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Blood pressure measurement is important in monitoring hypertension. However, blood pressure does not provide much information about renal condition in treated hypertension. This study aimed to evaluate renal oxygenation in hypertensive patients using T2* mapping. Subgroup analysis explored whether R2* values can guide adjustments in antihypertensive treatment. A total of 140 consecutive subjects were recruited: 87 hypertensive subjects and 53 normotensive subjects. Hypertensive subjects were classified into non-medication (non-med), angiotensin II receptor blocker (ARB), and non-ARB-treated groups. Each group was divided into good and poor control subgroups based on blood pressure at enrollment. T2* mapping was utilized to assess renal cortical and medullary R2* values. After a 2-year follow-up, subjects were categorized into stable and unstable based on the need for treatment modifications. The unstable subgroup had higher medullary R2* values than the stable subgroup in all followed patients (p < 0.05). Additionally, the unstable merged non-med with ARB subgroup had higher medullary R2* values overall (p < 0.05) and within the good control subgroup (p < 0.05). Patients with stable hypertension, especially those with good control managed through lifestyle modifications or ARBs, exhibited lower renal medullary R2* values, suggesting higher renal oxygenation.

In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS). These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC) and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it.