensive strict epidemic prevention and control actions reduced trip intensity and improved the air quality significantly.

A broad tunability of the thermoelectric and mechanical properties of CoSb3 has been demonstrated by adjusting the composition with the addition of an increasing number of elements. However, such a strategy may negatively impact processing repeatability and composition control. In this work, single-element-filled skutterudite is engineered to have high thermoelectric and mechanical performances. Increased Yb filling fraction is found to increase phonon scattering, whereas cryogenic grinding contributes additional microstructural scattering. A peak zT of 1.55 and an average zT of about 1.09, which is comparable to the reported results of multiple-filled SKDs, are realized by the combination of simple composition and microstructure engineering. Furthermore, the mechanical properties of Yb single-filled CoSb3 skutterudite are improved by manipulation of the microstructure through cryogenic grinding. These findings highlight the realistic prospect of producing high-performance thermoelectric materials with reduced compositional complexity. Keywords: Skutterudites, Thermoelectric material, Compositional complexity, Microstructure engineering, Cryogenic grinding

Background Studies have shown that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) plays critical roles in the genesis and development of human cancers. Aim To investigate the clinical significance and role of IGF2BP1 in pancreatic cancer. Methods Expression levels of IGF2BP1 and microRNA-494 (miR-494) were mined based on Gene Expression Omnibus datasets and validated in both clinical samples and cell lines by quantitative real-time polymerase chain reaction and Western blot. The relationship between IGF2BP1 expression and clinicopathological factors of pancreatic cancer patients was analyzed. The effect and mechanism of IGF2BP1 on pancreatic cancer cell proliferation were investigated in vitro and in vivo. Analyses were performed to explore underlying mechanisms of IGF2BP1 upregulation in pancreatic cancer and assays were carried out to verify the post-transcriptional regulation of IGF2BP1 by miR-494. Results We found that IGF2BP1 was upregulated and associated with a poor prognosis in pancreatic cancer patients. We showed that downregulation of IGF2BP1 inhibited pancreatic cancer cell growth in vitro and in vivo via the AKT signaling pathway. Mechanistically, we showed that the frequent upregulation of IGF2BP1 was attributed to the downregulation of miR-494 expression in pancreatic cancer. Furthermore, we discovered that reexpression of miR-494 could partially abrogate the oncogenic role of IGF2BP1. Conclusion Our results revealed that upregulated IGF2BP1 promotes the proliferation of pancreatic cancer cells via the AKT signaling pathway and confirmed that the activation of IGF2BP1 is partly due to the silencing of miR-494.

Hepatitis C virus (HCV) is one of the leading causes of chronic liver disease. HCV is not only related to hepatic malignancies but may also promote lymphoid neoplasms. Currently, research has confirmed HCV-related lymphoma, including marginal zone lymphoma (MZL), lymphoplasmacytic lymphoma (LPL), follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and Burkitt lymphoma (BL). Many types of research have shown that antiviral therapy can improve or even remission several HCV-related lymphomas. The direct-acting antiviral agents (DAAs) (such as NS5A protease inhibitors, NS4/4A protease inhibitors and viral polymerase inhibitors) have shown clinical advantages of high efficacy and low side effects for both virus elimination and tumor regression in several HCV-related lymphomas, which may make the selected HCV-related lymphoma patients treated without chemotherapy. In this review the research progress and development direction of antiviral therapy in treating HCV-related lymphoma has summarized briefly.抗病毒治疗在HCV相关淋巴瘤中的治疗现状及研究进展.丙型肝炎病毒（hepatitis C virus，HCV）是全球慢性肝病的主要病因之一，它不仅与肝脏恶性肿瘤相关，而且可能促进淋巴增殖性疾病的发生和发展。目前已证实与HCV有关的淋巴系统增殖性疾病包括边缘区淋巴瘤、淋巴浆细胞性淋巴瘤、滤泡淋巴瘤、弥漫性大B细胞淋巴瘤和Burkits淋巴瘤。许多研究表明，抗病毒治疗后，这些HCV相关的淋巴瘤会随着HCV的消除而减轻甚至缓解。随着NS5A蛋白酶抑制剂、NS4/4A蛋白酶抑制剂和病毒聚合酶抑制剂的出现，它们在HCV相关淋巴瘤中表现出高疗效、低副作用的临床优势，可能使特定的丙肝相关淋巴瘤患者免于免疫化疗。本文对抗病毒治疗在HCV相关淋巴瘤治疗中的研究进展和发展方向作一综述.

Objective To study the correlation between peripheral blood lymphocytes, f/t PSA and LUTS symptoms, and prostatic inflammation in BPH patients.Materials and Methods From May 2020 to October 2020, 120 patients (aged 56-85 years) with BPH undergoing elective transurethral resection of the prostate (TURP) were selected. Peripheral blood lymphocyte counts and f/t PSA values were measured preoperatively, and IPSS scores were assessed. Postoperative prostate tissues were sent for pathological examination, and the relationship between peripheral blood lymphocyte count, TPSA, f/t PSA values, relevant clinical laboratory parameters, and relevant LUTS symptoms and the distribution of prostate tissue inflammation was analyzed.Results with the aggravation of prostatic inflammation, IPSS score and TPSA value were lower, while f/t PSA value and lymphocyte count were lower. Multivariate logistic regression analysis of 120 BPH patients showed that age (> = 60) [odds ratio (OR) = 0.29, 95% CI = 0.31-2.10; P = 0.02], IPSS score [OR = 1.24, 95% CI = 1.13-1.37; P < 0.01], TPSA [OR = 1.10, 95% CI = 1.02-1.19; P = 0.02], f/t PSA [OR = 1.03, 95% CI = 0.01-0.15; P = 0.02], and lymphocytes [OR = 1.70, 95% CI = 0.78-3.77; P = 0.04] were related to the formation of prostatic inflammation in BPH patients. Conclusion Peripheral blood lymphocyte count, TPSA, LUTS severity, and f/t PSA ratio can predict the severity of prostatic inflammation, which may be used as diagnostic markers for BPH patients with LUTS symptoms who have prostatitis and promote the development of drug treatment for LUTS symptoms in BPH patients with prostatitis.

In this paper, a high-efficiency Doherty power amplifier (DPA) using an InGaP/GaAs heterojunction bipolar transistor (HBT) process is presented. The DPA aims for the application of 2.4 GHz wireless local area network (WLAN) systems with a high peak-to-average power ratio (PAPR). The traditional bulky quarter-wavelength line is realized using a low-pass n-type network for miniaturization and low loss. A thermally compensated dynamic bias circuit is applied to increase thermal stability. Under the excitation of a 40-MHz 64-quadratic-amplitude modu-lation(QAM) signal, the proposed DPA achieves a gain of 29 dB gain, an average power of 26 dBm, and an average power added efficiency (PAE) up to 21%. Good error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR) performance are also measured, which demonstrates EVM and ACLR after digital pre-distortion (DPD) are −42 dB and −50.7 dBc. respectively.

Transition metal dichalcogenides (TMDs) have attracted wide attention due to their quasi-two-dimensional layered structure and exotic properties. Plenty of efforts have been done to modulate the interlayer stacking manner for novel states. However, as an equally important element in shaping the unique properties of TMDs, the effect of intralayer interaction is rarely revealed. Here, we report a particular case of pressure-tuned re-arrangement of intralayer atoms in distorted 1T-NbTe

Ionic covalent organic frameworks (ICOFs) have recently emerged as promising candidates for solid-state electrolytes. Herein, we report the first example of a series of crystalline imidazolate-containing ICOFs as single-ion conducting COF solid electrolyte materials, where lithium cations freely travel through the intrinsic channels with outstanding ion conductivity (up to 7.2 × 10-3 S cm-1) and impressively low activation energy (as low as 0.10 eV). These properties are attributed to the weak Li ion-imidazolate binding interactions and well-defined porous 2D framework structures of such ICOFs. We also investigated the structure-property relationship by varying the electronic properties of substituents (electron donating/withdrawing) that covalently attached to the imidazolate groups. We found electron-withdrawing substituents significantly improve the ion-conducting ability of imidazolate-ICOF by weakening ion-pair interactions. Our study provides a convenient bottom-up approach toward a novel class of highly efficient single-ion conducting ICOFs which could be used in all solid-state electrolytic devices.

Ultra-high-quality perfect optical absorption structures based on quasi-bound states in the continuum (quasi-BICs) are investigated and numerically demonstrated. When the radiation rate of the magnetic dipole quasi-BICs resonance is equal to the dissipate loss rate of the system, the critical coupling condition is satisfied and the perfect absorption (nearly 100%) is obtained. The ultra-high-quality factor (1.7 × 105) perfect absorption in the proposed design is mainly attributed to the extremely low external leakage loss rate of quasi-BIC and relatively small intrinsic absorption loss rate in the constituent materials. The structure exhibits excellent sensing properties with a sensitivity of 108 nm/RIU and ultra-high FOM of ∼12013. The proposed scheme is of importance in potential biosensing applications.

We report the preparation of a highly fluoro-substituted crystalline covalent organic framework (COF) and its application as a cathode material in lithium-sulfur batteries (LSBs) upon sulfur confinement. A sulfur-functionalized COF with high sulfur content (60 wt %) was obtained through physisorption of elemental sulfur and subsequent SNAr reaction of sulfur with aromatic fluorides on the COF backbone. After such physical and chemical confinement of sulfur through a postfunctionalization approach, the COF material still shows some structural order, allowing us to investigate the structure-property relationship of such COF materials in LSB application. We compared the electrochemical performances of the two cathode materials prepared from a crystalline COF and its amorphous counterpart and studied the important factors that affect battery capacity, reaction kinetics, and cycling stability.