Nanodrugs based on co-delivery strategies to combat cisplatin resistance.

Cisplatin (CDDP), as a broad-spectrum anticancer drug, is able to bind to DNA and inhibit cell division. Despite the widespread use of cisplatin since its discovery, cisplatin resistance developed during prolonged chemotherapy, similar to other small molecule chemotherapeutic agents, severely limits its clinical application. Cisplatin resistance in cancer cells is mainly caused by three reasons: DNA repair, decreased cisplatin uptake/increased efflux, and cisplatin inactivation. In earlier combination therapies, the emergence of multidrug resistance (MDR) in cancer cells prevented the achievement of the desired therapeutic effect even with the accurate combination of two chemotherapeutic drugs. Therefore, combination therapy using nanocarriers for co-delivery of drugs is considered to be ideal for alleviating cisplatin resistance and reducing cisplatin-related toxicity in cancer cells. This article provides an overview of the design of cisplatin nano-drugs used to combat cancer cell resistance, elucidates the mechanisms of action of cisplatin and the pathways through which cancer cells develop resistance, and finally discusses the design of drugs and related carriers that can synergistically reduce cancer resistance when combined with cisplatin.

A new method for accurate inversion of Forel-Ule index using MODIS images - revealing the water color evolution in China's large lakes and reservoirs over the past two decades.

The Forel Ule water color index (FUI) based on satellite inversion can characterize the comprehensive characteristics of water quality on a large spatiotemporal scale. The high-frequency observations and rich historical data of the MODIS surface reflectance product (MODIS-500 m) provide important data support for monitoring the FUI of inland lakes. However, MODIS-500 m has only three bands in the visible light range, resulting in significant uncertainty in FUI inversion. To address this problem, this study developed an improved FUI inversion model using 500 synthetic spectra covering natural waters. The model, with a performance threshold set at 170° (FUI = 8), used a segmented algorithm across the entire color space. Validated with on-site measurement datasets (3500 samples), the model exhibited excellent performance, with mean relative error (MRE) and root mean square error (RMSE) of 1.71 % and 3.63°, respectively. Compared to existing models, it was more suitable for long-term FUI inversion in various types of lakes, particularly in eutrophic regions. Subsequently, the model was applied to MODIS-500 m observations from 2000 to 2022, revealing the spatiotemporal dynamics of FUI in 180 large lakes and reservoirs (hereinafter referred to as lakes) in China. The results indicated that the long-term mean FUI in the study area was 9, with 7 and 12 in the western and eastern regions, respectively, showing a distinct spatial distribution of "blue in the west and green in the east." The mean change rate of hue angle for all lakes was -0.085°/yr, showing an overall decreasing trend. Environmental factors' relative contributions to long-term water color changes in each lake region were quantified using the multiple general linear model (GLM). Although each lake region exhibited different driving forces, they were primarily influenced by vegetation, lake surface area, and anthropogenic factors. Additionally, the seasonal types of lake water color were analyzed, with the west and east showing opposite patterns, reflecting the significant influence of topographic features and seasonal changes in climate on water color. The research results provide techniques for accurate inversion of FUI using MODIS-500 m data, while deepening the understanding of long-term water color changes in inland lakes in China.

Preparation and Application of High-Efficiency, Antibacterial, and Antiviral PET-PTHP Fibers.

Transmission through the respiratory tract is one of the most important ways for bacteria and viruses to infect the human body; the use of high-performance antibacterial and antiviral protective equipment is the most effective way to prevent the spread of respiratory diseases. However, at present, most personal protective equipment lacks the ability to kill pathogens. In this paper, a kind of polytetrahydropyrimidine-polyethylene terephthalate functional fiber (PET-PTHP fibers) with highly sustained antibacterial and antiviral properties was prepared. The inactivation rate of the fibers against Staphylococcus aureus and Escherichia coli was as high as 99.99%, and the antibacterial time was more than 72 h. The fibers have an obvious destructive effect on lentiviruses and can reduce the infection rate of lentiviruses in BxPC-3 cells from 25.4 to 9.7%. The cytotoxicity test, cell live/dead staining test, and cell proliferation test all confirmed that PET-PTHP fibers have no obvious cytotoxicity and good cytocompatibility. By applying the functional fibers to the inner layer of the masks, a new type of mask with adsorption, filtration, and killing properties against pathogens was prepared. The filtration efficiency of the new masks was 99.3%, and the pressure drop was 104 Pa. The new masks have excellent air permeability and filtration effect, meet the practical application conditions, and are of grade A; therefore, these masks provide medical protection as well as kill pathogens at the same time, further reducing the risk of human infection.

Four decades of hydrological response to vegetation dynamics and anthropogenic factors in the Three-North Region of China and Mongolia.

Afforestation has been initiated in Northeast Asia to improve ecological status. The responses of the regional hydrological cycle to vegetation restoration remain insufficiently explored. This study uses a variety of satellite-derived vegetation variables and hydrological cycle components to scan the eco-hydrological regimes in the Three-North Region of China and Mongolia during the past four decades. We observe that vegetation productivity increases mainly in North China (NC), Northeast China (NEC), Northwest China (NWC), and the north of Inner Mongolia and Mongolia. Precipitation and runoff show a decreasing trend (-0.4 mm/year and - 0.6 mm/year, respectively), yet they are less correlated to the normalized difference vegetation index and leaf area index. Along with increasing vegetation productivity, evapotranspiration increases (0.05 mm/year) obviously in NC and NEC, while root soil moisture (-0.001 m3/m3/year) and terrestrial water storage (-2.0 mm/year) decrease in NC and parts of NEC and NWC. The correlation coefficient between evapotranspiration and vegetation variables is up to 0.73. Collectively, results imply one potential adverse response of terrestrial water fluxes to increasing vegetation. Independent ecological and hydrological datasets further corroborate our work. Climatic factors (i.e., downward shortwave radiation and air temperature) and human activities (i.e., aerosol optical depth, carbon dioxide, and water withdrawal) substantially affect regional hydrological cycles. Considering the increasing vegetation productivity in the Three-North Region of China and Mongolia is likely to continue in the 21st century based on the Sixth Coupled Model Intercomparison Project (CMIP6) simulations, the terrestrial water fluxes may undergo deficit pressure. Overall, this study comprehensively investigates the vegetation and hydrology interplays, and provides a reference for protecting and improving ecological-hydrological conditions in Northeast Asia.

The potential for carbon sequestration by afforestation can be limited in dryland river basins under the pressure of high human activity.

Dryland regions cover >40 % of the Earth's land surface. Both human activities and climate change have driven forest expansion in parts of dryland regions. Afforestation has been implemented widely to enhance carbon sequestration and benefit the ecological environment of many global drylands. However, the potential and available afforestation space in drylands is uncertain due to the conflicts between additional forest areas and available water. How afforestation will affect the potential for forest carbon stock is also unclear. This paper assessed the future spatial distribution of afforestation and potential forest carbon stock in a typical dryland region, the Yellow River Basin (YRB), which has experienced rapid afforestation and high human activity pressure over the past several decades. Combining the future land use change model (FLUS) and local important development planning, we simulated future afforestation distributions and estimated potential forest carbon stock under the ecological restoration, urban expansion, and cultivated land protection scenarios. The afforestation carbon stock was predicted by considering the dynamic change trends of the mature forest, the immature forest, and new afforestation. The results demonstrated that the potential afforestation area would be limited to 4000 km2 in the YRB accounting for less than one-twentieth of the total forest area. Accordingly, the maximum potential forest carbon stock would increase only 59.5 × 106 t. These findings implies that afforestation programs in drylands should further consider the optimum allocation of afforestation space and the balance between carbon and water in drylands, especially under a changing climate with increasing human activities.

Remote sensing assessment and spatiotemporal variations analysis of ecological carrying capacity in the Aral Sea Basin.

The severe shrinkage of Aral Sea and water resources coordination issues in upstream and downstream regions lead to the serious ecological crisis in the Aral Sea Basin (ASB). Comprehensive ecological carrying capacity (ECC) assessment is of great significance for the ecological restoration and sustainable development. Based on the Analytic Hierarchy Process (AHP) and Experts Mark, this paper established the index evaluation system according to the specific ecological situation of the ASB. Combining remote sensing (RS) data and geographic information systems (GIS) technology, the paper assessed the ECC from 2001 to 2018 and explained the variations of the ECC by various data. The results indicate that the ECC is getting better in eighteen years. In 2009, the ECC condition is the best. ECC of the upstream region is better than that of the downstream region. The cause analysis that highlights the precipitation and enforcement of ecological policy has a positive impact on the ECC change. And the disparity of water body in upstream and downstream watercourses contributes to the regional difference of ECC. The paper provides an evaluation system of the ECC in the ASB. The analysis of the ECC variations is instructive to the sustainable development and ecological restoration in the ASB and other similar areas.

A Normalized Difference Spectral Recognition Index for Azurite Pigment.

Hyperspectral technology is a nondestructive, fast, and reliable method for the detection and restoration of relics. Most of the band characteristics of mineral pigment are concentrated between 2200 and 2400 nm, and these data are expensive to obtain (the required imaging sensor is expensive). We are pursuing a hyperspectral index mean that can effectively distinguish pigments in shorter band ranges to achieve high application value that is much less expensive. In this study, based on the spectral features of azurite at 400-1500 nm, we created an azurite normalized difference spectral index (ANDSI) through feature band selection, derivation of characteristic formulae, and discrimination analysis. Reflectivity bands at 458, 806, and 1373 nm were selected to build the ANDSI. Azurite was compared with 25 other common pigments and it was found that the discrimination values between azurite and the other pigments exceeded 0.88 (where values >0.5 indicate discriminable pigments), demonstrating that the ANDSI is suitable for detecting azurite.

The evolution of landscape ecological security in Beijing under the influence of different policies in recent decades.

Urbanization is an important force driving the development of the social, economic, and ecological environments in urban China. As the capital of China, Beijing has experienced a shift in the development process from emphasizing economic development to emphasizing ecological livability in recent decades. During this period, the Olympic Games, real estate development, and environmentally friendly construction policies were major events that affected Beijing's urban ecosystem and its safety. Based on the Pressure-State-Response (P-S-R) framework model, this paper establishes an indicator system for assessing the ecological security of Beijing from 1995 to 2015. The indicators were generated through coupling of an ecological model with time-series multi-source remote sensing data such as night light images and Landsat ETM images. We assessed ecological security during different policy periods and developed an ecological security early warning system for Beijing. After the effects of the economic development policy and the bid for the Olympic Games from 1995 to 2005, the urban area of Beijing with falling ecological security continues to expand. From 2005 to 2010, due to the joint effect of 2008 Olympic venue construction, urban environmental remediation policies, and real estate policies, the overall safety level in the central city was better, but the suburbs showed the opposite trend. In 2010-2015, real estate developed explosively in Beijing, while environmentally friendly development became strongly emphasized and the economic status of the capital weakened. The ecological security of the main urban area began to improve significantly, but the outer urban area and suburban areas were greatly affected by real estate development and exhibited a clear decline in ecological security.

Blood hyperviscosity identification with reflective spectroscopy of tongue tip based on principal component analysis combining artificial neural network.

BACKGROUND: With spectral methods, noninvasive determination of blood hyperviscosity in vivo is very potential and meaningful in clinical diagnosis. In this study, 67 male subjects (41 health, and 26 hyperviscosity according to blood sample analysis results) participate. METHODS: Reflectance spectra of subjects' tongue tips is measured, and a classification method bases on principal component analysis combined with artificial neural network model is built to identify hyperviscosity. Hold-out and Leave-one-out methods are used to avoid significant bias and lessen overfitting problem, which are widely accepted in the model validation. RESULTS: To measure the performance of the classification, sensitivity, specificity, accuracy and F-measure are calculated, respectively. The accuracies with 100 times Hold-out method and 67 times Leave-one-out method are 88.05% and 97.01%, respectively. CONCLUSIONS: Experimental results indicate that the built classification model has certain practical value and proves the feasibility of using spectroscopy to identify hyperviscosity by noninvasive determination.

[Tongue Coat Information Extraction of the Traditional Chinese Medicine with Hyperspectral Image].

Tongue coat information extraction plays an important role in disease diagnosis for the traditional Chinese medicine. For the purpose of quantifying the tongue coat properties in traditional Chinese medicine, most of the existing methods are based on computerized image analysis, carrying out RGB color space in a tongue imaging captured with digital camera. However, those methods cannot meet the requirements of clinical medicine. To explore more information about the tongue objectively, a new approach to analyze tongue information based on hyperspectral images is presented. Hyperspectral images are acquired using the hyperspectral imaging system in the spectral range of 370.200 0 to 992.956 0 nm (343bands), and the traditional Chinese medicine clinical diagnosis information is recorded. The main region of interest (ROI) in the samples is extracted while the background is removed from the tongue image, then tongue information of ROI is analyzed. The largest different spectral characteristics between tongue proper and tongue coat are found in the wavelength range of about 525 to 600 nm. Nine wavelengths tongue spectral images from 382.108 0 to 963.668 0 nm are extracted, then comparing with the actual tongue situation, we find that the spectral image at 527.548 0 nm band can better reflect the actual tongue situation than others. The experiment results show that hyperspectral imaging technique is very helpful for tongue coat information extraction of the traditional Chinese medicine, and this new analysis approach can provide a fast and simple non-invasive detection method for tongue coat segmentation and tongue coat information extraction.

Shortwave Infrared Imaging Spectroscopy for Analysis of Ancient Paintings.

Spectral analysis is one of the main non-destructive techniques used to examine cultural relics. Hyperspectral imaging technology, especially on the shortwave infrared (SWIR) band, can clearly extract information from paintings, such as color, pigment composition, damage characteristics, and painting techniques. All of these characteristics have significant scientific and practical value in the study of ancient paintings and other relics and in their protection and restoration. In this study, an ancient painting, numbered Gu-6541, which had been found in the Forbidden City, served as a sample. A ground-based SWIR imaging spectrometer was used to produce hyperspectral images with high spatial and spectral resolution. Results indicated that SWIR imaging spectral data greatly facilitates the extraction of line features used in drafting, even using a single band image. It can be used to identify and classify mineral pigments used in paintings. These images can detect alterations and traces of daub used in painting corrections and, combined with hyperspectral data analysis methods such as band combination or principal component analysis, such information can be extracted to highlight outcomes of interest. In brief, the SWIR imaging spectral technique was found to have a highly favorable effect on the extraction of line features from drawings and on the identification of colors, classification of paintings, and extraction of hidden information.

Development of a Portable Field Imaging Spectrometer: Application for the Identification of Sun-Dried and Sulfur-Fumigated Chinese Herbals.

We fabricated a visible-near-infrared (Vis-NIR) portable field imaging spectrometer with a prism-grating-prism element and a scanning mirror. The developed Vis-NIR imaging spectrometer, consisting of an INFINITY 3-1 detector and a V10E spectrometer from Specim Corporation, is designed to measure the spectral range between 0.4 and 1 µm with spectral resolution of 2-4 nm. In recent years, sulfur fumigation has been abused during the processing of certain freshly harvested Chinese herbs. Fourier transform infrared spectroscopy, fiber optic NIR spectrometry, and liquid chromatography-mass spectrometry are typically used to analyze the chemical profiles of sulfur-fumigated and sun-dried Chinese herbs. Field imaging spectrometry is rarely used to identify sulfur-fumigated herbs. In this study, field imaging spectrometry, principal component analysis, and the partial least squares-discriminant analysis multivariate data analysis method are used to distinguish sun-dried and sulfur-fumigated Chinese medicinal herbs with a sensitivity of 96.4% and a specificity of 98.3% for RPA identification. These results suggest that hyperspectral imaging is a potential technique to control medicine quality for medical applications.

Analyzing Spectral Characteristics of Water Involving In-Situ Multiangle Polarized Reflectance and Extraction of Water-Leaving Radiance.

Polarization is defined as an asymmetry in the direction of vibration with respect to the direction of light propagation. Polarization information is an important component to remote sensed data, which comprises spatial, spectral, and radiation information. In optical remote sensing, polarization information supplements spectral information. Polarization-based remote sensing has a significant application potential for analyzing the spectral characteristics of water bodies, wherein a very important technique is eliminating the mirror reflection caused by skylight on the water surface and extracting water-leaving radiance that carry the constituent information. The incident sunlight on the surface of water either reflects or scatters owing to the existence of particles in water, which results in water-leaving signals with strong polarization characteristics. The ongoing experiments on remote sensing involve water polarization cover either clean ocean waters under natural light or indoor simulations of water under artificial light; however, turbid inland waters under natural light have rarely been investigated. Through the combination of a field spectroradiometer and a Thompson polarizing prism, this study obtained in-situ measurements of the spectral polarization reflectance over inland waters under natural light conditions. Using the obtained multiangle polarized reflectance spectra, the polarization spectral characteristics of water under multiangle viewing conditions were quantitatively analyzed, and the water-leaving radiance was achieved by eliminating skylight reflection. When observing water bodies at an azimuth of 135° and a zenith of 53°, the measurement of polarization to eliminate skylight reflection had better elimination efficiency than at other viewing angles, and this observation angle was recommended for conducting spectral polarized above-water observations. Compared with the traditional methods including non-polarized above-water measurements, the proposed method is less prone to being affected by changes in weather conditions, and it can extract water-leaving radiance more accurately.

Airborne validation of ground-object detection from polarized neutral-point atmosphere.

Based on the object's polarization effects, polarization is a newly emerging method in the field of remote sensing. Both objects and atmosphere have polarization effects, however, the atmosphere's polarization effects are much stronger than that of objects'. Consequently, atmosphere polarization effects will interfere or even cover objects' when observing with sensors. How to maximally eliminate the polarized effects generated by the atmosphere is a crucial problem in polarization remote sensing. Atmospheric neutral point is an area where the degree of atmosphere polarization is near to zero; therefore, if sensors are set up in this area, atmosphere polarization would be greatly eliminated, which is the main content of separating the effects between objects and atmosphere by its neutral point method. In this paper, after processing and analyzing the experimental data got from the first polarization remote sensing flight experiment with atmosphere neutral point, the degree of polarization images captured in neutral and non-neutral point area were obtained, and it can be seen that the main value of polarized degree of images got in neutral point area was obviously smaller than that in non-neutral point area. The results showed that the theory mentioned above was logical and practical. An innovation in our study is that the requirements needed in polarization remote sensing flight with neutral point were clarified. In the meantime, a qualitative conclusion was drawn that observing with longer wavelength is more applicable to polarization remote sensing.

[Research on the model of spectral unmixing for minerals based on derivative of ratio spectroscopy].

The precise analysis of mineral abundance is a key difficulty in hyperspectral remote sensing research. In the present paper, based on linear spectral mixture model, the derivative of ratio spectroscopy (DRS) was introduced for spectral unmixing of visible to short-wave infrared (Vis-SWIR; 0.4 - 2.5 microm) reflectance data. The mixtures of different proportions of plaster and allochite were analyzed to estimate the accuracy of the spectral unmixing model based on DRS. For the best 5 strong linear bands, the Pearson correlation coefficient (PCC) of the abundances and the actual abundances were higher than 99.9%, while the root mean square error (RMSE) is less than 2.2%. The result shows that the new spectral unmixing model based on DRS is simple, of rigorous mathematical proof, and highly precise. It has a great potential in high-precision quantitative analysis of spectral mixture with fixed endmembers.

Laboratory calibration of a field imaging spectrometer system.

A new Field Imaging Spectrometer System (FISS) based on a cooling area CCD was developed. This paper describes the imaging principle, structural design, and main parameters of the FISS sensor. The FISS was spectrally calibrated with a double grating monochromator to determine the center wavelength and FWHM of each band. Calibration results showed that the spectral range of the FISS system is 437-902 nm, the number of channels is 344 and the spectral resolution of each channel is better than 5 nm. An integrating sphere was used to achieve absolute radiometric calibration of the FISS with less than 5% calibration error for each band. There are 215 channels with signal to noise ratios (SNRs) greater than 500 (62.5% of the bands). The results demonstrated that the FISS has achieved high performance that assures the feasibility of its practical use in various fields.

[The multi-angle polarization spectral character of water and its applications in water color remote sensing].

The reflectance of pure water is very low at visible and near infrared bands. Its spectral characteristics are not obvious. Water always shows dark hue in optical remote sensing images. This dark hue causes the difficulties in water remote sensing identification. There is an interesting phenomenon when the authors research the water polarization spectroscopy. The authors measured water's polarization spectra and reflectance spectra at different view zenith angles using the ASD spectrometer. When the view zenith angle was zero (measured vertically), as the spectrum people commonly measure, there was no polarization phenomenon at the water surface, and the reflectance was low at each band. Along with the increase in view zenith angle, the DOP spectra curves increased evidently, while the reflectance curves only changed a little. When the view zenith angle was over 30 degree, the values of DOP spectrum were much larger than the reflectance spectrum values at the entire visible and near infrared bands. At some bands, the DOP value was several dozen times than its reflectance value. This phenomenon shows that the water's brightness in DOP image is much higher than its brightness in intensity image under the same condition. This rule was verified by the PARASOL multiangle polarization satellite data. Comparing the average brightness of DOP images with the average brightness of intensity images at 490, 670 and 865 nm band, the former is higher than the latter apparently. The brighter DOP images are better for water remote sensing identification It is the first time that the authors found this special multiangle polarization spectral character of water. It revealed the advantage of water detection using the multiangle polarization remote sensing data. This method solved the low reflectivity problem of water color remote sensing. It will greatly improve the capability of water remote sensing identification and the retrieval accuracy of water quality parameters.