Highly sensitive and stable probe refractometer based on configurable plasmonic resonance with nano-modified fiber core

A dispersion model is developed to provide a generic tool for configuring plasmonic resonance spectral characteristics.The customized design of the resonance curve aiming at specific detection requirements can be achieved.According to the model,a probe-type nano-modified fiber optic configurable plasmonic resonance(NMF-CPR)sensor with tip hot spot enhancement is demonstrated for the measurement of the refractive index in the range of 1.3332-1.3432 corresponding to the low-concentration biomarker solution.The new-type sensing structure avoids excessive broadening and redshift of the resonance dip,which provides more possibilities for the surface modification of other functional nanomaterials.The tip hot spots in nanogaps between the Au layer and Au nanostars(AuNSs),the tip electric field enhancement of AuNSs,and the high carrier mobility of the WSe_(2)layer synergistically and significantly enhance the sensitivity of the sensor.Ex-perimental results show that the sensitivity and the figure of merit of the tip hot spot enhanced fiber NMF-CPR sensor can achieve up to 2995.70 nm/RIU and 25.04 RIU^(−1),respectively,which are 1.68 times and 1.29 times higher than those of the conventional fiber plasmonic resonance sensor.The results achieve good agreements with numerical simulations,demonstrate a better level compared to similar reported studies,and verify the correctness of the dispersion model.The detection resolution of the sensor reaches up to 2.00×10^(−5)RIU,which is obviously higher than that of the conventional side-polished fiber plasmonic resonance sensor.This indicates a high detection accuracy of the sensor.The dense Au layer effectively prevents the intermediate nanomaterials from shedding and chemical degradation,which enables the sensor with high stability.Furthermore,the terminal reflective sensing structure can be used as a practical probe and can allow a more convenient operation.

HIGHLY SENSITIVE SPECTROPHOTOMETRY OF NIOBIUM

In pH 2.0-3.0 medium,niobium(v)forms molybdoniobic acid with sodium molybdate.A spectrophotometric method has been developed for the determination of niobium based on the formation of ion-associate compound of molybdoniobate with butyl Rhodamine B in aqueous solution in the presence of polyvinyl alcohol and 0.4-0.7 mol/L H_2SO_4.The molar absorptivity is 7.5×10~5 L.mol^(-1).cm^(-1) for niobium at 585 nm.

Highly Sensitive Detection of Deoxyribonucleic Acid Hybridization Using Au-Gated AlInN/GaN High Electron Mobility Transistor-Based Sensors

Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.

Highly Sensitive Fiber-Optic Faraday-Effect Magnetic Field Sensor Based on Yttrium Iron Garnet

The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber links the sensor head to the source and detection system, in which the technique of phase shift cancellation is used to cancel the phase shift that accumulatein the optical fiber. Flux concentrators were exploited to enhance the YIG crystal magneto-optic sensitivity .The sensor system exhibited a noise-equivalent field of 8 pT/√Hz and a 3 dB bandwidth of ～10 MHz.

The Influence of Regular Hemodialysis on the Highly Sensitive Troponin-I Level in Children without Any Symptoms

Backgrounds: Cardiovascular diseases are still the prominent cause of death in cases of end-stage renal disease, cardiac troponin I (cTnI) can be used for detecting cardiac involvement in asymptomatic cases of end-stage renal disease on hemodialysis. Aim: Determine the direct cardiac consequence of dialysis treatments in children on hemodialysis by measuring high-sensitive troponin-I as a marker of myocardial injury. Subjects and Methods: This case-control study included thirty children with end-stage renal disease on regular hemodialysis;the study group was selected from the nephrology hemodialysis unit of Al-Zahraa Hospital, Al-Azhar University. Another group of thirty healthy children matches age and sex with the patient’s group as a control. Highly Sensitive cTnI (hsTnI) was measured pre and post hemodialysis with a sensitive assay;moreover, ECG, lipid profile including cholesterol, triglyceride, low and high-density lipoprotein (HDL) in the same line with routine investigations for those patients, we used bioimpedance for dry weight assessment in the hemodialysis (HD) group. Results: Children on (HD) have a significantly higher (hsTnI) pre-dialysis (0.250 ± 0.069 ng/ml) compared to post-dialysis (0.187 ± 0.004 ng/ml) with (p, 0.001). With no significant difference between post HD (0.187 ± 0.004 ng/ml) and the control group (0.189 ± 0.005) with (p, 0.090). cTnI is detected in (73.3%) of children pre-dialysis above the cut-off value compared to (3.31%) had a high-level post-dialysis. cTnI is positively correlated with systolic, diastolic blood pressure and heart rate with (r. 0.333, p, 0.001: r. 0.343, p, 0.001: r. 0.276, p, 0.033) respectively and (hsTnI) is negatively correlated with Hb and HDL (r. -0.333, p, 0.009: r. 0.324, p, 0.011). Meanwhile (hsTnI) is positively correlated with serum urea, creatinine, ph, PTH, serum ferritin and positively correlated with QT interval and QTC. Conclusion: cTnI levels rise significantly before hemodialysis, so those patients are exposed to silent myocardial injury pre HD, and fortunately, it is not persistent after hemodialysis except for a few of them had a high level. We strongly advised not to delay dialysis appointments;the nephrology team should aggressively treat those patients to prevent further myocardial damage.

HIGHLY SENSITIVE SPECTROPHOTOMETRY OF NIOBIUM

In pH2.0-3.0,niobium(V)forms molybdonlobic acid with sodium molybdate.A spectrophotometric method has been developed for the deter- mination of niobium based on the formation of ion-associate compound of molybdoniobate with Butyl Rhodamine B in aqueous solution in the presence of polyvinyl alcohol and 0.4-0.7 mol/L H_2SO_4.The maximum absorption of ion-associate compound exhioits at 85 nm and the molar absorptivity is 7.5×1.0~5 L.mol^(-1).cm^(-1)for niobium.The new method has been applied to the determination of microamounts niobium in silicate rock,when niobium content is at the level of 8×10^(-3)%,with the relative standard deviation of about 3%.

Highly sensitive digital optical sensor with large measurement range based on the dual-microring resonator with waveguide-coupled feedback

We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.

Tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber

Optical fiber temperature sensors have been widely employed in enormous areas ranging from electric power industry,medical treatment,ocean dynamics to aerospace.Recently,graphene optical fiber temperature sensors attract tremendous attention for their merits of simple structure and direct power detecting ability.However,these sensors based on transfer techniques still have limitations in the relatively low sensitivity or distortion of the transmission characteristics,due to the unsuitable Fermi level of graphene and the destruction of fiber structure,respectively.Here,we propose a tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber(Gr-PCF)with the non-destructive integration of graphene into the holes of PCF.This hybrid structure promises the intact fiber structure and transmission mode,which efficiently enhances the temperature detection ability of graphene.From our simulation,we find that the temperature sensitivity can be electrically tuned over four orders of magnitude and achieve up to~3.34×10^(-3) dB/(cm·℃)when the graphene Fermi level is~35 meV higher than half the incident photon energy.Additionally,this sensitivity can be further improved by~10 times through optimizing the PCF structure(such as the fiber hole diameter)to enhance the light–matter interaction.Our results provide a new way for the design of the highly sensitive temperature sensors and broaden applications in all-fiber optoelectronic devices.

Highly sensitive and stretchable piezoelectric strain sensor enabled wearable devices for real-time monitoring of respiratory and heartbeat simultaneously

The World Health Organization has declared COVID-19 a pandemic.The demand for devices or systems to diagnose and track COVID-19 infections noninvasively not only in hospitals but also in home settings has led to increased interest in consumer-grade wearables.A common symptom of COVID-19 is dyspnea,which may manifest as an increase in respiratory and heart rates.In this paper,a novel piezoelectric strain sensor is presented for real-time monitoring of respiratory and heartbeat signals.A highly sensitive and stretchable piezoelectric strain sensor is fabricated using a piezoelectric film with a serpentine layout.The thickness of the patterned PVDF flexible piezoelectric strain sensor is only 168μm,and the voltage sensitivity reaches 0.97 mV/με.The effective modulus is 13.5 MPa,which allows the device to fit to the skin and detect the small strain exhibited by the human body.Chest vibrations are captured by the piezoelectric sensor,which produces an electrical output voltage signal conformally mapped with respiratory–cardiac activities.The separate heart activity and respiratory signals are extracted from the mixed respiratory–cardiac signal by an empirical mode decomposition data processing algorithm.By detecting vital signals such as respiratory and heart rates,the proposed device can aid early diagnosis and monitoring of respiratory diseases such as COVID-19.

A Photonic Crystal Fiber Based Asymmetric Slotted Structured Highly Sensitive Refractive Index Plasmonic Biosensor

Surface plasmon resonance (SPR) sensors have grown in popularity owing to their sensitivity, precision, and capacity for a variety of applications, including detection, monitoring, and sensing, among others. Sensitivity and resolution are two areas where this technology has room for development. A plasmonic biosensor based on an asymmetric slotted PCF structure with extremely high sensitivity has been described and theoretically investigated. This high performance sensor is constructed and completely characterized using finite element method in COMSOL Multiphysics software environment. Sensitivity and resolution are analyzed as performance parameters for the proposed sensor. Numerical simulation exhibits the maximum wavelength-sensitivity of 1100 nm/RIU with 9.09 × 10-6 RIU resolution in the broad measurement range of refractive index from 1.30 to 1.44. A polarization controller can be used to fine-tune this extremely sensitive and wide-ranging refractive index sensor to fulfil a variety of practical needs. This is performed with the consideration of the variation in the refractive index (RI) of the analyte channels. In comparison with earlier PCF-based sensors, the fiber design structure is basic, symmetrical, simple to produce, and cost-effective. Because of the asymmetric air holes and higher sensitivities of the refractive index detector, it is possible to identify biomolecules, biochemicals and other analytes.

A multiple flame-retardant,early fire-warning,and highly sensitive thread-shaped all-fabric-based piezoresistive sensor

In the artificial intelligence age,multifunctional and intelligent fireproof fabric-based electronics are urgently needed.Herein,a novel thread-shaped all-fabric-based piezoresistive sensor(denoted as TAFPS)with properties such as flame retardancy,firewarning,and piezoresistivity is proposed,which is composed of an inner nickel-plated fabric electrode,a multifunctional double helix fabric,and an external flame-retardant encapsulation fabric.Owing to the multiple flame-retardant properties of glass fiber tubular fabric,aminated carbon nanotubes(ACNTs),and ammonium polyphosphate,the char residue of the TAFPS reaches40.3 wt%at 800℃.In addition,the heat-sensitive effect of ACNTs during combustion causes a rapid decrease in the TAFPS resistance,triggering the fire alarm system within 2 s.Additionally,benefiting from the force-sensitive behavior of the double helix layer and tightly wrapped pattern of the external heat-shrinkable tubular fabric,TAFPS demonstrated a high sensitivity of4.40 kPa^(-1)(0–5.81 k Pa)and good stability for 10000 s.Considering its excellent flame resistance,high sensitivity,and agreeable stability,the developed TAFPS can be integrated into fire suits to monitor the exercise training process and the external fire environment.This work offers a novel approach for fabricating all-fabric-based piezoresistive sensors in the future for fire prevention and fire alarms,with promising applications in fire protection,the Internet of Things,and smart apparel.

Highly sensitive Fe^(3+)luminescence detection via single-ion adsorption

To achieve a lower detection limit has always been a goal of analytical chemists.Herein,we demonstrate the first picomolar level detection capability for Fe3+ion via luminescence detection technology.The results of structural analysis and theoretical calculation show that Fe3+ions are adsorbed on the central node of Eu-DBM(DBM=dibenzoylmethane)sensor in the form of single ion at ultralow concentration.Subsequently,the pathways of photo-induced charge and energy transfer of the obtained Eu-DBM@Fe^(3+)material have been changed,from the initial DBM-to-Eu^(3+)before Fe^(3+)adsorption to the ultimate DBM-to-Fe^(3+)after adsorption process,which quenches the luminescence of Eu3+ion.This work not only obtains the highly sensitive luminescence detection ability,but also innovatively proposes the single-ion adsorption mechanism,both of which have important scientific and application values for the development of more efficient detection agents in the future.

Highly sensitive H_(2)O_(2)-scavenging nano-bionic system for precise treatment of atherosclerosis

In atherosclerosis,chronic inflammatory processes in local diseased areas may lead to the accumulation of reactive oxygen species(ROS).In this study,we devised a highly sensitive H_(2)O_(2)-scavenging nanobionic system loaded with probucol(RPP-PU),to treat atherosclerosis more effectively.The RPP material had high sensitivity to H_(2)O_(2),and the response sensitivity could be reduced from 40 to 10μmol/L which was close to the lowest concentration of H_(2)O_(2)levels of the pathological environment.RPP-PU delayed the release and prolonged the duration of PU in vivo.In Apolipoprotein E deficient(ApoE-/-)mice,RPP-PU effectively eliminated pathological ROS,reduced the level of lipids and related metabolic enzymes,and significantly decreased the area of vascular plaques and fibers.Our study demonstrated that the H_(2)O_(2)-scavenging nanobionic system could scavenge the abundant ROS in the atherosclerosis lesion,thereby reducing the oxidative stress for treating atherosclerosis and thus achieve the therapeutic goals with atherosclerosis more desirably.

Synergistic piezoelectricity enhanced BaTiO_(3)/polyacrylonitrile elastomer-based highly sensitive pressure sensor for intelligent sensing and posture recognition applications

Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is reported.The ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency response.All components were fabricated using silicone,affording satisfactory skinconformality for sensing postures.Through cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and recognition.The home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.

Rational design of an AIE-active metal-organic framework for highly sensitive and portable sensing nitroaromatic explosives

Herein,we report a new metal-organic framework with an AIE ligand (H_(4)TCPP=2,3,5,6-tetra-(4-carboxyphenyl)pyrazine) and Mg^(2+) ions,that is,[Mg_(2)(H_(2)O)_(4)TCPP]·DMF·5CH_(3)CN (Mg-TCPP,TCPP=tetra-(4-carboxyphenyl)pyrazine) for detection of nitroaromatic explosives.Due to the coordination effect and restricted intramolecular rotation,Mg-TCPP exhibits bright blue light.As a fluorescent sensor,Mg-TCPP exhibits high selectivity and sensitivity for sensing 2,4,6-trinitrophenol (TNP) by quenching behaviors with the Stern-Volmer quenching constant (K_(SV)) of 3.63×10^(5)L/mol and achieves the low limit of detection of 25.6 ppb,which is beyond most of the previously reported fluorescent materials.Notably,the portable Mg-TCPP films are prepared and it can be used for rapid and sensitive TNP detection in a variety of environments including organic solvent and aqueous solution.Moreover,TNP vapor can be detected within 3 min by naked eye and the film could be regenerated under simple solvent cleaning.

Highly sensitive glucose sensor based on hierarchical CuO

The fabrication of high performance CuO based glucose sensors remains a great challenge due to the "trade-off effect" between sensitivity and linear range. In this study, a hierarchical CuO nanostructure with a great number of firecracker-shaped nanorods along the ligament and three-dimensional interconnected nanoporous is obtained by dealloying and post oxidation process of Al-33.3 wt% Cu eutectic alloy ribbons. Because of the precise structural design, not only the number of active sites for glucose electro-oxidation is significantly increased but also the glucose diffusion under high concentration is greatly accelerated, leading to a high sensitivity of 1.18 mA cm^(-2) mM^(-1) and a wider linear range up to 5.53 mM for glucose detection. This work provides a potential approach to design hierarchical nanostructure for other metal oxides with desirable properties for electrocatalytic applications.

Multidimensional Co_3O_4 nano sponge for the highly sensitive SERS applications

In this work,surface enhanced Raman spectroscopy(SERS) substrates with Ag nanoparticles(NPs) decorated Co_3O_4nanowires(NWs) grafted on the three-dimensional(3D) network architecture of Ni foam(denoted as Ag-NP@Co_3O_4^-NW/Ni-foam) arrays are manufactured. In the experiment,the hierarchical Ag-NP@Co_3O_4^-NW/Ni-foam arrays exhibit strong SERS activity due to the higher density of the "hot spots" created from the large quantities of neighboring Ag NPs. Using this hierarchical 3D SERS substrates,the crystal violet(a banned drug of aquaculture) with concentration down to 10^(-14) mol/L can be detected,which shows potential application in SERS-based rapid trace-level detection of harmful food additives.

Highly sensitive detection of NT-proBNP by molecular motor

FoF1-ATPase is an active rotary motor,and generates three-ATP for each rotation.At saturated substrate concentration,the motor can achieve about 103 r.p.m,which means one motor can generate about 105 ATP molecules during 30 min.Here,we constituted a novel nanodevice with a molecular rotary motor and a“battery”,FoF1-ATPase and chromatophore,and presented a novel method of sandwich type rotary biosensor based on εsubunit with one target-to-one motor,in which one target corresponds 105 ATP molecules as detection signals during 30 min.The target such as NT-proBNP detection demonstrated that this novel nanodevice has potential to be developed into an ultrasensitive biosensor to detect low expressed targets.

Highly sensitive hybrid nanofiber-based room-temperature CO sensors： Experiments and density functional theory simulations

Chemical sensors （CSs） are an emerging area in nanoscience research, which focuses on the highly sensitive detection of toxic and hazardous gases and disease- related volatile organics. While the field has advanced rapidly in recent years, it lacks the theoretical support required for the rational design of innovative materials with tunable measurement responses. Herein, we present a one-dimensional （1D） hybrid nanofiber decorated with ultrafine NiO nanoparticles （NiO NPs） as an efficient active component for CSs. Highly dispersed （110）-facet NiO NPs with a high percentage of Ni2~ active sites with unsaturated coordination were confined in a TiO2 nanofiber （TiO2 NF） matrix that is favorable for surface catalytic reactions. The CSs constructed using the 1D heterostructure NiO/TiO2 nanofibers （NiOdrio2 HNFs） exhibited a highly selective response to trace CO gas molecules （1 ppm） with high sensitivity （AR/Ro = 1.02）, ultrafast response/ recovery time （T 〈 20 s）, and remarkable reproducibility at room tem- perature. The density functional theory （DFT） simulations and experimental results confirmed that the selective response could be attributed to the high molecular adsorption energy of the NiO nanoparticles with （110） facets and abundant interfaces, which act synergistically to promote CO adsorption and facilitate charge transfer.

A NEW EXPERIMENTAL AND CLINICAL APPROACH OF COMBINING USAGE OF HIGHLY ACTIVE TUMOR-INFILTRATING LYMPHOCYTES AND HIGHLY SENSITIVE ANTITUMOR DRUGS FOR THE ADVANCED MALIGNANT TUMOR

In recent years, tumor-nfiltrating lymphocytes (TILs) have been reported to be effective for tumors in experimental and clinical research. In order to increase the therapeutical effect, we modified some steps of Rosenberg's approach a. cold digestion with collagenase at 4C for 24 hours; b. sedimentation instead of centrifugation; c. elimination of tumor cells before the cultivation procedure. Compared with the original approach, the proliferation, activity and cytotoxicity of TILs obtained by the modified procedure were much improved. TILs' expansion-old was greater than that with the original approach. Cytotoxicity against rumor cells was more potent. Increased TILs' subsets were CD3 and CD8 cells. Meanwhile, we took tumor cells from tumor tissues to test their in vitro chemosensitivities to different drugs in order to select highly sensitive antitumor drugs for treatment of cases with advanced tumors. According to the design of using highly active TILs and highly sensitive drugs (H & H therapy), preliminary clinical results of 50 cases showed higher response rates than those in treatment with TIL / IL2, LAK / 1L2 and TIL+IL2+CTX. Less toxic side effects were observed in 14 patients.