bluuebunny/crossref_metadata_2025 huggingface dataset:
Ins(1,4,5)P3 interacts with PIP2 to regulate activation of TRPC6/C7 channels by diacylglycerol in native vascular myocytes
Authors: Ju Min , Shi Jian , Saleh Sohag N. , Albert Anthony P. , Large William A.
Published: March 2010

We investigated synergism between inositol 1,4,5‐trisphosphate (Ins(1,4,5)P3) and diacylglycerol (DAG) on TRPC6‐like channel activity in rabbit portal vein myocytes using single channel recording and immunoprecipitation techniques. Ins(1,4,5)P3 at 10 μm increased 3‐fold TRPC6‐like activity induced by 10 μm 1‐oleoyl‐2‐acetyl‐sn‐glycerol (OAG), a DAG analogue. Ins(1,4,5)P3 had no effect on OAG‐induced TRPC6 activity in mesenteric artery myocytes. Anti‐TRPC6 and anti‐TRPC7 antibodies blocked channel activity in portal vein but only anti‐TRPC6 inhibited activity in mesenteric artery. TRPC6 and TRPC7 proteins strongly associated in portal vein but only weakly associated in mesenteric artery tissue lysates. Therefore in portal vein the conductance consists of TRPC6/C7 subunits, while OAG activates a homomeric TRPC6 channel in mesenteric artery myocytes. Wortmannin at 20 μm reduced phosphatidylinositol 4,5‐bisphosphate (PIP2) association with TRPC6 and TRPC7, and produced a 40‐fold increase in OAG‐induced TRPC6/C7 activity. Anti‐PIP2 antibodies evoked TRPC6/C7 activity, which was blocked by U73122, a phospholipase C inhibitor. DiC8‐PIP2, a water‐soluble PIP2 analogue, inhibited OAG‐induced TRPC6/C7 activity with an IC50 of 0.74 μm. Ins(1,4,5)P3 rescued OAG‐induced TRPC6/C7 activity from inhibition by diC8‐PIP2 in portal vein myocytes, and this was not prevented by the Ins(1,4,5)P3 receptor antagonist heparin. In contrast, Ins(1,4,5)P3 did not overcome diC8‐PIP2‐induced inhibition of TRPC6 activity in mesenteric artery myocytes. 2,3,6‐Tri‐O‐butyryl‐Ins(1,4,5)P3/AM (6‐Ins(1,4,5)P3), a cell‐permeant analogue of Ins(1,4,5)P3, at 10 μm increased TRPC6/C7 activity in portal vein and reduced association between TRPC7 and PIP2, but not TRPC6 and PIP2. In contrast, 10 μm OAG reduced association between TRPC6 and PIP2, but not between TRPC7 and PIP2. The present work provides the first evidence that Ins(1,4,5)P3 modulates native TRPC channel activity through removal of the inhibitory action of PIP2 from TRPC7 subunits.
Female mice target deleted for the neuromedin B receptor have partial resistance to diet‐induced obesity
Authors: Paula Gabriela Silva Monteiro , Souza Luana Lopes , Cabanelas Adriana , Bloise Flavia Fonseca , Mello‐Coelho Valéria , Wada Etsuko , Ortiga‐Carvalho Tania Maria , Oliveira Karen Jesus , Pazos‐Moura Carmen Cabanelas
Published: March 2010

Previous studies have proposed a role for neuromedin B (NB), a bombesin‐like peptide, in the control of body weight homeostasis. However, the nature of this role is unclear. The actions of NB are mediated preferentially by NB‐preferring receptors (NBRs). Here we examined the consequences of targeted deletion of NBRs in female mice on body weight homeostasis in mice fed a normolipid diet (ND) or a high‐fat diet (HFD) for 13 weeks. Body weight and food ingestion of neuromedin B receptor knockout (NBR‐KO) mice fed a normolipid diet showed no difference in relation to wild‐type (WT). However, the high‐fat diet induced an 8.9‐ and 4.8‐fold increase in body weight of WT and NBR‐KO, respectively, compared to their controls maintained with a normolipid diet, even though the mice ingested the same amount of calories, regardless of genotype. Comparing mice fed the high‐fat diet, NBR‐KO mice accumulated approximately 45% less fat depot mass than WT, exhibited a lower percentage of fat in their carcasses (19.2 vs. 31.3%), and their adipocytes were less hypertrophied. Serum leptin and leptin mRNA in inguinal and perigonadal fat were lower in HFD NBR‐KO than HFD WT, and serum adiponectin was similar among HFD groups and unaltered in comparison to ND‐fed mice. HFD‐fed WT mice developed glucose intolerance but not the HFD‐fed NBR‐KO mice, although they had similar glycaemia and insulinaemia. NBR‐KO and WT mice on the normolipid diet showed no differences in any parameters, except for a trend to lower insulin levels. Therefore, disruption of the neuromedin B receptor pathway did not change body weight homeostasis in female mice fed a normolipid diet; however, it did result in partial resistance to diet‐induced obesity.
Attenuated baroreflex control of sympathetic nerve activity in obese Zucker rats by central mechanisms
Authors: Huber Domitila A. , Schreihofer Ann M.
Published: March 2010

Adult obese Zucker rats (OZRs) have reduced sympathetic responses to evoked changes in arterial pressure (AP) compared to lean Zucker rats (LZRs). This study examined whether attenuated sympathetic baroreflexes in OZRs may be due to altered sensory or central mechanisms. The OZRs had elevated baseline splanchnic sympathetic nerve activity (SNA) and mean AP (MAP) compared to age‐matched LZRs under urethane anaesthesia (P < 0.05). Aortic depressor nerve activity (ADNA) was measured while AP was altered by infusions of phenylephrine or nitroprusside (±60 mmHg over 60–90 s) in rats treated with atropine and propranolol to eliminate changes in heart rate. Although baseline ADNA was higher in the hypertensive OZRs, the relationship between MAP and ADNA was comparable in OZRs and LZRs. In contrast, electrical stimulation of the ADN afferent fibres (5 s train, 2 ms pulses, 4 V, 0.5–48 Hz) produced dramatically smaller reductions in SNA and MAP in OZRs compared to LZRs (P < 0.05). After blockade of α‐adrenergic receptors to prevent sympathetically mediated depressor responses, OZRs still had reduced sympathetic responses to stimulation of the ADN. In addition, stimulation of vagal afferent nerves electrically or with phenylbiguanide (1, 2, 4 and 8 μg, i.v.) produced smaller inhibitions of SNA in OZRs compared with LZRs (P < 0.05). These data suggest that attenuated sympathetic baroreflexes are the result of altered central mechanisms in OZRs, and not deficits in the responsiveness of aortic baroreceptors to AP. Furthermore, central deficits in the regulation of SNA in OZRs extend to other sympathoinhibitory reflexes initiated by vagal afferent nerves.
Obligatory role of hyperaemia and shear stress in microvascular adaptation to repeated heating in humans
Authors: Green Daniel J. , Carter Howard H. , Fitzsimons Matthew G. , Cable N. Timothy , Thijssen Dick H.J. , Naylor Louise H.
Published: March 2010

The endothelium, a single layer of cells lining the entire circulatory system, plays a key role in maintaining vascular health. Endothelial dysfunction independently predicts cardiovascular events and improvement in endothelial function is associated with decreased vascular risk. Previous studies have suggested that exercise training improves endothelial function in macrovessels, a benefit mediated via repeated episodic increases in shear stress. However, less is known of the effects of shear stress modulation in microvessels. In the present study we examined the hypothesis that repeated skin heating improves cutaneous microvascular vasodilator function via a shear stress‐dependent mechanism. We recruited 10 recreationally active males who underwent bilateral forearm immersion in warm water (42°C), 3 times per week for 30 min. During these immersion sessions, shear stress was manipulated in one arm by inflating a pneumatic cuff to 100 mmHg, whilst the other arm remained uncuffed. Vasodilatation to local heating, a NO‐dependent response assessed using laser Doppler, improved across the 8 week intervention period in the uncuffed arm (cutaneous vascular conductance week 0 vs. week 4 at 41°C: 1.37 ± 0.45 vs. 2.0 ± 0.91 units, P= 0.04; 42°C: 2.06 ± 0.45 vs. 2.68 ± 0.83 units; P= 0.04), whereas no significant changes were evident in the cuffed arm. We conclude that increased blood flow, and the likely attendant increase in shear stress, is a key physiological stimulus for enhancing microvascular vasodilator function in humans.
Thermal Wave Applications in Flow Fields With Steady Velocity Profile
Authors: Wang Zhefu , Peterson Richard B.
Published: March 2010

This study explores the use of a thermal wave approach for flow field measurement applications, such as flow diagnostics near surfaces and in microfluidic systems. The basic mathematical characteristics of the governing equations of heat convection, with periodic heating boundary conditions in steady flow, are discussed and the validity of applying the complex combination method to this problem is illustrated. A scaling analysis of a two-dimensional thermal wave configuration with a linear velocity profile is performed to provide important insights into this type of heat transfer phenomena. A two-dimensional conjugate heat transfer model is developed and solved numerically with a finite difference method to demonstrate an example of imposing a thermal wave onto a flow field. The simulation results show that the temperature signal, especially the phase information, can be used for the measurement of flow properties near the surface, such as the wall shear stress.
A Phase-Sensitive Technique for Measurements of Liquid Thermal Conductivity
Authors: Wang Zhefu , Peterson Richard B.
Published: March 2010

An experimental technique based on the thermal wave approach for measuring the thermal conductivity of liquids is developed in this paper. A stainless steel strip functions as both a heating element and a sealing cover for a chamber containing a test liquid. A periodic current passing through this metal strip generates a periodic Joule heating source. An infrared detector measures the temperature response at the front surface of the stainless steel strip. The phase and magnitude of the temperature response with respect to the heating signal were measured by a lock-in amplifier at various frequencies from 22 Hz to 502 Hz. A one-dimensional, two-layered transient heat conduction model was developed to predict the temperature response on the front surface of the stainless steel strip. The phase information from this temperature response shows high sensitivity to the change in thermal properties of the liquid layer and is employed to match experimental data to find the thermal properties of the test liquid. The measured thermal conductivities of water and ethylene glycol agree quite well with the data from literature and support the validity of this measurement technique. An aqueous fluid consisting of gold nanoparticles is tested and anomalous thermal conductivity enhancement is observed. A discrepancy in the thermal transport behavior between pure liquids and nanofluids is suggested from our experimental results.
Inverse Determination of Eroded Smelter Wall Thickness Variation Using an Elastic Membrane Concept
Authors: Baker Daniel , Dulikravich George S. , Dennis Brian H. , Martin Thomas J.
Published: March 2010

A novel algorithm has been developed for the nondestructive determination of the shape of the interface between a melt and a refractory material wall in smelter furnaces. This method uses measurements of temperature and heat flux at a number of points on the outer surface of the furnace, and assumes that the inner (guessed) surface of the furnace wall is isothermal. The temperature field is then predicted in the entire furnace wall material by numerically solving a steady state heat conduction equation subject to the measured temperature values on the external surface and the isothermal melt material solidus temperature on the inner surface of the wall. The byproduct of this analysis is the computed heat flux on the external surface. The difference between the measured and the computed heat fluxes on the outer surface of the furnace is then used as a forcing function in an elastic membrane motion concept to determine perturbations to the inner (melt-refractory) surface motion. The inverse determination of the melt-refractory interface shape can be achieved by utilizing this algorithm and any available analysis software for the temperature field in the refractory wall. The initial guess of the inner shape of the wall can be significantly different from the final (unknown) wall shape. The entire wall shape determination procedure requires typically 5–15 temperature field analyses in the furnace wall material.
Effects of Variable Viscosity and Thermal Conductivity of CuO-Water Nanofluid on Heat Transfer Enhancement in Natural Convection: Mathematical Model and Simulation
Authors: Abu-Nada Eiyad
Published: March 2010

Heat transfer enhancement in horizontal annuli using variable thermal conductivity and variable viscosity of CuO-water nanofluid is investigated numerically. The base case of simulation used thermal conductivity and viscosity data that consider temperature property dependence and nanoparticle size. It was observed that for Ra≥104, the average Nusselt number was deteriorated by increasing the volume fraction of nanoparticles. However, for Ra=103, the average Nusselt number enhancement depends on aspect ratio of the annulus as well as volume fraction of nanoparticles. Also, for Ra=103, the average Nusselt number was less sensitive to volume fraction of nanoparticles at high aspect ratio and the average Nusselt number increased by increasing the volume fraction of nanoaprticles for aspect ratios ≤0.4. For Ra≥104, the Nusselt number was deteriorated everywhere around the cylinder surface especially at high aspect ratio. However, this reduction is only restricted to certain regions around the cylinder surface for Ra=103. For Ra≥104, the Maxwell–Garnett and the Chon et al. conductivity models demonstrated similar results. But, there was a deviation in the prediction at Ra=103 and this deviation becomes more significant at high volume fraction of nanoparticles. The Nguyen et al. data and the Brinkman model give completely different predictions for Ra≥104, where the difference in prediction of the Nusselt number reached 50%. However, this difference was less than 10% at Ra=103.
Numerical
Simulation of Transient Thermal Transport on a Rotating Disk Under Partially Confined Laminar Liquid
Jet Impingement
Authors: Lallave Jorge
C. , Rahman Muhammad
M.
Published: March 2010

This paper considers the transient conjugate heat transfer characterization of a partially confined liquid jet impinging on a rotating and uniformly heated solid disk of finite thickness and radius. A constant heat flux was imposed at the bottom surface of the solid disk at t=0, and heat transfer was monitored for the entire duration of the transient until the steady state condition was reached. Calculations were done for a number of disk materials using water as the coolant, covering a range of Reynolds numbers (225–900), Ekman numbers (7.08×10−5−∞), nozzle-to-target spacing (β=0.25–1.0), confinement ratios (rp/rd=0.2–0.75), disk thicknesses to nozzle diameter ratios (b/dn=0.25–1.67), and solid to fluid thermal conductivity ratios (36.91–697.56). It was found that a higher Reynolds number decreases the time to achieve the steady state condition and increases the local and average Nusselt number. The duration of the transient increases with the increment of the Ekman number and disk thickness, and the reduction in the thermal diffusivity of the disk material.
The Effect of Spatially Correlated Roughness and Boundary Conditions on the Conduction of Heat Through a Slab
Authors: Emery A. F. , Dillon H. , Mescher A. M.
Published: March 2010

The nominally one-dimensional conduction of heat through a slab becomes two dimensional when one of the surfaces is rough or when the boundary conditions are spatially nonuniform. This paper develops the stochastic equations for a slab whose surface roughness or convective boundary condition is spatially correlated with correlation lengths ranging from 0 (white noise) to a length long in comparison to the slab thickness. The effect is described in terms of the standard deviation and the resulting spatial correlation of the heat flux as a function of depth into the slab. In contrast to the expectation that the effect is monotonic with respect to the correlation length, it is shown that the effect is maximized at an intermediate correlation length. It is also shown that roughness or a random convective heat transfer coefficient have essentially the same effects on the conducted heat, but that the combination results in a much deeper penetration than does each effect individually. In contrast to the usual methods of solving stochastic problems, both the case of a rough edge and a smooth edge with stochastic convective heat transfer coefficients can only be treated with reasonable computational expense by using direct Monte Carlo simulations.
Temperature Measurements of Diesel Fuel Combustion With Multicolor Pyrometry
Authors: Fu Tairan , Wang Zhe , Cheng Xiaofang
Published: March 2010

Optical diagnostics techniques to measure diesel combustion flame temperatures are useful for evaluation and control of combustion processes. In this paper, diesel combustion flame temperatures are measured based on a multicolor pyrometry method respectively adopting an optical fiber spectrometer and a color charge coupled device (CCD). The intensity ratios for various wavelengths/wavebands are utilized as the analytical variables to deduce the temperatures to avoid the need to calibrate each system for the specific geometry conditions. The measured multicolor data can determine the temperature T and the soot factor KL. Extra data collected at many wavelengths is used to reduce the noise and random fluctuations in the measurements. To improve the solving precision, a data-processing method based on the least-squares technique is proposed to fit the data for approximate solutions. Verification experiments using the multicolor pyrometry were conducted in a 54–120 kW test furnace with diesel fuel. Data for 16 wavelengths detected by a fiber optic spectrometer from a diesel flame is analyzed to determine how to choose a suitable combination of three wavelengths for three-color pyrometry. The CCD-based three-color measurements, which would be much more practical in field measurements, are compared with the spectrometer-based results.
Design and Test of Carbon Nanotube Biwick Structure for High-Heat-Flux Phase Change Heat Transfer
Authors: Cai Qingjun , Chen Chung-Lung
Published: March 2010

With the increase in power consumption in compact electronic devices, passive heat transfer cooling technologies with high-heat-flux characteristics are highly desired in microelectronic industries. Carbon nanotube (CNT) clusters have high thermal conductivity, nanopore size, and large porosity and can be used as wick structure in a heat pipe heatspreader to provide high capillary force for high-heat-flux thermal management. This paper reports investigations of high-heat-flux cooling of the CNT biwick structure, associated with the development of a reliable thermometer and high performance heater. The thermometer/heater is a 100-nm-thick and 600 μm wide Z-shaped platinum wire resistor, fabricated on a thermally oxidized silicon substrate of a CNT sample to heat a 2×2 mm2 wick area. As a heater, it provides a direct heating effect without a thermal interface and is capable of high-temperature operation over 800°C. As a thermometer, reliable temperature measurement is achieved by calibrating the resistance variation versus temperature after the annealing process is applied. The thermally oxidized layer on the silicon substrate is around 1-μm-thick and pinhole-free, which ensures the platinum thermometer/heater from the severe CNT growth environments without any electrical leakage. For high-heat-flux cooling, the CNT biwick structure is composed of 250 μm tall and 100 μm wide stripelike CNT clusters with 50 μm stripe-spacers. Using 1×1 cm2 CNT biwick samples, experiments are completed in both open and saturated environments. Experimental results demonstrate 600 W/cm2 heat transfer capacity and good thermal and mass transport characteristics in the nanolevel porous media.
Constructal
Allocation of Nanoparticles in Nanofluids
Authors: Bai Chao , Wang Liqiu
Published: March 2010

We perform a constructal design of heat conduction in a blade-configured disk-shaped domain with uniform heat generation and periphery heat-sink by introducing a transition line from two-path conduction to one-path conduction in the domain. This orderly arranged blade configuration can offer significantly smaller constructal overall temperature difference than that of the dispersed configuration and thus performs much better. The constructal allocation of nanoparticles inside the base fluids and thus the heat-conduction design inside the nanofluids are very important for better system performance. This work shows that the search for heat-flow configuration is a key to performance, and the constructal theory is the strategy for discovering the configuration and the significantly better performance.
Pin1 and PKMζ Sequentially Control Dendritic Protein Synthesis
Authors: Westmark Pamela R. , Westmark Cara J. , Wang SuQing , Levenson Jonathan , O’Riordan Kenneth J. , Burger Corinna , Malter James S.
Published: March 2010

A feedback loop involving Pin1, protein synthesis, and protein kinase M ζ regulates a persistent form of synaptic plasticity.
Double-Duty MicroRNA: Destroy and Decoy
Authors: Gough Nancy R.
Published: March 2010

miR-328 promotes the production of a protein by competing with its transcript for an inhibitory RNA binding protein.
Corpse-Sorting Machinery
Authors: Hurtley Stella M.
Published: March 2010

An intracellular membrane-sorting machinery participates in cellular corpse clearance.
Eating by the Clock
Authors: Adler Elizabeth M.
Published: March 2010

Circadian oscillators in gustatory receptor neurons mediate rhythms in taste sensitivity and modulate feeding behavior in
Drosophila.
Reexamining Glial Function
Authors: Stern Peter R.
Published: March 2010

Previous reports of glial cell activity may reflect the pharmacological approaches used and not endogenous activity.
PINing for Things Past
Authors: Sacktor Todd Charlton
Published: March 2010

Memory storage requires the inhibition of a peptidyl-prolyl isomerase to enable synthesis of the kinase PKMζ.
Treatment with Fluoroquinolones or with β-Lactam-β-Lactamase Inhibitor Combinations Is a Risk Factor for Isolation of Extended-Spectrum-β-Lactamase-Producing
Klebsiella
Species in Hospitalized Patients
Authors: Wener Kenneth M. , Schechner Vered , Gold Howard S. , Wright Sharon B. , Carmeli Yehuda
Published: March 2010

Antibiotic exposure exerts strong selective pressure and is an important modifiable risk factor for antibiotic resistance. We aimed to identify the role of various antibiotics as risk factors for the isolation of extended-spectrum-β-lactamase (ESBL)-producing
Klebsiella
spp. in hospitalized patients at a tertiary-care hospital. A parallel multivariable model was created to compare two groups of cases with either nosocomially acquired ESBL- or non-ESBL-producing
Klebsiella
spp. to a common control group of hospitalized patients (a case-case-control design). Seventy-eight ESBL cases, 358 non-ESBL cases, and 444 controls were analyzed. Significant factors associated with the isolation of
Klebsiella
spp. were an age of >65 years, transfer from a health care facility, an intensive care unit (ICU) stay, and the presence of a comorbid malignancy or lung, hepatic, or renal disease. A propensity score was generated from the above, and our ability to discriminate between
Klebsiella
cases and controls (area under the receiver-operating-characteristic [ROC] curve, 0.78) was good. The ESBL phenotype was tightly linked with fluoroquinolone resistance (95% versus 18%,
P
< 0.001). Factors associated with isolation of ESBL
Klebsiella
spp. in a multivariable analysis, adjusting for the propensity score, included exposure to β-lactam-β-lactamase inhibitor combinations (odds ratio [OR], 10.17; 95% confidence interval [CI], 1.19 to 86.92) and to fluoroquinolones (OR, 2.86; 95% CI, 1.37 to 5.97). Exposure to broad-spectrum cephalosporins was statistically associated with ESBL
Klebsiella
spp. only among the subgroup of patients not treated with fluoroquinolones. In our institution, where the ESBL
-
producing-
Klebsiella
phenotype is coselected with fluoroquinolone resistance, fluoroquinolone and β-lactam-β-lactamase inhibitor combinations, rather than cephalosporins, are the main risk factors for ESBL isolates. Formulary interventions to limit the spread of ESBL-producing isolates should be tailored to each setting.
Systematic Approach to Optimizing Specifically Targeted Antimicrobial Peptides against
Streptococcus mutans
Authors: He Jian , Yarbrough Daniel K. , Kreth Jens , Anderson Maxwell H. , Shi Wenyuan , Eckert Randal
Published: March 2010

Previously we reported a novel strategy of “targeted killing” through the design of narrow-spectrum molecules known as specifically targeted antimicrobial peptides (STAMPs) (R. Eckert et al., Antimicrob. Agents Chemother. 50:3651-3657, 2006; R. Eckert et al., Antimicrob. Agents Chemother. 50:1480-1488, 2006). Construction of these molecules requires the identification and the subsequent utilization of two conjoined yet functionally independent peptide components: the targeting and killing regions. In this study, we sought to design and synthesize a large number of STAMPs targeting
Streptococcus mutans
, the primary etiologic agent of human dental caries, in order to identify candidate peptides with increased killing speed and selectivity compared with their unmodified precursor antimicrobial peptides (AMPs). We hypothesized that a combinatorial approach, utilizing a set number of AMP, targeting, and linker regions, would be an effective method for the identification of STAMPs with the desired level of activity. STAMPs composed of the Sm6
S. mutans
binding peptide and the PL-135 AMP displayed selectivity at MICs after incubation for 18 to 24 h. A STAMP where PL-135 was replaced by the B-33 killing domain exhibited both selectivity and rapid killing within 1 min of exposure and displayed activity against multispecies biofilms grown in the presence of saliva. These results suggest that potent and selective STAMP molecules can be designed and improved via a tunable “building-block” approach.
Identification of
katG
Mutations Associated with High-Level Isoniazid Resistance in
Mycobacterium tuberculosis
Authors: Ando Hiroki , Kondo Yuji , Suetake Toshinori , Toyota Emiko , Kato Seiya , Mori Toru , Kirikae Teruo
Published: March 2010

Isoniazid (INH) is an effective first-line antituberculosis drug. KatG, a catalase-peroxidase, converts INH to an active form in
Mycobacterium tuberculosis
, and
katG
mutations are major causes of INH resistance. In the present study, we sequenced
katG
of 108 INH-resistant
M. tuberculosis
clinical isolates. Consequently, 9 novel KatG mutants with a single-amino-acid substitution were found. All of these mutants had significantly lower INH oxidase activities than the wild type, and each mutant showed various levels of activity. Isolates having mutations with relatively low activities showed high-level INH resistance. On the basis of our results and known mutations associated with INH resistance, we developed a new hybridization-based line probe assay for rapid detection of INH-resistant
M. tuberculosis
isolates.
Anaplasma phagocytophilumAPH_1387 Is Expressed throughout Bacterial Intracellular Development and Localizes to the Pathogen-Occupied Vacuolar Membrane
Authors: Huang Bernice , Troese Matthew J. , Ye Shaojing , Sims Jonathan T. , Galloway Nathan L. , Borjesson Dori L. , Carlyon Jason A.
Published: March 2010

Obligate vacuolar pathogens produce proteins that localize to the host cell-derived membranes of the vacuoles in which they reside, yielding unique organelles that are optimally suited for pathogen survival.Anaplasma phagocytophilumis an obligate vacuolar bacterium that infects neutrophils and causes the emerging and potentially fatal disease human granulocytic anaplasmosis. Here we identified APH_1387 as the firstA. phagocytophilum-derived protein that associates with theA. phagocytophilum-occupied vacuolar membrane (AVM). APH_1387, also referred to as P100, is a 61.4-kDa acidic protein that migrates with an apparent molecular weight of 115 kDa on SDS-PAGE gels. It carries 3 tandem direct repeats that comprise 58% of the protein. Each APH_1387 repeat carries a bilobed hydrophobic alpha-helix domain, which is a structural characteristic that is consistent with the structure of chlamydia-derived proteins that traverse inclusion membranes. APH_1387 is not detectable on the surfaces ofA. phagocytophilumdense core organisms bound at the HL-60 cell surface, but abundant APH_1387 is detected on the surfaces of intravacuolar reticulate cell and dense core organisms. APH_1387 accumulates on the AVM throughout infection. It associates with the AVM in human HL-60, THP-1, and HMEC-1 cells and tick ISE6 cells. APH_1387 is expressed and localizes to the AVM in neutrophils recovered fromA. phagocytophilum-infected mice. This paper presents the first direct evidence thatA. phagocytophilumactively modifies its host cell-derived vacuole.
How much anonymity does network latency leak?
Authors: Hopper Nicholas , Vasserman Eugene Y. , Chan-TIN Eric
Published: March 2010

Low-latency anonymity systems such as Tor, AN.ON, Crowds, and Anonymizer.com aim to provide anonymous connections that are both untraceable by “local” adversaries who control only a few machines and have low enough delay to support anonymous use of network services like Web browsing and remote login. One consequence of these goals is that these services leak some information about the network latency between the sender and one or more nodes in the system. We present two attacks on low-latency anonymity schemes using this information. The first attack allows a pair of colluding Web sites to predict, based on local timing information and with no additional resources, whether two connections from the same Tor exit node are using the same circuit with high confidence. The second attack requires more resources but allows a malicious Web site to gain several bits of information about a client each time he visits the site. We evaluate both attacks against two low-latency anonymity protocols—the Tor network and the MultiProxy proxy aggregator service—and conclude that both are highly vulnerable to these attacks.
New payload attribution methods for network forensic investigations
Authors: Ponec Miroslav , Giura Paul , Wein Joel , Brönnimann Hervé
Published: March 2010

Payload attribution can be an important element in network forensics. Given a history of packet transmissions and an excerpt of a possible packet payload, a payload attribution system (PAS) makes it feasible to identify the sources, destinations, and the times of appearance on a network of all the packets that contained the specified payload excerpt. A PAS, as one of the core components in a network forensics system, enables investigating cybercrimes on the Internet by, for example, tracing the spread of worms and viruses, identifying who has received a phishing e-mail in an enterprise, or discovering which insider allowed an unauthorized disclosure of sensitive information.

Due to the increasing volume of network traffic in today's networks, it is infeasible to effectively store and query all the actual packets for extended periods of time in order to allow analysis of network events for investigative purposes; therefore, we focus on extremely compressed digests of the packet activity. We propose several new methods for payload attribution, which utilize Rabin fingerprinting, shingling, and winnowing. Our best methods allow building practical payload attribution systems, which provide data reduction ratios greater than 100:1 while supporting efficient queries with very low false positive rates. We demonstrate the properties of the proposed methods and specifically analyze their performance and practicality when used as modules of a network forensics system ForNet. Our experimental results outperform current state-of-the-art methods both in terms of false positives and data reduction ratio. Finally, these approaches directly allow the collected data to be stored and queried by an untrusted party without disclosing any payload information nor the contents of queries.
Split-ballot voting
Authors: Moran Tal , Naor Moni
Published: March 2010

In this article, we propose a new voting protocol with several desirable security properties. The voting stage of the protocol can be performed by humans without computers; it provides every voter with the means to verify that all the votes were counted correctly (universal verifiability) while preserving ballot secrecy. The protocol has “everlasting privacy”: Even a computationally unbounded adversary gains no information about specific votes from observing the protocol's output. Unlike previous protocols with these properties, this protocol distributes trust between two authorities: a single corrupt authority will not cause voter privacy to be breached. Finally, the protocol is receipt-free: A voter cannot prove how she voted even if she wants to do so. We formally prove the security of the protocol in the universal composability framework, based on number-theoretic assumptions.
Authenticated error-correcting codes with applications to multicast authentication
Authors: Lysyanskaya Anna , Tamassia Roberto , Triandopoulos Nikos
Published: March 2010

We consider the problem of authenticating a stream of packets transmitted over a network controlled by an adversary who may perform arbitrary attacks on the stream: He may drop or modify chosen packets, rearrange the order of the packets in any way, and inject new, random, or specially crafted packets into the stream. In contrast, prior work on the multicast authentication problem has focused on a less powerful adversarial network model or has examined a considerably more restrictive setting with specific timing or structural assumptions about the network.

We model the ability of the network to modify a stream of
n
packets with two parameters: the
survival rate
α (0 <α≤ 1) denoting the fraction of the packets that are guaranteed to reach any particular receiver unmodified and the
flood rate
β (β ≥ 1) indicating the factor by which the size of the received stream at any particular receiver may exceed the size of the transmitted stream. Combining error-correcting codes with standard cryptographic primitives, our approach gives almost the same security guarantees as if each packet were individually signed, but requires only one signature operation for the entire stream and adds to each transmitted packet only a small amount of authentication information, proportional to β/α
2
. We prove the security and correctness of our scheme and analyze its performance in terms of communication overhead and computational effort at the sender and the receiver. Our results demonstrate how list decoding can be transformed into unambiguous decoding in the public-key model and the bounded computational model for the underlying communication channel. Overall, our technique provides an authenticated error-correcting code of independent interest that may be useful in other settings.
Deterring voluntary trace disclosure in re-encryption mix-networks
Authors: Wang Xiaofeng , Golle Philippe , Jakobsson Markus , Tsow Alex
Published: March 2010

Mix-networks, a family of anonymous messaging protocols, have been engineered to withstand a wide range of theoretical internal and external adversaries. An undetectable insider threat—voluntary partial trace disclosures by server administrators—remains a troubling source of vulnerability. An administrator's cooperation could be the resulting coercion, bribery, or a simple change of interests. While eliminating this insider threat is impossible, it is feasible to deter such unauthorized disclosures by bundling them with additional penalties. We abstract these costs with collateral keys, which grant access to customizable resources. This article introduces the notion of trace-deterring mix-networks, which encode collateral keys for every server-node into every end-to-end message trace. The network reveals no keying material when the input-to-output transitions of individual servers remain secret. Two permutation strategies for encoding key information into traces, mix-and-flip and all-or-nothing, are presented. We analyze their trade-offs with respect to computational efficiency, anonymity sets, and colluding message senders. Our techniques have sufficiently low overhead for deployment in large-scale elections, thereby providing a sort of publicly verifiable privacy guarantee.
Design Learner Success Into Your Curriculum
Authors: May Jeff
Published: March 2010

As facilitators of e-learning in corporate environments, it is our responsibility to do what we can to ensure that both the organization and the individual learners gain the maximum benefit from all learning or training initiatives. We have a responsibility to ensure that as many success factors as possible are in play.
How to Outline an E-Learning Product
Authors: Warner Tim
Published: March 2010

Just as the quality of an automobile can be judged by its engine construction, so too can the caliber of an e-learning course be evaluated by its outline structure. An effective e-learning project starts with an effective project outline.
NMOS Narrow Width Devices Drive Current Improvements through STI Processes and Channel Implantation Optimization
Authors: Shen Zhaoxu , Ju Jianhua , Wang Brisk , Zhou Allan , Liu Jinhua , Ho H.-M. , Ning X.-J.
Published: March 2010

NMOS narrow width transistor driving current as a function of shallow trench isolation (STI) processes and channel implant conditions were studied on a 65nm CMOS technology. It is found that the magnitude of compressive stress in STI could modulate the trend of NMOS drive current versus width dependence that was attributed to channel dose profile uneven distribution under the influence of stress. It is seen that the channel body effect factor (gamma) of large width (W=10um) transistor is smaller than that of narrow width device (W=0.12um). This difference increases as STI compressive stress scales up. The phenomena are consistent with the analysis that Boron dose distribution varies as STI stress changes. it is shown that the down trend of drive current for narrow width transistors could be minimized by STI process optimization, or by introducing indium implantation during channel implantation processes.
Design and Fabrication Using Hot Embossing Lithography of a Microfluidic Chip for Microsphere Single-Pass Applications
Authors: Qu Huaibo , Yang Ruixia , Yao Suying , Gao Peng
Published: March 2010

Polymer-based microfluidic chips are fabricated to demonstrate three-dimensional(3-D) spatial confinement of microspheres and fluids for microsphere single-pass biological applications and fluidic control. In this article, we report a novel fabrication process of a Poly(dimethylsiloxane) (PDMS) device by soft lithography, which involves creation of positive mold containing the sub-20µm width microchannels microstructures that were fabricated by Hot Embossing Lithography(HEL). The microspheres with the diameter of 13~15µm were injected directly into the inlet reservoirs and passed through one by one in the microchannels by the external pumps which has great potential for low-cost and more efficient detection and counting based on microspheres.
Reduction of Kink Effect in SOI LDMOS Structure with Linear Drift Region Thickness
Authors: Sheu Gene , Wu Cheng-yen , Yang Shao-Ming , Guo Yu-Feng
Published: March 2010

This paper reports a novel device structure which operates at low electrical field and high potential at internal drain point .The kink and quasi-saturation effects were minimized for this small 0.15 micron SOI LDNMOS with 0.13 micron gate length. Numerical simulation is used to show that the potential and electric field distribution within a small linear thickness (LT) LDMOS SOI device is quite different from that observed lateral linear doping (LD), uniform and vertical linear doping (VLD) devices. Reduction of drain electric field and of inter drain point potential barrier brings about a dramatic decrease of Kink effect improvement of quasi-saturation, large safe operate area (SOA) performance and lower on-resistance (Ron).
Modeling of Variability in Geometric Parameters of MOSFETs for DFM Applications
Authors: Liu Danqing , Jiang Lele , Qin Xiaojing , Cheng Yuhua
Published: March 2010

For improving manufacturability and yield, proactive DFM (design for manufacture) at device level is required. This paper proposes an improved methodology to obtain the effective channel length of MOS transistors with non-rectangular gates for modeling the process variability.
Design and Optimization of Power Devices in a BCD Process
Authors: Xu Fan , Fu Chunxiao , Cheng Yuhua
Published: March 2010

We present the results of design and optimization of high-voltage devices (170V) in a novel 0.35um BCD process. This process is based on a 0.35um BCD process. Process parameter optimization and device structures have been designed after detailed TCAD simulation and experimental device characterization. Several approaches such as adjusting field plate and optimizing LDD structure have been tried to improve breakdown voltage of the devices. By analyzing experiment results from several process splits, designs of 170V high voltage devices have been finalized. Good performance and very competitive specific on-resistances of devices after optimizition have been achieved.
Advanced In-Line Monitoring BrightField Inspection Tool for E-Test Correlation and Yield Analysis on 45nm Test Chips
Authors: Kwon YoungHun , Yoon HakY , Kang HoSeong , Kim KiHo , Kim Minho , Oh YoungSun , Lee JunWoo , Gunda Vikram , Choi HeungSoo , Shoji Grant , Jung Keebum , Choi HyeongJu , Kim JongPil , Ramani Vijay , Kurada Satya
Published: March 2010

With advanced design rules, yield learning challenges have scaled up. Identifying and analyzing yield killer defects are one of the major part of the issue. In this work, an advanced Inspection platform - '2810 DUV Broadband Brightfield' Inspection tool and Stack CV® (Characterization Vehicle®) test chips developed by PDF Solutions are used to identify systematic as well as random defects causing yield drop, and monitor key DOI (Defects-of-Interest) for accelerated defect-based yield learning at the 45nm technology node. 2810 DUV Broadband illumination, in-line defect organizer [iDO] & RICO [Review inspector cycle optimization] of eDR SEM review tool were key features employed during inspection recipe optimization. Stack CV® test chips contained diverse pattern lay-outs which provide platform for characterization of yield limiting factors. Using this methodology, 'E-test - In-line defect detection correlation' was matched to target benchmark capture rate values for FEOL and BEOL at Samsung S-1, a leading 300mm fab. Learnings derived from this study have enabled faster yield ramp-up on production devices.
Effects of Moisture Content on Dielectric Constant and Dissipation Factor of Printed Circuit Board Materials
Authors: Ma Lili , Sood Bhanu , Pecht Michael
Published: March 2010

In the past we conducted experiments to measure the dielectric properties of PCB materials as per industry adopted methods, including preconditioning of test samples. It was observed that some measurement results were not in accordance with manufacturer datasheets. This paper presents follow-up experimental studies on the dependence of dielectric constant and dissipation factor on the moisture content of laminates. Four types of PCB materials from two manufacturers, including two halogen-free and two halogenated, were tested in this study. The paper further establishes whether preconditioning steps outlined in the IPC-TM-650 2.5.5.9 test method account for varying moisture contents in laminate samples.
Effect of Oxidation Enhanced Diffusion on Hot Carrier Injection Induced Degradation in N-Type High-Voltage DDDMOSFET
Authors: Deng ZhangPeng , Li Xi , Zhang Rui H. , Yun Yueyun , Huang Aibo , Cao Gang , Shi Yanling
Published: March 2010

This paper investigates how the oxidation enhanced diffusion effect influences the reliability of hot carrier injection (HCI) in N-type high-voltage double-diffused drain MOSFET (DDDMOSFET). The oxidation enhanced diffusion influences impurity diffusion in silicon evidently, thus changes the device characteristic and reliability. By NDD drive-in at high temperature with N2 + O2 mixed atmosphere, we make use of the oxidation enhanced diffusion effect in NDD region of N-type HV DDDMOSFET to improve the HCI reliability. And the results are accordant with reliability simulation of TCAD softwar.
Failure Analysis of Cracked Die
Authors: Ma Lili , Bao Sheng Xiang
Published: March 2010

Aimed at crack die problem of micro-package, a series of experiments on failure components were conducted by using optical microscope, scanning electron microscope (SEM), Fein focus X-ray, cross section and various chemical etched methods. The failure analysis technique of cracked die in microelement was presented in detail, and the cause of these failure components was found finally. Wafer processing defect on the die has proven to be a contributing factor in the cracking of die. Mechanical damage acted as a stress riser from which the die crack may propagate. The root cause of die cracking in this failure was a consequence of the force inequality which came from mechanical loads in the package.
Anomalous Off-Leakage Currents in CMOS Devices and Its Countermeasures
Authors: He Yonggen , Kuo Jared , Chen Yong , Zhou Dibao , Ju Jianhua , Tang Ji Yue , Zhao Zhibiao , Yin Ming , Lu Junfeng
Published: March 2010

In this paper, an anomalous off-leakage current (AOLC) issue in CMOS devices is reported. As observed in pMOS universal curve (Ioff vs. Idsat), for AOLC, there are some scattering points with 2~3 magnitude order higher off-leakage current as compared with normal ones. We have identified this AOLC mechanism as that PMOS implanted dopant species penetrate through gate-stack with narrow process window. This is resulted from shrinking of poly-SiON gate length and high dose source-drain (SD), as well as source-drain extension ion implants applied in these devices. To suppress AOLC, several process factors have been investigated and optimized from an integration point of view, including: a) nitrogen concentration and profile control in SiON gate; b) poly thickness optimization and grain size reduction; and c) ion implant optimization, especially by reducing or eliminating energy contamination (EC).
Thin Wafer Stencil Print Coating
Authors: Schake Jeff , Whitmore Mark , Foggie David , Brown Michael
Published: March 2010

Applications for wafer print coating include protective coating and die attach adhesive applied on the backside and non-capillary active component protection on the front side. A preceding study examined the coating thickness distributions achieved comparing metal stencil print and mesh screen print processes using standard thickness 200mm diameter wafers. Despite mesh screen printing typically exhibiting better coating thickness uniformity results, the stencil print process is more commonly implemented. The process advantages provided by stencil printing include compatibility across a wider range of material rheology, smoother coating surface finish results, and complementing modern industry practice in using standard metal stencils. To that end, additional experiments have utilized the metal stencil printing process exclusively with 200mm wafers thinned to 150um, imitating more challenging process conditions that customers are now encountering. The primary objective of this study is to identify correlation between coating thickness control and wafer support tooling surface metrology. The data indicates coating thickness capability ratio (Cp) improvement exceeds 4x between best and worst performing wafer chucks, confirming our prediction that stricter chuck design tolerances are required for stencil print coating thinner wafers. This updated study improves our competency to satisfy demand for processing thinned wafers successfully.