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Prenatal ozone (O3) exposure may disrupt normal offspring growth. However, epidemiological evidence that prenatal O3 exposure affects the physical development of offspring early in life is far from adequate. A total of 4909 maternal–child pairs from the Shanghai Maternal–Child Pairs Cohort were included. A high-resolution random forest model was utilized to evaluate prenatal exposure levels of O3 based on the home addresses of pregnant women. Group-based trajectory and mixed-effects models were used to assess associations between prenatal O3 exposure and physical parameters. Each 10 μg/m³ increase in O3 concentration was associated with 0.084, 0.048, and 0.082-unit increases in body mass index (BMI) for age Z score (BAZ), weight for age Z score (WAZ), and weight for length Z score (WLZ), respectively. Specifically, a 10 μg/m³ increase in O3 concentration was linked to a 1.208-fold and 1.209-fold increase in the elevated-increasing group for the BAZ and WLZ trajectories, respectively. Moreover, each 10 μg/m³ increases in prenatal O3 was associated with a 1.396-fold and 0.786-fold increase in the risk of BAZ and length for age Z score (LAZ) accelerated growth, respectively. Furthermore, a 10 μg/m³ increase in prenatal O3 was linked to a 1.355-fold increase in the risk of overweight and obesity (OAO). Our study revealed that prenatal O3 exposure is associated with accelerated BMI gain or decelerated body length gain in the early life of children. Prenatal O3 may also increase the risk of OAO in children for the first two years.

Abstract Background Metastasis renal cell carcinoma (RCC) patients have extremely high mortality rate. A predictive model for RCC micrometastasis based on pathomics could be beneficial for clinicians to make treatment decisions. Methods A total of 895 formalin-fixed and paraffin-embedded whole slide images (WSIs) derived from three cohorts, including Shanghai General Hospital (SGH), Clinical Proteomic Tumor Analysis Consortium (CPTAC) and Cancer Genome Atlas (TCGA) cohorts, and another 588 frozen section WSIs from TCGA dataset were involved in the study. The deep learning-based strategy for predicting lymphatic metastasis was developed based on WSIs through clustering-constrained-attention multiple-instance learning method and verified among the three cohorts. The performance of the model was further verified in frozen-pathological sections. In addition, the model was also tested the prognosis prediction of patients with RCC in multi-source patient cohorts. Results The AUC of the lymphatic metastasis prediction performance was 0.836, 0.865 and 0.812 in TCGA, SGH and CPTAC cohorts, respectively. The performance on frozen section WSIs was with the AUC of 0.801. Patients with high deep learning-based prediction of lymph node metastasis values showed worse prognosis. Conclusions In this study, we developed and verified a deep learning-based strategy for predicting lymphatic metastasis from primary RCC WSIs, which could be applied in frozen-pathological sections and act as a prognostic factor for RCC to distinguished patients with worse survival outcomes.

Glioma is the most common malignant tumor of the nervous system in recent centuries, and the incidence rate of glioma is increasing year by year. Its invasive growth and malignant biological behaviors make it one of the most challenging malignant tumors. Maximizing the resection range (EOR) while minimizing the impact on normal brain tissue is crucial for patient prognosis. Changes in metabolites produced by tumor cells and their microenvironments might be important indicators. As a powerful spectroscopic technique, surface-enhanced Raman scattering (SERS) has many advantages, including ultra-high sensitivity, high specificity, and non-invasive features, which allow SERS technology to be widely applied in biomedicine, especially in the differential diagnosis of malignant tumor tissues. This review first introduced the clinical use of responsive SERS probes. Next, the sensing mechanisms of microenvironment-responsive SERS probes were summarized. Finally, the biomedical applications of these responsive SERS probes were listed in four sections, detecting tumor boundaries due to the changes of pH-responsive SERS probes, SERS probes to guide tumor resection, SERS for liquid biopsy to achieve early diagnosis of tumors, and the application of free-label SERS technology to detect fresh glioma specimens. Finally, the challenges and prospects of responsive SERS detections were summarized for clinical use.

Abstract Neurotoxicity of organophosphate compounds (OPs) can catastrophically cause nervous system injury by inhibiting acetylcholinesterase (AChE) expression. Although artificial systems have been developed for indirect neuroprotection, they are limited to dissociating P-O bonds for eliminating OPs. However, these systems have failed to overcome the deactivation of AChE. Herein, we report our finding that Al3+ is engineered onto the nodes of metal–organic framework to synthesize MOF-808-Al with enhanced Lewis acidity. The resultant MOF-808-Al efficiently mimics the catalytic behavior of AChE and has a self-defense ability to break the activity inhibition by OPs. Mechanism investigations elucidate that Al3+ Lewis acid sites with a strong polarization effect unite the highly electronegative –OH groups to form the enzyme-like catalytic center, resulting in superior substrate activation and nucleophilic attack ability with a 2.7-fold activity improvement. The multifunctional MOF-808-Al, which has satisfactory biosafety, is efficient in reducing neurotoxic effects and preventing neuronal tissue damage.

Abstract The transportation of hydrogen is a weak link in the large‐scale development of the hydrogen energy industry. Injecting hydrogen into the natural gas pipeline network for transportation is an efficient way to achieve the large‐scale, long‐distance, and low‐cost transportation of hydrogen. Hydrogen can lead to hydrogen embrittlement in natural gas pipelines and cause safety incidents if hydrogen and natural gas are not mixed uniformly. Therefore, it is necessary to study the blending process and blending uniformity of hydrogen and natural gas. In this study, a three‐dimensional model of the hydrogen‐injected natural gas pipeline was constructed. The effects of hydrogen injection inlet and turbulator configuration on the mixing process of hydrogen and natural gas were investigated using a computational fluid dynamics approach. The results show that increasing the number of hydrogen injection inlets shortens the distance L98% of uniform mixing of hydrogen and natural gas. Increasing the radial distance r from the initial hydrogen mixing positions to the center of the pipeline will shorten the distance for uniform gas mixing in the pipeline. The addition of turbulator configurations in the pipeline significantly reduces the distance to uniform gas mixing. Changing the distance Lturb from the turbulator to the initial mixing position further shortens the distance between hydrogen and natural gas mixing uniformly. The results of this study provide a reference for the structural design of the hydrogen–natural gas mixing pipeline and the gas distribution state during the mixing process.

Hydrogen is a clean energy source, and blending it with natural gas in existing pipeline networks is a key transition solution for transportation cost reduction. However, during the transportation process, a non-uniform distribution of hydrogen concentration occurs in the pipeline due to gravity. Therefore, it is necessary to study the hydrogen concentration distribution law of hydrogen-blended natural gas in pipelines. The undulation and ball valve pipelines, which are common in transport pipelines, were constructed in this study. The effects of the undulation angle, height, pipeline diameter, ball valve opening, and temperature on the distribution of the hydrogen concentration were investigated using computational fluid dynamic (CFD) methods. The results indicated that the hydrogen concentration gradient changed gently with the larger diameter of the undulating pipeline, minimizing hydrogen accumulation. Higher undulation angle and smaller height differences reduces the hydrogen accumulation risk. Increasing vertical height difference of the pipeline from 5 m to 15 m increased the hydrogen volume fraction gradient by1.3 times. In the ball valve pipeline, the velocity fluctuation decreased as the ball valve opening increased. However, the hydrogen accumulation phenomenon was obvious. The opening increased from 25% to 100% and the hydrogen volume fraction gradient increased more than two times. Selecting delivery conditions with low hydrogen blending ratios, high temperatures, low pressures, and high flow rates reduces the occurrence of hydrogen buildup in the pipeline.

Hydrogen mixing in existing natural gas pipelines efficiently achieves large-scale, long-distance, and low-cost hydrogen delivery. The physical properties of hydrogen and natural gas differ significantly. Hydrogen-mixed natural gas modifies the flow state and thermodynamic properties of the original natural gas in the pipeline. Hydrogen-mixed natural gas can lead to increased errors in ultrasonic flow metering because of the high sound speed and low density of hydrogen. Ultrasonic flowmeter installation distances need to be re-determined. In this study, a Lamb wave non-contact ultrasonic gas flow meter is used to measure the flow of hydrogen-mixed natural gas in a T-type pipeline. The greater the hydrogen mixing ratio, the higher the flow rate of the branch pipeline, and the shorter the installation distance of the ultrasonic flow meter, for example, 10% at 150D, 20% at 110D, and 30% at 20D. The time-difference method with high accuracy and broad applicability is used to calculate the flow rates of COMSOL simulated values. The errors between COMSOL simulation and theoretical flow rates at the shortest installation distance downstream do not exceed 3%. The errors at the position where the mixing uniformity is 80% are significantly higher than those at the shortest installation distance, and the maximum error is about 7.7%. The COMSOL simulation results show the feasibility and accuracy of ultrasonic gas flow metering of hydrogen-mixed natural gas.

Hydrogen-blended natural gas transportation can effectively solve the problem of wind and photovoltaic energy curtailment and reduction of greenhouse gas emission, and realize the low-cost transportation of hydrogen in large scale, so it becomes an important way to achieve the "double carbon" goal. However, the risk of hydrogen embrittlement will be brought by blending hydrogen to the existing natural gas pipeline system and relevant transportation facilities. Therefore, the mechanism of hydrogen embrittlement was analyzed based on the structural composition of hydrogen-blended natural gas transportation system. Meanwhile, investigation was performed for the hydrogen embrittlement of the pipelines, welds, valves, compression devices, storage units and terminals of the hydrogen-blended natural gas transportation system. On this basis, countermeasures for prevention of hydrogen embrittlement were put forward. Then, the prospect and development of hydrogen-blended natural gas transportation system were forecast. Generally, the research results could provide reference for the large-scale and market-oriented development of hydrogen-blended natural gas transportation in China, and the improvement of research and development of pipeline hydrogen transportation technology and equipment, further accelerating the safe development of hydrogen economy.

Food safety has become a subject of major concern in controlling food contamination and supervision. Effective detection and analysis methods need to be urgently exploited to cope with this grand global challenge. Among conventional methods for food safety analysis, enzyme-based biosensing methods serve a critical role in the monitoring of food safety. However, some long-lasting challenges, like high cost and low stability, hinder enzyme-based biosensing systems. In this regard, nanozymes with superior enzyme-like activity and special physical and chemical characteristics gradually emerge as excellent tools for quality and safety analysis in agricultural fields. In this review, recent advances made in the food safety analysis based on nanozymes are summarized. Firstly, an introduction of nanozymes containing their definition, classification, and modulation is provided. Subsequently, four main sensing modes used in nanozyme-based biosensing are discussed in detail. Taking advantage of nanozyme-based biosensing platforms, great achievements made in food safety are highlighted, where biological hazards, heavy metal ions, antibiotics, pesticide residues, and additives are involved. At last, personal views of the progress and perspective in this evolving field are proposed. This review not only shows great reference significance for the construction and application of nanozyme-based analysis methods but also promotes solutions to some challenges existing in food safety.

Abstract Vapor‐compression refrigeration systems are widely used in refrigeration equipment. Theoretically, the process is typically divided into two isobaric processes: an adiabatic isentropic compression process and adiabatic isentropic throttling process. The refrigeration compressor is the main energy‐consuming component in vapor‐compression refrigeration systems. However, this device has a large energy loss and low overall efficiency in the adiabatic isentropic compression process. In this study, a modified vapor‐compression refrigeration cycle with an isothermal piston is proposed to realize near‐isothermal compression of a refrigerator to significantly reduce the energy loss in the compression process and improve the system performance. A real‐gas compression process model is established, and the heat transfer index Hex is set. By changing the heat transfer index Hex, the performances of the vapor‐compression refrigeration system under ideal and real compression conditions are compared and analyzed. Compared with a traditional vapor‐compression refrigeration system, the coefficient of performance of the compressor with an isothermal compression process is increased by approximately 17%. The results also demonstrate that the lower the evaporation temperature Te and higher the condensation temperature Tc, the greater the optimization effect of the isothermal compression.

The resistance mechanism of microbial communities in contaminated groundwater under combined stresses of aromatic hydrocarbons (AHs), NH4+, and Fe–Mn exceeding standard levels was studied in an abandoned oil depot in Northeast China. The response of environmental parameters and microbial communities under different pollution levels in the study area was discussed, and microscopic experiments were conducted using background groundwater with different AHs concentrations. The results showed that indigenous microbial community were significantly affected by environmental factors, including pH, TH, CODMn, TFe, Cr (VI), NH4+, NO3-, and SO42-. AHs likely had a limited influence on microbial communities, mainly causing indirect changes in the microbial community structure by altering the electron donor/acceptor (mainly Fe, Mn, NO3-, NO2-, NH4+, and SO42-) content in groundwater, and there was no linear effect of AHs content on the microbial community. In low- and medium-AHs-contaminated groundwater, the microbial diversity increased, whereas high AHs contents decreased the diversity of the microbial community. The microbial community had the strongest ability to metabolize AHs in the medium-AHs-contaminated groundwater. In the high-AHs-contaminated groundwater, microbial communities mainly degraded AHs through a complex co-metabolic mechanism due to the inhibitory effect caused by the high concentration of AHs, whereas in low-AHs-contaminated groundwater, microbial communities mainly caused a mutual transformation of inorganic electron donors/acceptors (mainly including N, S), and the microbial community’s ability to metabolize AHs was weak. In the high-AHs-contaminated groundwater, the microbial community resisted the inhibitory effect of AHs mainly via a series of resistance mechanisms, such as regulating their life processes, avoiding unfavorable environments, and enhancing their feedback to the external environment under high-AHs-contaminated conditions.

The unique climate and the landscape of severely cold regions in winter attract many tourists. The outdoor thermal environment affects the space use and the tourist experience, becoming one of the key factors in the design of tourist attractions. The outdoor thermal comfort of tourists from different regions should be considered, but it has been poorly studied in winter in severely cold regions. This paper explores the differences in outdoor thermal comfort in winter between local and non-local tourists through the field measurement of the thermal environment and a questionnaire survey of thermal comfort at tourist attractions in Harbin, China. The results show that the proportion of local tourists who expect the air temperature and solar radiation to rise in winter is higher than that of non-local tourists. The thermal sensation vote of local tourists is generally higher than that of non-local tourists. When the Physiologically Equivalent Temperature (PET) < −6 °C, the thermal satisfaction of non-local tourists is higher than that of local tourists. When the PET value is −10 °C, the thermal comfort of non-local tourists is the highest. The thermal comfort decreases with the rise or fall of the PET value. When −28 °C < PET < −7 °C, the thermal comfort of non-local tourists is generally higher than that of local tourists. This paper provides a reference and evaluation basis for urban tourist attractions’ outdoor thermal environment design in severely cold regions.

Abstract Although nanozymes have been widely developed, accurate design of highly active sites at the atomic level to mimic the electronic and geometrical structure of enzymes and the exploration of underlying mechanisms still face significant challenges. Herein, two functional groups with opposite electron modulation abilities (nitro and amino) were introduced into the metal–organic frameworks (MIL-101(Fe)) to tune the atomically dispersed metal sites and thus regulate the enzyme-like activity. Notably, the functionalization of nitro can enhance the peroxidase (POD)-like activity of MIL-101(Fe), while the amino is poles apart. Theoretical calculations demonstrate that the introduction of nitro can not only regulate the geometry of adsorbed intermediates but also improve the electronic structure of metal active sites. Benefiting from both geometric and electronic effects, the nitro-functionalized MIL-101(Fe) with a low reaction energy barrier for the HO* formation exhibits a superior POD-like activity. As a concept of the application, a nitro-functionalized MIL-101(Fe)-based biosensor was elaborately applied for the sensitive detection of acetylcholinesterase activity in the range of 0.2–50 mU mL−1 with a limit of detection of 0.14 mU mL−1. Moreover, the detection of organophosphorus pesticides was also achieved. This work not only opens up new prospects for the rational design of highly active nanozymes at the atomic scale but also enhances the performance of nanozyme-based biosensors.

With the emergence of X-ray free-electron lasers, it is possible to investigate the structure of nanoscale samples by employing coherent diffractive imaging in the X-ray spectral regime. In this work, we developed a refinement method for structure reconstruction applicable to low-quality coherent diffraction data. The method is based on the gradient search method and considers the missing region of a diffraction pattern and the small number of detected photons. We introduced an initial estimate of the structure in the method to improve the convergence. The present method is applied to an experimental diffraction pattern of an Xe cluster obtained in an X-ray scattering experiment at the SPring-8 Angstrom Compact free-electron LAser (SACLA) facility. It is found that the electron density is successfully reconstructed from the diffraction pattern with a large missing region, with a good initial estimate of the structure. The diffraction pattern calculated from the reconstructed electron density reproduced the observed diffraction pattern well, including the characteristic intensity modulation in each ring. Our refinement method enables structure reconstruction from diffraction patterns under difficulties such as missing areas and low diffraction intensity, and it is potentially applicable to the structure determination of samples that have low scattering power.

Ultrashort pulse X-ray free electron lasers (XFFLs) provided us with an unprecedented regime of X-ray intensities, revolutionizing ultrafast structure determination and paving the way to the novel field of non-linear X-ray optics. While pioneering studies revealed the formation of a nanoplasma following the interaction of an XFEL pulse with nanometer-scale matter, nanoplasma formation and disintegration processes are not completely understood, and the behavior of trapped electrons in the electrostatic potential of highly charged species is yet to be decrypted. Here we report the behavior of the nanoplasma created by a hard X-ray pulse interacting with xenon clusters by using electron and ion spectroscopy. To obtain a deep insight into the formation and disintegration of XFEL-ignited nanoplasma, we studied the XFEL-intensity and cluster-size dependencies of the ionization dynamics. We also present the time-resolved data obtained by a near-infrared (NIR) probe pulse in order to experimentally track the time evolution of plasma electrons distributed in the XFEL-ignited nanoplasma. We observed an unexpected time delay dependence of the ion yield enhancement due to the NIR pulse heating, which demonstrates that the plasma electrons within the XFEL-ignited nanoplasma are inhomogeneously distributed in space.

Abstract Pneumatic system has been widely used throughout industry, and it consumes more than billions kW h of electricity one year all over the world. So as to improve the efficiency of pneumatic system, its power evaluation as well as measurement methods should be proposed, and their applicability should be validated. In this paper, firstly, power evaluation and measurement methods of pneumatic system were introduced for the first time. Secondly, based on the proposed methods, power distributions in pneumatic system was analyzed. Thirdly, through the analysis on pneumatic efficiencies of typical compressors and pneumatic components, the applicability of the proposed methods were validated. It can be concluded that, first of all, the proposed methods to evaluation and measurement the power of pneumatic system were efficient. Furthermore, the pneumatic power efficiencies of pneumatic system in the air production and cleaning procedure are respectively about 35%–75% and 85%–90%. Moreover, the pneumatic power efficiencies of pneumatic system in the transmission and consumption procedures are about 70%–85% and 10%–35%. And the total pneumatic power efficiency of pneumatic system is about 2%–20%, which varies largely with the system configuration. This paper provides a method to analyze and measure the power of pneumatic system, lay a foundation for the optimization and energy-saving design of pneumatic system.

The waterfront park in northern China always has two parallel leisure pathways, a sunshine pathway and a tree-shaded pathway, which is attributed to the seasonal variations in water level. To provide some design suggestions according to the local characteristics of the waterfront park in northern China, this study selected six young volunteers to take part in an outdoor field experiment and a questionnaire survey in Stalin Park of Songhua River in Harbin, China. During the experiment, the volunteers’ local skin temperature and core temperature were recorded, with their subjective responses recorded every 5 min, including thermal comfort, thermal sensation, thermal pleasure, and fatigue scale vote. This study found that, compared with the sunshine pathway, the tree-shaded pathway not only optimized people’s outdoor thermal comfort and thermal pleasure, but also improved their fatigue scale vote experience. Some evidence showed that people’s subjective response to the outdoor thermal environment might be influenced by physical factors (temperature, velocity, humidity, radiation, etc.) and may also be influenced by the surrounding landscape view (water, square, lawn, tree, etc.). The first piece of evidence is that, during the first 10 min, people’s thermal sensation in the sunshine pathway group was high, but they kept voting for high thermal comfort, which may be due to the influence of the waterfront view on people’s subjective response to thermal comfort. The second piece of evidence shows that people’s overall thermal sensation was calculated by their local thermal sensation, looking at former research, with the voting results very different to the calculated results, which could be attributed to the influence of diversity landscape elements on people’s subjective response to thermal sensation. Based on these results, some suggestions for the leisure pathway design along Stalin Park of Songhua River in Harbin, China, were given. The shaded device of the sunshine pathway should be designed in 15-min-walk intervals and accessible ways to the tree-shaded pathway should be added. The other facilities should be designed with 30 min walking distance on the tree-shaded pathway and 20 min walking distance to the sunshine pathway. Diversified landscapes should be designed for both the tree-shaded pathway and sunshine pathway, which could improve people’s outdoor thermal comfort and the general subjective response to the environment. It is worth noting that the sample size of this study was small (6), and the participants were all homogenous young people (age, height, weight); thus, this study could be considered a preliminary work and the results and applicability have limitations.

Energy saving is one of the main technique routes for net zero carbon emissions. Air compressor systems take up a large part of energy consumption in the industrial field. A pre-cooling air compressor system was proposed for energy saving by cooling the air before it flows in a compressor. The energy efficiency of the proposed system was analyzed. As additional energy consumption is required for air cooling, the feasibility of the pre-cooling method for energy saving was analyzed. As the efficiency of the pre-cooling air compressor system is mainly influenced by the environment temperature and humidity, applicability of the system in different regions and at different seasons was discussed. A pilot project was performed to verify the technical feasibility and economics of the proposed system. When the precooling temperature of the pilot system was set to 2 °C, the annual pneumatic-electrical ratio of the system can be increased by approximately 2% in several regions of China. This paper shows the pre-cooling air compressor system is feasible for energy saving.

The demand for mass custom parts is increasing, estimating the cost of parts to a high degree of efficiency is a matter of great concern to most manufacturing companies. Under the premise of machining operations, cost estimation based on features and processes yields high estimation accuracy, but it necessitates accurately identifying a part’s machining features and establishing the relationship between the feature and the cost. Accordingly, a feature recognition method based on syntactic pattern recognition is proposed herein. The proposed method provides a more precise feature definition and easily describes complex features using constraints. To establish the relationships between geometric features, processing modes, and cost, this study proposes a method of describing the features and the processing mode using feature quantities and adopts deep learning technology to establish the relationship between feature quantities and cost. By comparing a back propagation (BP) network and a convolutional neural network (CNN) it can be concluded that a CNN using the “RMSProp” optimizer exhibits higher accuracy.

Summary: Integration of disease diagnosis and therapy in vivo by nanotechnology is a challenge in the design of multifunctional nanocarriers. Herein, we report an intelligent and degradable nanoreactor, an assembly of the 4-mercaptobenzonitrile-decorated silver nanoparticles (AgNPs@MBN) and the glucose oxidase (GOx)-loaded metal-organic-framework (ZIF-8@GOx), which can be activated by tumor microenvironment to start the catalytic cascade-enhanced chemo-starvation synergistic therapy and simultaneous self-sense of cellular glucose level. Under the mild acidic microenvironment of tumor, the nanoreactor will collapse to release GOx that triggers a catalytic cascade reaction in vivo, depleting glucose, etching AgNPs@MBN, and producing toxic H2O2, Ag+, and Zn2+ ions, all of which work together to inhibit tumor growth. The AgNPs@MBN as SERS nanoprobe reads out glucose concentration noninvasively in tumor to achieve instant feedback of therapeutic progression. This work proposes a promising example of using enzyme-encapsulated biomineralized MOFs as an effective anticarcinogen for clinical applications.

Carbon materials have been widely used as nanozymes in bioapplications, attributing to their intrinsic enzyme-like activities. Nitrogen (N)-doping has been explored as a promising way to improve the activity of carbon material-based nanozymes (CMNs). However, hindered by the intricate N dopants, the real active site of N-doped CMNs (N-CMNs) has been rarely investigated, which subsequently retards the further progress of high-performance N-CMNs. Here, a series of porous N-CMNs with well-controlled N dopants were synthesized, of which the intrinsic peroxidase (POD)like activity has a positive correlation with the pyridinic N content. Density functional theory calculations also reveal that pyridinic N boosts the intrinsic POD-like activity of N-CMNs. Pyridinic-N dopant can effectively promote the first H2O desorption process in comparison with the graphitic and pyrrolic N, which is the key endothermic reaction during the catalytic process. Then, utilizing the optimized nanozymes with high pyridinic N content (NP-CMNs) and superior POD-like activity, a facile total antioxidant capacity (TAC) assay was developed, holding great promise in the quality assessment of medicine tablets and antioxidant food for healthcare and healthy diet.

Waveguide-enhanced Raman scattering (WERS) is a powerful branch of enhanced Raman technologies that has gained significant progress in recent years because of its advantages, such as reproducibility and robustness. As a complementary tool to surface-enhanced Raman spectroscopy (SERS), WERS provides a powerful solution for reproducible quantification of analytes. According to different Raman enhancement mechanisms, five major WERS implementation strategies, namely, (1) single-mode dielectric waveguide, (2) liquid core waveguide, (3) metal cladding waveguide, (4) resonance mirror waveguide, and (5) double metal cladding waveguide, are classified and described in detail in this review. The flexibility of WERS structures makes them easy to be integrated with 2D devices to obtain a complete on-chip detection scheme, allowing the WERS chip to combine excitation, detection, and data analysis in integrated chips, providing a powerful prospect for real-time and on-site analysis of target samples. This article highlights the principles, implementations, and application scenarios of WERS techniques and evaluates their advantages and limitations, respectively. Finally, the strengths and weaknesses of WERS techniques are summarized, and promising future applications are proposed. This review provides a panoramic view for researchers interested in waveguide-enhanced Raman technology. [ABSTRACT FROM AUTHOR]

Velocity map imaging (VMI) spectrometry is widely used to measure the momentum distribution of charged particles with the kinetic energy of a few tens of electronVolts. With the progress of femtosecond laser and X-ray free-electron laser, it becomes increasingly important to extend the electron kinetic energy to 1 keV. Here, we report on a recently built composite VMI spectrometer at the Shanghai soft X-ray free-electron laser, which can measure ion images and high-energy electron images simultaneously. In the SIMION simulation, we extended the electron kinetic energy to 1 keV with a resolution O+ kinetic energy spectrum from dissociative ionization of O2 by 800 nm femtosecond laser. We reached a resolution of 1.5% at the electron kinetic energy of 500 eV. When the electron arm is set for 100 eV, a resolution of 4% is reached at the ion kinetic energy of 5.6 eV. This composite VMI spectrometer will support the experiment, such as X-ray multi-photon excitation/ionization, Auger electrons emission, attosecond streaking.

Photodynamic therapy (PDT) involves the uptake of photosensitizers by cancer cells and the irradiation of a light with a specific wavelength to trigger a series of photochemical reactions based on the generation of reactive oxygen, leading to cancer cell death. PDT has been widely used in various fields of biomedicine. However, the molecular events of the cancer cell nucleus during the PDT process are still unclear. In this work, a nuclear-targeted gold nanorod Raman nanoprobe combined with surface-enhanced Raman scattering spectroscopy (SERS) was exploited to investigate the dynamic intranuclear molecular changes of B16 cells (a murine melanoma cell line) treated with a photosensitizer (Chlorin e6) and the specific light (650 nm). The SERS spectra of the cell nucleus during the PDT treatment were recorded in situ and the spectroscopic analysis of the dynamics of the nucleus uncovered two main events in the therapeutic process: the protein degradation and the DNA fragmentation. We expect that these findings are of vital significance in having a better understanding of the PDT mechanism acting on the cancer cell nucleus and can further help us to design and develop more effective therapeutic platforms and methods.

Raman spectroscopy has been widely used as an important clinical tool for real-time in vivo cancer diagnosis. Raman information can be obtained from whole organisms and tissues, at the cellular level and at the biomolecular level. The aim of this paper is to review the newest developments of Raman spectroscopy in the field of breast cancer diagnosis and treatment. Raman spectroscopy can distinguish malignant tissues from noncancerous/normal tissues and can assess tumor margins or sentinel lymph nodes during an operation. At the cellular level, Raman spectra can be used to monitor the intracellular processes occurring in blood circulation. At the biomolecular level, surface-enhanced Raman spectroscopy techniques may help detect the biomarker on the tumor surface as well as evaluate the efficacy of anticancer drugs. Furthermore, Raman images reveal an inhomogeneous distribution of different compounds, especially proteins, lipids, microcalcifications, and their metabolic products, in cancerous breast tissues. Information about these compounds may further our understanding of the mechanisms of breast cancer.

To fabricate a new surface-enhanced Raman scattering (SERS)-active optical fiber sensor, the design and preparation of SERS-active sensing layer is one of important topics. In this study, we fabricated a highly sensitive three-dimensional (3D) SERS-active sensing layer on the optical fiber terminal via in situ polymerizing a porous polymer material on a flat optical fiber terminal through thermal-induced process, following with the photochemical silver nanoparticles growth. The polymerized polymer formed a 3D porous structure with the pore size of 0.29–0.81 μm, which were afterward decorated with abundant silver nanoparticles with the size of about 100 nm, allowing for higher SERS enhancement. This SERS-active optical fiber sensor was applied for the determination of 4-mercaptopyridine, crystal violet and maleic acid The enhancement factor of this SERS sensing layer can be reached as about 108. The optical fiber sensor with high sensitive SERS-active porous polymer is expected for online analysis and environment detection. Keywords: Optical fiber sensor, 3D SERS substrate, Porous polymer, Laser-induced growth, Ag nanoparticles

X-ray free-electron lasers (XFELs) deliver ultrashort coherent laser pulses in the X-ray spectral regime, enabling novel investigations into the structure of individual nanoscale samples. In this work, we demonstrate how single-shot small-angle X-ray scattering (SAXS) measurements combined with fluorescence and ion time-of-flight (TOF) spectroscopy can be used to obtain size- and structure-selective evaluation of the light-matter interaction processes on the nanoscale. We recorded the SAXS images of single xenon clusters using XFEL pulses provided by the SPring-8 Angstrom compact free-electron laser (SACLA). The XFEL fluences and the radii of the clusters at the reaction point were evaluated and the ion TOF spectra and fluorescence spectra were sorted accordingly. We found that the XFEL fluence and cluster size extracted from the diffraction patterns showed a clear correlation with the fluorescence and ion TOF spectra. Our results demonstrate the effectiveness of the multispectroscopic approach for exploring laser−matter interaction in the X-ray regime without the influence of the size distribution of samples and the fluence distribution of the incident XFEL pulses.

Air is usually compressed adiabatically in the compressor. As the operating speed of compressors can be several thousand rpm, heat generated during compression cannot be sufficiently transmitted to the environment in such a short time. It is for this reason that compressor efficiency is limited. Isothermal compression could be an alternative choice applied on industrial compressor and compressed air energy storage (CAES). This paper proposed a new kind of piston to perform isothermal compression. Surface area of such isothermal piston structure is larger. A certain amount of fluid at the chamber bottom absorbs the heat from the isothermal piston. Heat transfer between piston and fluid during compression is investigated. Air pressure is measured to validate the effectiveness of this proposed piston structure in heat transfer. Compression work of the proposed isothermal piston and conventional one is compared. One issue of this comparison is that air-liquid dissolution can affect the pressure and compression work. The influence of dissolution is quantified with Henry’s Law. Quantitative analysis is performed to determine that heat transfer is the dominant factor affecting the pressure and compression work. Some simple experiments are described in this paper, which shed light on that heat transfer could be significantly improved adopting this proposed isothermal piston.