The equations governing high-frequency oscillatory viscous flows are investigated through the separation of the steady and the unsteady parts. All Reynolds number ranges are studied and the orders of magnitude of the steady streaming produced by the Reynolds stresses are established.The oscillating circular cylinder at low Reynolds numbers is studied through the method of inner and outer expansions. Steady recirculating cells exist near the cylinder. The results compare very well with experiments. Analytic expressions for the streamfunction and the drag coefficient are obtained.The oscillating flow towards an infinite plate is investigated in detail. The steady streaming is caused by the steady component of the Reynolds stress. The pressure gradient always causes reverse flow near the solid boundary.

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Type 2 diabetes mellitus (T2DM) is a major public health problem in China. Diagnostic markers are urgently needed to identify individuals at risk of developing T2DM and encourage them to adapt to a healthier life style. Circulating miRNAs present important sources of noninvasive biomarkers of various diseases. Recently, a novel plasma microRNA signature was identified in T2DM. Here, we evaluated the T2DM-related miRNA signature in plasma of three study groups: normal (fasting glucose (FG), 4.8–5.2 mmol/L), T2DM-susceptible (FG, 6.1–6.9 mmol/L), and T2DM individuals (FG, ≥7.0 mmol/L) and tested the feasibility of using circulating miRNAs to identify individuals at risk of developing T2DM. Among the 5 miRNAs included in the signature, miR-29b and miR-28-3p are not detectable. miR-15a and miR-223 have comparable expression levels among three groups. Notably, miR-126 is the only miRNA that showed significantly reduced expression in susceptible individuals and T2DM patients compared to normal individuals, suggesting that miR-126 in circulation may serve as a potential biomarker for early identification of susceptible individuals to T2DM.

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Due to the inherent nonlinearity of the Navier-Stokes equations, there exist onlythree exact solutions of stagnation flows: Hiemenz [1] found a solution to the twodimensional stagnation flow against a plate, Homann [2] investigated the axisymmetric stagnation flow, also against a plate, and Howarth [3] and Davey [4] extended the results to unsymmetric cases.The present note presents a new exact solution, namely, axisymmetric stagnation flow on an infinite circular cylinder. Fig. 1 shows a cylinder described by r = a in the cylindrical polar coordinates. The flow is axisymmetric about the z axis and also symmetric to the z = 0 plane. The stagnation "line" is at z = 0, r = a. This flow may be useful in certain cooling processes.Let u and w be the velocities in the directions r and z respectively. If the flow is inviscid, the potential velocity and pressure distribution in the neighborhood of the stagnation line arew = 2 kz,where fc is a given constant of dimensions [1 /T], p0 is the stagnation pressure, and p is the density. We expect the viscous flow to approach the potential solution as r -► <». The constant-density Navier-Stokes equations in cylindrical coordinates are uur + wu, = --pr + v\urr + -u, + uzz -") , rw2 + (ru)r = 0.Let u = -kav~1/2Kv),w = 2kf'(rj)z,where -q = (r/a)2. After some algebra, Eqs. (4) and (5) reduce to vf" + ]" + R(l + 11" -f) = o,p = Po -pl^Y {j + 2ukl' + ,

Stroke is the leading cause of permanent disability in China, 1 and ischemic stroke (IS) accounts for almost 80% of all strokes, 2 whereas coronary heart disease (CHD) is a major worldwide health threat. In tandem with the economic success of China, the number of individuals in China with IS and CHD has increased significantly in recent years, with stroke resulting in 301 million disability-adjusted life-years. 3CHD in Chinese adults aged 35 to 84 years is predicted to increase by 64% during the period 2020-2029. 4 Although numerous epidemiology studies have researched the association between hyperhomocysteinemia and IS or CHD, the results have been conflicting. Most studies have been retrospective and focused on healthy populations in the developed world, whereas data from developing countries remains limited.Vitamins B12 and B6 and folate are involved in the metabolism of methionine, and deficiency of these B vitamins can cause elevation of total homocysteine (tHcy) levels.5 Deficiencies in these nutrients are more prevalent in developing countries. A meta-analysis of randomized trials demonstrated that homocysteine-lowering interventions for stroke seem not to have a significant effect in geographic regions with high dietary folate intake, but may have a substantial effect in regions with low folate intake, such as Asia. 6 Regarding public health guidelines,Background and Purpose-Total homocysteine level (tHcy) is a risk factor of ischemic stroke (IS) and coronary heart disease. However, the results are conflicting and mainly focused on healthy individuals in developed countries. Methods-A prospective, population-based cohort study was conducted among 5935 participants from 60 communities in the city of Shenzhen, China. A Cox regression analysis was applied to evaluate the contribution of tHcy to the risk of IS and coronary heart disease. The effect of folic acid supplementation on tHcy levels was also evaluated among 501 patients with essential hypertension, who received an average of 2.5 years of folic acid supplementation. Results-After adjustment for confounding factors, the hazard ratios (95% confidence intervals) of IS caused by hyperhomocysteinemia were 2.18 (1.65-2.89), 2.40 (1.56-3.67), and 2.73 (1.83-4.08) in the total, male, and female participants, respectively. Compared with normal levels of tHcy (<15 μmol/L), the hazard ratios (95% confidence intervals) for IS in the highest tHcy category (≥30 μmol/L) were 4.96 (3.03-8.12), 6.11 (3.44-10.85), and 1.84 (0.52-6.46) in the total, males, and females participants, respectively. However, we did not observe a significant relationship between tHcy and the risk of coronary heart disease. The 2.5 years of folic acid supplementation reduced tHcy levels by 6.7 μmol/L (27.92%) in patients with essential hypertension. Conclusions-Hyperhomocysteinemia in Chinese hypertensive patients is significantly associated with IS risk but not coronary heart disease susceptibility, and folic acid supplementation can efficiently reduce tHcy levels.

Background and Purpose: We aimed to use novel whole-brain vessel-wall magnetic resonance imaging (WB-VWI) to investigate the association between plaque distribution of middle cerebral artery (MCA) and morphological changes of the lenticulostriate arteries (LSAs) in single subcortical infarctions. Methods: Forty single subcortical infarction patients with no relevant MCA disease on magnetic resonance angiography were prospectively enrolled. Plaque location in the MCA was dichotomized as proximal (located adjacent to the LSA origin) or distal (located distal to the LSA origin) on whole-brain vessel-wall magnetic resonance imaging. The MCAs with proximal plaques were divided into the symptomatic and asymptomatic side, and asymptomatic side MCAs without proximal plaques were the control group. The morphological characteristics of the LSAs and features of proximal plaques were analyzed. Results: A total of 71 MCAs in 40 patients were analyzed (31 on the symptomatic side, 22 on the asymptomatic side, and 18 in the control group). Superior-wall plaques of MCAs were observed more frequently on the symptomatic side than the asymptomatic side (45.2% versus 9.1%, P =0.005). The wall area index, plaque burden, and remodeling index did not differ significantly between the symptomatic and asymptomatic side. The number of LSA branches was smaller ( P =0.011) in the symptomatic side (5.48±1.88) compared with the control group (6.83±1.92). The symptomatic side exhibited shorter average length of the LSAs (23.23±3.44 versus 25.75±3.76 mm, P =0.025) and shorter average distance of the LSAs (16.47±3.11 versus 21.53±4.76 mm, P <0.001) compared with the asymptomatic side. Conclusions: Superiorly distributed MCA plaques at the LSA origin are closely associated with morphological changes of the LSA in symptomatic MCAs, suggesting that the distribution, rather than the inherent features of plaques, determines the occurrence of single subcortical infarctions. Our findings provide insight into the etiologic mechanism of branch atheromatous disease in single subcortical infarctions.