Rapid and quantitative detection of DNA hybridization using a simplified Fabry-Perot interferometric biosensor.

This study introduces a miniaturized fiber-optic Fabry-Perot (FP) interferometric biosensor, distinctively engineered for cost-effective, rapid, and quantitative DNA sequence detection. By leveraging the interference patterns generated within a Fabry-Perot microcavity, our sensor precisely monitors DNA hybridization events in real-time. We have verified the sensor's biofunctionalization via fluorescent labeling and have extensively validated its performance through numerous hybridization and regeneration cycles with 1 µM single-stranded DNA (ssDNA) solutions. Demonstrating remarkable repeatability and reusability, the sensor effectively discerns ssDNA sequences exhibiting varying degrees of mismatches. Its ability to accurately distinguish between sequences with 2 and 7 mismatches underscores its potential as a valuable asset for swift DNA analysis. Characterized by its rapid response time-typically yielding results within 6 minutes-and its adeptness at mismatch identification, our biosensor stands as a potent tool for facilitating accelerated DNA diagnostics and research.

Feasibility Analysis and Implementation of Head-Mounted Electrical Impedance Respiratory Monitoring.

The respiratory rate is one of the crucial indicators for monitoring human physiological health. The purpose of this paper was to introduce a head-mounted respiratory monitoring solution based on electrical impedance sensing. Firstly, we constructed a finite element model to analyze the feasibility of using head impedance for respiratory sensing based on the physiological changes in the pharynx. After that, we developed a circuit module that could be integrated into a head-mounted respiratory monitoring device using a bioelectrical impedance sensor. Furthermore, we combined adaptive filtering and respiratory tracking algorithms to develop an app for a mobile phone. Finally, we conducted controlled experiments to verify the effectiveness of this electrical impedance sensing system for extracting respiratory rate. We found that the respiration rates measured by the head-mounted electrical impedance respiratory monitoring system were not significantly different from those of commercial respiratory monitoring devices by a paired t-test (p > 0.05). The results showed that the respiratory rates of all subjects were within the 95% confidence interval. Therefore, the head-mounted respiratory monitoring scheme proposed in this paper was able to accurately measure respiratory rate, indicating the feasibility of this solution. In addition, this respiratory monitoring scheme helps to achieve real-time continuous respiratory monitoring, which can provide new insights for personalized health monitoring.

Spectral filtering method for improvement of detection accuracy of Mg, Cu, Mn and Cr elements in aluminum alloys using femtosecond LIBS.

In this work, magnesium (Mg), copper (Cu), manganese (Mn) and chromium (Cr) in aluminum alloy samples were quantified by femtosecond laser-induced breakdown spectroscopy (fs-LIBS). The different parameters affecting the experimental results, including the laser pulse energy, moving speed of the 2D platform and spectral average number were optimized. The background signal preprocessing methods of median filtering (MF corrected) and Savitzky-Golay filtering (SG corrected) algorithms were used and the effect of the LIBS spectral analysis in the experiment investigated. The calibration curves of Mg, Cu, Mn and Cr elements were established separately and their corresponding detection limits (LODs) were calculated. After background correction, the LODs of Mg, Cu, Mn and Cr elements in MF corrected were 54.52, 11.69, 7.33 and 27.72 ppm, and in SG corrected were 59.15, 17.48, 14.75 and 31.97 ppm. The LODs of these elements in MF corrected and SG corrected have 1.4-5.2 and 1.2-2.5 improvement factors compared to those obtained using the fs-LIBS technique. This work demonstrates that background signal preprocessing methods are very helpful for improving analytical sensitivity and accuracy in quantitative analyses of aluminum alloys.

A novel indicator for defining plain urban river network cyanobacterial blooms: resource use efficiency.

Increasing eutrophication and climate change have led to heavy cyanobacterial blooms in water diversion sources (e.g., lakes, reservoirs), which can potentially cause algae-bearing water to spread to downstream to an urban river network via diversion channels. Defining the extent of cyanobacterial blooms in an urban river network has become a novel concern in urban river management. In this paper, we investigated the physicochemical and algae community characteristics of a small, closed, urban river network, JiangXinZhou (JXZ), in the Lake Taihu basin. We propose a novel indicator, resource use efficiency (RUE), for defining the extent of cyanobacterial blooms in JXZ, whose recreational drinking water comes entirely from outside diversion sources. The results show that the JXZ's aquatic habitat conditions (mean water temperature, total nitrogen concentration, total phosphorus concentration, and nitrogen to phosphorus ratio) are highly suitable for the proliferation of cyanobacterial biomass during the high-water period. The RUE was used for calculation and shows a strong relationship with algae density, which means that it can be used as an index to define the degree of urban river cyanobacterial blooms. The findings indicate that the risk of cyanobacterial bloom is absent when the RUE is less than 46.81; blooms appear in the water bodies when the RUE reaches up to 106.68. This work provides theoretical support for the sustainable use of regional water resources.

[Ten-year Trend Analysis of Eutrophication Status and the Related Causes in Lake Hongze].

In order to propose pertinent suggestions regarding eutrophication control for Lake Hongze, we used monthly monitoring data from 2011 to 2020 to elucidate the spatiotemporal changing characteristics of eutrophic status and the relevant driving factors. As the main river entering Lake Hongze, River Huaihe experienced an increase in permanganate index and a decrease in TN in the last 10 years. Meanwhile, Secchi depth, TP, and permanganate index increased, whereas TN and Chl-a concentration decreased significantly in Lake Hongze. As a result, the eutrophic status TLI index of Lake Hongze declined over the past 10 years. The change trend of TLI in Lake Hongze differed spatially. As the main water passage of River Huaihe, the algal biomass was lower in the eastern region than that in the other two lake regions, regardless of the relatively high nutrient concentration, due to the short water retention time. Furthermore, the water quality of River Huaihe improved; thus, the TLI index decreased significantly in the eastern lake region. The northern region had a high coverage of aquatic vegetation, which not only reduced the concentration of water nutrients but also provided a habitat for zooplankton and fish, effectively inhibiting algal growth. Thus, the TLI index was lowest among the three lake areas and showed a downward trend over the last 10 years. In the western region, the algal biomass was the highest due to the intensification of phosphorus release from sediment in summer. Thus, the TLI index was the highest and had not improved in the past 10 years. There were also significant seasonal differences in the TLI of Lake Hongze, which was highest in summer, due to the relatively high algal biomass. Moreover, the algal biomass in summer was mainly affected by the concentration of nitrate. According to the spatiotemporal distribution characteristics of eutrophic status and the impacting factors in Lake Hongze, corresponding measures for eutrophication control should be taken for different seasons and lake areas.

Lake ecosystem health assessment using a novel hybrid decision-making framework in the Nam Co, Qinghai-Tibet Plateau.

Lake health assessment (LHA), a powerful tool for lake ecological protection, provides the foundation for sustainable water environment management. However, existing methods have not yet considered the effects of fuzziness and randomness on LHA. In addition, most of the current studies on LHA focus on the plain areas, lack of quantitative studies in mountain areas, such as the Qinghai-Tibet Plateau. The Pythagorean fuzzy cloud (PFC) integration algorithm drawing on the advantages of Pythagorean fuzzy sets (PFS) and cloud model was proposed. A novel hybrid decision-making framework combining PFC integration algorithm and TOPSIS model was developed to determine the lake health levels with fuzziness and randomness. An indicator system incorporating ecosystem integrity (physical habitat, water quantity and quality, aquatic life) and non-ecological performance (social services) was established. To comprehensively investigate the lake health level in the Qinghai-Tibet Plateau, the Nam Co was selected as study area. Our results confirm that the developed framework in this study can overcome the shortcomings of existing methods and provide a more effective approach for LHA with fuzziness and randomness. In Nam Co, the non-ecological performance was significantly better than the ecosystem integrity. Health levels exhibited a remarkable spatial variation influenced by tourism and grazing, with decreasing health status from the northwestern to southeastern Nam Co. Approximately 85% of the sampling sites were at excellent or healthy levels, 15% were subhealthy, and no sampling sites were unhealthy and sick. Our results highlight that tourism has affected health levels at Nam Co, and effective measures are needed to minimize the impact in ecological fragile areas.

Splicing point tapered fiber Mach-Zehnder interferometer for simultaneous measurement of temperature and salinity in seawater.

Combined with non-adiabatic tapering and mode field mismatch between two different fibers, a splicing point tapered fiber Mach-Zehnder interferometer is proposed. Theoretically, two sensing units are carefully designed for dual-parameter sensing, and mode exciting and evolution in fibers are analyzed and shown dynamically. In experiment, transmission spectrum is obtained with two sets of clear interference as designed. After a simple capsulation, simultaneous measurement of seawater temperature and salinity are realized with sensitivities of -994.83pm/°C and 290.47pm/‰, respectively. Additionally, short response time of 33ms and good repeatability are also demonstrated. And effects of encapsulation on avoiding strain and press are verified experimentally. The MZI demonstrated here shows advantages of low cost, easy fabrication, simple construction, compact and robust structure, and dual-parameter sensing with high sensitivity and fast response.

Ultrasensitive optical sensing in aqueous solution based on microfiber modal interferometer.

In this paper, an ultrahigh sensitivity sensing in aqueous solution for microfiber modal interferometer (MMI) is realized. The group refractive index (RI) difference between HE11 and HE12 mode will come down to 0 at a certain wavelength, resulting in ultrahigh sensitivity near this wavelength. MMI with different diameters have their individual ultrasensitive wavelength band, which indicates the broad range of optional probing wavelength and more liberal diameter condition on fiber fabrication. In the experimentation, infrared absorption band in water around 1360-1600nm is easy to keep away by adjusting the microfiber diameter. As a result, an ultrahigh sensitivity of 14.95 pm/ppm is realized for sodium nitrate at 1320nm, whose equivalent sensitivity is about 1.26 × 105-nm/RIU for RI, which is much higher than most of the existing naked sensors with magnitude of 102-104nm/RIU.

Prenatal Perfluorooctyl Sulfonate Exposure and Alu DNA Hypomethylation in Cord Blood.

BACKGROUND: Perfluoroalkyl substances (PFASs) are stable and persistent in the environment, animals, and humans. PFASs can penetrate placenta and affect fetal growth. We investigated associations between prenatal exposure to perfluorooctanoic acid (PFOA), perfluorooctyl sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUA) and global methylation levels. Specific Aims and Methods: The study used the subjects from Taiwan Birth Panel birth cohort study, including all pregnant women who gave birth between July 2004 and June 2005 in four hospitals in Taipei city and New Taipei City. A total of 363 mother-infant pairs were included in the final analyses. PFOA, PFOS, PFNA, and PFUA were measured by UPLC-MS/MS in cord blood. LINE-1 and Alu repeated elements from cord blood was used to represent global DNA methylation levels. Multivariable regression models were used to adjust potential confounders. RESULTS: After controlling for potential confounders, each unit increase in the natural log-transformed PFOS exposure was associated with an adjusted OR of 1.72 (95% CI: 1.03, 2.88) for low Alu methylation level when dichotomized methylation level by medium. No significant effects between PFOA, PFNA, PFUA and methylation levels in the multivariable regression models were observed. CONCLUSIONS: Our findings suggest that prenatal PFOS exposure may be associated with low Alu methylation level.

All-fiber Mach-Zehnder interferometer for tunable two quasi-continuous points' temperature sensing in seawater.

An all-fiber Mach-Zehnder interferometer (MZI) for two quasi-continuous points' temperature sensing in seawater is proposed. Based on the beam propagation theory, transmission spectrum is designed to present two sets of clear and independent interferences. Following this design, MZI is fabricated and two points' temperature sensing in seawater are demonstrated with sensitivities of 42.69pm/°C and 39.17pm/°C, respectively. By further optimization, sensitivity of 80.91pm/°C can be obtained, which is 3-10 times higher than fiber Bragg gratings and microfiber resonator, and higher than almost all similar MZI based temperature sensors. In addition, factors affecting sensitivities are also discussed and verified in experiment. The two points' temperature sensing demonstrated here show advantages of simple and compact construction, robust structure, easy fabrication, high sensitivity, immunity to salinity and tunable distance of 1-20 centimeters between two points, which may provide references for macroscopic oceanic research and other sensing applications based on MZIs.

[Analysis of Microfiber Knot Resonator Spectrum for Seawater Temperature].

As a sensing device, microfiber knot resonator (MKR) has been widely used in sensing field due to its advantages of high sensitivity and fast response. It is important to analyze the spectrum of MKR for detecting environmental parameters in that the spectrum can reflect the change of ambient environment. In this paper, the relationship between spectrum of MKR and seawater temperature has been studied theoretically and experimentally. Firstly, the dependences of the propagation constants of fundamental mode (HE11) on the fiber diameter and the probing wavelength are studied theoretically in this paper, including two orthogonal polarization states of fundamental mode. The calculated results show that the propagation constant increases with the increasing fiber diameter and the decreasing probing wavelength. Simultaneously, the dependence of propagation constant of fundamental mode on seawater temperature is studied. The results show that the larger propagation constant corresponds to the higher seawater temperature, which indicates that the seawater temperature affect the mode propagation constant. Thus, the seawater temperature can be obtained by detecting the resonant spectrum. Secondly, the experimental system for seawater temperature sensing is set up, with which the resonant spectrum of MKR for seawater temperature sensing are obtained. The experimental results show that two sets of resonant peak exist on the spectrum, which are corresponding to TE and TM modes of fundamental mode. The sensing sensitivities of the two polarization modes are 5.54 pm/°C and 5.24pm/°C, respectively. Finally, the reason for resonant spectrum of the two polarization states is discussed, which is that the separation of the two modes resulting from the twisted coupler of the knot zone, and the resonant intensity of the two polarization modes is analyzed. The resonant intensities of the two modes are different and one increases while the other one decreases with the increasing probing wavelength. It is determined by the coupling coefficients and attenuations of the two coupled states，which are affected by the probing wavelength. The experimental and theoretical results agree well.

[Near Infrared Spectroscopy of the Cretaceous Red Beds in Inner Mongolia Dongshengmiao].

Take the cores and surface weathered soil from the Cretaceous red beds in the western of Dongshengmiao mine of Inner Mongolia and analysis with near-infrared spectroscopy. The result shows that near-infrared spectroscopy can identify mineral quickly through the characteristic absorption peaks of each group. The Cretaceous red beds in the western of Dongshengmiao mine is argillaceous cementation, it is mainly composed of quartz, feldspar, montmorillonite, illite, chlorite, muscovite etc, the mineral composition is mainly affected by the upstream source area. The clay mineral like montmorillonite water swelling and uneven drying shrinkage expands the original crack and creates new cracks, reduces its strength, which is the mainly reason of its disintegration. According to the composition of clay mineral, we speculate its weathering process is mainly physical weathering, the climate during the weathering is cold and dry. The results can not only improve the geological feature of the mining area, but also show that the near-infrared spectroscopy technology can analyze the mineral composition of soil and rock effectively on the basis of Mineral spectroscopy, which demonstrates the feasibility of the near-infrared spectroscopy can analyze minerals in soil and rock quickly, that shows the feasibility in geology study, provides new ideas for the future research of soil and rock.

Modeling seawater salinity and temperature sensing based on directional coupler assembled by polyimide-coated micro/nanofibers.

The salinity and temperature of seawater are important parameters in oceanography. Based on the directional coupler assembled by polyimide-coated micro/nanofibers, optical sensors with high sensitivity for simultaneous salinity and temperature sensing in seawater are proposed. Dependences of sensitivities on wavelength, salinity, and temperature are investigated theoretically, with which performances of such sensor under general sea conditions can be evaluated. Results show that salinity and temperature sensitivities can reach levels of nm/‰ and nm/°C, which are much higher than those of fiber Bragg gratings, knot resonators, and photonic crystal fibers. Other considerations for system design such as the length of the coupling area, the diameter difference between two fibers, and the thickness of polyimide coatings are also discussed. Sensors proposed here suggest a simple approach to realize high-sensitivity micro/nanofiber optical sensing of salinity and temperature in seawater simultaneously and may find applications in developing miniature sensors used in seawater.

[Near infrared spectrum analysis and meaning of the soil in 512 earthquake surface rupture zone in Pingtong, Sichuan].

Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Ping- tong town,Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite; talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region. By analyzing and comparing it was revealed that part of mineral compositions of the soil are in accordance with the characteristics of the rock mineral compositions below the rupture zone, indicating that part of the minerals of the soil's evolution is closely related to the rock compositions in this area; and the compositions of the clay mineral in the rupture zone is similar to the Ma Lan loess in the north of China, so it is presumed that the clay minerals in these two kinds of soil have the same genetic type. The characteristic of the mineral composition of the soil is in accordance with evolution characteristics of the rocks which is bellow the rupture zone, also it was demonstrated that the results of soil minerals near-infrared analysis can effectively analyze the mineral particles in the soil and indicate the pedogenic environment. Therefore, the result shows the feasibility of adopting modern near-infrared spectrum for rapid analysis of mineral particles of the soil and research of geology. Meanwhile, the results can be the foundation of this region's soil mineral analysis, and also provide new ideas and methods for the future research of soil minerals and the earthquake rupture zone.

Temperature sensing in seawater based on microfiber knot resonator.

Ocean internal-wave phenomena occur with the variation in seawater vertical temperature, and most internal-wave detections are dependent on the measurement of seawater vertical temperature. A seawater temperature sensor based on a microfiber knot resonator (MKR) is designed theoretically and demonstrated experimentally in this paper. Especially, the dependences of sensing sensitivity on fiber diameter and probing wavelength are studied. Calculated results show that sensing sensitivity increases with the increasing microfiber diameter with the range of 2.30-3.91 µm and increases with the increasing probing wavelength, which reach good agreement with results obtained by experiments. By choosing the appropriate parameters, the maximum sensitivity measured can reach to be 22.81 pm/°C. The seawater temperature sensor demonstrated here shows advantages of small size, high sensitivity, easy fabrication, and easy integration with fiber systems, which may offer a new optical method to detect temperature of seawater or ocean internal-wave phenomenon and offer valuable reference for assembling micro sensors used for other parameters related to seawater, such as salinity, refractive index, concentration of NO3- and so on.

[X-ray diffraction and infrared spectrum analysis of fault gouge in Wenchuan seismic belt].

Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, and its characteristics such as mineral compositions, clay mineral contents and combinations were comprehensively analyzed. The results display obvious differences between the new and old fault gouge, showing that the old fault gouge is mainly composed of wall rock debris or milled powders, while the main components of new fault gouge are clay minerals. The assemblage of clay minerals composition shows that the environment of the fault activity was mainly warm and humid, and the clay minerals were mainly transformed by low temperature and low pressure dynamic metamorphism. And this also partly indicates that the latest way of the fault activity in this area may be a creeping. However the previous researches on the fault gouge of Wenchuan earthquake fault zone are mainly focused on its mechanical properties as well as its texture and structure, the research in this paper is to determine the physical and chemical environment of fault activity through the mineral compositions and clay mineral contents in the fault gouge characteristics, and this research has important scientific significance to the researches on the evolution of the fault environment and the activity mechanism of the earthquake.