Showing papers by "Yu Huang published in 2007"

Optimizing the laser-pulse configuration for coherent Raman spectroscopy.

Abstract: We introduce a hybrid technique that combines the robustness of frequency-resolved coherent anti-Stokes Raman scattering (CARS) with the advantages of time-resolved CARS spectroscopy. Instantaneous coherent broadband excitation of several characteristic molecular vibrations and the subsequent probing of these vibrations by an optimally shaped time-delayed narrowband laser pulse help to suppress the nonresonant background and to retrieve the species-specific signal. We used this technique for coherent Raman spectroscopy of sodium dipicolinate powder, which is similar to calcium dipicolinate (a marker molecule for bacterial endospores, such as Bacillus subtilis and Bacillus anthracis), and we demonstrated a rapid and highly specific detection scheme that works even in the presence of multiple scattering.

Adiponectin-induced endothelial nitric oxide synthase activation and nitric oxide production are mediated by APPL1 in endothelial cells.

Abstract: Adiponectin protects the vascular system partly through stimulation of endothelial nitric oxide (NO) production and endothelium-dependent vasodilation. The current study investigated the role of two recently identified adiponectin receptors, AdipoR1 and -R2, and their downstream effectors in mediating the endothelium actions of adiponectin. In human umbilical vein endothelial cells, adiponectin-induced phosphorylation of endothelial NO synthase (eNOS) at Ser1177 and NO production were abrogated when expression of AdipoR1 and -R2 were simultaneously suppressed. Proteomic analysis demonstrated that the cytoplasmic tails of both AdipoR1 and -R2 interacted with APPL1, an adaptor protein that contains a PH (pleckstrin homology) domain, a PTB (phosphotyrosine-binding) domain, and a Leucine zipper motif. Suppression of APPL1 expression by RNA interference significantly attenuated adiponectin-induced phosphorylation of AMP-activated protein kinase (AMPK) at Thr172 and eNOS at Ser1177, and the complex formation between eNOS and heat shock protein 90, resulting in a marked reduction of NO production. Adenovirus-mediated overexpression of a constitutively active version of AMPK reversed these changes. In db/db diabetic mice, both APPL1 expression and adiponectin-induced vasodilation were significantly decreased compared with their lean littermates. Taken together, these results suggest that APPL1 acts as a common downstream effector of AdipoR1 and -R2, mediating adiponectin-evoked endothelial NO production and endothelium-dependent vasodilation.

Adiponectin is a novel humoral vasodilator

Abstract: Objectives Perivascular adipose tissue secretes an adipocyte-derived relaxing factor(s) (ADRF) that opens Kv channels in rat arteries. Visceral fat accumulation causes adipocyte dysfunction, including hyposecretion of adiponectin. We tested the hypothesis that ADRF might be adiponectin and that adiponectin plays a role in the paracrine control of vascular tone by perivascular adipose tissue. Methods and results We studied Sprague–Dawley rats, wild-type and adiponectin gene-deficient (Apn 1−/−) mice, and New Zealand obese (NZO) mice. In rat aortas, recombinant adiponectin at serum levels (2–5 μg/ml) inhibited serotonin-induced contractions. The effects were abolished by Kv channel inhibition with 4-aminopyridine (4-AP, 2 mM). Similar effects were observed in NZO mouse mesenteric arteries. To study vascular function in Apn 1−/− mice, the mesenteric vascular bed was isolated, cannulated, and perfused at a constant 4–5-ml/min flow in the absence and presence of serotonin. 4-AP (2 mM) induced a similar increase in perfusion pressure in the Apn 1−/− perfused isolated mesenteric vascular bed, compared to wild-type mice. Removal of perivascular fat increased the vasoconstrictor responses, but abolished the 4-AP effects. The anti-contractile effects of perivascular fat were similar in mesenteric artery and aortic rings from Apn 1−/− and wild-type mice. Despite high adiponectin levels, the anti-contractile effects of perivascular fat were diminished in mesenteric arteries of NZO mice with age. Conclusion Adiponectin is a novel humoral vasodilator that relaxes aortic and mesenteric rings by opening Kv channels. Similar to the rat, perivascular adipose tissue of the mouse harbors an ADRF, which is malfunctional in NZO mice and is not adiponectin.

Apelin modulates aortic vascular tone via endothelial nitric oxide synthase phosphorylation pathway in diabetic mice.

Abstract: Objective : The apelin receptor APJ is a putative receptor protein related to angiotensin (Ang) type 1 receptor. The apelin-APJ system has been implicated in diabetes, but its role in the diabetic vasculature and the mechanisms involved remain unclear. Our aim here was to explore the regulatory role of apelin in the aortic vascular tone in diabetic mice. Methods : A Multi Myograph system was used to determine the isometric vessel tone in aortic rings from diabetic db / db and control db / m + mice. The mRNA, phosphorylation, and protein levels of APJ, Akt, and endothelial nitric oxide synthase (eNOS) were analyzed by reverse transcription–polymerase chain reaction and Western blotting, respectively. Results : There is depressed expression of APJ, enhanced contractile response to Ang II, and reduced relaxation response to acetylcholine in aortas from db / db mice. Apelin treatment strikingly reversed the altered aortic vascular responsiveness to Ang II and acetylcholine in db / db mice, both of which were abolished by the eNOS inhibitor N G-nitro-l-arginine methyl ester. Finally, in db / db mice, considerable increases in phosphorylation of Akt on serine 473 and of eNOS on serine 1177 were found in aortas pretreated with apelin. Conclusions : Apelin treatment modulates the abnormal aortic vascular tone in response to Ang II and acetylcholine by potentiating phosphorylation of Akt and eNOS in diabetic mice, suggesting that the apelin-APJ system might be an important regulator of vascular function in diabetes.

Calcium and reactive oxygen species increase in endothelial cells in response to releasers of endothelium-derived contracting factor

Abstract: Background and Purpose: Experiments were designed to assess whether or not the intracellular concentration of calcium and reactive oxygen species (ROS) increase in endothelial cells of the rat thoracic aorta in response to releasers of endothelium-derived contracting factor (EDCF) and if so, whether or not a difference exists between spontaneously hypertensive (SHR) and normotensive (WKY) rats. Experimental approach: Calcium and ROS were measured by confocal microscopy, using Fura-red in combination with Fluo-4 and dichlorodihydrofluorescein diacetate, respectively. Key results: Acetylcholine caused a rapid increase in cytosolic calcium concentration in endothelial cells of both SHR and WKY, which was significantly more pronounced in aortae of the former strain. This rise of calcium was not affected by indomethacin (an inhibitor of cyclooxygenase) or Tiron plus diethyldithiocarbamate acid (DETCA) (membrane permeable antioxidants). In the presence of a nitric oxide synthase blocker, acetylcholine also caused a rapid increase in ROS in endothelial cells of SHR but not in those of WKY. The burst of ROS was prevented by indomethacin or Tiron plus DETCA. Conclusions and implications: These experiments show that endothelial cells of SHR are more prone to calcium and ROS overload upon stimulation with acetylcholine. The abnormal accumulation of calcium is a prerequisite to initiate the release of EDCF and can be mimicked using the calcium ionophore A23187. The sequence of events occurring during endothelium-dependent contractions firstly requires the accumulation of calcium, which then activates cyclooxygenase and produces ROS along with EDCF that in turn stimulates TP-receptors, resulting in EDCF-mediated contractions. British Journal of Pharmacology (2007) 151, 15–23. doi:10.1038/sj.bjp.0707190

Green tea catechins upregulate superoxide dismutase and catalase in fruit flies.

Abstract: Chinese Longjing green tea is an excellent source of polyphenol antioxidants. HPLC analysis revealed that Longjing green tea catechin extract (GTC) contained 62% epigallocatechin gallate (EGCG), 19% epigallocatechin (EGC), 9% epicatechin gallate (ECG), and 7% epicatechin (EC). Investigating the effect of GTC on the lifespan of Drosophila melanogaster, we observed that a 10 mg GTC/mL diet could prolong its 50% survival time by 36% and mean lifespan by 16%. This was consistent with 17% reduction in total body lipid hydroperoxide (LPO) level in GTC-treated flies compared to the control group. Supplementation of 10 mg GTC/mL diet increased the survival time only in wild type Oregon-R-C (OR) but not in two mutant fly lines, SOD(n108)/TM3 (gene for superoxide dismutase (SOD) was knocked out) and Cat(n1)/TM3 (gene for catalase was knocked out), when the flies were challenged with paraquat or hydrogen peroxide. Accordingly, SOD and catalase activities in OR wild type increased by 40 and 19%, respectively. RT-PCR analysis indicated that the genes for copper-zinc containing SOD (CuZnSOD), manganese containing SOD (MnSOD), and catalase were upregulated. It was concluded that prolonging lifespan by GTC in D. melanogaster was influenced, among others, by upregulation of endogenous antioxidant enzymes.

Players and ball detection in soccer videos based on color segmentation and shape analysis

Abstract: This paper proposes a scheme to detect and locate the players and the ball on the grass playfield in soccer videos. We put forward a shape analysis-based approach to identify the players and the ball from the roughly extracted foreground, which is obtained by a trained, color histogram-based playfield detector and connected component analysis. We employ Euclidean distance transform to extract skeletons for every foreground blob, and then perform shape analysis to remove false alarms (non-player and non-ball blobs) and cut-off the artifacts (mostly due to playfield lines) based on skeleton pruning and reverse Euclidean distance transform. Results are given to demonstrate the proposed algorithm works well in soccer video clips.

Effects of Embedded Decompression and Compaction Architectures on Side-Channel Attack Resistance

Abstract: Attack resistance has been a critical concern for security-related applications. Various side-channel attacks can he launched to retrieve security information such as encryption key. Prior work does not consider the presence of embedded compression architectures and their impacts on security. This paper analyzes the complexity of side-channel attacking on designs with embedded decompression and compaction circuit. A possible attacking strategy was first presented and performs analysis on the complexity of attacking circuits with EDT architecture. The probabilistic analysis was then extended to the more general compaction schemes using distance coding. The authors have shown that successful attacking of designs with embedded decompressor and compactor is extremely difficult. The complexity is much higher than the results shown in prior work assuming no decompression and compaction. It indicates that the use of embedded compression architectures can achieve higher security level.

Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats

Abstract: Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats

Fault Dictionary Based Scan Chain Failure Diagnosis

Abstract: In this paper, we present a fault dictionary based scan chain failure diagnosis technique. We first describe a technique to create small dictionaries for scan chain faults by storing differential signatures. Based on the differential signatures stored in a fault dictionary, we can quickly identify single stuck-at fault or timing fault in a faulty chain. We further develop a novel technique to diagnose some multiple stuck-at faults in a single scan chain. Comparing with fault simulation based diagnosis technique, the proposed fault dictionary based diagnosis technique is up to 130 times faster with same level of diagnosis accuracy and resolution.

Estimating a location of an object in an image

Abstract: An implementation provides a method for estimating a location for an object in a particular image of a sequence of images The location is estimated using a particle-based framework, such as a particle filter It is determined that the estimated location for the object in the particular image is occluded A trajectory is estimated for the object based on one or more previous locations of the object in one or more previous images in the sequence of images The estimated location of the object is changed based on the estimated trajectory

Dynamic learning based scan chain diagnosis

Abstract: Scan chain defect diagnosis is important to silicon debug and yield enhancement. Traditional simulation-based chain diagnosis algorithms may take long run time if a large number of simulations are required. In this paper, a novel dynamic learning based scan chain diagnosis is proposed to speedup the diagnosis run time. Experimental results illustrate that by using the proposed dynamic learning techniques, the diagnosis run time can be reduced about 10X on average

A complete test set to diagnose scan chain failures

Abstract: In this paper, we present a test generation algorithm to improve scan chain failure diagnosis resolution. The proposed test generation algorithm creates a complete test set that guarantees each defective scan cell has unique failing behavior. This algorithm handles stuck-at fault and timing fault models. Problems and solutions that may happen in practical usage are discussed. We further extend the test generation algorithm to handle multiple failing scan chains and designs with embedded scan compression logic. Experimental results show the effectiveness of the proposed diagnostic test generation algorithm.

Raloxifene, tamoxifen and vascular tone.

Abstract: 1. Oestrogen deficiency causes progressive reduction in endothelial function. Despite the benefits of hormone-replacement therapy (HRT) evident in earlier epidemiological studies, recent randomized trials of HRT for the prevention of heart disease found no overall benefit. Instead, HRT users had higher incidences of stroke and heart attack. Most women discontinue HRT because of its many side-effects and/or the increased risk of breast and uterine cancer. This has contributed to the development of selective oestrogen receptor modulators (SERMs), such as tamoxifen and raloxifene, as alternative oestrogenic agents. 2. A SERM is a molecule that binds with high affinity to oestrogen receptors but has tissue-specific effects distinct from oestrogen, acting as an oestrogen agonist in some tissues and as an antagonist in others. Clinical and animal studies suggest multiple cardiovascular effects of SERMs. For example, raloxifene lowers serum levels of cholesterol and homocysteine, attenuates oxidation of low-density lipoprotein, inhibits endothelial-leucocyte interaction, improves endothelial function and reduces vascular smooth muscle tone. 3. Available evidence suggests that raloxifene and tamoxifen are capable of acting directly on both endothelial cells and the underlying vascular smooth muscle cells and cause a multitude of favourable modifications of the vascular wall, which jointly contribute to improved local blood flow. The outcome of the Raloxifene Use for the Heart (RUTH) trial will determine whether raloxifene, currently approved for the treatment of post-menopausal osteoporosis, could substitute for HRT in alleviating cardiovascular symptoms in post-menopausal women.

Diagnose compound scan chain and system logic defects

Abstract: Scan based diagnosis can be of great help to guide physical failure analysis, which is critical for the success of silicon debug and yield ramp up. In practice, diagnosis becomes more difficult if scan chain defects and system logic defects co-exist on one die, which are called compound defects in this paper. We first describe the challenges in diagnosing this type of compound defects. A novel diagnosis flow is proposed to diagnose the compound defects on scan chain and system logic. The diagnosis methodology was successfully applied in industrial designs.

Therapeutic concentrations of raloxifene augment nitric oxide‐dependent coronary artery dilatation in vitro

Abstract: Background and purpose: Raloxifene improves cardiovascular function. This study examines the hypothesis that therapeutic concentrations of raloxifene augment endothelium-dependent relaxation via up-regulation of eNOS expression and activity in porcine coronary arteries. Experimental approach: Isometric tension was measured in rings from isolated arteries. Intracellular Ca2+ concentrations ([Ca2+]i) in arterial endothelial cells were detected by Ca2+ fluorescence imaging. Phosphorylation of eNOS at Ser-1177 was assayed by Western blot analysis. Key results: In arterial rings pre-contracted with 9,11-dideoxy-11α,9α-epoxy-methano-prostaglandin F2α (U46619), treatment with raloxifene (1-3 nM) augmented bradykinin- or substance P-induced relaxation and this effect was antagonized by ICI 182,780, an estrogen receptor antagonist. The enhanced relaxation was abolished in rings treated with inhibitors of nitric oxide/cyclic GMP-dependent dilation, NG-nitro-L-arginine methyl ester (L-NAME) plus 1H-[1,2,4]oxadizolo[4,3-a]quinoxalin-1-one (ODQ). In contrast, effects of raloxifene were unaffected after inhibition of endothelium-derived hyperpolarizing factors by charybdotoxin plus apamin. Raloxifene (3 nM) did not influence endothelium-independent relaxation to sodium nitroprusside. 17s-Estradiol (3-10 nM) also enhanced bradykinin-induced relaxation, which was inhibited by ICI 182,780. Treatment with raloxifene (3 nM) did not affect bradykinin-stimulated rise in endothelial cell [Ca2+]i. Raloxifene, 17s-estradiol, and bradykinin increased eNOS phosphorylation at Ser-1177 and ICI 182,780 prevented effects of raloxifene or 17s-estradiol but not that of bradykinin. Raloxifene had neither additive nor antagonistic effects on 17s-estradiol-induced eNOS phosphorylation. Conclusions and implications: Raloxifene in therapeutically relevant concentrations augmented endothelial function in porcine coronary arteries in vitro through ICI 182,780-sensitive mechanisms that were associated with increased phosphorylation of eNOS but independent of changes in endothelial cell [Ca2+]i. British Journal of Pharmacology (2007) 152, 223–229; doi:10.1038/sj.bjp.0707387

The hydrogen permeation investigation of API X56 steel in sea mud

Abstract: It was found that the corrosion rate of steel in the sea mud with sulfate-reducing bacteria (SRB) could be as high as 10 times of that in the sea mud without SRB. And the hydrogen permeation reaction would occur when metals were corroded. So it is necessary to investigate the effect of living SRB on hydrogen permeation in the sea mud. Cathodic potential was often added to metals in order to protect them. But hydrogen permeation could be affected by the cathodic potential. So it is also necessary to study the effect of cathodic potential on hydrogen permeation. In this paper, the hydrogen permeation actions of APT X56 steel in the sea mud with and without SRB at corrosion and cathodic potential were studied with an improved Devanathan-Stachurski's electrolytic cell. Experimental results showed that during the growth of SRB, the current density curve of hydrogen permeation was accordant with the growth curve of SRB. But the hydrogen permeation current density of APT X56 steel hardly changed in the sterilized sea mud. Compared with the hydrogen permeation current density of APT X56 steel in the sterilized sea mud, the hydrogen permeation of APT X56 steel in the sea mud could be accelerated by living SRB. Experimental results also showed that the hydrogen permeation current density increased rapidly when the cathodic potential was added to the three-electrode system of the cathodic cell, and then the hydrogen permeation current density could obtain a stable value slowly. So the cathodic potential added to the cathodic cell could accelerate hydrogen permeation.

Method and apparatus for detecting objects of interest in soccer video by color

Abstract: A method is disclosed for detecting and locating players in soccer video frames without errors caused by artifacts by a shape analysis-based approach to identify the players and the ball from roughly extracted foregrounds obtained by color segmentation and connected component analysis, by performing a Euclidean distance transform to extract skeletons for every foreground blob, by performing a shape analysis to remove false alarms (non-players and non-ball), and then by performing skeleton pruning and a reverse Euclidean distance transform to cut-off the artifacts primarily caused by playing field lines.

Diagnosing mixed scan chain and system logic defects

Abstract: Technologies disclosed herein can be used to diagnose defects on die having both scan chain and system logic defects, including in situations where the presence of one or more faults in the system logic potentially obscures the detectability of one or more faults in the scan chains (or channels) and vice versa. At least some embodiments employ an iterative approach where at least some scan chain faults are identified, these chain faults are used to identify system logic faults, and then additional chain faults are identified using the system logic faults and vice versa. Failing bits can be partitioned into at least two groups: failing bits determined as being caused by system logic failures, and failing bits determined as being possibly caused by chain defects, system logic defects, or the compound effects of both types of defects.

Raloxifene modulates pulmonary vascular reactivity in spontaneously hypertensive rats.

Abstract: :Selective estrogen receptor modulators (SERMs) reduce vascular tone in the systemic circulation. Their effects on the pulmonary circulation are unknown. The present study examined the effect of oral treatment with raloxifene (a second-generation SERM) on vasomotor reactivity in pulmonary ar

Effect of IR-Drop on Path Delay Testing Using Statistical Analysis

Abstract: IR-drop has become a major source of delay defects in deep sub-micron VLSI designs. In this work, we analyze the effect of IR-drop in path-delay test and how to obtain more accurate delay information of critical paths. For possible regions with IR-drop, we perform timing analysis on these nodes such that a certain amount of voltage drop can be associated with extra delays on victim nodes. Power analysis is conducted to determine the occurrence probability of a certain voltage drop. These probability values are used to weigh the extra delays caused by IR-drop of all victim nodes, which are then accumulated along each path. Experimental results show that such a process can effectively take the small delays caused by IR-drop into consideration and can have a significant impact on the identification and analysis of critical paths.

Hydrogen permeation behavior and corrosion monitoring of steel in cyclic wet–dry atmospheric environment

Abstract: Hydrogen permeation of 16Mn steel under a cyclic wet-dry condition was investigated by Devanathan-Stachurski's electrolytic cell with a membrane covered on the exit side by a nickel layer and the weight loss was measured for each wet-dry cycle. The results show that hydrogen permeation current change with different atmospheric environment: distilled water, seawater, and seawater containing 100 ppm H2S. The results show that seawater can induce an increase in the hydrogen permeation current due to the hydrolyzation reaction. And after the increase, equilibrium is reached due to the equilibrium of hydrolyzation reaction effect and the block of the rust layer. On the other hand, H2S contamination also can induce an increase in the maximum hydrogen permeation current due to the hydrolyzation reaction. And H2S contamination delays the time that hydrogen permeation is detected because of the formation of the FeS(1-x) film. The FeS(1-x) film can block the absorption of hydrogen onto the specimen surface. The surface potential change and the pH change of the metal surface control the hydrogen permeation current. And a clear linear correlation exists between the quantities of hydrogen permeated through the 16Mn steel and the weight loss. Based on the linear correlation, we monitored the corrosion rate by monitoring the hydrogen permeation current by a sensor outside. Good coherences were shown between results in laboratory and outside.

Cyclic nucleotides and Ca2+ influx pathways in vascular endothelial cells.

Abstract: Ca(2+) mobilizing agonists and hemodynamic shear stress both elicit a rise in endothelial cytosolic Ca(2+) [Ca(2+)](i), which then acts to stimulate nitric oxide synthase and phospholipase A(2), leading to the production and release of nitric oxide (NO) and other vascular substances such as prostacyclin and endothelium-derived hyperpolarizing factors (EDHF). In this article, regulatory mechanisms of agonist-induced and mechanosensitive Ca(2+) influx pathways in vascular endothelial cells will be discussed. Special emphasis will be placed on the regulation of agonist-induced Ca(2+) influx by protein kinase G (PKG). Flow-induced Ca(2+) influx in relation to vascular dilation and the vasodilator produced will also be discussed.