Semi-implantable device based on multiplexed microfilament electrode cluster for continuous monitoring of physiological ions

Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical indicators.Ion sensors based on potentiometric methods are a promising platform for monitoring physiological ions in biological subjects.Current semi-implantable devices are mainly based on single-parameter detection.Miniaturized semi-implantable electrodes for multiparameter sensing have more restrictions on the electrode size due to biocompatibility considerations,but reducing the electrode surface area could potentially limit electrode sensitivity.This study developed a semi-implantable device system comprising a multiplexed microfilament electrode cluster(MMEC)and a printed circuit board for real-time monitoring of intra-tissue K^(+),Ca^(2+),and Na^(+)concentrations.The electrode surface area was less important for the potentiometric sensing mechanism,suggesting the feasibility of using a tiny fiber-like electrode for potentiometric sensing.The MMEC device exhibited a broad linear response(K^(+):2–32 mmol/L;Ca^(2+):0.5–4 mmol/L;Na^(+):10–160 mmol/L),high sensitivity(about 20–45 mV/decade),temporal stability(>2weeks),and good selectivity(>80%)for the above ions.In vitro detection and in vivo subcutaneous and brain experiment results showed that the MMEC system exhibits good multi-ion monitoring performance in several complex environments.This work provides a platform for the continuous real-time monitoring of ion fluctuations in different situations and has implications for developing smart sensors to monitor human health.

Frequency-modulated continuous-wave multiplexed gas sensingbased on optical frequency comb calibration

Laser absorption spectroscopy has proven to be an effective approach for gas sensing, which plays an important rolein the fields of military, industry, medicine and basic research. This paper presents a multiplexed gas sensing system basedon optical frequency comb (OFC) calibrated frequency-modulated continuous-wave (FMCW) tuning nonlinearity. Thesystem can be used for multi-parameter synchronous measurement of gas absorption spectrum and multiplexed opticalpath. Multi-channel parallel detection is realized by combining wavelength division multiplexing (WDM) and frequencydivision multiplexing (FDM) techniques. By introducing nonlinear optical crystals, broadband spectrum detection is simultaneouslyachieved over a bandwidth of hundreds of nanometers. An OFC with ultra-high frequency stability is used asthe frequency calibration source, which guarantees the measurement accuracy. The test samples involve H13C14N, C_(2)H_(2)and Rb vapor cells of varying densities and 5 parallel measurement experiments are designed. The results show that themeasurement accuracies of spectral absorption line and the optical path are 150 MHz and 20 m, respectively. The schemeoffers the advantages of multiplexed, multi-parameter, wide spectrum and high resolution detection, which can realize theidentification of multi-gas components and the high-precision inversion of absorption lines under different environments.The proposed sensor demonstrates great potential in the field of high-resolution absorption spectrum measurement for gassensing applications.

A High Spectral Efficient Frequency-Domain Channel-Estimation Method for the Polarization-Division-Multiplexed CO-OFDM-OQAM System

Contrary to the other multi-carrier modulation systems, the coherent optical orthogonal frequency division multiplexing communication system with an offset quadrature amplitude modulation (CO-OFDM-OQAM) possesses inherent imaginary interference (IMI). This has an important impact on the channel estimation process. Currently, a variety of frequency-domain channel estimation methods have been proposed. However, there are various problems that still exist. For instance, in order to reduce the influence of IMI, it is necessary to insert more guard intervals between the training sequence and the payload, leading to the occupation of excessive spectrum resources. In order to address this problem, this work designs a high spectral efficient frequency-domain channel estimation method for the polarization-division-multiplexing CO-OFDM-OQAM systems. First, the working principle of the proposed method is described in detail. Then, its spectral efficiency, power peak-to-average ratio, and channel estimation performance are studied based on simulations. The simulation results show that the proposed method improves the spectral efficiency without worsening the power peak-to-average ratio. The channel estimation capability of this method is verified in three scenarios of long-distance transmissions, including back-to-back, 100 km, and 200 km transmissions. .

Rapid Isolation and Multiplexed Detection of Exosome Tumor Markers Via Queued Beads Combined with Quantum Dots in a Microarray

Tumor-derived exosomes are actively involved in cancer progression and metastasis and have emerged as a promising marker for cancer diagnosis in liquid biopsy.Because of their nanoscale size,complex biogenesis,and methodological limitations related to exosome isolation and detection,advancements in their analysis remain slow.Microfluidic technology offers a better analytic approach compared with conventional methods.Here,we developed a bead-based microarray for exosome isolation and multiplexed tumor marker detection.Using this method,exosomes are isolated by binding to antibodies on the bead surface,and tumor markers on the exosomes are detected through quantum dot(QD)probes.The beads are then uniformly trapped and queued among micropillars in the chip.This design benefits fluorescence observation by dispersing the signals into every single bead,thereby avoiding optical interference and enabling more accurate test results.We analyzed exosomes in the cell culture supernatant of lung cancer and endothelial cell lines,and different lung cancer markers labeled with three QD probes were used to conduct multiplexed detection of exosome surface protein markers.Lung cancer-derived samples showed much higher(~sixfold-tenfold)fluorescence intensity than endothelial cell samples,and different types of lung cancer samples showed distinctive marker expression levels.Additionally,using the chip to detect clinical plasma samples from cancer patients showed good diagnostic power and revealed a well consistency with conventional tests for serological markers.These results provide insight into a promising method for exosome tumor marker detection and early-stage cancer diagnosis.

Upconversion Nanoparticles-Encoded Hydrogel Microbeads-Based Multiplexed Protein Detection

Fluorescently encoded microbeads are in demand for multiplexed applications in different fields.Compared to organic dye-based commercially available Luminex's x MAP technology, upconversion nanoparticles(UCNPs) are better alternatives due to their large antiStokes shift, photostability, nil background, and single wavelength excitation. Here, we developed a new multiplexed detection system using UCNPs for encoding poly(ethylene glycol) diacrylate(PEGDA) microbeads as well as for labeling reporter antibody. However, to prepare UCNPs-encoded microbeads, currently used swellingbased encapsulation leads to non-uniformity, which is undesirable for fluorescence-based multiplexing. Hence,we utilized droplet microfluidics to obtain encoded microbeads of uniform size, shape, and UCNPs distribution inside. Additionally, PEGDA microbeads lack functionality for probe antibodies conjugation on their surface.Methods to functionalize the surface of PEGDA microbeads(acrylic acid incorporation, polydopamine coating)reported thus far quench the fluorescence of UCNPs. Here,PEGDA microbeads surface was coated with silica followed by carboxyl modification without compromising the fluorescence intensity of UCNPs. In this study, droplet microfluidics-assisted UCNPs-encoded microbeads of uniform shape, size, and fluorescence were prepared.Multiple color codes were generated by mixing UCNPs emitting red and green colors at different ratios prior to encapsulation. UCNPs emitting blue color were used to label the reporter antibody. Probe antibodies were covalently immobilized on red UCNPs-encoded microbeads for specific capture of human serum albumin(HSA) as a model protein. The system was also demonstrated for multiplexed detection of both human C-reactive protein(hCRP) and HSA protein by immobilizing anti-h CRP antibodies on green UCNPs.

Multiplexed Profiling of Extracellular Vesicles for Biomarker Development

Extracellular vesicles(EVs)are cell-derived membranous particles that play a crucial role in molecular trafficking,intercellular transport and the egress of unwanted proteins.They have been implicated in many diseases including cancer and neurodegeneration.EVs are detected in all bodily fluids,and their protein and nucleic acid content offers a means of assessing the status of the cells from which they originated.As such,they provide opportunities in biomarker discovery for diagnosis,prognosis or the stratification of diseases as well as an objective monitoring of therapies.The simultaneous assaying of multiple EV-derived markers will be required for an impactful practical application,and multiplexing platforms have evolved with the potential to achieve this.Herein,we provide a comprehensive overview of the currently available multiplexing platforms for EV analysis,with a primary focus on miniaturized and integrated devices that offer potential step changes in analytical power,throughput and consistency.

Implementation of Phase Generated Carrier Technique for FBG Laser Sensor Multiplexed System Based on Compact RIO

This paper presents the fundamental technique of phase generated carrier （PGC） and its realization on compact reconfigurable input and output （RIO） which adopts real-time and field programmable grate array （FPGA） techniques. Improvement of the PGC technique is also introduced by using peak-to-peak value detection method to reduce the influence of variation of the light intensity. A four-element fibre Bragg gratings （FBG） laser sensor system is conducted in the experiment and the demodulated results demonstrate correlation coefficient as high as 0.995 with the reference signal and the dynamic range to be 120dB@63Hz.

Fiber Laser Based Multiplexed Sensing System

A laser sensing system based on beat frequency demodulation is proposed. The sensor uses a single-longitudinal-mode distributed Bragg reflector （DBR） fiber laser as a sensing element. This laser sensor has great multiplexing capability due to its wide free spectral range. Wavelength-division-multiplex （WDM） and frequency-division-multiplex （FDM） techniques are studied. The sensing system has high sensitivity and multiplexing channels.

Impact of multiplexed reading scheme on nanocrossbar memristor memory's scalability

Nanocrossbar is a potential memory architecture to integrate memristor to achieve large scale and high density mem- ory. However, based on the currently widely-adopted parallel reading scheme, scalability of the nanocrossbar memory is limited, since the overhead of the reading circuits is in proportion with the size of the nanocrossbar component. In this paper, a multiplexed reading scheme is adopted as the foundation of the discussion. Through HSPICE simulation, we reanalyze scalability of the nanocrossbar memristor memory by investigating the impact of various circuit parameters on the output voltage swing as the memory scales to larger size. We find that multiplexed reading maintains sufficient noise margin in large size nanocrossbar memristor memory. In order to improve the scalability of the memory, memristors with nonlinear I-V characteristics and high LRS （low resistive state） resistance should be adopted.

Remote structural health monitoring with serially multiplexed fiber optic acoustic emission sensors

Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points along the length of a single fiber.Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of' crack locations,Labora- tory experiments on plain concrete beams and post-tensioned FRP tendons were pcrlormed to evaluate the crack detection capability of the sensor system.The acoustic emission sensor was able to detect initiation,growth and location of the cracks in concrete as well as in the FRP tendons.The AE system is potentially suitable lot applications involving health monitoring of structures following an earthquake.

Deep‐learning powered whispering gallery mode sensor based on multiplexed imaging at fixed frequency

During the last decades the whispering gallery mode based sensors have become a prominent solution for label-free sensing of various physical and chemical parameters.At the same time,the widespread utilization of the approach is hindered by the restricted applicability of the known configurations for ambient variations quantification outside the laboratory conditions and their low affordability,where necessity on the spectrally-resolved data collection is among the main limiting factors.In this paper we demonstrate the first realization of an affordable whispering gallery mode sensor powered by deep learning and multi-resonator imaging at a fixed frequency.It has been shown that the approach enables refractive index unit(RIU)prediction with an absolute error at 3×10^(-6) level for dynamic range of the RIU variations from 0 to 2×10^(-3) with temporal resolution of several milliseconds and instrument-driven detection limit of 3×10−5.High sensing accuracy together with instrumental affordability and production simplicity places the reported detector among the most cost-effective realizations of the whispering gallery mode approach.The proposed solution is expected to have a great impact on the shift of the whole sensing paradigm away from the model-based and to the flexible self-learning solutions.

Turbulence mitigation scheme based on multiple-user detection in an orbital-angular-momentum multiplexed system

Atmospheric turbulence（AT） induced crosstalk can significantly impair the performance of a free-space optical（FSO）communication link using orbital angular momentum（OAM） multiplexing.In this paper,we propose a multiple-user detection（MUD） turbulence mitigation scheme in an OAM-multiplexed FSO communication link.First,we present a MUD equivalent communication model for an OAM-multiplexed FSO communication link under AT.In the equivalent model,each input bit stream represents one user＇s information.The deformed OAM spatial modes caused by AT,instead of the pure OAM spatial modes,are used as information carriers,and the overlapping between the deformed OAM spatial modes are computed as the correlation coefficients between the users.Then,we present a turbulence mitigation scheme based on MUD idea to enhance AT tolerance of the OAM-multiplexed FSO communication link.In the proposed scheme,the crosstalk caused by AT is used as a useful component to deduce users＇ information.The numerical results show that the performance of the OAM-multiplexed communication link has greatly improved by the proposed scheme.When the turbulence strength C_n^2 is 1 × 10^（-15） m^（-2/3）,the transmission distance is 1000 m and the channel signal-to-noise ratio（SNR）is 26 dB,the bit-error-rate（BER） performance of four spatial multiplexed OAM modes l_m = ＋ 1,＋2,＋3,＋4 are all close to 10-5,and there is a 2-3 fold increase in the BER performance in comparison with those results without the proposed scheme.In addition,the proposed scheme is more effective for an OAM-multiplexed FSO communication link with a larger OAM mode topological charge interval.The proposed scheme is a promising direction for compensating the interference caused by AT in the OAM-multiplexed FSO communication link.

Dark diffusional enhancement of holographic multiplexed gratings in phenanthrenequinone doped poly(methyl methacrylate) photopolymer

In this paper, we experimentally investigate the dark diffusional enhancement of the optimized multiplexed grating in the phenanthrenequinone doped poly （methyl methacrylate） （PQ-PMMA） photopolymer. The possibility of improving the holographic characteristics of the material through the dark enhancement is demonstrated. The optimal preillumination exposure and the optimal time interval between exposures are extracted to obtain the optimized diffraction efficiency, and their values are 3.4×103 mJ/cm2 and 2 min, respectively. The dark enhancement of the multiplexed grating is presented as an effective method to improve the response region and the dynamic range and to prevent saturation of the material. The dependence of the phenanthrenequinone concentration on the increment of the refractive index modulation is quantitatively studied, which provides a significant basis for improving the homogeneity in the multiplexed gratings using a quantitative strategy. Finally, a simple experimental procedure using the dark enhancement is introduced to improve the homogeneity of the diffraction efficiency and to avoid the complex schedule exposure.

STUDY ON STATISTICALLY-FAIR SERVICE IN STATISTICALLY-MULTIPLEXED NETWORKS

A new type of fair service, referred to as Statistically-Fair Service (SFS), is proposed in this paper. The SFS discipline is given based on the SFS criterion. Compared to "strict" fair service available, SFS is mainly characterized by its flexible suitability for the nature of statistically-multiplexed networks. By its statistically-fair service to users, therefore, SFS can ensure well end-to-end QoS requirements on a statistical basis with a benefit of enhancement in network utilization. Two useful properties of SFS is presented. One of them, the property of retaining Exponentially Bounded Burstiness(EBB), can facilitate end-to-end delay estimation of EBB-type traffic. Finally, some numerical results obtained from a simulation study on SFS shows that an SFS-equipped node in steady states will in deed retain the EBB attribute of any input flow.

Research on Raman Crosstalk in Broadband Wavelength Division Multiplexed Systems

After a theoretical model is put forward on the base of accurate description of the Raman gain profile and the physical quantity, maximum Raman crosstalk(MRC), which quantificationally depicts the intensity of Raman crosstalk is defined. The influences of launch power, fiber effective core area, fiber nonlinear index, fiber length, channel number and channel interval on MRC are deduced. The result indicates that compared with low speed and narrowband optical fiber communication system, serious Raman crosstalk lies in high speed and broadband system, which impacts the performance of the system badly. The result is useful for forecasting Raman crosstalk in broadband and high speed optical fiber communication system.

A homing rescue gene drive with multiplexed gRNAs reaches high frequency in cage populations but generates functional resistance

CRISPR homing gene drives have considerable potential for managing populations of medically and agriculturally significant insects.They operate by Cas9 cleavage followed by homology-directed repair,copying the drive allele to the wild-type chromosome and thus increasing in frequency and spreading throughout a population.However,resistance alleles formed by end-joining repair pose a significant obstacle.To address this,we create a homing drive targeting the essential hairy gene in Drosophila melanogaster.Nonfunctional resistance alleles are recessive lethal,while drive carriers have a recoded“rescue”version of hairy.The drive inheritance rate is moderate,and multigenerational cage studies show drive spread to 96%–97%of the population.However,the drive does not reach 100%due to the formation of functional resistance alleles despite using four gRNAs.These alleles have a large deletion but likely utilize an alternate start codon.Thus,revised designs targeting more essential regions of a gene may be necessary to avoid such functional resistance.Replacement of the rescue element’s native 3'UTR with a homolog from another species increases drive inheritance by 13%–24%.This was possibly because of reduced homology between the rescue element and surrounding genomic DNA,which could also be an important design consideration for rescue gene drives.

Dual-assisted high-precision tracking technique for wideband multiplexed signals in new generation GNSS

With the evolution of Global Navigation Satellite System(GNSS),new generation GNSS signals have adopted the dual-frequency multiplexing modulation techniques,which jointly modulate multiple signals located on multiple sub-frequencies into a Wideband Multiplexed Signal(WMS).Although WMSs were proposed initially to reduce the complexity of satellite transmitters and improve the transmission efficiency of signals,their multi-component structures and wide root mean square bandwidths introduced by high-frequency subcarriers also provide the possibility to improve the GNSS ranging precision.Therefore,this paper proposes a Dual-assisted Multi-component Tracking(DMT)technique,which can not only fully use high-frequency subcarriers in WMSs,but also effectively track carrier,subcarrier,and code by jointly utilizing all components in WMS.In this paper,the tracking and ranging performances of DMT are comprehensively analyzed theoretically and by simulation and real experiments.The results show that compared with existing WMS tracking methods,DMT can achieve tracking results with lower tracking jitters and ranging results with higher precision,providing a highly advantageous solution for new generation GNSS signal processing.

High-efficiency Multiplexed Buck-type PFC Converter

This paper proposes a high-efficiency PFC rectifier based on multiplexing the switches.Compared with a traditional six-switch PFC rectifier,the proposed rectifier extends the switches’active angle by making use of three bridge rectifiers.As a result,lower conduction resistance can be realized for switches.Consequently,system efficiency can be improved.Compared with a traditional six-switch PFC rectifier with doubled switches,the proposed rectifier can achieve almost the same efficiency improvement while no additional switches are needed.Since continuous inductor current is chopped and resulting current pulses cannot be injected into the grid directly,input filter design and resonance damping are discussed for the proposed rectifier.The controller design of the rectifier is analyzed.The inductor current reference is shaped considering the input voltage envelope and forward duties.Finally,the effectiveness of the proposed rectifier is verified through simulations and experiments.

Information transmission through parallel multi-task-based recognition of high-resolution multiplexed orbital angular momentum

Orbital angular momentums(OAMs)greatly enhance the channel capacity in free-space optical communication.However,demodulation of superposed OAM to recognize them separately is always difficult,especially upon multiplexing more OAMs.In this work,we report a directly recognition of multiplexed fractional OAM modes,without separating them,at a resolution of 0.1 with high accuracy,using a multi-task deep learning(MTDL)model,which has not been reported before.Namely,two-mode,four-mode,and eight-mode superposed OAM beams,experimentally generated with a hologram carrying both phase and amplitude information,are well recognized by the suitable MTDL model.Two applications in information transmission are presented:the first is for 256-ary OAM shift keying via multiplexed fractional OAMs;the second is for OAM division multiplexed information transmission in an eightfold speed.The encouraging results will expand the capacity in future free-space optical communication.

Diagnostic performance of a multiplexed gastrointestinal PCR panel for identifying diarrheal pathogens in children undergoing hematopoietic stem cell transplant

Background Diarrhea is a common complication of hematopoietic stem cell transplantation(HSCT)and is associated with substantial morbidity,but its etiology is often unknown.Etiologies of diarrhea in this population include infectious causes,chemotherapy-or medication-induced mucosal injury and graft-versus-host disease(GVHD).Distinguishing these potential causes of diarrhea is challenging since diarrheal symptoms are often multifactorial,and the etiologies often overlap in transplant patients.The objectives of this study were to evaluate whether the FilmArray gastrointestinal(GI)panel would increase diagnostic yield and the degree to which pre-transplantation colonization predicts post-transplantation infection.Methods From November 2019 to February 2021,a total of 158 patients undergoing HSCT were prospectively included in the study.Stool specimens were obtained from all HSCT recipients prior to conditioning therapy,28±7 days after transplantation and at any new episode of diarrhea.All stool samples were tested by the FilmArray GI panel and other clinical microbiological assays.Results The primary cause of post-transplantation diarrhea was infection(57/84,67.86%),followed by medication(38/84,45.24%)and GVHD(21/84,25.00%).Ninety-five of 158 patients were colonized with at least one gastrointestinal pathogen before conditioning therapy,and the incidence of infectious diarrhea was significantly higher in colonized patients(47/95,49.47%)than in non-colonized patients(10/63,15.87%)(P<0.001).Fourteen of 19(73.68%)patients who were initially colonized with norovirus pre-transplantation developed a post-transplantation norovirus infection.Twenty-four of 62(38.71%)patients colonized with Clostridium difficile developed a diarrheal infection.In addition,FilmArray GI panel testing improved the diagnostic yield by almost twofold in our study(55/92,59.78%vs.30/92,32.61%).Conclusions Our data show that more than half of pediatric patients who were admitted for HSCT were colonized with various gastrointestinal pathogens,and more than one-third of these pathogens were associated with post-transplantation diarrhea.In addition,the FilmArray GI panel can increase the detection rate of diarrheal pathogens in pediatric HSCT patients,but the panel needs to be optimized for pathogen species,and further studies assessing its clinical impact and cost-effectiveness in this specific patient population are also needed.