Local Contrast-Based Pixel Ordering for Exact Histogram Specification.

Histogram equalization is one of the basic image processing tasks for contrast enhancement, and its generalized version is histogram specification, which accepts arbitrary shapes of target histograms including uniform distributions for histogram equalization. It is well known that strictly ordered pixels in an image can be voted to any target histogram to achieve exact histogram specification. This paper proposes a method for ordering pixels in an image on the basis of the local contrast of each pixel, where a Gaussian filter without approximation is used to avoid the duplication of pixel values that disturbs the strict pixel ordering. The main idea of the proposed method is that the problem of pixel ordering is divided into small subproblems which can be solved separately, and then the results are merged into one sequence of all ordered pixels. Moreover, the proposed method is extended from grayscale images to color ones in a consistent manner. Experimental results show that the state-of-the-art histogram specification method occasionally produces false patterns, which are alleviated by the proposed method. Those results demonstrate the effectiveness of the proposed method for exact histogram specification.

Ring-opening cyclization of spirocyclopropanes with stabilized sulfonium ylides for the construction of a chromane skeleton.

Regioselective ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes with stabilized sulfonium ylides provided 2,3-trans-disubstituted 2,3,4,6,7,8-hexahydro-5H-1-benzopyran-5-ones in high yields without the formation of any isomers. The obtained product was readily converted into highly substituted chromane.

An Efficient Method for the Synthesis of 2',3'-Nonsubstituted Cycloalkane-1,3-dione-2-spirocyclopropanes Using (2-Bromoethyl)diphenylsulfonium Trifluoromethanesulfonate.

An efficient and practical synthesis of 2',3'-nonsubstituted cyclohexane-1,3-dione-2-spirocyclopropanes using a sulfonium salt was achieved. The reaction of 1,3-cyclohexanediones and (2-bromoethyl)diphenylsulfonium trifluoromethanesulfonate with powdered K2CO3 in EtOAc at room temperature (r.t.) provided the corresponding spirocyclopropanes in high yields. The synthetic method was also applied to 1,3-cyclopentanedione, 1,3-cycloheptanedione, 1,3-indanedione, acyclic 1,3-diones, ethyl acetoacetate, and Meldrum's acid.

Microfluidic analysis of pressure drop and flow behavior in hypertensive micro vessels.

The retinal arterial network is the only source of the highly nutrient-consumptive retina, thus any insult on the arteries can impair the retinal oxygen and nutrient supply and affect its normal function. The aim of this work is to study the influences of vascular structure variation on the flow and pressure characteristics via microfluidic devices. Two sets of micro-channel were designed to mimic the stenosed microvessels and dichotomous branching structure in the retinal arteries. Three working fluids including red blood cell (RBC) suspension were employed to investigate the pressure drop in the stenosed channel. The flow behaviors of RBC suspensions inside the micro channels were observed using high speed camera system. Pressure drop of different working fluids and RBC velocity profiles in the stenosed channel were obtained. Moreover, hematocrit levels of RBC suspensions inside the bifurcated channels were analyzed from the sequential images of RBC flow. The results of the flow in the stenosed channel show that RBCs drift from the center of the channels, and RBC velocity is influenced not only by the inlet flow rate but also the interaction between RBCs. The measured pressure drops in the stenosed channel increase notably with the increase of fluid viscosity. Furthermore, the dimensionless pressure drop due to the stenosis decreases with Reynolds number. On the other hand, the results of flow through the bifurcated channels show that as the ratio of the daughter-branch width to the mother-channel width increases, the ratio of hematocrit in two connected branches (Ht/Hd) decreases, which is in favorable agreement with the available analysis results.

Late functional outcomes after repair of tetralogy of Fallot with atrioventricular septal defect: a double case-match control study.

OBJECTIVES: We sought to elucidate late functional outcomes of the right ventricular outflow tract and atrioventricular valves after repair of tetralogy of Fallot with atrioventricular septal defect. METHODS: From 1990 to 2010, the data from 41 patients who underwent repair were retrospectively reviewed. The median age at repair was 22.4 months (interquartile range, 10.8-41.6 months). Of the 41 patients, 13 (32%) had received previous palliations. The preoperative anatomic differences, physiologic differences, and long-term functional outcomes were determined using a double case-matched control with isolated tetralogy of Fallot and isolated atrioventricular septal defect. RESULTS: The right ventricular outflow tract was reconstructed, with the pulmonary valve preserved in 23 patients (56%). There were 3 early deaths and no late deaths. Survival was 92.1% at 15 years. During a median follow-up period of 5.9 years (interquartile range, 0.14-13.7 years), 29 reinterventions were performed in 13 (32%) patients. Freedom from all reintervention at 15 years was 52.8%. Of the 29 procedures, 12 (41%) were related to the right ventricular outflow tract. Freedom from right ventricular outflow tract-related reintervention was greater in patients who had their pulmonary valve preserved (95% vs 70% at 10 years; P = .046). Reinterventions were performed for the atrioventricular valve in 2 (5%) patients and subaortic stenosis in 1 (2%) patient. Freedom from right ventricular outflow tract-related reintervention (tetralogy of Fallot with atrioventricular septal defect, 88.6% vs tetralogy of Fallot alone, 83.9% at 5 years; P = .809) and atrioventricular valve/left ventricular outflow tract-related reintervention (tetralogy of Fallot with atrioventricular septal defect, 95.2% vs atrioventricular septal defect alone, 86.0% at 5 years; P = .332) were comparable between the tetralogy of Fallot with atrioventricular septal defect and matched control groups. CONCLUSIONS: Late survival and atrioventricular valve function after repair of tetralogy of Fallot with atrioventricular septal defect were excellent. Pulmonary valve preservation and avoidance of an artificial conduit were associated with greater freedom from right ventricular outflow tract reintervention. In the current era, the surgically modified history of tetralogy of Fallot with atrioventricular septal defect is not significantly different from that of isolated tetralogy of Fallot or isolated atrioventricular septal defect.

Effective collection of hydrophobic organic pollutants in water with aluminum hydroxide and hydrophobically modified polyacrylic acid.

Polyacrylic acid was hydrophobically modified with dodecylamine and used as a coagulant for coprecipitation of hydrophobic organic pollutants from water. The polymer coagulant induced effective aggregation of aluminum hydroxide having hydrophobic regions which are essential for the incorporation of hydrophobic organic pollutants. Recoveries of the organic pollutants increased with increasing the dodecylamine content, which indicated that the dodecylamine moiety played an important role in the formation of hydrophobic area on the precipitate. Different hydrophobic organic pollutants that had hardly been removed by the conventional coprecipitation were successfully collected by the proposed method.