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Subject. This article discusses the issues of modernization of China's economy. Objectives. The article aims to analyze the development of China's digital infrastructure. Methods. For the study, we used the general scientific research methods. Results. The article highlights the problems of the development of China's digital infrastructure in the context of the country's regions. Conclusions. It is necessary to develop a general plan for the development of China's digital infrastructure, which includes support for the cross-border integration of enterprises of the digital ecosystem, financing companies specializing in the development of key technologies.

pH neutralization reaction process plays a crucial role in Waste Water Treatment Process (WWTP). Traditional PID Proportion Integral Differential, (or even advanced PID control) algorithms have poor performance on WWTP due to the strong non-linearity, large time lag, and large inertia characteristics of pH neutralization. Therefore, finding a superior control method to maintain the pH value of wastewater within the normal range will greatly help to improve the efficiency and effectiveness of wastewater treatment. The chemical reaction mechanism of pH neutralization reaction process is first analyzed, and a mechanistic model of pH neutralization reaction process is developed based on the reaction of ions during acid-alkali neutralization and the electric balance equation. Then, combining the characteristics of generalized predictive control and Model-Free Adaptive Control (MFAC), a Model-Free Adaptive Predictive Control (MFAPC) method based on compact format dynamic linearization is introduced. An Improved Model Free Adaptive PI Predictive Control algorithm (IMFAPC) with proportional (P) and integral (I) algorithms is proposed to further improve the control performance. IMFAPC is proposed on the basis of MFAPC, combining the advantages of generalized predictive control, introducing a PI module consisting of error and error sum, and predicting the PI module, making it possible to produce more accurate constraints on the control inputs, avoiding increasing errors, and improving the control effect of delayed systems at the same time. pH neutralization process simulation experimental results show that compared with the ordinary Model-Free Adaptive Control (MFAC) and MFAPC, the IMFAPC control algorithms has the best performance in terms of accuracy, overshoot, and the robustness.

With the advent of the era of the digital economy, the role of digital infrastructure is becoming increasingly prominent. Digital infrastructure will accelerate the digital transformation of traditional industries, will contribute to the development and prosperity of many new industries, new formats and new models of the digital economy. The world's major economies have invested heavily in new areas of infrastructure to reap huge economic returns. Under the "Digital China" development strategy, the scale of China's digital infrastructure is expanding rapidly and in many areas occupies a significant share of the world. The article discusses the concept and classification of digital infrastructure. Compared with other countries in the world, the development status and existing problems of China's digital infrastructure are analyzed, and relevant proposals are put forward for the development of China's digital infrastructure.

We demonstrate vertical cross-sectional (XZ-plane) images of near-infrared (NIR) fluorescence with a handheld dual axes confocal endomicroscope that reveals specific binding of a Cy5.5-labeled peptide to pre-malignant colonic mucosa. This view is perpendicular to the tissue surface, and is similar to that used by pathologists. The scan head is 10 mm in outer diameter (OD), and integrates a one dimensional (1-D) microelectromechanical systems (MEMS) X-axis scanner and a bulky lead zirconate titanate (PZT) based Z-axis actuator. The microscope images in a raster-scanning pattern with a ±6 degrees (mechanical) scan angle at ~3 kHz in the X-axis (fast) and up to 10 Hz (0–400 μm) in the Z-axis (slow). Vertical cross-sectional fluorescence images are collected with a transverse and axial resolution of 4 and 5 μm, respectively, over a field-of-view of 800 μm (width) × 400 μm (depth). NIR vertical cross-sectional fluorescence images of fresh mouse colonic mucosa demonstrate histology-like imaging performance with this miniature instrument.

This paper presents the design, fabrication and characterization of a femto-farad capacitive sensor, intended for pico-liter liquid measurements in microfluidic channels. The sensor has vertical silicon electrodes integrated into a through-wafer channel to measure the liquid level variations in the channel. An equivalent electrical model is developed to analyze the sensor's behavior. A six-mask, IC-compatible process is developed to fabricate the device. The optimization of critical process steps is discussed. The fabricated channel is 40 μm in diameter and 50 μm deep, corresponding to a total liquid volume of 63 pL. The sensor capacitance varies from 1.5 fF (empty channel) to 13.1 fF (channel filled with water). To reliably detect such small capacitance changes, a low-noise measurement system, based on a lock-in amplifier, is implemented. The measured sensitivity of the system is 14.1 mV/fF, and the capacitance detection limit as determined by thermal noise is 0.057 aF/Hz 1/2 .

Step height and line-width are two key parameters in the metrology of micro-electronic masks. A novel common-path heterodyne interferometric confocal measuring system is presented to measure the step height of masks. It combines both the methods of heterodyne interferometry and confocal microscopy. The resolution is 0.01 nm and the measurement range is around 8 µm. The procedure is direct by the integration of the measurement of intensity and phase, hereby faster than a normal scanning microscope. For the line-width measurement of masks, a polarization heterodyne interferometric confocal microscope is proposed, which combines a polarization interferometer with a confocal microscope. An ideal beam spot is obtained and precise focus is realized by using the confocal technique. The phase shifts of the two orthogonal polarization beams differ from each other when they are reflected at the edge of a sample. The experimental results show that the uncertainty of line-width measurement is 21 nm. Both of the systems satisfy the common-path principle, so as to get high ability of resistance to environment disturbances.

Plane mirror interferometers are usually utilized to nano-position large-range scanning stage in microelectronic mask measurement systems. To avoid Abbe-error the centerline of measurement light beams of X Y Z should be intersected at the upper surface of the mask. But the different thickness of masks can also lead to Abbe errors. In this paper a novel plane mirror interferometer is designed, in which the measurement centerline can be accurately adjusted in coincidence with the upper surface of the mask according to their different thickness. The Abbe arm of this interferometer can be decreased to zero and the Abbe-error is avoided completely. The range of different thickness that can be adapted in this interferometer is ±3 mm. In this paper a quadrant photoelectric cell adapter is used to measure the centerline of the measurement light beams and the uncertainty of this method is better than 0.02 mm, which can meet the needs of nano-positioning of microelectronic mask measurement.

A novel roll angle interferometer using a transverse Zeeman laser (TZL) is proposed in this paper. The orthogonally linearly-polarized light from TZL is changed to be slightly elliptically-polarized light by a quarter wave plate (QWP) when the principal axis of the QWP is at a small angle with the basis of the direction of polarization. The beam then passes through a half wave plate (HWP) that is employed as a sensor. After that it is reflected by a right angle prism (RAP) and returns to the HWP again. Owing to the reasonable transformation of coordinates by the prism, the change of direction of polarization is accumulated twice when the beam passes forward and back through the HWP. Theoretical analysis and experimental results show that the sensitivity of roll measurement can reach sub-second and be improved four times than that we had reported. This system of implementing roll measurement takes the advantage of compactness, stable performance, low cost and robust to the environment disturbance.

Objective To demonstrate a near-infrared (NIR) peptide that is highly specific for colonic adenomas on fluorescence endoscopy in vivo. Design A 3 mm diameter endoscope was adapted to deliver 671 nm illumination and collect NIR fluorescence (696–736 nm). Target (QPIHPNNM) and control (YTTNKH) peptides were labelled with Cy5.5, a NIR dye, and characterised by mass spectra. The peptides were topically administered separately (100 μM) through the endoscope9s instrument channel into the distal colon of CPC;Apc mice, genetically engineered to spontaneously develop adenomas. After 5 min for incubation, the unbound peptides were rinsed off, and images were collected at a rate of 10 frames/s. Regions of interest were identified around the adenoma and adjacent normal-appearing mucosa on white light. Intensity measurements were made from these same regions on fluorescence, and the target-to-background ratio (TBR) was calculated. Results An image resolution of 9.8 μm and field of view of 3.6 mm was achieved at a distance of 2.5 mm between the distal end of the instrument and the tissue surface. On mass spectra, the experimental mass-to-charge ratio for the Cy5.5-labelled target and control peptides agreed with expected values. The NIR fluorescence images of adenomas revealed individual dysplastic crypts with distorted morphology. By comparison, only amorphous surface features could be visualised from reflected NIR light. The average TBR for adenomas was found to be 3.42±1.30 and 1.88±0.38 for the target and control peptides, respectively, p=0.007. Conclusion A NIR peptide was shown to be highly specific for colonic adenomas on fluorescence endoscopy in vivo and to achieve sub-cellular resolution images.

A diode-pumped solid state laser is used to deliver excitation at O ex = 671 nm. The beam is expanded by a pair of relay lenses (f 1 = 30 and f 2 = 50 mm) to 3 mm diameter, filling the aperture of a fluid light cable that is coupled to a Hopkins® II rigid endoscope. Near-infrared fluorescence images are collected by the endoscope and transmitted by another set of relay lenses onto a CCD detector that has dimensions of 8.7x6.9 mm 2 (1388x1040 pixels). A zoom lens system (F#1.6-16 aperture) with a tunable focal length (20-100 mm) magnifies the image to fill the dimensions of the CCD. A band pass filter allows fluorescence with spectral range O em = 696 to 736 nm to be collected. The system achieves a resolution of 9.8 P m and field-of-view of 3.6 mm at a dist ance of 2.5 mm between the distal end of the endoscope and the tissue. Images are collected at a ra te of 10 frames per second. A filter wheel is incorporated into the handle of the instrument housing to rapidly switch between reflectance and fluorescence images. Cy5.5-labeled peptides were delivered through the 1 mm diameter instrument channel in the endoscope. Near-infrared fluorescence images demonstrated specific peptide binding to spontaneous adenomas that developed beginning at 2 months of age in a genetically-engineered mouse with mutation of one allele in the APC gene. This integrated methodology represents a powerful tool th at can achieve real time detection of disease in the colon and other hollow organs. Keywords : endoscope, CCD, imaging, fluorescence, ne ar-infrared, real-time, colon, cancer

We engineered a flexible fiber-optic microendoscope for longitudinal optical imaging studies in a mouse model of disseminated ovarian cancer.The microendoscope delivers 470 nm excitation light from a light-emitting diode through a fiber-optic bundle with outer diameter of 680 μm. Optics were optimized to maximize power and lateral resolution. We used this instrument to repetitively monitor intraperitoneal growth of HeyA8 ovarian cancer cells stably transduced with green fluorescent protein over 4 weeks.The microendoscope achieves 0.7 mW power and lateral resolution of 4 μm. Initial in vivo imaging studies visualized single cells and small clusters of malignant cells with subsequent studies showing tumor masses and vasculature. We also resolved single cells within intraperitoneal tumor masses.These studies establish microendoscope technology with single cell resolution for minimally-invasive, longitudinal imaging in living animals. This technology will advance future molecular imaging studies of ovarian cancer and other diseases.

Eosinophils trigger symptoms in allergic rhinitis. New diagnostic methods for identifying nasal eosinophils based on autofluorescence of flavin adenine dinucleotide in eosinophil granules could offer rapid monitoring without fixation or staining. Two-photon excitation is a powerful method for detecting this intrinsic fluorescence.To demonstrate the use of 2-photon excited fluorescence (TPEF) to detect eosinophils from nasal mucosa in a proof-of-concept study for a future miniature in vivo imaging instrument.Thirty subjects with rhinitis were recruited. Results of our standard environmental panel were recorded. Fluorescence images were collected from nasal cytology smears with a 2-photon microscope. Cells were evaluated for intensity and size, and compared with Hansel stains. Correlation of cell count was made by linear regression, diagnostic performance was evaluated at various intensity thresholds, and correlation of nasal eosinophil count to allergic status was done through the Wilcoxon rank-sum test.The fluorescence intensity of eosinophils compared with epithelial cells was 13.8 ± 4.3 versus 3.7 ± 1.8 (P.01), and the size was 27.0 ± 10.2 versus 392.0 ± 214.6 μm2 (P.01), respectively. Using both fluorescence intensity and size, a total accuracy of 100% is achieved. Eosinophil count on TPEF correlates with Hansel stain, R(2) = 0.91. Nasal eosinophil count correlates with allergic status on both TPEF (P = .008) and Hansel stain images (P = .027).TPEF is a promising novel technique for identifying and quantifying nasal eosinophils on nasal cytology specimens without the need for fixation or staining. Future development of a rhinoscope-compatible 2-photon microscope could be used as a clinical adjunct for the diagnosis and management of rhinitis patients in vivo.

A novel transmitted-light differential interference contrast (DIC) system is used for nondestructive measurement of the refractive-index profile (RIP) of an optical fiber. By means of this system the phase of a measured light beam can be modulated with an analyzer, and the phase distribution of a fiber is obtained by calculation of the various interference patterns. The measurement theory and structure and some typical applications of this system are demonstrated. The results of measuring RIPs in graded-index fiber are presented. Both the experimental results and theoretical analysis show that the system takes the advantage of high index resolution and of sufficient measurement accuracy for measuring the refractive index of the optical fiber. The system has strong ability to overcome environmental disturbance because of its common-path design. Moreover, one can use the system to measure the RIP along the fiber axis and acquire an image of the three-dimensional RIP of the fiber.

Fluorescent-labeled peptides are being developed to improve the endoscopic detection of colonic dysplasia.To demonstrate a near-infrared peptide multimer that functions as a phage mimic for in vivo detection of colonic adenomas.A peptide multimer was synthesized by using trilysine as a dendritic wedge to mimic the presentation of peptides on phage, and all peptides, including the multimer, were fluorescent-labeled with Cy5.5.Small-animal imaging facility. ANIMAL SUBJECTS: Genetically engineered CPC;Apc mice that spontaneously develop colonic adenomas.Near-infrared-labeled AKPGYLS peptide multimer was administered topically into the distal colons of the mice, and endoscopic images of adenomas were captured. Fluorescence intensities were quantified by target-to-background (T/B) ratios, and adenoma dimensions were measured with calipers after imaging. Validation of specific peptide binding was performed on cryosectioned specimens and cells by using confocal microscopy and flow cytometry.Fluorescence T/B ratios from colonic adenomas and adjacent normal-appearing mucosa.AKP-multimer, monomer, trilysine core, and Cy5.5 resulted in mean (± SD) T/B ratios of 3.85 ± 0.25, 2.21 ± 0.13, 1.56 ± 0.12, and 1.19 ± 0.11, respectively, P.01 on in vivo imaging. Peptide multimer showed higher contrast and greater specificity for dysplastic crypts as compared with other probes. Peptide multimer demonstrated significantly greater binding to HT29 cells on flow cytometry and fluorescence microscopy in comparison to monomer and trilysine core. A binding affinity of 6.4 nm/L and time constant of 0.1136 minutes(-1) (8.8 minutes) was measured for multimer.Only distal colonic adenomas were imaged.Peptide multimers combine strengths of multiple individual peptides to enhance binding interactions and demonstrate significantly higher specificity and affinity for tumor targets.

Eosinophilic esophagitis (EoE) is a relatively new disease with ~10-fold increase in prevalence over the past 20 years,1,2 and has been found in ~6.5% of the population undergoing upper endoscopy.3 This disease has become one of the leading causes of dysphagia and food impaction in adults. For diagnosis, an endoscopy is performed where multiple biopsies are collected at random throughout the length of the esophagus, including the proximal and distal regions. On histopathology, the primary feature of EoE is infiltration of eosinophils into the mucosa. These mediators of inflammation may contribute to the development of structural abnormalities of the esophagus, including edema, rings, furrows, and strictures.4 Clinical symptoms do not improve with high-dose proton pump inhibitor therapy, and the pH in distal esophagus is usually normal.5 However, the diagnostic criteria for this disease appear to lack clarity. EoE may be difficult to distinguish from GERD,6 which is also associated with increased eosinophilia but to a lesser extent, and the two diseases may be present at the same time. Eosinophils can also trigger allergic symptoms in other parts of the gastrointestinal tract.7 The degree of mucosal hypereosinophilia that defines EoE is controversial. While a diagnostic criteria of ≥15 eosinophils per high-power-field (hpf) on histology has been proposed,5 values as high as 30 eosinophils per hpf have been used, and no single number is widely accepted.8–10 Diagnostic uncertainty for this disease may be attributed in part to its patchy and focal nature. In addition, there is little known about the density or spatial distribution of eosinophils throughout the mucosa. Marked variability has been found within and between biopsy specimens of individual patients, resulting in a low sensitivity for detection. Currently, biopsy specimens are sectioned along a plane whose orientation to the mucosal surface is unknown. A non-uniform distribution of infiltrating eosinophils within the mucosa could result in a highly variable cell count that depends on the angle of sectioning, resulting in an inaccurate result. A novel method that can quickly and reliably quantify the number of cells over a 3-dimensional (3D) volume could be used to overcome this tissue processing limitation. Human eosinophils contain granules that produce an intense autofluorescence in comparison to surrounding squamous epithelium.11–13 There is evidence to support flavin adenine dinucleotide (FAD) as the source of this endogenous fluorescence.14 FAD is a coenzyme in the mitochondrial electron transport chain that has a maximum absorption at 445 nm, resulting in a peak fluorescence emission of 525 nm.15 Multi-photon microscopy (MPM) is a powerful method for collecting fluorescence images from cells and tissues,16 and has been used to perform in vivo imaging of FAD from squamous epithelium in animals.17,18 MPM imaging has inherent 3D resolution, uses near-infrared excitation for superior tissue penetration, has lower photobleaching effects, and is capable of providing quantitative information.19 We have previously demonstrated the use of MPM imaging as a highly accurate method for identifying and quantifying human eosinophils from mucosal smears of patients with allergic rhinitis.20 In this study, we aim to demonstrate the use of MPM to detect eosinophils within squamous epithelium, characterize the distribution of eosinophils with depth below the mucosal surface, and quantify the number of eosinophils within a 3D volume.

A novel instrument, the dual-frequency interferometric confocal microscope (DICM), which facilitates the measurement of step features, is investigated. It combines the advantages of the high resolution (subnanometer) of heterodyne interferometry and the relatively large measurement range (approximately 5 microm) of confocal microscopy. The axial response curves of the confocal microscopy system are compared in experiments in which microscopic objects with various numerical apertures and magnifications are used. The results prove that the variation in light intensity is enough to permit discrimination of different orders of interference fringes. The DICM has been successfully utilized to measure the step height of a standard mask, and the experimental results agree well with those measured by scanning probe microscopes. The results also show that the system has good repeatability, with a maximum deviation of 5 nm.