Analysis of influencing factors of multiple urethrocutaneous fistula after urethroplasty in children with hypospadias.

Objective: The objective of this study was to investigate the influencing factors of multiple urethrocutaneous fistula (UF) after urethroplasty in children with hypospadias. Methods: The clinical data of 195 children with UF after urethroplasty treated surgically in the Third Affiliated Hospital of Zhengzhou University from August 2015 to August 2022 were retrospectively analyzed and divided into the single UF group (n = 134) and the multiple UF group (n = 61) according to whether multiple UF occurred after urethroplasty. The possible correlated factors were collected and compared between the two groups, including hypospadias degree, length of formed urethra, time of urethroplasty, pre-urethroplasty weight, age at urethroplasty, urethroplasty style, season of urethroplasty, the first fistula repair method, season of the first fistula repair, diameter of the largest fistula of the first fistula repair, time of the first fistula repair surgery, and other 13 factors. Results: By univariate analysis, statistically significant differences were found between the two groups in age at urethroplasty, length of the formed urethra, method of urinary drainage after urethroplasty, whether or not purulent urethral drainage after first fistula repair was present, the first fistula repair method, and diameter of the largest fistula of the first fistula repair (P < 0.05). After multifactorial analysis, the independent risk factors associated with multiple UF after urethroplasty were determined to be use of a vesicostomy tube as the urinary drainage method after urethroplasty (P < 0.05, OR = 6.574, 95% CI: 2.720-15.891) and the presence of purulent urethral drainage after first fistula repair (P < 0.05, OR = 2.723, 95% CI: 1.214-6.109). Conclusions: A catheter as the drainage method after urethroplasty is an independent protective factor for multiple urethrocutaneous fistula, and the existence of purulent urethral secretions after the first fistula repair is an independent risk factor.

Accurate method of generating infrared imaging features by the angular disturbance of an airborne platform.

The imaging quality of an airborne infrared (IR) system is limited by the angular disturbance of the airborne platform. Based on the full-chain (IR scene-atmosphere-optical system-detector-airborne platform) signal transmission process, this study focused on the low-frequency sinusoidal angular disturbance features of the airborne platform and accurately calculated the point spread function caused by the angular disturbance and the IR imaging features when the IR system's different locations were dynamically simulated in a three-dimensional scene. First, the degradation mechanism of the IR imaging features resulting from the angular disturbance was analyzed from the viewpoint of scene radiation signal transmission and detector sampling. Then, the dynamic simulation in the three-dimensional scene resulting from the angular disturbance was realized by considering the geometric transformation of the spatial imaging, scale registration of the spatial sampling, radiation coupling, and angular disturbance caused by the airborne platform. Finally, the distances detected under different disturbance conditions were predicted using the established model. The obtained results provide data supporting the demonstration, verification, and optimization of the IR imaging system's design scheme.

Performance analysis of the infrared imaging system for aircraft plume detection from geostationary orbit.

In view of the optical detection requirements of wide-area and continuous surveillance of air targets, the detection ability of an infrared imaging system in geostationary orbit for aircraft plumes is studied. The point spread model of the subpixel imaging of the full chain, including the aircraft plume, the sea surface, the environmental atmosphere, the optical system, and the imaging detector is established. The detection ability of the typical imaging system in geostationary orbit is analyzed from the signal-to-noise ratio (SNR) and the detection range in combination with the effect of the point spread function (PSF) of the optical system. Meanwhile, the optimal coupling condition of the PSF to the spatial resolution is discussed. The imaging characteristics of the aircraft target on the focal plane of the infrared imaging system under different spatial sampling rates are simulated and verified. Research shows that the SNR of the system first increases, and then decreases gradually with an increase of the spatial sampling rate. The detectable range covered by the pixel footprint decreases as the detector size increases. When the detector size is 15, 20, and 30 µm, the target can be detected with a spatial resolution of 200-700, 300-700, and 400-600 m, respectively.

Accurate deduction of infrared imaging features of subpixel targets based on the conversion of radiation fields of measured area targets.

The accurate generation of infrared (IR) imaging features of subpixel targets plays a very important role in the demonstration, verification, and optimization of system design schemes as well as in research into detection algorithms for small targets in the development of remote IR early warning systems. Based on the generation mechanism of target full-link IR imaging features, this study theoretically considers target radiation characteristics, the working environment, and the spatial response and energy-conversion characteristics of IR sensors, and an accurate deduction model of IR imaging features of subpixel targets is proposed and established. First, the surface-radiation field distribution of the target and background are inverted based on the measured data and the model of radiation calibration; then, the accurate simulation of IR imaging features of subpixel targets is realized by considering the geometric transformation of the spatial imaging, the aperiodic transfer function, scale registration of spatial sampling, and radiation coupling. Finally, the accuracy of the proposed model is verified by using the outfield experiment data. The experimental results show that the IR imaging-diffusion features of subpixel targets with different duty cycles are in good agreement with the prediction results of the model. The results obtained provide data support for the demonstration, verification, and optimization of the system design scheme, as well as for research into detection algorithms of small targets in the development of remote IR early warning systems.

Bidirectional reflectance characteristics of the sea surface based on midinfrared measured data.

In order to establish a more realistic radiation model of the sea surface, the effects of solar radiation, sky radiation, and atmospheric thermal radiation on sea surface radiation are taken into consideration, on the basis of which the infrared radiative transfer equation of the sea surface is deduced in this paper. A method for calculating the bidirectional reflection characteristics of the sea surface based on measured data is proposed according to the projection imaging of beam propagation. Based on the measurements of sea surface temperature, incident sky radiation, incident solar radiation, and radiance of sea crests at different times, the radiative transfer equation is used to retrieve the bidirectional reflectance of a midwave infrared sea surface. Meanwhile, the results of the method mentioned above are compared with the calculated results of Cox-Munk, Mermelstein, Wu, and Beckmann bidirectional reflection characteristics models. Research shows that the bidirectional reflectance at the wave crest of a sea surface increases gradually, when the solar incident zenith angle changes from 56.39° to 76.02° as well as the direction of observation remaining constant (θr=80.0°; ϕr=73.0°). The reflection ability at the wave crest of the sea surface is strongest when the incident direction of the sun is close to the observation direction, which is in accordance with the law of reflection. The Cox-Munk model and Wu model are closer to our values when the solar incidence zenith angle is small (θi≤65.93°). On the other hand, the calculated values of the Mermelstein and Wu models are closer to the values in this paper when the solar incidence zenith angle is large (θi≤65.93°). In general, the error of the Beckmann model is a little greater than that of the other three models.

Imaging method based on the combination of microlens arrays and aperture arrays.

Conventional imaging methods will cause a serious distortion for large object plane imaging with a limited object-to-sensor distance (OTSD). Here, we propose an imaging method based on the combination of microlens arrays and aperture arrays to realize the low-distortion, large object plane imaging range (OPIR) and compact design imaging at a close OTSD. Two-stage microlens arrays are utilized to reduce the distance between the object and sensor with low distortion, and two-stage aperture arrays are sandwiched between the microlens arrays to eliminate stray light between different microlenses. The theoretical analysis and simulation results indicate that our proposed method can realize low-distortion imaging with a large OPIR when the OTSD is seriously limited. This imaging method can be used widely in small-size optical devices where the OTSD is extremely limited.

Association of methylenetetrahydrofolate reductase gene-gene interaction and haplotype with susceptibility to acute lymphoblastic leukemia in Chinese children.

The aim of this study was to investigate the association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and additional gene-gene interaction with acute lymphoblastic leukemia (ALL) risk. Logistic regression was performed to investigate the association between two single nucleotide polymorphisms (SNPs) within MTHFR gene and ALL risk and additional gene-gene interaction between rs1801133 and rs1801131. The minor allele of rs1801133 and rs1801131 is associated with decreased ALL risk, OR (95% CI) were 0.61 (0.38-0.89), and 0.68 (0.50-0.96), respectively. We also found a significantly interaction between the two SNPs, participants with rs1801133 - CT or TT and rs1801131 - AC or CC genotype have the lowest ALL risk, compared with participants with rs1801133 - CC and rs1801131 - AA genotype, OR (95% CI) was 0.32 (0.12-0.63). We did not find any haplotype between the rs1801133 and rs1801131 associated with ALL risk. rs1801133 and rs1801131 within MTHFR gene and their interaction were both associated with ALL risk in Chinese children.

Feasibility study for pseudoscopic problem in integral imaging using negative refractive index materials.

To solve the pseudoscopic problem, we propose a one-step integral imaging system with negative refractive index materials, which can avoid the deterioration in resolution inherent to the optical or digital two-step processes. Specifically, the proposed method is based on the novel feature of negative refractive index materials, bending light to a negative angle relative to the surface normal. The pseudoscopic imaging property of the negative refractive index material slab is theoretically investigated. For formation of orthoscopic reconstructed images, the matching condition of the negative index lens array and the positive index lens array is deduced. Two types of conceptual prototypes of integral imaging system with negative refractive index materials are designed. Experimental results show the validity of the proposed method. To the best of our knowledge, this is the first time to explore the application of negative index materials in eliminating the pseudoscopic effect in integral imaging.

Resolution improvement of integral imaging based on time multiplexing sub-pixel coding method on common display panel.

Considering the limited pixel number and large pixel size of common display panel, the captured elemental images (EIs) array of high density pixels cannot be reconstructed sufficiently in the display process of integral imaging, because of matched display requirement. To solve this problem, this paper presents a novel approach to improve integral imaging resolution by designing a coded sub-pixel mask on common display panel. Specifically, multi-pixels in the captured EIs are displayed in a pixel in the common display panel with time multiplexing along with the corresponding aperture switched on/off of the coded sub-pixel mask periodically, in which the resolution of the reconstructed image is determined by the coded aperture size of the sub-pixel mask rather than the pixel size of the display panel. Then, the mapping relationship between the displayed pixel and the position of the switched on aperture of the coded sub-pixel mask is established theoretically. Computational reconstruction and optical experimental results show that this method can match the pixel number of the captured EIs with that of the display panel and the resolution of integral imaging can be improved significantly.

Does crystal deposition in genetic hypercalciuric rat kidney tissue share similarities with bone formation?

OBJECTIVE: To address the effect of bone-related factors and 1,25(OH)2D3/vitamin D receptor (VDR) on renal stone formation in idiopathic hypercalciuria using genetic hypercalciuric rats. METHODS: The basal levels of bone-related factors were detected in Sprague-Dawley and genetic hypercalciuric rats. In VDR silenced kidneys, the expression levels of bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (Runx2), Osterix, and osteopontin (OPN) were measured, respectively. Tubular calcium phosphate deposits in kidneys and renal tubular epithelial cells (RTECs) were assessed using von Kossa stain. Kidneys were stained with immunohistochemical staining for OPN expression. Gene and protein expression levels of BMP2, Runx2, and Osterix were examined in RTECs incubated with 1,25(OH)2D3. RESULTS: The basal levels of BMP2, Runx2, Osterix, and OPN were significantly increased in genetic hypercalciuric rats, whereas there were no differences in the expression levels of msh homeobox homolog 2 and alkaline phosphatase between the genetic hypercalciuric and normal control rats. VDR knockdown in genetic hypercalciuric rats reduced the expression levels of BMP2, Runx2, Osterix, and OPN. Tubular calcium phosphate deposits were also decreased in VDR silenced kidneys. Immunohistochemical staining showed that there was a reduction in OPN expression in RTECs along with reduction in calcification. Gene and protein expression levels of BMP2, Runx2, and Osterix were upregulated in RTECs incubated with 1,25(OH)2D3. The calcium phosphate deposits in RTECs were also increased by elevated 1,25(OH)2D3. CONCLUSION: Our findings indicate that BMP2, Runx2, Osterix, and OPN might play an important role in renal stone formation in idiopathic hypercalciuria, and 1,25(OH)2D3/VDR might be the significant regulator in this process.