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This paper integrates carbon emission reduction via technological innovation with consumer channel preferences in both single- and dual-channel supply chains selling low-carbon products. Linear demand functions which simultaneously reflect the consumers’ channel preferences and low-carbon sensitivity are developed by considering the consumers’ segmentation. On this basis, we present two Stackelberg game models: one for each of the single- and dual-channel supply chains. In the first, the manufacturer sells low-carbon products through a traditional retailer who has a physical store, while in the second the manufacturer opens an online direct channel to compete with the traditional retailer. For the two models developed, the optimal pricing decisions, carbon emission reduction level, and profits are derived and discussed. Numerical examples are given to verify the effectiveness and practicality of the proposed models and solutions. The results show that supply chain members’ profits are affected by system parameters such as the carbon price, consumers’ low-carbon sensitivity, channel preference, etc. Furthermore, although the aforementioned parameters stimulate the manufacturer to reduce carbon emission, this does not always benefit the retailer. Comparison of the two models indicates that dual-channel selling is only the better choice for both the manufacturer and the retailer under certain conditions.

Objective The aim of this study was to investigate the clinical significance of serum homocysteine (Hcy) as a biomarker for early diagnosis of diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) patients. Methods Fifty-five T2DM patients with DN and 51 T2DM patients without DN were prospectively recruited from January 2016 to May 2020 in our hospital. The serum Hcy was tested by electrochemiluminescence assay in DN and T2DM groups and compared. The diagnostic efficacy of serum Hcy as a biomarker for early diagnosis of DN was evaluated by calculating the diagnostic sensitivity, specificity and area under the ROC curve (AUC). Results The serum levels of Hcy were 15.49 ± 5.40 and 9.23 ± 3.15 μmol/L for DN and T2DM patients, respectively, with statistical difference (t = 7.21, P < 0.001). In the DN group, the serum Hcy levels for patients with hyperfiltration, intermittent proteinuria, microalbuminuria, macroalbuminuria and uremic were 10.99 ± 2.57, 13.90 ± 2.86, 15.38 ± 4.77, 18.98 ± 4.36 and 23.31 ± 5.22 μmol/L, respectively, which indicated that serum Hcy levels in DN were higher than those of T2DM patients and correlated with patient’s renal damage. Using the serum Hcy level as the reference, the diagnostic sensitivity, specificity and AUC were 84.31 (71.41–92.98)%, 74.55 (61.00–85.33)% and 0.85 (0.78–0.92)%, respectively, with the cutoff value of 12.08 between DN and T2DM. The serum Hcy also had relatively good differential diagnostic efficacy between different DN stages with high sensitivity, specificity and AUC. Conclusion Serum Hcy was obviously elevated in DN compared to T2MD and correlated with the renal damage severity, which can be applied as a potential serological marker for early diagnosis of DN.