A Method for Measuring Shaft Diameter Based on Light Stripe Image Enhancement.

When the workpiece surface exhibits strong reflectivity, it becomes challenging to obtain accurate key measurements using non-contact, visual measurement techniques due to poor image quality. In this paper, we propose a high-precision measurement method shaft diameter based on an enhanced quality stripe image. By capturing two stripe images with different exposure times, we leverage their different characteristics. The results extracted from the low-exposure image are used to perform grayscale correction on the high-exposure image, improving the distribution of stripe grayscale and resulting in more accurate extraction results for the center points. The incorporation of different measurement positions and angles further enhanced measurement precision and robustness. Additionally, ellipse fitting is employed to derive shaft diameter. This method was applied to the profiles of different cross-sections and angles within the same shaft segment. To reduce the shape error of the shaft measurement, the average of these measurements was taken as the estimate of the average diameter for the shaft segment. In the experiments, the average shaft diameters determined by averaging elliptical estimations were compared with shaft diameters obtained using a coordinate measuring machine (CMM) the maximum error and the minimum error were respectively 18 µm and 7 µm; the average error was 11 µm; and the root mean squared error of the multiple measurement results was 10.98 µm. The measurement accuracy achieved is six times higher than that obtained from the unprocessed stripe images.

Rapid and Non-Destructive Prediction of Moisture Content in Maize Seeds Using Hyperspectral Imaging.

The moisture content of corn seeds is a crucial indicator for evaluating seed quality and is also a fundamental aspect of grain testing. In this experiment, 80 corn samples of various varieties were selected and their moisture content was determined using the direct drying method. The hyperspectral imaging system was employed to capture the spectral images of corn seeds within the wavelength range of 1100-2498 nm. By utilizing seven preprocessing techniques, including moving average, S-G smoothing, baseline, normalization, SNV, MSC, and detrending, we preprocessed the spectral data and then established a PLSR model for comparison. The results show that the model established using the normalization preprocessing method has the best prediction performance. To remove spectral redundancy and simplify the prediction model, we utilized SPA, CASR, and UVE algorithms to extract feature wavelengths. Based on three algorithms (PLSR, PCR, and SVM), we constructed 12 predictive models. Upon evaluating these models, it was determined that the normalization-SPA-PLSR algorithm produced the most accurate prediction. This model boasts high RC2 and RP2 values of 0.9917 and 0.9914, respectively, along with low RMSEP and RMSECV values of 0.0343 and 0.0257, respectively, indicating its exceptional stability and predictive capabilities. This suggests that the model can precisely estimate the moisture content of maize seeds. The results showed that hyperspectral imaging technology provides technical support for rapid and non-destructive prediction of corn seed moisture content and new methods in seed quality evaluation.

An Investigation of a Biomimetic Optical System and an Evaluation Model for the Qualitative Analysis of Laser Interference Visual Levels.

To objectively quantify the level of visual interference induced by lasers, we developed a biomimetic optical system designed to emulate human vision. This system is based on an optical model of the eye and synthetic imaging principles, allowing it to generate biomimetic optical images that closely mimic human visual perception. Upon exposure to a 532 nm laser, biomimetic optical images were captured under various ambient lighting conditions. By employing a contrast threshold model for human visual target detection and grayscale hierarchy analysis, we devised an evaluation model to quantify the levels of laser-induced visual interference. The bionic images obtained from our experiments, in conjunction with the constructed model, enabled us to assess the degree of laser-induced visual interference. Our results indicate that this system can effectively substitute the human eye when testing laser imaging effects, with the generated bionic images achieving up to 90% concordance with human vision. The proposed evaluation model facilitates the quantitative analysis of laser-induced visual impairment. This apparatus and evaluation model hold significant promise for the precise quantification of laser-induced visual interference levels.

Serum S-adenosylhomocysteine levels are associated with first stroke in Chinese adults with hypertension.

BACKGROUND: The association between S-adenosylhomocysteine (SAH) and stroke has not been confirmed due to the specialized equipment and time requirements necessary for S-adenosylhomocysteine testing. We aimed to explore the association between SAH and stroke. METHODS: A nested, case-control study drawn from the China Stroke Primary Prevention Trial of rural adults with hypertension, including 557 first stroke cases and 557 matched controls was conducted. Serum SAH was measured by stable-isotope dilution liquid chromatography-tandem mass spectrometry using 4500MD. Multiple conditional logistic regression models were used to evaluate the association between SAH and first stroke. RESULTS: In females, SAH levels were significantly higher in the stroke population than in the control group (16.0 ng/mL vs. 14.6 ng/mL). When SAH was assessed as quartiles, the odds of stroke were 1.78 (95 % CI: 1.02-3.09) in Quartile 2, 1.31 (95 % CI: 0.73-2.33) in Quartile 3, and 1.93 (95 % CI: 1.03-3.62) in Quartile 4, compared to Quartile 1. When Quartiles 2-4 were combined, the adjusted odds ratio of first stroke was 1.64 (95 % CI: 1.03-2.62) compared with Quartile 1. In subgroup analysis, a significant SAH-stroke association was observed in the lower vitamin D3 group (OR = 3.35, 95 % CI:1.72-6.53; P interaction, 0.035). In males, higher levels of SAH were associated with an increased risk of stroke in those under age 60. Compared with the reference group, the adjusted odds ratio of total stroke was 2.40 (95 % CI: 1.02-5.91) in the combined group (Quartile 2-4). In contrast, no significant association between SAH and stroke was found in males aged 60 or older. CONCLUSIONS: This study reveals that SAH is associated with a higher risk of stroke independently of homocysteine, especially in females. SAH may be a second predictor of stroke in the metabolic pathway of methionine, after homocysteine.

The combined effect of MTHFR C677T and A1298C polymorphisms on the risk of digestive system cancer among a hypertensive population.

BACKGROUND AND PURPOSE: The enzyme methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in directing folate species towards nucleotide synthesis or DNA methylation. The MTHFR polymorphisms C677T and A1298C have been linked to cancer susceptibility, but the evidence supporting this association has been equivocal. To investigate the individual and joint associations between MTHFR C677T, A1298C, and digestive system cancer in a Chinese hypertensive population, we conducted a population-based case-control study involving 751 digestive system cancer cases and one-to-one matched controls from the China H-type Hypertension Registry Study (CHHRS). METHODS: We utilized the conditional logistic regression model to evaluate multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of digestive system cancer. RESULTS: The analysis revealed a significantly lower risk of digestive system cancer in individuals with the CT genotype (adjusted OR: 0.71; 95% CI 0.52, 0.97; P = 0.034) and TT genotype (adjusted OR: 0.57; 95% CI 0.40, 0.82; P = 0.003; P for trend = 0.003) compared to those with the 677CC genotype. Although A1298C did not show a measurable association with digestive system cancer risk, further stratification of 677CT genotype carriers by A1298C homozygotes (AA) and heterozygotes (AC) revealed a distinct trend within these subgroups. CONCLUSION: These findings indicate a potential protective effect against digestive system cancer associated with the T allele of MTHFR C677T. Moreover, we observed that the presence of different combinations of MTHFR polymorphisms may contribute to varying susceptibilities to digestive system cancer.

Molecular characterization and structure basis of a malonyltransferase with both substrate promiscuity and catalytic regiospecificity from Cistanche tubulosa.

Enzymatic malonylation of natural glycosides provides a promising alternative method for drug-like malonylated glycosides supply. However, the catalytic potential and structural basis of plant malonyltransferase are far from being fully elucidated. This work identified a new malonyltransferase CtMaT1 from Cistanche tubulosa. It displayed unprecedented mono- and/or di-malonylation activity toward diverse glucosides with different aglycons. A "one-pot" system by CtMaT1 and a malonyl-CoA synthetase was established to biosynthesize nine new malonylated glucosides. Structural investigations revealed that CtMaT1 possesses an adequately spacious acyl-acceptor pocket capable of accommodating diverse glucosides. Additionally, it recognizes malonyl-CoA through strong electrotactic and hydrogen interactions. QM/MM calculation revealed the H167-mediated SN2 reaction mechanism of CtMaT1, while dynamic simulations detected the formation of stable hydrogen bonds between the glucose-6-OH group and H167, resulting in its high malonylation regiospecificity. Calculated energy profiles of two isomeric glycosides highlighted lower reaction energy barriers towards glucoside substrates, emphasizing CtMaT1's preference for glucosides. Furthermore, a mutant CtMaT1H36A with notably increased di-malonylation activity was obtained. The underlying molecular mechanism was illuminated through MM/GBSA binding free energy calculation. This study significantly advances the understanding of plant acyltransferases from both functional and protein structural perspectives, while also providing a versatile tool for enzymatic malonylation applications in pharmacology.

Evaluation of plasma vitamin E and development of proteinuria in hypertensive patients.

Background: The prospective relationship between plasma vitamin E levels and proteinuria remains uncertain. We aimed to evaluate the association between baseline plasma vitamin E levels and the development of proteinuria and examine any possible effect modifiers in patients with hypertension. Methods: This was a post hoc analysis of the renal sub-study of the China Stroke Primary Prevention Trial (CSPPT). In total, 780 participants with vitamin E measurements and without proteinuria at baseline were included in the current study. The study outcome was the development of proteinuria, defined as a urine dipstick reading of a trace or ≥ 1+ at the exit visit. Results: During a median follow-up duration of 4.4 years, the development of proteinuria occurred in 93 (11.9%) participants. Overall, there was an inverse relationship between plasma vitamin E and the development of proteinuria (per standard deviation [SD] increment; odds ratio [OR]: 0.73, 95% confidence interval [CI]: 0.55-0.96). Consistently, when plasma vitamin E was assessed as quartiles, lower risk of proteinuria development was found in participants in quartiles 2-4 (≥ 7.3 µg/mL; OR: 0.57, 95% CI: 0.34-0.96) compared to those in quartile 1. None of the variables, including sex, age, and body mass index, significantly modified the association between vitamin E and proteinuria development. Conclusion: There was a significant inverse association between plasma vitamin E levels and the development of proteinuria in patients with hypertension. The results were consistent among participants with different baseline characteristics.

Associations between brachial-ankle pulse wave velocity and hypertensive retinopathy in treated hypertensive adults: Results from the China Stroke Primary Prevention Trial (CSPPT).

Although the association between persistent hypertension and the compromise of both micro- and macro-circulatory functions is well recognized, a significant gap in quantitative investigations exploring the interplay between microvascular and macrovascular injuries still exists. In this study, the authors looked into the relationship between brachial-ankle pulse wave velocity (baPWV) and hypertensive retinopathy in treated hypertensive adults. The authors conducted a cross-sectional study of treated hypertensive patients with the last follow-up data from the China Stoke Primary Prevention Trial (CSPPT) in 2013. With the use of PWV/ABI instruments, baPWV was automatically measured. The Keith-Wagener-Barker classification was used to determine the diagnosis of hypertensive retinopathy. The odds ratio (OR) and 95% confidence interval (CI) for the connection between baPWV and hypertensive retinopathy were determined using multivariable logistic regression models. The OR curves were created using a multivariable-adjusted restricted cubic spline model to investigate any potential non-linear dose-response relationships between baPWV and hypertensive retinopathy. A total of 8514 (75.5%) of 11,279 participants were diagnosed with hypertensive retinopathy. The prevalence of hypertensive retinopathy increased from the bottom quartile of baPWV to the top quartile: quartile 1: 70.7%, quartile 2: 76.1%, quartile 3: 76.7%, quartile 4: 78.4%. After adjusting for potential confounders, baPWV was positively associated with hypertensive retinopathy (OR = 1.05, 95% CI, 1.03-1.07, p < .001). Compared to those in the lowest baPWV quartile, those in the highest baPWV quartile had an odds ratio for hypertensive retinopathy of 1.61 (OR = 1.61, 95% CI: 1.37-1.89, p < .001). Two-piece-wise logistic regression model demonstrated a nonlinear relationship between baPWV and hypertensive retinopathy with an inflection point of 17.1 m/s above which the effect was saturated .