Artificial intelligence-assisted colorimetry for urine glucose detection towards enhanced sensitivity,accuracy,resolution,and anti-illuminating capability

Colorimetry often suffers from deficiency in quantitative determination,susceptibility to ambient illuminance,and low sensitivity and visual resolution to tiny color changes.To offset these deficiencies,we incorporate deep machine learning into colorimetry by introducing a convolutional neural network(CNN)with powerful parallel processing,self-organization,and self-learning capabilities.As a proof of concept,a plasmonic nanosensor is proposed for the colorimetric detection of glucose by coupling Benedict’s reagent with gold nanoparticles(AuNPs),which relies on the assemble of AuNPs into dendritic nanochains by Cu2O.The distinct difference of refractive index between Cu2O and Au and the localized surface plasmon resonance coupling effect among AuNPs leads to a broad spectral shift as well as abundant color changes,thereby providing sufficient data for selflearning enabled by machine learning.The CNN is then used to fully diversify the learning and training of the images from standard samples under different ambient conditions and to obtain a classifier that can not only recognize tiny color changes that are imperceptible to human eyes,but also exhibit high accuracy and excellent anti-environmental interference capability.This classifier is then compiled as an application(APP)and implanted into a smartphone with Android environment.306 clinical urine samples were detected using the proposed method and the results showed a satisfactory correlation(87.6%)with that of a standard blood glucose test method.More importantly,this method can be generalized to other applications in colorimetry,and more broadly,in other scientific domains that involve image analysis and quantification.

超小NiFe水滑石耦合单原子FeCo-NC纳米花用于可充电锌空气电池

单原子分散的FeCo-NC材料,具有特殊的花状结构和原子级分散Fe/Co位点,适用于可控沉积超小NiFe水滑石纳米点(NiFeND),从而制备具有优异氧还原(ORR)和氧析出(OER)性能的双功能催化材料.FeCo-NC材料本身具有三维立体花状介孔结构和丰富的N/O功能位点,可以实现对NiFe-ND尺寸的有效控制(直径约4 nm),使得制备的特殊复合材料的OER和ORR活性位暴露度达最大值.电化学测试表明在0.1 mol L-1KOH电解液中NiFe-ND/FeCo-NC的ORR半波电势为0.85 V,当电流密度为10 mA cm-2时的OER电势为1.66 V.原位拉曼结果进一步证实了NiFe-ND/FeCo-NC材料优良的OER活性来源于电化学过程中产生的丰富Ni(Fe)OOH活性相.采用NiFe-ND/FeCo-NC组装的锌空气电池具有较小的充放电电压差(0.87 V,20 mA cm-2)和持久的循环稳定性.同时,NiFe-ND/FeCo-NC也可以应用于全固态锌空气电池,即使在形变的情况下仍然具有良好的循环稳定性.本工作可为单原子金属氮碳催化剂作为特殊基底材料应用于新型多功能催化剂的研发提供指导.

Trees as large-scale natural phononic crystals: Simulation and experimental verification

Urban trees are usually planted on a periodic layout in the spatial configuration.We regard urban trees as large-scale natural phononic crystals.The entire forest is reduced to a reasonable 'tree-soil' unit cell based on the phononic crystal theory and finite element method by COMSOL software is used to obtain the dispersion curves.The Rayleigh wave band gaps of phononic trees are distinguished by the sound cone method.The influences of soil elastic modulus and tree height on band gaps are investigated.A three-dimensional simulation model and experiment test are applied to validate the effect of phononic trees on vibration control.The numerical frequency reduction zones coincide exactly with the theoretical band gaps.Increasing soil stiffness results in a higher-frequency and wider band gap.An increasing tree height is beneficial to obtain low-frequency band gaps.A periodically arranged plantation that Rayleigh wave band gaps at frequency ≤60 Hz could be designed.This study opens up a new theoretical basis for the quantitative analyses of urban trees to the ground vibration mitigation at a certain frequency range.

Magnetic rod-based metal-organic framework metal composite as multifunctional nanostirrer with adsorptive,peroxidase-like and catalytic properties

Although magnetic stirring is frequently used to enhance the kinetics for adsorption,chemical and biochemical reactions,the introduction of stirrers inevitably leads to the adsorption of analytes and thus interferes with the efficiency of the chemical process or reaction.In this work,magnetic Fe_(3) O_(4) nanorods with tunable length-to-diameter ratio were synthesized via a hydrothermal method and used as templates for the in-situ depositing of MIL-100(Fe) and gold nanoparticles.Such nanorod-based material can not only function as an adsorbent,nanozyme,and a heterogeneous catalyst for corresponding applications but also serve as a magnetic nanostirrer to enhance kinetics.As a proof-of-concept,the capture of bacteria pathogen,mimic-peroxidase-based colorimetric detection of hydrogen peroxide,and the catalytic reduction of selected organic pollutants were conducted using the as-synthesized Fe_(3) O_(4)@MIL-100(Fe)-Au nanostirrer with and without magnetic field.The results show that the rates of bacteria capture,mimetic enzyme reaction and catalysis were tremendously expedited.We believe this magnetic field-assisted approach holds great promise for future applications,because,not only does it eliminate the use of external magnetic stirrers and thereby decrease the risk of foreign pollution but also,is adaptable for nanoscale reaction systems where conventional stirring is not applicable due to size limitations.