A 24−30 GHz 8-element dual-polarized 5G FR2 phased-array transceiver IC with 20.8-dBm TX OP1dB and 4.1-dB RX NF in 65-nm CMOS

This article presents an 8-element dual-polarized phased-array transceiver(TRX)front-end IC for millimeter-wave(mm-Wave)5G new radio(NR).Power enhancement technologies for power amplifiers(PA)in mm-Wave 5G phased-array TRX are discussed.A four-stage wideband high-power class-AB PA with distributed-active-transformer(DAT)power combining and multi-stage second-harmonic traps is proposed,ensuring the mitigated amplitude-to-phase(AM-PM)distortions across wide carrier frequencies without degrading transmitting(TX)power,gain and efficiency.TX and receiving(RX)switching is achieved by a matching network co-designed on-chip T/R switch.In each TRX element,6-bit 360°phase shifting and 6-bit 31.5-dB gain tuning are respectively achieved by the digital-controlled vector-modulated phase shifter(VMPS)and differential attenuator(ATT).Fabricated in 65-nm bulk complementary metal oxide semiconductor(CMOS),the proposed TRX demonstrates the measured peak TX/RX gains of 25.5/21.3 dB,covering the 24−29.5 GHz band.The measured peak TX OP1dB and power-added efficiency(PAE)are 20.8 dBm and 21.1%,respectively.The measured minimum RX NF is 4.1 dB.The TRX achieves an output power of 11.0−12.4 dBm and error vector magnitude(EVM)of 5%with 400-MHz 5G NR FR2 OFDM 64-QAM signals across 24−29.5 GHz,covering 3GPP 5G NR FR2 operating bands of n257,n258,and n261.

On the Identification of N-rich Metal-poor Field Stars with Future Chinese Space Station Telescope

During the long term evolution of globular clusters(GCs), some member stars are lost to the field. The recently found nitrogen-rich(N-rich) metal-poor field stars are promising candidates of these GC escapees, since N enhancement is the fingerprint of chemically enhanced populations in GCs. In this work, we discuss the possibility of identifying N-rich metal-poor field stars with the upcoming Chinese Space Station Telescope(CSST). We focus on the main survey camera with NUV, u, g, r, i, z, y filters and slitless spectrograph with a resolution about 200.The combination of UV sensitive equipment and prominent N-related molecular lines in the UV band bodes well for the identification: the color–color diagram of(u-g) versus(g-r) is capable of separating N-rich field stars from normal halo stars, if metallicity can be estimated without using the information on u-band photometry.Besides, the synthetic spectra show that a signal-to-noise ratio of 10 is sufficient to identify N-rich field stars. In the near future, a large sample of N-rich field stars found by CSST, combined with state-of-the-art N-body simulations will be crucial to deciphering GC-Galaxy co-evolution.

Review of the Clinical Applications of Metagenomic Next-Generation Sequencing in Bloodstream Infection

Bloodstream infection (BSI) is an important cause of morbidity and mortality worldwide. If we can make early diagnosis and start effective antibiotic treatment in time, the hospitalization time of patients with bloodstream infection can be significantly shortened. However, the current diagnosis of bloodstream infection cannot achieve the ideal therapeutic effect to a large extent because of the matrix effect of blood and the long turnaround time of blood culture. Therefore, a new detection method with a short turnaround time and high sensitivity is needed for the early diagnosis and timely treatment to improve the prognosis of patients. Metagenomic next-generation sequencing (mNGS) is a recently developed method for the comprehensive analysis of all microorganisms and genetic materials in clinical samples and is expected to be the main method for the early diagnosis of bloodstream infections. This review discusses the clinical application of mNGS in bloodstream infections. We also discuss technical challenges that need to be addressed to improve the diagnostic applicability of mNGS.

Hydrogel bioadhesives harnessing nanoscale phase separation for Achilles tendon repairing

Repairing Achilles tendon has emerged as a long-standing challenge in the orthopaedic surgeries.Although suture is the gold standard for re-attaching and repairing the fractured Achilles tendons in clinical surgeries,it is still subjected to numerous adverse side-effects,including chronic inflammatory,tendon tissue re-rupture,scar formation,and post-surgical peritendinous adhesion.In this work,we develop a class of hydrogel bioadhesives with tailored nanoscale phase separation for Achilles tendon repairing.To address the existing limitations of sutures,our hydrogel bioadhesives encompass three core functionalities:(i)instant and tough adhesion to Achilles tendon tissues,(ii)extraordinary long-term adhesion robustness under wet and dynamic in vivo conditions,and(iii)anti-postsurgical peritendinous adhesion.Combining our hydrogel bioadhesives with sutures,such kind of integrated approach enables a conformable yet robust biointerface with the tendon tissues,and prevents the fibroblast migration and formation of connective tissues,thus facilitating the tendon repairing.The hydrogel bioadhesives reported here open up new opportunities for the repairing of fractured Achilles tendons in diverse and complicated clinical scenarios.

结核分枝杆菌突破宿主上皮屏障的新机制

结核病是主要由结核分枝杆菌引起的一种人兽共患传染病。据估计,2022年全球约有1060万新发结核病患者,其中死亡约130万人,结核病严重威胁着人类健康和公共卫生安全,迫切需要阐明结核分枝杆菌的感染和致病机制。上皮屏障在抵御病原菌入侵中发挥着非常重要的作用。据报道,A型链球菌等多种病原菌,通过其胞外蛋白酶切割闭合蛋白和E-钙黏蛋白等细胞间连接,穿越上皮屏障后入侵更深的组织,从而促进病原菌的体内扩散和传播。然而,结核分枝杆菌穿越宿主肺泡上皮屏障及其扩散的机制目前还不清楚。

Plasma microRNA-15a/16-1-based machine learning for early detection of hepatitis B virus-related hepatocellular carcinoma

Background and aims:Hepatocellular carcinoma(HCC),which is prevalent worldwide and has a high mortality rate,needs to be effectively diagnosed.We aimed to evaluate the significance of plasma microRNA-15a/16-1(miR-15a/16)as a biomarker of hepatitis B virus-related HCC(HBV-HCC)using the machine learning model.This study was the first large-scale investigation of these two miRNAs in HCC plasma samples.Methods:Using quantitative polymerase chain reaction,we measured the plasma miR-15a/16 levels in a total of 766 participants,including 74 healthy controls,335 with chronic hepatitis B(CHB),47 with compensated liver cirrhosis,and 310 with HBV-HCC.The diagnostic performance of miR-15a/16 was examined using a machine learning model and compared with that of alpha-fetoprotein(AFP).Lastly,to validate the diagnostic efficiency of miR-15a/16,we performed pseudotemporal sorting of the samples to simulate progression from CHB to HCC.Results:Plasma miR-15a/16 was significantly decreased in HCC than in all control groups(P<0.05 for all).In the training cohort,the area under the receiver operating characteristic curve(AUC),sensitivity,and average precision(AP)for the detection of HCC were higher for miR-15a(AUC=0.80,67.3%,AP=0.80)and miR-16(AUC=0.83,79.0%,AP=0.83)than for AFP(AUC=0.74,61.7%,AP=0.72).Combining miR-15a/16 with AFP increased the AUC to 0.86(sensitivity 85.9%)and the AP to 0.85 and was significantly superior to the other markers in this study(P<0.05 for all),as further demonstrated by the detection error tradeoff curves.Moreover,miR-15a/16 impressively showed potent diagnostic power in early-stage,small-tumor,and AFP-negative HCC.A validation cohort confirmed these results.Lastly,the simulated follow-up of patients further validated the diagnostic efficiency of miR-15a/16.Conclusions:We developed and validated a plasma miR-15a/16-based machine learning model,which exhibited better diagnostic performance for the early diagnosis of HCC compared to that of AFP.

大模型时代的自然语言处理:挑战、机遇与发展

近期发布的ChatGPT和GPT-4等大型语言模型,不仅能高质量完成自然语言生成任务,生成流畅通顺,贴合人类需求的语言,而且具备以生成式框架完成各种开放域自然语言理解任务的能力.在少样本、零样本场景下,大模型可取得接近乃至达到传统监督学习方法的性能,且具有较强的领域泛化性,从而对传统自然语言核心任务产生了巨大的冲击和影响.本文就大模型对自然语言处理的影响进行了详细的调研和分析,试图探究大模型对自然语言处理核心任务带来哪些挑战和机遇,探讨大模型将加强哪些自然语言处理共性问题的研究热度,展望大模型和自然语言处理技术的未来发展趋势和应用.分析结果表明,大模型时代的自然语言处理依然大有可为.我们不仅可以将大模型作为研究方法和手段,学习、借鉴大型语言模型的特点和优势,变革自然语言处理的主流研究范式,对分散独立的自然语言处理任务进行整合,进一步提升自然语言核心任务的能力;还可就可解释性、公平性、安全性、信息准确性等共性问题开展深入研究,促进大模型能力和服务质量的提升.未来,以大模型作为基座,拓展其感知、计算、推理、交互和控制能力,自然语言处理技术将进一步助力通用人工智能的发展,促进各行各业的生产力进步,更好地为人类社会服务.

Transformer: A General Framework from Machine Translation to Others

Machine translation is an important and challenging task that aims at automatically translating natural language sentences from one language into another.Recently,Transformer-based neural machine translation(NMT)has achieved great break-throughs and has become a new mainstream method in both methodology and applications.In this article,we conduct an overview of Transformer-based NMT and its extension to other tasks.Specifically,we first introduce the framework of Transformer,discuss the main challenges in NMT and list the representative methods for each challenge.Then,the public resources and toolkits in NMT are listed.Meanwhile,the extensions of Transformer in other tasks,including the other natural language processing tasks,computer vision tasks,audio tasks and multi-modal tasks,are briefly presented.Finally,possible future research directions are suggested.

隐形“世界帝国”:一种重新认识美国的元框架

人类正处于数百年全球化运动所造就的“深度全球化”时代,其底层架构是大航海时代以来步步建构、最终在美国手里编织成型的世界帝国。如果说世界帝国得益于理性化的孕育而难逃理性化的“铁笼”,那么美国也正是在建构隐形世界帝国的过程中,陷入欲望与权力、技术化与动物化的纠缠,从而锁定了美国自己:不仅以基于“历史终结”的普世文明为人类文明模式的终结版,把自己锁定为文明冲突中的优胜者;也以世界帝国为私器,把自己锁定为中心地带不可撼动的既得利益者。美国的这种自我锁定缺乏真正文明意义上的“王道”的规训,随之而来的权力任性、野蛮扩张和利益垄断,也会遭到世界性的反抗。这是我们重新认识所获得的一个警醒。

语言认知与语言计算--人与机器的语言理解

语言理解是认知科学和计算机科学交叉领域共同关心的问题,但两个学科在选择具体研究问题时却十分不同.认知科学领域的研究侧重解析大脑的工作机制,更多地关注于描述大脑对语言的响应,缺乏对大脑语言功能整体化、系统化的研究,而计算机科学家在选择研究问题时重点关注实际应用效能,往往忽略了对语言最本质规律的研究.那么,如何实现两种思路的交叉融合,为智能语言计算模型的构建和语言认知机理的研究带来新的机遇和启发呢?本文首先简要回顾了认知科学和计算机科学在语言理解方向上的研究问题、发展历程和研究方法,重点阐述研究现状和面临的挑战,之后对比认知科学和计算机科学领域对于语言理解问题的主要观点,分析两者之间的异同.最后对现有语言认知和语言计算两个领域的交叉融合方法进行归纳和总结,并对未来发展趋势予以展望.

Elemental Sulfur and Dimethyl Sulfoxide-Promoted Oxidative Cyclization of Trifluoroacetimidohydrazides with Methylheta-renes for the Synthesis of 3-Hetaryl-5-trifluoromethyl-1,2,4-triazoles

A metal-free approach for the synthesis of 3-hetaryl-5-trifluoromethyl-1,2,4-triazoles via sulfur/dimethyl sulfoxide-promoted oxidative cyclization of readily available trifluoroacetimidohydrazides with methylhetarenes has been developed.This transformation proceeds in cascade sulfur-mediated generation of thioaldehyde,condensation,intramolecular cyclization and oxidative aromatization sequence.

Crosslinking and functionalization of acellular patches via the self-assembly of copper@tea polyphenol nanoparticles

Decellularization is a promising technique to produce natural scaffolds for tissue engineering applications.However,non-crosslinked natural scaffolds disfavor application in cardiovascular surgery due to poor biomechanics and rapid degradation.Herein,we proposed a green strategy to crosslink and functionalize acellular scaffolds via the self-assembly of copper@tea polyphenol nanoparticles(Cu@TP NPs),and the resultant nanocomposite acellular scaffolds were named as Cu@TP-dBPs.The crosslinking degree,biomechanics,denaturation temperature and resistance to enzymatic degradation of Cu@TP-dBPs were comparable to those of glutaraldehyde crosslinked decellularized bovine pericardias(Glut-dBPs).Furthermore,Cu@TP-dBPs were biocompatible and had abilities to inhibit bacterial growth and promote the formation of capillary-like networks.Subcutaneous implantation models demonstrated that Cu@TP-dBPs were free of calcification and allowed for host cell infiltration at Day 21.Cardiac patch graft models confirmed that Cu@TP-dBP patches showed improved ingrowth of functional blood vessels and remodeling of extracellular matrix at Day 60.These results suggested that Cu@TP-dBPs not only had comparable biomechanics and biostability to Glut-dBPs,but also had several advantages over Glut-dBPs in terms of anticalcification,remodeling and integration capabilities.Particularly,they were functional patches possessing antibacterial and proangiogenic activities.Thesematerial properties and biological functionsmade Cu@TP-dBPs a promising functional acellular patch for cardiovascular applications.

Metal-free synthesis of 3-trifluoromethyl-1,2,4-triazoles via oxidative cyclization of trifluoroacetimidohydrazides with N,N-dimethylformamide as carbon synthons

A metal-free approach for the synthesis of 3-trifluoromethyl-1,2,4-triazoles via I2-mediated oxidative cyclization of readily accessible trifluoroacetimidohydrazides with N,N-dimethylformamide(DMF)has been disclosed.In this transformation,the commonly used organic solvent DMF is applied as a C1 synthon and the methine unit of the 1,2,4-triazole products is independently from N-methyl and N-acyl of DMF.The application potential of the developed method has been demonstrated by the synthesis of the key skeleton of factor IXa inhibitors.

Improving flight performance of UAVs by ice shape modulation

Aircraft icing poses a great threat to flight safety.In response to the characteristics of high-power consumption,large volume,and heavy weight of traditional anti-/de-icing technologies,the concept of ice shape modulation is proposed,which is called ice tolerant flight.Firstly,the flight performance of Unmanned Aerial Vehicle(UAV)was compared in three states:no ice,full ice,and modulated ice through flight tests.It was found that ice shape modulation has a significant improvement effect on the aerodynamic performance of aircraft under icing conditions.Under the three modulated ice shape conditions in this experiment,the lift coefficient of the UAV under different ice shape modulation conditions increased by 18%–33%,and the stalling angle was delayed by 3°-5°.Subsequently,the pressure distribution,streamlines in the flow field,and detached vortex distribution of the UAV model in these three states were obtained through numerical simulation,to study the mechanism of ice shape modulation on the aerodynamic performance of aircraft.The simulation found that the reason for the improvement of the wings effect after ice shape modulation is that the modulated area forms a leading-edge protrusion structure similar to a vortex generator.This structure prolongs the mixed flow region on the wings surface and reduces the trend of flow separation,which plays a role in increasing lift and reducing drag for UAVs under icing conditions.Finally,a reverse reachable set that can be used for unexpected state recovery is used as the definition of flight safety boundaries,and an aircraft dynamics model is established to obtain flight safety boundaries for different states.Research has found that the flight safety boundary of the UAV in a no ice state is greater than that in a modulated ice state,and the safety boundary in a modulated ice state is greater than that in a full ice state.Compared with the full ice state,the flight safety boundary after modulation has expanded by 27.0%.The scheme of ice shape modulation can provide a basis for the flight safety of aircraft under icing conditions.

Fully umbilical cord-derived adhesive materials enable to recruit and segregate immune cells for the reversal of acute liver failure

Inflammatory cytokine storms can trigger disease exacerbation and even death and have reached a consensus in the clinical treatment of acute organ failure.However,the existing strategies remain a great challenge to efficiently suppress inflammatory cytokine storms for promoting organ repair and regeneration.Herein,fully human umbilical cord(UC)-derived adhesive materials(UCAM)that integrate decellularized extracellular matrix(ECM)nanofiber hydrogel and homologous mesenchymal stem cells(MSCs)are demonstrated to greatly suppress inflammatory cytokine storms,demonstrating high efficacy in treating acute liver failure(ALF)in rats with 90%hepatectomy.The UC-derived adhesive materials have the capacity to secrete a significant quantity of cytokines by MSCs to recruit activated immune cells to migrate into their ECM nanofiber networks,segregating them away from the infection area and thereby greatly suppressing the inflammatory cytokine storms.As expected,the UC-derived adhesive materials can significantly promote hepatocyte proliferation to achieve functional recovery and regeneration of the liver,significantly improving the survival rate in rats.Our fully human UC-derived adhesive materials provide a new avenue in suppressing inflammatory cytokine storms for promoting organ regeneration that would be really utility in clinical organ transplantation-related treatment.