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A 1.8-V 98.1-dB SNDR analog front-end with a low offset and low 1/f noise PGIA for sensing applications

Biao Kang Sen Zhu Xin Xin Xingyuan Tong

School of Electronics Engineering Xi'an University of Posts and Telecommunications Xi'an 710121 China

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关键词： Analog front end Chopper Dual-Phase-Ping-Pong auto-zero Programmable instrumentation amplifier Sigma-Delta modulator

摘要： An analog front-end (AFE) with a 500-Hz bandwidth and a signal-to-noise and distortion ratio (SNDR) of 98.1 dB is presented for biological signal acquisition. To reduce structural complexity, the proposed dual-amplifier programmable gain instrumentation amplifier (PGIA) integrates the functions of instrumentation amplifier (IA) and programmable gain amplifier (PGA). To minimize the offset voltage and 1/f noise of the PGIA, dual-phase ping-pong auto-zero (DPAZ) and chopper stabilization techniques are employed. Compared to traditional input-offset and output-offset storage techniques, the DPAZ method not only doubles the signal bandwidth but also eliminates signal-path capacitance and relaxes the stability requirements for operational amplifiers. Moreover, the chopper technique is applied to the first-stage integrator of a second-order cascade of integrators feedback (CIFB) Sigma-Delta modulator (SDM), effectively overcoming the limitations of AFE accuracy caused by offset voltage and 1/f noise. The proposed AFE is designed with 0.18-μm CMOS and occupies an active area of 0.237 mm². Simulation results show that under 1.8-V supply, the DPAZ technique reduces the average offset voltage of the PGIA from 28.2 μV to 3.02 μV, and the root mean square (RMS) equivalent input-referred noise (IRN) voltage within 500-Hz bandwidth decreases from 9.9 μV to 1.64 μV. At a sampling rate of 1.024 MHz, an oversampling ratio (OSR) of 1024, and an input signal level of −5 dBFS, the SNDR of the SDM with the chopper technique improves from 97.7 dB to 99.4 dB with negligible additional power consumption, achieving a FoM_SNDR of 166.5 dB.

Expression, purification and biochemical characterization of the periplasmic nitrate reductase NapA from Magnetospirillum gryphiswaldense MSR-1

Chenchen Xu Hengjia Wan Yaoyao Zhang Jing Zhang Wanyu Chen Ming Li Jiarong Wang Kun Ma Yujuan Wang Junfeng Wang

High Magnetic Field Laboratory Key Laboratory of High Magnetic Field and Ion Beam Physical Biology Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei Anhui 230031 PR ChinaUniversity of Science and Technology of China Hefei Anhui 230036 PR ChinaCenter for Translational Medicine Suizhou Hospital Hubei University of Medicine Suizhou 441300 PR ChinaInstitutes of Physical Science and Information Technology Anhui University Hefei 230039 PR China

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关键词： EPR spectroscopy Magnetospirillum gryphiswaldense MSR-1 NAPA Periplasmic nitrate reductase

摘要： Magnetospirillum gryphiswaldense MSR-1 is a model magnetotactic bacterium whose magnetosome biomineralization is closely linked to intracellular redox regulation. Although the periplasmic nitrate reductase NapA plays an essential role in denitrification and redox control, its biochemical properties in MSR-1 have remained unexplored. In this study, we constructed a heterologous co-expression system for MSR-1 NapA together with its cognate chaperone NapD, successfully producing soluble and biologically active recombinant NapA. The purified enzyme exhibited a characteristic iron–sulfur absorption band near 400 nm, and metal content analysis confirmed the presence of both iron and molybdenum cofactors. Electron paramagnetic resonance spectroscopy further demonstrated the presence of a redox-active [4Fe–4S] cluster and a Mo(V) center, indicating correct cofactor assembly. Enzymatic assays showed that MSR-1 NapA follows typical Michaelis–Menten kinetics toward nitrate, with optimal activity near neutral pH and moderate temperatures. These results establish MSR-1 NapA as a functionally active and structurally stable molybdoenzyme. Collectively, this work provides the first comprehensive biochemical characterization of NapA from a magnetotactic bacterium and offers a solid molecular foundation for understanding how nitrogen metabolism is coupled to redox regulation and magnetosome biomineralization in M. gryphiswaldense MSR-1.

Weak type (1,1) bounds for singular integrals with rough kernels on block spaces

Yanping Chen Teng Wang Huoxiong Wu

School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 ChinaDepartment of Mathematics Northeastern University Shenyang 110004 ChinaSchool of Mathematical Sciences Xiamen University Xiamen Fujian 361005 China

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关键词： Block spaces Rough kernels Singular integrals Weak type (1,1) bounds

摘要： Let $Ω \in L^{1} (S^{n - 1})$ be a homogeneous function of degree zero and have mean value zero. Consider the rough singular integral $T_{Ω} f (x) = p . v . \int_{R^{n}} \frac{Ω (x - y)}{| x - y |^{n}} f (Helical l-phenylalanine-derived polyisocyanide catalyst for recyclable asymmetric aldol reactions and domino Aza-Michael-Aldol synthesis of 1,2-dihydroquinoline derivativeChonglong Li Shuyi Wang Chaoxing ChenSchool of Chemistry and Chemical Engineering North Minzu University Yinchuan 750021 PR ChinaKey Laboratory for Chemical Engineering and Technology State Ethnic Affairs Commission North Minzu University Yinchuan 750021 PR China来源 ScienceCitationIndex... ScienceDirectJournal 详细信息在线全文 ScienceCitationIndexExpanded ScienceDirectJournal关键词： Phenylalanine Supported catalyst Asymmetric catalysis Aldol reaction Aza-Michael-aldol reaction 摘要： A helical polyisocyanide catalyst bearing l -phenylalanine-derived pendants was successfully synthesized. The well-defined chiral microenvironment created by the helical scaffold enabled excellent stereocontrol in the asymmetric Aldol reaction between cyclopentanone and 4-nitrobenzaldehyde in water, affording the product in up to 100% enantiomeric excess (ee) value with a diastereomeric ratio (dr) of 64/36. The polymeric catalyst could be readily recovered and reused for at least three cycles without significant loss of enantioselectivity. Beyond Aldol reaction, the catalyst also promoted one-pot tandem aza-Michael-aldol cascade reactions, providing direct access to chiral 1,2-dihydroquinoline derivative—biologically relevant heterocycles—with good enantioselectivity (up to 70% ee). This work demonstrates the design of a versatile and recyclable helical polymer catalyst that combines high enantioselectivity in fundamental transformations with expandable utility in the synthesis of valuable heterocyclic scaffolds, offering a sustainable strategy for asymmetric synthesis.Continuous-flow hydrogenation ofp -phenylenediamine to 1,4-cyclohexylenediamine: An efficient and sustainable process via CSTR cascade Qilong Zhang Zhongqian Cui Guangdong Gao QingDong Liu BingBing Pan Gengxiu Zheng Lingfeng Gao MingZe Wu Minggang Tian School of Chemistry and Chemical Engineering University of Jinan No. 336 West Road of NanXinzhuang Jinan 250022 PR ChinaTongChuang Chemical (ShanDong) CO. LTD Jining Shandong 272600 PR China 来源 ScienceDirectJournal ScienceCitationIndex... 详细信息在线全文 ScienceDirectJournal ScienceCitationIndexExpanded 关键词： Continuous-flow hydrogenation Efficient p -Phenylenediamine 1,4-Cyclohexylenediamine 摘要： The continuous-flow hydrogenation of p -phenylenediamine (PPDA) to 1,4-cyclohexylenediamine (1,4-CHDA) was efficiently catalyzed using a cascade of continuous stirred tank reactor (CSTR). This strategy was developed to provide a safer and more efficient alternative to conventional batch hydrogenation. Systematic optimization of key reaction parameters-including temperature, pressure, residence time, solvent, and alkaline promoters-yielded a highly selective process. Under optimal conditions (120 °C, 6.0 MPa, 6 h total residence time, THF solvent, LiOH promoter), complete PPDA conversion was achieved with 98.5% selectivity to 1,4-CHDA and a trans -isomer content of 28%. The Ru/Al 2 O 3 catalyst demonstrated exceptional stability, retaining high activity over 1000 h of continuous operation. Furthermore, the process proved generally applicable for the hydrogenation of m -phenylenediamine, while the o -phenylenediamine presented significant challenges due to steric hindrance and rapid catalyst deactivation. This work establishes a scalable, stable, and sustainable continuous-flow approach for the synthesis of alicyclic diamines.Innovative multi-resonant plasmonic cup-shaped biosensors for ultra-wide detection ranges and ultra-low detection limits. The case of interleukin-1β detection Chiara Marzano Francesco Arcadio Rosalba Pitruzzella Luigi Zeni Stefano Toldo Antonio Abbate Nunzio Cennamo University of Campania Luigi Vanvitelli Department of Engineering Aversa 81031 ItalyUniversity of Virginia Berne Cardiovascular Research Center and Division of Cardiovascular Medicine Charlottesville VA 22908 USA 来源 ScienceDirectJournal 详细信息在线全文 ScienceDirectJournal 关键词： Cup-shaped waveguide Surface plasmon resonance (SPR) Biosensors Ultra-wide detection range and ultra-low detection limit Point-of-care tests (POCTs) IL-1β detection 摘要： In this work, an innovative multi-resonant plasmonic cup-shaped platform was designed, developed, and combined with a bioreceptor layer to address two key issues in biosensing: the ultra-low limit of detection (LOD) and the ultra-wide detection range. A cup-shaped optical waveguide was utilized to achieve surface plasmon resonance (SPR) phenomena, exploiting a single fabrication step and featuring an integrated measurement cell, which enables easy integration into rapid and cost-effective point-of-care tests (POCTs). Changing the optical path in the cup-shaped waveguide, its peculiar geometry allows different plasmonic resonances to be triggered and monitored. To this end, as a proof-of-concept, three experimental configurations were explored and tested by simply changing the altitude from which light is launched/collected to/from the plasmonic cup-shaped waveguide through plastic optical fibers (POFs). For all three experimental configurations, the plasmonic cup-shaped sensor was first optically characterized to determine its bulk sensitivity. Then, after a functionalization procedure of the gold nanofilm with a bioreceptor layer specific for interleukin-1β (IL-1β) detection, the plasmonic cup-shaped biosensor was characterized to obtain the binding performance parameters. More specifically, the multi-resonant plasmonic biosensor demonstrated selective detection of IL-1β, an ultra-low LOD (at femtomolar concentration), and an ultra-wide detection range (about five orders of magnitude) using the same functionalized sensing area monitored differently. The experimental results reveal the potential of the SPR cup-shaped biosensor in terms of performance, versatility, and its ability to achieve a scalable and low-cost point-of-care device.Sphingosine-1-phosphate drives astrocyte pyroptosis via activation of NLRC4 inflammasome in autism spectrum disorder Yaxin Shi Shuangshuang Chen Xirui Zhang Yuan Yang Anjie Chen Yaqi Sun Xiaotong Chen Shan Zhao Tikang Zhu Wanying Qiao Lili Fan Lijie Wu Department of Children’s and Adolescent Health Public Health College Harbin Medical University Harbin 150081 ChinaKey Laboratory of Children development and genetic research Heilongjiang Province Harbin Medical University Harbin 150081 ChinaDepartment of Developmental Behavioral Pediatrics The Sixth Affiliated Hospital of Harbin Medical University Harbin 150023 China 来源 ScienceCitationIndex... ScienceDirectJournal 详细信息在线全文 ScienceCitationIndexExpanded ScienceDirectJournal 关键词： Autism spectrum disorder BTBR mice NLRC4 Astrocyte Pyroptosis 摘要： Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficits in social communication and cognitive functioning. Emerging evidence suggests that abnormal neuroinflammatory responses play a critical role in ASD pathogenesis. Our previous research studies have shown significantly elevated serum levels of Sphingosine-1-phosphate (S1P) in ASD patients, which correlate with clinical phenotypes. Given the key role of S1P in glial cells, we investigated its involvement in pyroptosis-related neuroinflammatory pathways. Mendelian randomization analysis revealed a genetic link between the pyroptosis-associated regulator CD122 and ASD risk. Consistent with this focus, blood samples from ASD patients showed elevated levels of key pyroptotic executioners (Caspase-1, GSDMD) and their downstream pro-inflammatory products (IL-1β, IL-18), confirming enhanced pyroptotic activity. In the BTBR mouse model, a validated ASD model, astrocytes exhibited increased expression of pyroptosis-related proteins and inflammatory cytokines, which were reversed following S1P depletion. Furthermore, hippocampal injection of S1P in wild-type mice induced astrocytic pyroptosis, confirming its direct pro-inflammatory effect. Mechanistic investigations identified NLRC4 as a key inflammasome component upregulated in astrocytes of BTBR mice. Suppression of Nlrc4 ameliorated cognitive deficits and social impairments in BTBR mice. Using astrocyte-specific Nlrc4 knockout models and in vitro assays, we demonstrated that S1P promotes astrocytic pyroptosis through NLRC4 activation, with ERK signaling identified as a critical downstream mediator in this process. These findings reveal a novel S1P-NLRC4-pyroptosis signaling axis in astrocytes that contributes to ASD-associated neuroinflammation, providing a potential molecular basis for targeted clinical intervention.Nonlinear response identification of a parametrically excited bistable magnetic rolling pendulum harvester by 0–1 test and recurrence plots Wei Wang Zihao Yang Enna Zhang Shuangyan Liu Xiaoqing Ma Zilin Li Ronghan Wei School of Mechanics and Safety Engineering Zhengzhou University Zhengzhou 450001 ChinaEngineering Technology Research Center of Henan Province for MEMS Manufacturing and Application Zhengzhou University Zhengzhou 450001 ChinaSchool of Aero Engine Zhengzhou University of Aeronautics Zhengzhou 450046 ChinaSchool of Cyber Science and Engineering Zhengzhou University Zhengzhou 45000l China 来源 ScienceDirectJournal ScienceCitationIndex... 详细信息在线全文 ScienceDirectJournal ScienceCitationIndexExpanded 关键词： 0–1 test Bistable Electromagnetic energy harvesting Magnetic rolling pendulum Recurrence plot 摘要： Owing to the low damping characteristics, magnetic rolling pendulum gains extensive adoption in vibration energy harvesting. Bistable magnetic rolling pendulum harvester (BMRPH) exhibits chaotic and (quasi-)periodic vibrational responses, and effectively identifying the complex dynamic behaviors is essential for advancing practical applications. Therefore, this paper utilizes 0–1 test and recurrence plot (RP) to examine the nonlinear voltage response time series of a parametrically excited BMRPH. By analyzing the nonlinear dynamics of the BMRPH, multiple vibrational patterns are emphasized. Results indicate that 0–1 test could easily distinguish between chaotic and periodic responses through the trajectory plot of (p, q), total mean square displacement, and asymptotic growth rate. Unlike 0–1 test, which provides a binary classification (0 for periodic and 1 for chaotic systems), RP offers a more nuanced approach by not only distinguishing between chaotic and periodic dynamics but also revealing the relative complexity within periodic regimes. In general, the identification results align well with complementary diagnostic methods, including phase portraits, Poincaré maps, frequency spectra, and multiscale entropy, thereby offering valuable insights for optimizing the dynamic performance and enhancing energy harvesting efficiency.The function and molecular mechanism of HIF-1α interacted with p-STAT3 in promoting G6PD overexpression in chronic myelogenous leukemia cells Yueli Ni Lifeng Wang Yongping Li Youbin Duan Hanyue Shao Yurong Dong Jinshan Zhang Zhe Xu Lu Yuan Yu Dou Ziyuan Bai Kun Cui Zhuoran Teng Asif Shahzad Wenjing Liu Zhe Yang Qiao Zhang Tumor Prevention Treatment and Translational Research Center School of Basic Medical Sciences Kunming Medical University Kunming Yunnan ChinaDepartment of Biochemistry and Molecular Biology School of Basic Medical Sciences Kunming Medical University Yunnan Kunming Yunnan ChinaDepartment of Blood Screening Laboratory Yunnan Kunming Blood Center ChinaDepartments of Pathology The First Affiliated Hospital of Kunming Medical University Yunnan Kunming Yunnan China 来源 ScienceDirectJournal ScienceCitationIndex... 详细信息在线全文 ScienceDirectJournal ScienceCitationIndexExpanded 关键词： CML Drug resistance G6PD HIF-1α Tumorigenesis p-STAT3 摘要： Chronic myeloid leukemia (CML) is a malignant myeloproliferative neoplasm originating from hematopoietic stem cells, which substantially contributes to the morbidity and mortality among leukemia patients. Our findings demonstrated that glucose-6-phosphate dehydrogenase (G6PD) is aberrantly overexpressed in CML, where it promotes the proliferation of CML cells and modulates their cell cycle distribution. Furthermore, we observed a positive correlation between G6PD overexpression and the resistance of CML cells to imatinib. Subsequent mechanistic investigations revealed that the complex formed by the interaction of phosphorylated STAT3 (p-STAT3) and hypoxia-inducible factor 1α (HIF-1α) functions as a novel transcriptional regulator of G6PD, thereby driving its increased expression. Collectively, this study provides compelling evidence that strategies directly targeting p-STAT3/HIF-1α-G6PD may represent an effective therapeutic approach to suppress CML cells proliferation and overcome drug resistance, offering new insights into the diagnosis and clinical management of CML patients.Catalyst-free visible-light mediatedα -alkylation of quinazolines and pyrrolo[2,1-f ]triazine Jhonathan R.N. dos Santos Victor Biagio A. Sciota Geovana F. Vargas Camila Batista Pinto Giovanni W. Amarante Javier Ellena Arlene G. Corrêa Centre of Excellence for Research in Sustainable Chemistry Federal University of São Carlos 13565-905 São Carlos SP BrazilDepartment of Chemistry Federal University of Juiz de Fora Juiz de Fora MG 36036-900 BrazilSão Carlos Institute of Physics University of São Paulo São Carlos SP 13563-120 Brazil 来源 ScienceDirectJournal ScienceCitationIndex... 详细信息在线全文 ScienceDirectJournal ScienceCitationIndexExpanded 关键词： Quinazoline pyrrolo[2,1-f]triazine Photochemistry C–H functionalization N-heterocycles 摘要： Quinazolines are found in numerous commercially available drugs. Herein, we report a catalyst-free photochemical approach for the direct alkylation of these N -heterocycles under mild conditions. Additionally, late-stage functionalization of bioactive natural products—including caffeine, quinine derivative and flavone—was successfully achieved. Notably, the protocol also enabled the selective C7-functionalization of the pyrrolo[2,1- f][1,2,4]triazine core without requiring pre-functionalization, representing the first example of this transformation accomplished through a photochemical process. Using the optimized reaction condition, 17 alkylated heterocycles were prepared in 10-81% yield.共500页 << < 16171819202122232425 > >>检索报告对象比较合并检索 0 隐藏清空合并搜索回到顶部执行限定条件//加载检索页面js
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