bluuebunny/crossref_metadata_2025 huggingface dataset:
Inflation dynamics and agricultural supply shocks in Uganda
Authors: Mawejje Joseph , Lwanga Musa Mayanja
Published: November 2016

Purpose

The purpose of this paper is to develop an empirical model for inflation in Uganda, highlighting the role of supply side factors in the domestic agricultural sector.

Design/methodology/approach

The adopted empirical analysis is based on a single equation model that exploits cointegration techniques and general-to-specific modeling. The analysis controls for historical, seasonal as well as policy factors such as the effects of the global financial crisis, change in monetary policy regime to inflation targeting and monthly seasonal effects.

Findings

Results indicate that disequilibrium in the money, external and agricultural sectors feed into the Ugandan inflation process in the long run. However, the external and monetary sectors have larger long-run effects on inflation than the agricultural sector. Other factors that influence inflation in the short run include: inflation inertia, real output, money supply, exchange rate movements, foreign prices, monetary policy instruments and seasonal factors. In addition, the paper shows that the inflation-targeting policy has been successful in containing inflationary pressures.

Practical implications

These findings suggest that in the long-run monetary policy will continue to play an important role in managing Ugandan inflation through money demand management. The inflationary effects of agricultural supply shocks could be mitigated with appropriate domestic actions. In particular, fiscal policy that targets increased productivity and efficiency in agriculture through increased focus on production, irrigation, storage and transportation could reduce the effects of agricultural supply variability on inflation. In addition, policies intended to improve economic growth by expanding total output, control money supply growth and maintaining stability in the foreign exchange markets will help to reduce inflation.

Social implications

Studies of inflation and its determinants have dominated macroeconomic debates in the past decades because of the importance of price stability in economic growth and household welfare. The major conclusions from those studies are that: high inflation is detrimental to investment and growth; erodes the purchasing power; reduces household welfare; and exacerbates income inequality. Moreover there is a growing strand of literature establishing a causal link between inflation and conflict. Particularly for agricultural households, the effects of inflation are usually felt through the increase in food prices with implications for consumption and food security. These findings indicate the important macro and social implications of inflation. By focusing on the importance of agricultural supply shocks, the paper contributes to a better understanding of the drivers of inflation and how the macro and social effects can be addressed.

Originality/value

The major contribution of this paper is to try and model an equilibrium relationship in the domestic agricultural sector rather than using proxies such as an output gap measure or rainfall.
The impact of the reputation of underwriter and sponsoring representative on IPO underwriting fees
Authors: Chen Chao , Wang Xinrong
Published: November 2016

Purpose

The purpose of this paper is to analyze the effect of the reputation of underwriters and sponsoring representatives on initial public offering (IPO) underwriting fees, and further investigates the role of ownership and political connection.

Design/methodology/approach

The methodology includes three models. Model 1 empirically investigates the effect of underwriter’s reputation on underwriting fee. Model 2 studies the effect of sponsoring representative’s reputation on underwriting fee. Model 3 further examines the effect of underwriter’s reputation and sponsoring representative reputation on the underwriting fee controlling for the impact of ultimate controlling ownership and political connection.

Findings

The study documents that underwriters’ and sponsoring representatives’ reputation can result in reputational premiums. In the IPO of state-owned enterprises (SOEs), the reputation of underwriters and sponsoring representatives does not significantly affect the underwriting fees. In the IPO of non-state-owned enterprises (NSOEs), there is a significantly positive correlation between underwriters’ and sponsoring representatives’ reputation and underwriting fees. Further research results show that, on the one hand, the effect of underwriters’ and sponsoring representatives’ reputation on underwriting fees is not significant in the IPO of NSOEs with political connection. On the other hand, underwriting fees are positively associated with underwriters’ and sponsoring representatives’ reputation in the IPO of NSOEs without political connection.

Research limitations/implications

The sponsoring representative’s fee is not disclosed separately, which makes it difficult to distinguish the incremental effect from underwriter’s services and reputation.

Practical implications

NSOEs relative to SOEs are more likely to pay higher underwriting fees for hiring underwriter and sponsoring representative with better reputation during the process of IPO.

Social implications

The reputation of underwriter and sponsoring representative does not matter to SOEs but does matter to NSOEs. However, NSOEs’ political connection affects underwriter fees.

Originality/value

This paper provides new evidence of sponsoring representatives’ reputation and political connection on the underwriting fees in the IPO in Chinese SOEs and NSOEs.
Instant death, slow death and the consequences of assumptions about prolonged dormancy for plant population dynamics
Authors: Alahuhta Kirsi , Crone Elizabeth , Ettinger Ailene , Hens Hilde , Jäkäläniemi Anne , Tuomi Juha
Published: November 2016

Many perennial plants experience prolonged dormancy, meaning they do not grow above‐ground for one or several growing seasons. When plants disappear (fail to sprout) and have not been recorded to re‐emerge, they either have died or are alive and dormant. In demographic studies of such species, researchers have been forced to make assumptions about death versus dormancy. Little is known about the consequences of these assumptions for predictions from the population models used in the studies.

Here, we define survival of dormancy‐prone plants in three distinct ways: Separate, Instant and Slow death. In the Separate death model, plants are assumed to die either in emergent or in dormant stages. Death can also be described as a process of disappearance followed by dying, either in the first year below‐ground (Instant death) or with constant mortality rate in any given dormant year (Slow death). Using simulated data with known parameter values, we test whether survival and re‐emergence rates are confounded in these life‐history models.

Using a general model and models for two orchid species (Epipactis atrorubensandIsotria medeoloides), we test how different assumptions about dormancy (Instant and Slow death) affect predictions about population dynamics: population growth rate, generation time, relative reproductive values, life expectancies, and sensitivity and elasticity of population growth rate to stage transitions and vital rates.

Our results confirm that survival and re‐emergence rates of dormancy‐prone plant species are difficult to estimate; parameters were separable only with the assumptions of Instant and Slow death. Both theoretical and empirical analyses show that the predictions of population growth rate and generation time do not depend on the assumptions made about the fate of the plants after their disappearance.

Synthesis. Assumptions about dormancy affect some, but not all predictions, about plant population dynamics. In the studies of species with unobservable stages, assumptions about dormancy should be carefully defined and possible consequences of these assumptions for the predictions of the population model should be evaluated. Nonetheless, if we are only interested in overall population viability,ad hocmodels of prolonged dormancy are sufficient as a first step.
Tolerability, pharmacokinetics and antiviral activity of rHSA/IFNα2a for the treatment of chronic hepatitis B infection
Authors: Ding Yanhua , Lou Jinfeng , Chen Hong , Li Xiaojiao , Wu Min , Li Cuiyun , Liu Jingrui , Liu Chengjiao , Li Qingmei , Zhang Hong , Niu Junqi
Published: November 2016

Aims

A recombinant human serum albumin‐interferon alpha2a fusion protein (rHSA/IFNα2a) is expected to extend the half‐life of IFNα2a. This study aims to evaluate the tolerability, safety and efficacy of rHSA/IFNα2a.

Methods

This is an open, randomized, positive control, multiple‐dose ascending Phase Ib study. A panel of 32 treatment naïve and non‐cirrhotic chronic hepatitis B patients were divided into four cohorts, and each received 600, 750 or 900 μg of rHSA/IFNα2a or 180 μg of PEG‐IFNα2a for 3 months. Tolerability, pharmacokinetics and antiviral responses were assessed.

Results

Thirty‐one of 32 enrolled patients completed the treatment study. The rHSA/IFNα2a treatment was better tolerated than the PEG‐IFNα2a 180 μg treatment, as evidenced by blood cell counts and higher serum albumin levels. Half‐life (t1/2) of rHSA/IFNα2a was estimated to be 120–140 h, and is potentially suitable for a dosing interval of 2 weeks or longer. Pharmacokinetics of the last dose between rHSA/IFNα2a 750 μg and PEG‐IFNα2a 180 μg, with the exception of t1/2, was comparable, and a similar kinetics of inhibiting HBV DNA replication was observed in both groups. Mean reductions in serum HBV DNA levels after treatment were −1.32, −2.13, −1.10 and −2.48 log10 IU/ml in the 600, 750 and 900 μg rHSA/IFNα2a groups and PEG‐IFNα2a group, respectively.

Conclusions

The rHSA/IFNα2a treatment was well tolerated and can be administered biweekly. Similar efficacy in inhibiting HBV replication was observed in both PEG‐IFNα2a and rHSA/IFNα2a 750 μg groups.
Networks, trust, and risk mitigation during the American Revolutionary War: a case study
Authors: Downs Carolyn
Published: November 2016

This article takes a case study approach to the question of how entrepreneurs developed and used networks to support trade during the American Revolutionary War (American War of Independence). Using the business letter books of Daniel Eccleston of Lancaster, covering January 1780 to December 1781, the article shows how he used trust‐building activities and developed open networks in Britain and the West Indies in order to build, sustain, maintain, and diversify his commercial activities to reduce risk and develop new opportunities. Eccleston's letters illustrate a competitive market in which entrepreneurs helped drive the industrial revolution through stimulating demand and encouraging trade. They show that mutual trust was the foundation of strong networks, and that networks were significant in underpinning entrepreneurial success through allowing the mitigation of business risk and offering the opportunity for diversification supported by the network. The article makes use of the work of Casson, Pearson and Richardson, and Wilson and Pop.
Distinct T helper cell dependence of memory B‐cell proliferation versus plasma cell differentiation
Authors: Zabel Franziska , Fettelschoss Antonia , Vogel Monique , Johansen Pål , Kündig Thomas M. , Bachmann Martin F.
Published: November 2016

Several memory B‐cell subclasses with distinct functions have been described, of which the most effective is the class‐switched (CS) memory B‐cell population. We have previously shown, using virus‐like particles (VLPs), that the proliferative potential of these CS memory B cells is limited and they fail to re‐enter germinal centres (GCs). However, VLP‐specific memory B cells quickly differentiated into secondary plasma cells (PCs) with the virtue of elevated antibody production compared with primary PCs. Whereas the induction of VLP+ memory B cells was strongly dependent on T helper cells, we were wondering whether re‐stimulation of VLP+ memory B cells and their differentiation into secondary PCs would also require T helper cells. Global absence of T helper cells led to strongly impaired memory B cell proliferation and PC differentiation. In contrast, lack of interleukin‐21 receptor‐dependent follicular T helper cells or CD40 ligand signalling strongly affected proliferation of memory B cells, but differentiation into mature secondary PCs exhibiting increased antibody production was essentially normal. This contrasts with primary B‐cell responses, where a strong dependence on CD40 ligand but limited importance of interleukin‐21 receptor was seen. Hence, T helper cell dependence differs between primary and secondary B‐cell responses as well as between memory B‐cell proliferation and PC differentiation.
Maneuvering for Paper: Physical and Social Experiences of Bureaucracy in Venezuelan Amazonia
Authors: Penfield Amy
Published: November 2016

El presente artículo explora un caso de aprendizaje de la burocracia venezolana, que los Sanema experimentan a través de su participación en los proyectos sociales de la Revolución Bolivariana de Chávez. Este análisis se enfoca en la capacidad de maniobra que genera el papeleo burocrático, y contribuye a la comprensión de las formas de movilidad y la experiencia del Estado de manera somática en la Amazonía contemporánea. Los nuevos patrones de movimiento que involucran un desplazamiento hacia y desde las ciudades, los trámites cotidianos y maniobras efectuadas en diversas esferas sociales, no solo deben entenderse en relación con el Estado y su omnipresencia burocrática, sino también como prácticas congruentes con las costumbres tradicionales de ‘viajar en busca de conocimiento’ que involucran un vínculo estrecho entre movilidad física y social. Así, los Sanema utilizan la experiencia burocrática adquirida en este ambiente político para conseguir sus propios objetivos, en lugar de aquellos del Estado.
Increasing Prevalence of US Elementary School Gardens, but Disparities Reduce Opportunities for Disadvantaged Students
Authors: Turner Lindsey , Eliason Meghan , Sandoval Anna , Chaloupka Frank J.
Published: November 2016

ABSTRACT

BACKGROUND

We examined the prevalence of school garden programs at US public elementary schools. The study examined time trends, demographic and regional disparities, and associations with related programs such as farm‐to‐school.

METHODS

Annual surveys were gathered from nationally representative samples of elementary schools between 2006‐2007 and 2013‐2014. Annual samples ranged from 553 to 748 schools.

RESULTS

The prevalence of gardens increased steadily from 11.9% in 2006‐2007 to 31.2% in 2013‐2014 (p < .001). In multivariate logistic regressions the prevalence of garden programs varied significantly by school characteristics. Gardens were more prevalent in the west than in other regions. Gardens were less prevalent at schools serving higher proportions of lower‐income students, and were more prevalent at urban schools than in suburbs, towns, or rural areas. Gardens were more common at schools with farm‐to‐school programs. Gardens also were associated with offering formal classroom‐based nutrition education.

CONCLUSIONS

Garden programs in elementary schools have increased over time, but there is room for wider implementation, particularly at schools serving lower‐income students. Given the role of childhood in establishing food preferences and dietary consumption habits, such programs are important and can reinforce the messages imparted through nutrition education.
Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C.Cheng. 1. Evidence from pressure‐volume curve analysis of dead tissue.
Authors: Yang Dongmei , Pan Shaoan , Ding Yiting , Tyree Melvin T.
Published: November 2016

This paper provides a mini‐review of evidence for negative turgor pressure in leaf cells starting with experimental evidence in the late 1950s and ending with biomechanical models published in 2014. In the present study, biomechanical models were used to predict how negative turgor pressure might be manifested in dead tissue, and experiments were conducted to test the predictions. The main findings were as follows: (i) Tissues killed by heating to 60 or 80 °C or by freezing in liquid nitrogen all became equally leaky to cell sap solutes and all seemed to pass freely through the cell walls. (ii) Once cell sap solutes could freely pass the cell walls, the shape of pressure‐volume curves was dramatically altered between living and dead cells. (iii) Pressure‐volume curves of dead tissue seem to measure negative turgor defined as negative when inside minus outside pressure is negative. (iv) Robinia pseudoacacia leaves with small palisade cells had more negative turgor than Metasequoia glyptostroboides with large cells. (v) The absolute difference in negative turgor between R. pseudoacacia and M. glyptostroboides approached as much as 1.0 MPa in some cases. The differences in the manifestation of negative turgor in living versus dead tissue are discussed.
Unforgiving motivations among divorced parents: Moderation of contact intention and contact frequency
Authors: KLUWER ESTHER S.
Published: November 2016

This research tests the prediction that unforgiving motivations (feelings of revenge and distance) toward the ex‐spouse are associated with less reported well‐being of divorced parents and their children when the intent to maintain contact with the ex‐partner is high rather than low. It is also predicted that unforgiving motivations are associated with more reported conflict with the ex‐partner and subsequently with less reported well‐being of their children when the actual contact frequency with the ex‐partner is high rather than low. Results from an Internet sample of Dutch divorced parents (N = 108) largely support these predictions. It is concluded that unforgiving motivations can have both intrapersonal and interpersonal negative effects for divorced parents, but only when contact is frequent or intended.
Heat Dissipation Beyond 1 kW/cm2 With Low Pressure Drop and High Heat Transfer Coefficient for Flow Boiling Using Open Microchannels With Tapered Manifold
Authors: Kalani Ankit , Kandlikar Satish G.
Published: November 2016

Heat dissipation beyond 1 kW/cm2 accompanied with high heat transfer coefficient and low pressure drop using water has been a long-standing goal in the flow boiling research directed toward electronic cooling application. In the present work, three approaches are combined to reach this goal: (a) a microchannel with a manifold to increase critical heat flux (CHF) and heat transfer coefficient (HTC), (b) a tapered manifold to reduce the pressure drop, and (c) high flow rates for further enhancing CHF from liquid inertia forces. A CHF of 1.07 kW/cm2 was achieved with a heat transfer coefficient of 295 kW/m2°C with a pressure drop of 30 kPa. Effect of flow rate on CHF and HTC is investigated. High speed visualization to understand the underlying bubble dynamics responsible for low pressure drop and high CHF is also presented.
Experimental and Numerical Study of the Pressure Drop in Transonic Micronozzle Flows Across Multiple Flow Regimes
Authors: Gomez Herrera Juan E. , Groll Rodion
Published: November 2016

In the present work, the behavior of a millimeter-scale cold-gas thruster operating with the noble gases neon, argon, krypton and xenon is investigated both experimentally and numerically. In the experimental setup, the cold-gas thruster operates under vacuum conditions and the pressure drop in the system is measured at several fixed mass flow rates ranging between 0.178 mg/s and 3.568 mg/s. The estimated Knudsen numbers for all the studied cases are above the continuum flow limit 0.01. At the higher mass flow rates the studied flows are in the slip-flow regime while at the lower mass flow rates, the transition regime is reached. The experimental pressure results are compared with numerical simulations based on the compressible Navier-Stokes equations with a no-slip boundary condition and with simulations based on the Direct Simulation Monte Carlo (DSMC) method. At high values of Kn, the pressure results of the Navier-Stokes based simulations show high deviations from both the DSMC and the experimental results. This is a consequence of the discrepancy between the no-slip boundary condition used for the Navier-Stokes simulations and gas rarefaction effects in the micronozzle becoming dominant at the lower mass flow rates.

Based on the comparison between the experimental results and the Navier-Stokes based simulations, a Knudsen-dependent correcting function with four gas-independent accommodation coefficients is developed. The accommodation coefficients allow the accurate estimation of the actual pressure drop along the nozzle based on usually computationally inexpensive Navier-Stokes simulations with no-slip boundary conditions. The flexibility of the proposed approach is advantageous for the study of experimental setups operating at a large range of mass flow rates, where several flow regimes might exist, provided that a rigorous numerical distinction between continuum, slip-flow and transition regime is not essential.
Enhancement of Mass and Heat Transfer Using Herringbone-Inspired Microstructures for Application in Microfluidic Redox Flow Cells
Authors: Marschewski Julian , Ruch Patrick , Michel Bruno , Poulikakos Dimos
Published: November 2016

Enhancing advection is of uttermost importance in many laminar microfluidic devices in order to thin boundary layers which limit both mass and heat transfer. We address this challenge by integrating herringbone-inspired flow promoters in channels for microfluidics. Due to the small dimensions of microchannels, microfluidic devices typically experience a purely laminar flow regime and are thus limited by diffusion. By augmenting diffusion limited transport to the wall of species and heat with advective transport mechanisms, the performance per unit area of microfluidic devices can be significantly improved. In the present contribution, we demonstrate that herringbone microstructures are a very promising class of flow promoters to passively increase both mass transfer in chemical reactions as well as heat transfer within the same device. This combined use of the same passive flow promoter microstructure is for example attractive for on-chip microfluidic redox flow cells for microprocessor power delivery with integrated cooling by using the same electrolyte as an energy carrier and as a coolant.
Effect of Nanostructures and Wettability on the Instability of Thin Water Films on a Solid Surface: A Molecular Dynamics Study
Authors: Sun Liyong , Zhou Jun , Jones Phil
Published: November 2016

Molecular dynamics simulations are performed to investigate the stability of thin water films on square gold nanostructures of varying depth and wavelength. The critical film thickness of breakup is shown to increase linearly with nanostructure depth, and is not affected by nanostructure wavelength. In addition, the wettability of the gold surface is controlled from superhydrophilic to hydrophobic by altering the energy parameter of the solid-liquid potential, and the equilibrium contact angle for each energy parameter is calculated using a droplet spreading simulation. Four different energy parameters of the solid-liquid potential are investigated. The ratio of the energy parameter to the energy parameter of water and gold is 1, 0.5, 0.25 and 0.1. The case for ratio of 1 represents water on superhydrophilic gold surfaces. The relationship between the critical film thickness of breakup and the equilibrium contact angle is demonstrated. The results of the present work will provide guidelines for nanostructure design for controlling thin film stability.
Microfluidic Measurements of Drug Dissolution Using a Quartz Crystal Microbalance
Authors: Gulati Shelly , Bonoan Janpierre A. , Schesser Kylee V. , Arucan Joshua F. , Li Xiaoling
Published: November 2016

This work describes a microfluidic drug dissolution testing method that was developed using a commercial quartz crystal microbalance (QCM) resonator combined with an axial microfluidic flow cell. Dissolution testing is used to obtain temporal dissolution profiles of drugs, which provide information on the bioavailability or the drug’s ability to be completely dissolved and then absorbed and utilized by the body. Feasibility of the QCM dissolution testing method was demonstrated using a sample drug system of thin films of benzoic acid dissolved in water, capturing the drug dissolution profile under different microflow conditions. Our analysis method uses the responses of resonance frequency and resistance of the quartz crystal during dissolution testing to determine the characteristic profiles of benzoic acid dissolved over a range of microflows (10–1000 μL/min). The initial dissolution rates were obtained from the characteristic profiles and found to increase with higher flow rates. This aligns with the expected trend of increased dissolution with higher hydrodynamic forces. The QCM-based microfluidic drug dissolution testing method has advantages over conventional dissolution test methods, including reduced sample sizes, rapid test durations, low resource requirements, and flow conditions that more closely model in vivo conditions.
Thermal Performance Analysis of Hybrid Jet Impingement/Microchannel Cooling for Concentrated Photovoltaic (CPV) Cells
Authors: Husain Afzal , Ariz Mohd , Al-Azri Nasser A. , Al-Rawahi Nabeel Z. H. , Ansari Mohd. Z.
Published: November 2016

The increase in the CPV temperature significantly reduces the efficiency of CPV system. To maintain the CPV temperature under a permissible limit and to utilize the unused heat from the CPVs, an efficient cooling and transportation of coolant is necessary in the system. The present study proposes a new design of hybrid jet impingements/microchannels heat sink with pillars for cooling densely packed PV cells under high concentration. A three-dimensional numerical model was constructed to investigate the thermal performance under steady state, incompressible and laminar flow. A constant heat flux was applied at the base of the substrate to imitate heated CPV surface. The effect of two dimensionless variables, i.e., ratios of standoff (distance from the nozzle exit to impingement surface) to jet diameter and jet pitch to jet diameter was investigated at several flow conditions. The performance of hybrid heat sink was investigated in terms of heat transfer coefficient, pressure-drop, overall thermal resistance and pumping power. The characteristic relationship between the overall thermal resistance and the pumping power was presented which showed an optimum design corresponding to S/Dj = 12 having lower overall thermal resistance and lower pumping power.
Influence of Physical Properties of Phases on Hydrodynamics and Mass Transfer Characteristics of a Liquid-Liquid Circular Microchannel
Authors: Sattari-Najafabadi Mehdi , Sundén Bengt , Wu Zan , Nasr Esfahany Mohsen
Published: November 2016

The influences of operating conditions and physical properties of the two phases on the hydrodynamics and mass transfer in a circular liquid-liquid microchannel have been investigated. The polytetrafluoroethylene (PTFE) microchannel has an internal diameter of 0.7 mm and a T-shaped mixing junction. Sodium hydroxide solution was used as the aqueous phase. N-hexane and toluene were employed as the organic phases to investigate the effect of physical properties. Regarding the results, at constant total flow rate, raising the flow rate ratio enhanced the overall volumetric mass transfer coefficient. Using toluene as the organic solvent enhanced the overall volumetric mass transfer coefficient in average by 64.7% and 100.27% comparing to n-hexane-water at flow rate ratio of 1 and 0.5, respectively. This increment resulted in a decrement in the required mass transfer time and length in the microchannel. The length of the slugs had no considerable variation as n-hexane was replaced with toluene. Thus, the significant improvement of the overall volumetric mass transfer coefficient was because of the increment of the overall mass transfer coefficient, not the specific interfacial area.
Investigating the Structure of the Bi-Layered Gas Diffusion Layer Using X-Ray Computed Tomography
Authors: Banerjee Rupak , Liu Hang , Hinebaugh James , Bazylak Aimy
Published: November 2016

One of the most important objectives of the GDL in a PEM fuel cell is the transport of reactant gases from the gas flow channels to the reaction sites at the catalyst layer. Most state-of-the-art GDLs are composed of a carbon fiber paper coated with a microporous layer composed of carbon nano-particles. This bi-layered GDL structure has been proven to provide significant improvement to the performance of PEM fuel cells.

In order to improve our understanding of reactant transport through these GDL materials, it is important for us to characterize the structure of these materials. In this study, we use X-ray Computed Tomography (X-CT) to study the structure of the bi-layered GDL at the microscale. This work presents a unique segmentation routine developed in-house to identify the distinct components of the bi-layer GDL, isolating the carbon fiber, the microporous layer and the void regions as individual phases.

Two commercially available GDL samples, SGL 35BA and SGL 35BC are segmented with this novel algorithm to obtain unique porosity profiles. The MPL is identified separately in SGL 35BC along with the fibrous substrate region. It is observed that in the case of this sample, there is no region where only the MPL is present. The entire thickness of the MPL region is within the substrate region with fibers present throughout the MPL region. The substrate region is 300 μm thick while the MPL is present up to 200 μm from one side.
Multi-Scale Modeling and Hybrid Atomistic-Continuum Simulation for Condensation of Gas Flow in a Micro-Channel
Authors: Vu Van Huyen , Trouette Benoît , To Quy-Dong , Chenier Eric
Published: November 2016

In this paper, we present a hybrid Molecular Dynamics/Finite Volume method to study flows in micro-channel involving phase changes. For the simulation of long micro/nano-channels, we adopt multiple molecular blocks along the flow direction, what enables the accurate capture of the velocity and temperature variations from the inlet to the outlet. The validity of the hybrid method is shown by comparisons with both analytical solutions and Finite Volume simulations. This method is then applied successfully to the study the hydrodynamic and thermal development of a fluid flow in a long micro/nano-channel with condensation.
Design of an Experimental Setup to Investigate an Oscillating and Evaporating Meniscus Using a Feedback Control Loop
Authors: Recinella Alyssa , Baldwin Joseph , Krouse Charles , Walkowiak Robert , Raghupathi Pruthvik , Kandlikar Satish G.
Published: November 2016

Nucleate boiling is one of the most efficient methods to dissipate heat. However, the complex physics of heat transfer near the contact line is not well understood. Due to the difficulty in measuring and analyzing heat transfer around a bubble at high heat fluxes, novel approaches must be taken. This paper focuses on the design of an experimental setup used to simulate heat transfer at the contact line by studying an oscillating meniscus on a heated surface. A preliminary design of the experimental test setup is described in this paper. The experimental test setup will be composed of a liquid injection system with a needle, an oscillator, a heated surface, and a sensor to measure the meniscus volume. A feedback loop will be used to control the liquid injection system and prevent dry out or flooding during evaporation. Furthermore, a conic speaker will be used to induce oscillations at a range of 10–200 Hz. These oscillations simulate liquid displacement during bubble nucleation, growth, and bubble departure. Finally, a sensor that measures the volume of the liquid will be connected to the heated plate and the needle in order to measure the volume of the meniscus while oscillating. A fundamental understanding of the heat transfer in the contact line region is expected.
The Leidenfrost Phenomenon on Silicon Nanowires
Authors: Auliano Manuel , Fernandino Maria , Zhang Peng , Dorao Carlos Alberto
Published: November 2016

In this paper, the effect of Si nanowires on the Leidenfrost point on impacting water droplet is presented. In the Leidenfrost regime, the low thermal conductivity of the vapor layer hinders the heat transfer from the hot surface. Nanostructured surfaces can dramatically increase the Leidenfrost temperature improving heat transfer at high temperature. To determine the point of the minimum efficient heat transfer, the droplet lifetime method was employed for both the polished and processed surfaces. The cooling performance was discussed in terms of the droplet evaporation time. The surface with the tallest NWs structure yielded the highest shift in the Leideinfrost point, about 156 % higher than a plain Si surface.
Generation of Uniform Liquid Droplets in a Microfluidic Chip Using a High-Speed Gaseous Microflow
Authors: Tirandazi Pooyan , Hidrovo Carlos H.
Published: November 2016

Miniaturized laboratory-on-a-chip systems have been extensively developed over the past decade as promising tools for a wide range of applications, specifically in chemical synthesis and biomedical diagnostics. Droplet-based microfluidic systems have become ubiquitous in such applications by providing essential tools to perform rapid as well as high throughput measurements on small volumes of fluids. Thus far, the majority of the research endeavors have been focused on liquid-liquid systems for generating microscale drops (typically water in oil). Droplets generated in liquid-liquid microfluidic systems tend to be very uniform in size, and due to high surface area to volume ratio of micro-droplets, heat and mass transfer occurs at higher rates as compared to continuous-flow microfluidics. Generation of droplets in a gaseous medium, on the other hand, have been widely used in applications that involve open environment liquid spraying, such as ink-jet printers. However, usually in such applications there is no control over either the size or frequency of the generated droplets, and as a result droplets formed in these systems are widely distributed in size. Here we demonstrate an alternative scheme for controlled generation of liquid droplets in a microfluidic chip using a high speed gas stream. We have incorporated the inertial effect of a high-speed gaseous medium with the flow-focusing geometry, fabricated in a PDMS chip, in order to generate droplets with controlled size. Flow regimes involved in this scheme may be divided in three main regions i.e. co-flow, jetting, and dripping among which only dripping regime is capable of producing distinct aqueous droplets in the channel. It should be noted that poor surface conditions and high gas flow rates may result in generation of satellite droplets together with the main droplet in the dripping region, which substantially affects the monodispersity of the droplets. The generated drops were collected thereafter and it is shown that monodisperse droplets with known size ranging from 50 μm to 100 μm in diameter can be achieved within the dripping flow regime. We believe this method offers beneficial opportunities for the next generation of Lab-on-a-chip devices in which the introduction of a gaseous medium is required, namely oxidation, detection of airborne particles, and formation of micro-particles and micro-gels. Furthermore, the high speed droplets generated in this method represent the basis for a new approach based on droplet pair collisions for fast efficient micromixing which provides a significant development in modern LOC and mTAS devices.
Investigation of Mixing in Colliding Droplets Generated in Flow-Focusing Configurations Using Laser Induced Fluorescence
Authors: Bedding David , Hidrovo Carlos
Published: November 2016

Increasing the mixing rate of fluid droplets within modern lab-on-a-chip technology is being increasingly stressed by members of the biological and chemical communities that wish to study reaction kinetics and mechanisms. Faster mixing allows for a more complete analysis of a wider range of chemical and biological reactions, and due to this technologies ability to help better characterize these reactions, there is an increasingly large number of demands for chips that can fully mix droplets in an order of microseconds. High speed mixing like this is difficult to characterize using standard microscopy. This article looks at how to achieve high-speed droplet collisions using flow focusing geometry, and how these collisions are visualized using a novel laser-imaging system.

Microchannel droplet mixing is plagued with severe limitations due to the restricted microchannel lengths between elements within the chips, as well as strong surface tension forces involved and low Reynolds numbers that are found in all microchannel flow. These characteristics further reduce the rate of mixing, and thus the rate of diffusion, between the two colliding droplets. Previous attempts at mixing droplets in microchannels stemmed from two methods; hydrodynamic flow focusing, and chaotic advection mixing, this later approach leading to the advent of inertial-based droplet micromixer technology. Both of these techniques rely on rapidly decreasing the diffusion length scales between the two mixing droplets through the creation of striations. Generating these droplets while developing a method for quantifying high-speed diffusion mixing is the main focus of this article. For this study, liquid droplets are formed in a flow-focusing configuration using a high speed gaseous flow and collided at angled Y-junctions in the microchannel fabricated in PDMS. In order to determine the instantaneous rates of mixing within the internal droplet flow during the collision process, an experimental setup using epi-fluorescence microscopy in conjunction with high speed laser-induced fluorescence was developed. This setup is capable of tracking and recording fluorophore concentration within the droplets during the collision and coalescence process in multiple images. The droplets are distinguished using differing concentrations of fluorophore which correspond to differing levels of fluorescent intensity while the colliding droplets remain unmixed, and consistent levels of fluorescent intensity when the colliding droplets are fully mixed. These images are then processed using a statistical analysis software to determine both the diffusion length scale as well as the quasi-instantaneous rate of mixing at all times during the collision process.
Transient Effects in High Power Electroosmotic Pumps
Authors: Tawfik Mena E. , Gupta Shashwat , Stern Aaron , Diez F. J.
Published: November 2016

On generating high electroosmotic flows in microfluidic pumps under applied DC voltage, the flow rate and the drawn current drop with time. When generating high electroosmotic flows using microfluidic pumps under applied DC voltage, the flow rate and current draw decrease with time. The electroosmotic (EO) pump efficiency decreases with time due to flow rate deterioration. In order to study the transient effect in EO pumps, the mass transport of ions in the membrane is investigated. Ions mass transport are affected by the membrane surface charge, ion diffusion, ion migration and flow convection. Many studies investigate the mass transport in ion selective membranes, micro-channels, and nano-channels without focus on the transient effects at high electric fields. In most of these studies, the Poisson-Nernst-Plank and the Naiver stokes equations are used to model the ion transport in electrokinetic devices. Without applying simplifying assumptions, these system of equations can be only solved numerically. A theoretical model, based on diffusion and ion migration, is developed to predict the current drop and experiments are conducted to verify this model. EO flow can be neglected when there is no membrane installed between the pump electrodes (electrochemical cell). The current drop is predicted under no flow conditions using the advection diffusion equation and it solved analytically using the Ogata and Banks solution. In order to predict the current drop in the EO pump under flow conditions, the Helmholtz-Smoluchowski equation is used to calculate the EO flow velocity. This equation holds under thin electrical double layer assumption and small zeta potential.

The current drop has been calculated theoretically and compared with the experimental data. The ion screening and depletion at the electrodes result in increasing the EO pump total resistance and decrease the total current. The calculated current drop time scale has been found to be in the order of 100 seconds under no flow conditions. As flow rate increases, the flow rate contributes to the mass transport of ions (convection current) and screens the ions faster, leading to a decrease in the current drop time scale. On the other hand, by increasing the fluid molar concentration, the current drop is much slower as more ions are available and need more time to be depleted. The current drop time scale decreases rapidly as higher DC voltages are applied, leading to low efficiency. The ion transport can be limited by applying a pulse voltage waveform instead of DC voltage, leading to more stable flow rate, current and hence constant EO efficiency. The pulse voltage waveform allows the ions to diffuse back from high to low concentration regions during the off-time, preventing ion depletion and current drop.
A Two-Phase Model for Analysis of Blood Flow and Rheological Properties in the Elastic Microvessel
Authors: Lin Xiaohui , Zhang Chibin , Wang Changbao , Chu Wenquan , Wang Zhaomin
Published: November 2016

The blood in microvascular is seemed as a two-phase flow system composed of plasma and red blood cells (RBCs). Based on hydrodynamic continuity equation, Navier-Stokes equation, Fokker-Planck equation, generalized Reynolds equation and elasticity equation, a two-phase flow transport model of blood in elastic microvascular is proposed. The continuous medium assumption of RBCs is abandoned. The impact of the elastic deformation of the vessel wall, the interaction effect between RBCs, the Brownian motion effect of RBCs and the viscous resistance effect between RBCs and plasma on blood transport are considered. Model does not introduce any phenolmeno-logical parameter, compared with the previous phenolmeno-logical model, this model is more comprehensive in theory. The results show that, the plasma velocity distribution is cork-shaped, which is apparently different with the parabolic shape of the single-phase flow model. The reason of taper angle phenomenon and RBCs “Center focus” phenomenon are also analyzed. When the blood vessel radius is in the order of microns, blood apparent viscosity’s Fahraeus-Lindqvist effect and inverse Fahraeus-Lindqvist effect will occur, the maximum of wall shear stress will appear in the minimum of diameter, the variations of blood apparent viscosity with consider of RBCs volume fraction and shear rate calculated by the model are in good agreement with the experimental values.
Phonetic imitation of coarticulatory vowel nasalization
Authors: Zellou Georgia , Scarborough Rebecca , Nielsen Kuniko
Published: November 2016

This study investigates the spontaneous phonetic imitation of coarticulatory vowel nasalization. Speakers produced monosyllabic words with a vowel-nasal sequence either from dense or sparse phonological neighborhoods in shadowing and word-naming tasks. During shadowing, they were exposed to target words that were modified to have either an artificially increased or decreased degree of coarticulatory vowel nasality. Increased nasality, which is communicatively more facilitative in that it provides robust predictive information about the upcoming nasal segment, was imitated more strongly during shadowing than decreased nasality. An effect of neighborhood density was also observed only in the increased nasality condition, where high neighborhood density words were imitated more robustly in early shadowing repetition. An effect of exposure to decreased nasality was observed during post-shadowing word-naming only. The observed imitation of coarticulatory nasality provides evidence that speakers and listeners are sensitive to the details of coarticulatory realization, and that imitation need not be mediated by abstract phonological representations. Neither a communicative account nor a representational account could single-handedly predict these observed patterns of imitation. As such, it is argued that these findings support both communicative and representational accounts of phonetic imitation.
Phosphoarginine for degradation
Authors: VanHook Annalisa M.
Published: November 2016

Arginine phosphorylation targets
Bacillus subtilis
proteins for proteolytic degradation in response to heat shock.
Misbehaving without MeCP2
Authors: Gough Nancy R.
Published: November 2016

The behavioral effects of loss or dysfunction of MeCP2 involve HDAC1 and -2 in the striatum and HDAC3 in the hippocampus.
Analysis of a suppressor mutation ssb (kinC) of sur0B20 (spo0A) mutation in Bacillus subtilis reveals that kinC encodes a histidine protein kinase
Authors: Kobayashi K , Shoji K , Shimizu T , Nakano K , Sato T , Kobayashi Y
Published: November 2016

sur0B20 is a mutation that suppresses the effects of spo0B delta B or spo0F221 mutations in Bacillus subtilis, sur0B20 is an allele of the spo0A gene (Glu-14 to Val-14 conversion) and restores the sporulation of spo0B or spo0F mutants to the wild-type level. Here, we report the isolation of suppressor mutations of sur0B20 (ssb). One of these mutations, ssb-12, severely impairs the suppressor activity of sur0B20. A 2.5-kbp MboI fragment which complements the ssb-12 mutation was cloned by the prophage transformation method using phi CM as a vector. Nucleotide sequencing of the fragment revealed two open reading frames (orf1 and orf2). Gene disruption and complementation experiments showed that orf2 is the ssb gene. ssb was shown to encode a protein with a molecular weight of 48,846 (428 amino acid residues) showing strong similarity to transmitter kinases, especially KinA, of two-component regulatory systems. Therefore, ssb was renamed kinC. Deletion of kinC had no observable effect on sporulation. kinC transcription was induced at the onset of sporulation, probably from a sigma A-dependent promoter, and its expression was shut off at T3. DNase I protection experiments showed that the Spo0A protein binds to two adjoining sites in the kinC promoter region with different affinities. These results suggest that kinC expression might be regulated by Spo0A.
Gin mutants that can be suppressed by a Fis-independent mutation
Authors: Spaeny-Dekking L , Schlicher E , Franken K , van de Putte P , Goosen N
Published: November 2016

The Gin invertase of bacteriophage Mu mediates recombination between two inverted gix sites. Recombination requires the presence of a second protein, Fis, which binds to an enhancer sequence. We have isolated 24 different mutants of Gin that are impaired in DNA inversion but proficient in DNA binding. Six of these mutants could be suppressed for inversion by introduction of a second mutation, which when present in the wild-type gin gene causes a Fis-independent phenotype. Only one of the six resulting double mutants shows an inversion efficiency which is comparable to that of the wild-type Gin and which is independent of Fis. The corresponding mutation, M to I at position 108 (M108I), is located in a putative alpha-helical structure, which in the homologous gamma delta resolvase has been implicated in dimerization. The properties of the M108I mutant suggest that in Gin this dimerization helix might also be the target for Fis interaction. The five other mutants that show a restored inversion after introduction of a Fis-independent mutation appear to be completely dependent on Fis for this inversion. The corresponding mutations are located in different domains of the protein. The properties of these mutants in connection with the role of Fis in inversion will be discussed.