bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of two dimensional composite surface grating structures with applications to low loss microacoustic resonators
Authors: Yantchev Ventsislav , Plessky Victor
Published: August 2013

2D composite grating building blocks with hexagonal symmetry are proposed and analyzed as efficient reflectors and transducers in the design of low loss surface acoustic wave (SAW) resonators. Eigen-frequency and frequency response finite element analyses are used to study the propagation and excitation characteristics of SAWs in the 2D composite structures. The proposed structures have the advantage of being compatible with the planar SAW technology, while introducing design principles reminiscent to the semiconductor devices. More specifically, the frequency bandgap characteristics of the various resonator building blocks can be adjusted so that losses related to the SAW diffraction, impedance mismatch, and parasitic SAW radiation from the electrical contacts can be suppressed. Three distinct types SAW resonant topologies employing 2D gratings are deduced from the analytical results.
Edge state in epitaxial nanographene on 3C-SiC(100)/Si(100) substrate
Authors: Velez-Fort E. , Silly M. G. , Belkhou R. , Shukla A. , Sirotti F. , Ouerghi A.
Published: August 2013

Epitaxial nanographene grown on SiC substrate is of great interest for electronic and optoelectronic applications. The shape and the size of nanographene dictates its electrical, optical, magnetic, and chemical properties including possible edge states and quantum confinement. Here, we report the epitaxial growth of nanographene on 3C-SiC(100) on silicon substrates. Raman spectroscopy determines the nanographene size to be around 20 nm, making it an ideal high edge density sample. Near edge x-ray absorption fine structure of nanographene reveals the appearance of an additional state located at the Fermi level, interpreted as an empty state corresponding to graphene edges.
Electrically driven nanoscale acoustic source based on a two-dimensional electron gas
Authors: Shao Lei , Zhang Meng , Banerjee Animesh , Bhattacharya Pallab K. , Pipe Kevin P.
Published: August 2013

Acoustic emission by a modulated two-dimensional electron gas (2DEG) is studied analytically, numerically, and experimentally. Optical reflectance measurements provide the full acoustic spectrum emitted by a modulated GaN-based 2DEG, including various surface acoustic wave (SAW) modes that propagate with different polarizations and penetration depths within the epitaxial layer structure. A 2DEG is shown to provide a source of SAWs that is several orders of magnitude more intense than an interdigital transducer (IDT) of the same chip area. Furthermore, a 2DEG SAW source is shown to have the ability to switch between different acoustic modes based on applied DC bias conditions.
The effect of magnetocrystalline anisotropy on the domain structure of patterned Fe2CrSi Heusler alloy thin films
Authors: Miyawaki T. , Foerster M. , Finizio S. , Vaz C. A. F. , Mawass M.-A. , Inagaki K. , Fukatani N. , Le Guyader L. , Nolting F. , Ueda K. , Asano H. , Kläui M.
Published: August 2013

The effects of magnetic anisotropy on domain structures in half-metallic Heusler alloy Fe2CrSi thin film elements were investigated using high resolution x-ray magnetic circular dichroism photoemission electron microscopy. The transition of the dominating contribution from the magnetocrystalline anisotropy to the shape anisotropy is observed in square-shaped elements when reducing the size below 2.0–2.5 μm. In particular, we identify in disk-shaped Heusler elements the vortex state as the ground state. The shape-anisotropy dominated, well-defined magnetization configuration shows the potential of the Fe2CrSi Heusler alloy for applications in vortex-core- or domain-wall-devices, where the high spin polarization is desirable.
Photon-modulated multiple-state memory cell in Josephson junction systems
Authors: Ho I-Lin , Shiau Shiue-Yuan
Published: August 2013

This work studies the multiple-state memory cell in weak-coupled Josephson junction systems, allowing for alternative occupations of the quasiparticle (QP) and Cooper pair (CP) in the memory node and presenting its adjustability (between the QP and CP) by electromagnetic modulations. We structure theoretical formulae considering these interactive dynamics by the golden approximation and perform the time evolutions of relevant function operations using Monte Carlo techniques. Numerical results demonstrate switchable hysteretic memory effects for devices under photon radiations or magnetic fields and signify other potential applications, e.g., on interconnections with optical computing systems.
Hybrid nanolaminate dielectrics engineered for frequency and bias stability
Authors: Sahoo S. K. , Patel R. P. , Wolden C. A.
Published: August 2013

Metal-insulator-metal capacitors were fabricated from hybrid alumina-silicone nanolaminates deposited by plasma-enhanced chemical vapor deposition. These two materials have complementary properties that produce dielectrics that are exceptionally stable with respect to frequency and dc bias. 50% alumina-silicone nanolaminates displayed low dielectric loss (tan δ = 0.04) and a negligible quadratic voltage coefficient (α = 7 ppm/V2). Both of these values are exceptionally improved over the properties of the individual components. This performance was achieved in 165 nm thick films that provide both high specific capacitance (30 nF/cm2) and extremely low leakage (∼10−9 A/cm2 at 1 MV/cm).
Reactive molecular dynamic simulations of early stage of wet oxidation of Si (001) surface
Authors: Pamungkas Mauludi Ariesto , Kim Byung-Hyun , Lee Kwang-Ryeol
Published: August 2013

We have investigated the initial stage of oxidation of Si (001) surface by water (H2O) molecules using reactive molecular dynamics (MD) simulation at 300 K and 1200 K without any external constraint on the water molecules. Previously, reported water reaction behaviors on silicon surface by ab initio calculations or experimental observations were reproduced by the present MD simulation. The present simulation further revealed that the hydrogen atom in H2O is more attractive than oxygen atom in O2 to bond with Si, such that it accelerates the dissociation process of H2O. It was also observed that the oxidation reaction was enhanced with increased number of the supplied water molecules. It was suggested that the repulsion between water molecules and their fragments facilitates the dissociation of both water molecules and hydroxyl decomposition on the Si surface. Therefore, the wet oxidation behavior appeared to have more temperature dependence even in the early stage of oxidation.
Ge/Si quantum dots thin film solar cells
Authors: Liu Zhi , Zhou Tianwei , Li Leliang , Zuo Yuhua , He Chao , Li Chuanbo , Xue Chunlai , Cheng Buwen , Wang Qiming
Published: August 2013

Thin film p-i-n solar cells (SCs) with 30 bilayers undoped or p-type self-assembled Ge/Si quantum dots (QDs) were fabricated on n+-Si(001) substrates by ultrahigh vacuum chemical vapor deposition. Compared with the SCs without Ge QDs, the external quantum efficiency in infrared region and the short-circuit current densities of the SCs with Ge QDs increased. However, their open-circuit voltages and efficiencies decreased. The open circuit voltages of p-type Ge/Si QDs SCs recovered significantly at low temperature, which was due to the suppression of recombination centers and longer carrier lifetime.
Hydrogen-related, deeply bound excitons in Mg-doped GaN films
Authors: Juday R. , Fischer A. M. , Huang Y. , Huang J. Y. , Kim H. J. , Ryou J.-H. , Dupuis R. D. , Bour D. P. , Ponce F. A.
Published: August 2013

Luminescence in the near band-edge spectral region of Mg-doped GaN films grown by metalorganic chemical vapor deposition has been studied at liquid-helium temperatures. Radiative transitions at 3.37 and 3.416 eV were observed to evolve in cathodoluminescence spectra during electron-beam irradiation at 5 kV. The intensity of the 3.37 eV peak correlates monotonically with the resistivity of the films. By annealing the films in N2 and N2/H2 atmospheres, the 3.37 and 3.416 eV transitions are shown to be related to hydrogen.
Potential for normally-off operation from GaN metal oxide semiconductor devices based upon semi-insulating GaN
Authors: Sakai Yusuke , Selvaraj S. Lawrence , Oda Osamu , Egawa Takashi
Published: August 2013

The conditions for preparing normally-off GaN devices incorporating semi-insulating (SI) GaN materials are explored. The properties of SI GaN where carbon behaves as a deep level acceptor are predicted using a Shockley diagram. Metal-oxide-semiconductor (MOS) structures based upon these on SI-GaN layers are designed. The bandgap alignment of these structures is analyzed using Poisson equations. Normally-off operation is shown to be possible in devices featuring a thin n-GaN layer and SI-GaN layer, because of a higher conduction band energy. It is also shown that higher threshold voltage can be achieved by reducing the carrier concentration of the n-GaN channel layer.
Genetic correlations of young bull reproductive traits and heifer puberty traits with female reproductive performance in two tropical beef genotypes in northern Australia
Authors: Johnston D. J. , Corbet N. J. , Barwick S. A. , Wolcott M. L. , Holroyd R. G.
Published: August 2013

Genetic correlations of young bull and heifer puberty traits with measures of early and lifetime female reproductive performance were estimated in two tropical beef cattle genotypes. Heifer age at puberty was highly (rg = –0.71 ± 0.11) and moderately (rg = –0.40 ± 0.20) genetically correlated with pregnancy rate at first annual mating (mating 1) and lifetime annual calving rate, respectively in Brahman (BRAH). In Tropical Composite (TCOMP), heifer age at puberty was highly correlated with reproductive outcomes from the first re-breed (mating 2), mainly due to its association with lactation anoestrous interval (rg = 0.72 ± 0.17). Scrotal circumference were correlated with heifer age at puberty (rg = –0.41 ± 0.11 at 12 months in BRAH; –0.30 ± 0.13 at 6 months in TCOMP) but correlations were lower with later female reproduction traits. Bull insulin-like growth factor-I was correlated with heifer age at puberty (rg = –0.56 ± 0.11 in BRAH; –0.43 ± 0.11 in TCOMP) and blood luteinising hormone concentration was moderately correlated with lactation anoestrous interval (rg = 0.59 ± 0.23) in TCOMP. Semen quality traits, including mass activity, motility and percent normal sperm were genetically correlated with lactation anoestrus and female lifetime female reproductive traits in both genotypes, but the magnitudes of the relationships differed with bull age at measurement. Preputial eversion and sheath scores were genetically associated with lifetime calving and weaning rates in both genotypes. Several of the early-in-life male and female measures examined were moderately to highly genetically correlated with early and lifetime female reproduction traits and may be useful as indirect selection criteria for improving female reproduction in tropical breeds in northern Australia.
Characteristics of refugia used by the threatened Australian growling grass frog (Litoria raniformis) during a prolonged drought
Authors: Clemann Nick , Scroggie Michael P. , Smith Michael J. , Peterson Garry N. L. , Hunter David
Published: August 2013

Context
Because they are dependent on water, drought can have a deleterious impact on aquatic-breeding amphibians. One such species, the threatened growling grass frog (Litoria raniformis) occurs in south-eastern Australia, a region that has recently emerged from a decade-long, severe drought.

Aims
We aimed to identify features of drought refugia that facilitate persistence of L. raniformis, so as to provide guidance to natural-resource managers attempting to conserve populations of this species during drought.

Methods
We conducted repeat surveys for L. raniformis at 90 water bodies at the end of the ‘millennium drought’. We recorded the following six environmental variables for each water body: origin (natural or not), type (lotic or lentic), proportion of aquatic vegetation cover, conductivity of water, riparian tree-canopy cover and distance to the nearest woodland. We used occupancy models to relate the presence of L. raniformis to these variables, while accounting for uncertain detection.

Key results
Water-body type (natural or artificial, lentic or lotic) had minimal influence on the probability of occupancy by L. raniformis. We found a strong negative relationship between occupancy and conductivity of water (a surrogate for salinity), and a positive relationship between occupancy and the proportion of aquatic vegetation. We found a negative relationship between detection and the extent of aquatic vegetation, and a mildly negative effect of canopy cover on occupancy.

Conclusions
Habitat characteristics are more important indicators of the quality of drought refugia for L. raniformis than is the type of water body per se. Consequently, we identified aquatic vegetation and salinity as important targets for management when planning the retention, creation or restoration of habitat to facilitate persistence of L. raniformis during drought.

Implications
Our results highlighted aquatic vegetation and water-quality parameters that are likely to facilitate the persistence of L. raniformis during drought. Assessing the effectiveness of our recommendations in an experimental framework would ensure that conservation management of this frog can be refined over time.
Validation and factorial invariance of children's attraction to physical activity (CAPA) scale in Portugal
Authors: Seabra Ana C. , Malina Robert M. , Parker Melissa , Seabra André , Brustad Robert , Maia José A. , Fonseca António M.
Published: August 2013

The Children's Attraction to Physical Activity (CAPA) scale assesses interest in and attraction to the physical activity (PA) of children of elementary school age. The original (25 items) and shorter versions (15 items) of the scale were developed and validated with American children. The purpose of this study was to cross‐validate the shorter version of the CAPA scale for use with Portuguese schoolchildren and to examine the invariance of the multidimensional factor structure of the scale in two samples. The sample comprised 683 children (7–10 years) from public primary schools. The sample was divided into calibration and cross‐validation samples. The scale was translated into Portuguese and underwent forward translation, synthesis of the translation and backward translation and was then subjected to expert committee review, pretest and reliability assessment. Internal consistency for each of the five subscales within the a priori 5‐factor structure of the CAPA scale was evaluated through Cronbach's alpha, followed by a series of confirmatory factor analyses (CFAs) for both the calibration and cross‐validation samples. The maximum likelihood robust estimation method was used. The CFA demonstrated that a 5‐factor structural model of the Portuguese translation of the CAPA scale was invariant. The construct analysed had the same basic meaning and structural and item differences within the two samples. The results indicated that the CAPA scale is appropriate for use with Portuguese schoolchildren. The availability of a valid and reliable scale should enhance opportunities for further understanding of children's involvement in PA.
Reactive and Proactive Control Adjustments under Increased Depressive Symptoms: Insights from the Classic and Emotional-Face Stroop Task
Authors: Saunders Blair , Jentzsch Ines
Published: August 2013

The current research investigated differences in reactive and proactive cognitive control as a function of depressive symptomatology. Three participant groups with varying symptom levels (Beck Depression Inventory–II, BDI–II score) completed both the classic and an emotional-face Stroop task separately under speed and accuracy instructions. All groups made equivalent speed–accuracy trade-offs independent of task, suggesting that proactive adjustments are unaffected by depressive symptoms. Additionally, groups made equivalent reactive control adjustments (Stroop effects, congruency sequence effects) in the classic Stroop task, suggesting that these reactive control adjustments are spared across a wide range of BDI–II scorers. In contrast, the high BDI–II group displayed a selective impairment in the resolution of conflict in the emotional-face Stroop task. Thus, while proactive control and many aspects of reactive control were unaffected by the level of depressive symptoms, specific impairments occurred when current task demands required the trial-to-trial regulation of emotional processing.
The Bruchpilot cytomatrix determines the size of the readily releasable pool of synaptic vesicles
Authors: Matkovic Tanja , Siebert Matthias , Knoche Elena , Depner Harald , Mertel Sara , Owald David , Schmidt Manuela , Thomas Ulrich , Sickmann Albert , Kamin Dirk , Hell Stefan W. , Bürger Jörg , Hollmann Christina , Mielke Thorsten , Wichmann Carolin , Sigrist Stephan J.
Published: August 2013

Synaptic vesicles (SVs) fuse at a specialized membrane domain called the active zone (AZ), covered by a conserved cytomatrix. How exactly cytomatrix components intersect with SV release remains insufficiently understood. We showed previously that loss of the Drosophila melanogaster ELKS family protein Bruchpilot (BRP) eliminates the cytomatrix (T bar) and declusters Ca2+ channels. In this paper, we explored additional functions of the cytomatrix, starting with the biochemical identification of two BRP isoforms. Both isoforms alternated in a circular array and were important for proper T-bar formation. Basal transmission was decreased in isoform-specific mutants, which we attributed to a reduction in the size of the readily releasable pool (RRP) of SVs. We also found a corresponding reduction in the number of SVs docked close to the remaining cytomatrix. We propose that the macromolecular architecture created by the alternating pattern of the BRP isoforms determines the number of Ca2+ channel-coupled SV release slots available per AZ and thereby sets the size of the RRP.
Aurora B and Kif2A control microtubule length for assembly of a functional central spindle during anaphase
Authors: Uehara Ryota , Tsukada Yuki , Kamasaki Tomoko , Poser Ina , Yoda Kinya , Gerlich Daniel W. , Goshima Gohta
Published: August 2013

The central spindle is built during anaphase by coupling antiparallel microtubules (MTs) at a central overlap zone, which provides a signaling scaffold for the regulation of cytokinesis. The mechanisms underlying central spindle morphogenesis are still poorly understood. In this paper, we show that the MT depolymerase Kif2A controls the length and alignment of central spindle MTs through depolymerization at their minus ends. The distribution of Kif2A was limited to the distal ends of the central spindle through Aurora B–dependent phosphorylation and exclusion from the spindle midzone. Overactivation or inhibition of Kif2A affected interchromosomal MT length and disorganized the central spindle, resulting in uncoordinated cell division. Experimental data and model simulations suggest that the steady-state length of the central spindle and its symmetric position between segregating chromosomes are predominantly determined by the Aurora B activity gradient. On the basis of these results, we propose a robust self-organization mechanism for central spindle formation.
A Systematic Literature Review and Meta-Analysis of Factors Associated with Methicillin-ResistantStaphylococcus aureusColonization at Time of Hospital or Intensive Care Unit Admission
Authors: McKinnell James A. , Miller Loren G. , Eells Samantha J. , Cui Eric , Huang Susan S.
Published: August 2013

Objective.

Screening for methicillin-resistantStaphylococcus aureus(MRSA) in high-risk patients is a legislative mandate in 9 US states and has been adopted by many hospitals. Definitions of high risk differ among hospitals and state laws. A systematic evaluation of factors associated with colonization is lacking. We performed a systematic review of the literature to assess factors associated with MRSA colonization at hospital admission.

Design.

We searched MEDLINE from 1966 to 2012 for articles comparing MRSA colonized and noncolonized patients on hospital or intensive care unit (ICU) admission. Data were extracted using a standardized instrument. Meta-analyses were performed to identify factors associated with MRSA colonization.

Results.

We reviewed 4,381 abstracts; 29 articles met inclusion criteria (n= 76,913 patients). MRSA colonization at hospital admission was associated with recent prior hospitalization (odds ratio [OR], 2.4 [95% confidence interval (CI), 1.3–4.7];P<.01), nursing home exposure (OR, 3.8 [95% CI, 2.3–6.3];P< .01), and history of exposure to healthcare-associated pathogens (MRSA carriage: OR, 8.0 [95% CI, 4.2–15.1];Clostridium difficileinfection: OR, 3.4 [95% CI, 2.2–5.3]; vancomycin-resistantEnterococcicarriage: OR, 3.1 [95% CI, 2.5–4.0];P< .01 for all). Select comorbidities were associated with MRSA colonization (congestive heart failure, diabetes, pulmonary disease, immunosuppression, and renal failure;P< .01 for all), while others were not (human immunodeficiency virus, cirrhosis, and malignancy). ICU admission was not associated with an increased risk of MRSA colonization (OR, 1.1 [95% CI, 0.6–1.8];P= .87).

Conclusions.

MRSA colonization on hospital admission was associated with healthcare contact, previous healthcare-associated pathogens, and select comorbid conditions. ICU admission was not associated with MRSA colonization, although this is commonly used in state mandates for MRSA screening. Infection prevention programs utilizing targeted MRSA screening may consider our results to define patients likely to have MRSA colonization.
Explicit bounds for the number of 𝑝-core partitions
Authors: Kim Byungchan , Rouse Jeremy
Published: August 2013

In this article, we derive explicit bounds on

c

t

(
n
)

c_{t} (n)

, the number of

t
t

-core partitions of

n
n

. In the case when

t
=
p

t = p

is prime, we express the generating function

f
(
z
)

f(z)

as the sum
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="f left-parenthesis z right-parenthesis equals e Subscript p Baseline upper E left-parenthesis z right-parenthesis plus sigma-summation Underscript i Endscripts r Subscript i Baseline g Subscript i Baseline left-parenthesis z right-parenthesis">

f
(
z
)
=

e

p

E
(
z
)
+

∑

i

r

i

g

i

(
z
)

f(z) = e_{p} E(z) + \sum _{i} r_{i} g_{i}(z)

\]
of an Eisenstein series and a sum of normalized Hecke eigenforms. We combine the Hardy-Littlewood circle method with properties of the adjoint square lifting from automorphic forms on

G
L

(
2
)

\rm {GL}(2)

to

G
L

(
3
)

\rm {GL}(3)

to bound

R
(
p
)
:=

∑

i

|

r

i

|

R(p) := \sum _{i} |r_{i}|

, solving a problem raised by Granville and Ono.

In the case of general

t
t

, we use a combination of techniques to bound

c

t

(
n
)

c_{t}(n)

and as an application prove that for all

n
≥
0

n \geq 0

,

n
≠
t
+
1

n \ne t+1

,
\[

c

t
+
1

(
n
)
≥

c

t

(
n
)

c_{t+1}(n) \geq c_{t}(n)

\]
provided

4
≤
t
≤
198

4 \leq t \leq 198

, as conjectured by Stanton.
Spatial distribution of nitrogen fixation in methane seep sediment and the role of the ANME archaea
Authors: Dekas Anne E. , Chadwick Grayson L. , Bowles Marshall W. , Joye Samantha B. , Orphan Victoria J.
Published: August 2013

Nitrogen (N2) fixation was investigated at Mound 12, Costa Rica, to determine its spatial distribution and biogeochemical controls in deep‐sea methane seep sediment. Using 15N2 tracer experiments and isotope ratio mass spectrometry analysis, we observed that seep N2 fixation is methane‐dependent, and that N2 fixation rates peak in a narrow sediment depth horizon corresponding to increased abundance of aggregates of anaerobic methanotrophic archaea (ANME‐2) and sulfate‐reducing bacteria (SRB). Using fluorescence in situ hybridization coupled to nanoscale secondary ion mass spectrometry (FISH‐NanoSIMS), we directly measured 15N2 uptake by ANME‐2/SRB aggregates (n = 26) and observed maximum 15N incorporation within ANME‐2‐dominated areas of the aggregates, consistent with previous analyses. NanoSIMS analysis of single cells (n = 34) from the same microcosm experiment revealed no 15N2 uptake. Together, these observations suggest that ANME‐2, and possibly physically associated SRB, mediate the majority of new nitrogen production within the seep ecosystem. ANME‐2 diazotrophy was observed while in association with members of two distinct orders of SRB: Desulfobacteraceae and Desulfobulbaceae. The rate of N2 fixation per unit volume biomass was independent of the identity of the associated SRB, aggregate size and morphology. Our results show that the distribution of seep N2 fixation is heterogeneous, laterally and with depth in the sediment, and is likely influenced by chemical gradients affecting the abundance and activity of ANME‐2/SRB aggregates.
CAP Subsidies and Productivity of the EU Farms
Authors: Rizov Marian , Pokrivcak Jan , Ciaian Pavel
Published: August 2013

The paper investigates the impact of the Common Agricultural Policy (CAP) subsidies on farm total factor productivity (TFP) in the European Union (EU). We employ a structural semi‐parametric estimation algorithm directly incorporating the effect of subsidies into a model of unobserved productivity. We empirically study the effects using the Farm Accountancy Data Network (FADN) samples for the EU‐15 countries. Our main findings are clear: subsidies impact negatively on farm productivity in the period before the decoupling reform was implemented; after decoupling the effect of subsidies on productivity is more nuanced and in several countries it turned positive.
Effects of Antimicrobial Coatings and Cryogenic Freezing on Survival and Growth of Listeria innocua on Frozen Ready‐to‐Eat Shrimp during Thawing
Authors: Guo Mingming , Jin Tony Z. , Scullen O. Joseph , Sommers Christopher H.
Published: August 2013

Foodborne pathogens such as Listeria monocytogenes could pose a health risk on frozen ready‐to‐eat (RTE) shrimp as the pathogen could grow following thawing. In this study, antimicrobial‐coating treatments alone, or in combination with cryogenic freezing, were evaluated for their ability to inhibit the growth of Listeria innocua, a surrogate for L. monocytogenes, on RTE shrimp. Cooked RTE shrimp were inoculated with L. innocua at 3 population levels and treated with coating solutions consisting of chitosan, allyl isothiocyanate (AIT), or lauric arginate ester (LAE). The treated shrimp were then stored at –18 °C for 6 d before being thawed at 4, 10, or 22 °C for either 24 or 48 h. Results revealed that antimicrobial coatings achieved approximately 5.5 to 1 log CFU/g reduction of L. innocua on RTE shrimp after the treatments, depending on the inoculated population levels. The coating‐treated shrimp samples had significantly (P < 0.05) less L. innocua than controls at each thawing temperature and time. Cryogenic freezing in combination with coating treatments did not achieve synergistic effects against L. innocua. Antimicrobial coatings can help to improve product safety by reducing Listeria on RTE shrimp.
Frequency and Correlation of Some Enteric Indicator Bacteria and Salmonella in Ready‐to‐Eat Raw Vegetable Salads from Mexican Restaurants
Authors: Gómez‐Aldapa Carlos A. , Rangel‐Vargas Esmeralda , Castro‐Rosas Javier
Published: August 2013

Data about Salmonella presence in ready‐to‐eat raw vegetable salads (REVS) consumed in restaurants or sold as REVS in México is not available. The objective of the study was to measure the frequency of coliform bacteria (CB), fecal coliform (FC), Escherichia coli, and Salmonella in REVS from different types of restaurants and determine the correlations of CB, FC, and E. coli versus Salmonella from frequencies and concentration data. The REVS were purchased from 3 types of restaurants: national chain restaurants (A1, A2); local restaurants (B1, B2); and small restaurants in local markets (C1, C2, C3). Two restaurants for each A and B, and 3 for C, were included. Forty REVS were purchased at each A and B restaurant, and 20 at each C restaurant. CB were tested by plate count using violet red bile agar, FC and E. coli were detected by the most probable number method and E. coli confirmed using IMViC test; conventional method of culture was used for Salmonella. Of 220 analyzed samples, 100% had CB, 95.5% had FC, 83.2% had E. coli, and 6.8% had Salmonella. E. coli frequency was equal to or exceeded 75% in all the cases: 75% (A1, C1, C2), 80% (B2), 85% (B1, C3), and 100% (A2). Salmonella frequency was equal to or exceeded 2.5% in all cases: 2.5% (A1), 5% (B2, C2), 7.5% (B1), and 10% (A2, C1, C3). No correlation was observed between FC or E. coli versus Salmonella in the analyzed salads. All the tested salads were of poor quality microbiologically, and microbiological quality did not differ between the restaurants types.
Suppression of Umami Aftertaste by Polysaccharides in Soy Sauce
Authors: Imamura Miho , Matsushima Kenichiro
Published: August 2013

Umami is one of 5 basic tastes that make foods savory and palatable. The umami aftertaste is a long‐lasting taste sensation that is important for Japanese broth (dashi) utilized for various Japanese foods. Soy sauce is usually added when making dashi‐based dishes; however, different soy sauces produce distinct effects on the umami aftertaste. In this study, we attempted to identify the substances that cause the suppression of the umami aftertaste in soy sauce by combining sensory analysis, size fractionation, chemical analysis, and enzymatic treatment. The suppressive substance was revealed to be polysaccharides with molecular weights between 44900 and 49700. The results of acid hydrolysis and enzymatic treatment suggested that the polysaccharides were cellulose. These results indicate that a type of water‐soluble cellulose derived from soybean, wheat, or microorganisms has a suppressive effect on the umami aftertaste of soy sauce. Future studies should focus on developing a strategy that regulates the amount of these polysaccharides generated during soy sauce production, to maintain or enhance the umami aftertaste.
Effects of Water Activity on the Lipid Oxidation and Antioxidants of Dried Laver (Porphyra) During Storage in the Dark
Authors: Choe Eunok , Oh Soojung
Published: August 2013

Lipid oxidation and antioxidant degradation in dried laver (Porphyra) were determined during storage at water activities (Aw) of 0.11, 0.30, 0.51, 0.75, or 0.89 in the dark at 40 °C for 15 d. Lipid oxidation was evaluated by measuring peroxide value (POV) and conjugated dienoic acid (CDA) contents, and fatty acid composition was analyzed by gas chromatography. Contents of polyphenols, tocopherols, and porphyran were determined by spectrophotometry, HPLC, and gravimetry, respectively. The POV and CDA contents of the dried laver lipids increased during storage as Aw increased from 0.11 to 0.30, 0.51, 0.75, and 0.89, whereas the relative content of eicosapentaenoic acid was decreased; however, the contents of polyphenols, α‐tocopherol, and porphyran in dried laver showed the reverse phenomena. Lipid oxidation and antioxidant degradation in dried laver sharply increased at an Aw of 0.51. Polyphenols, α‐tocopherol, and porphyran contributed to reduction of lipid oxidation in dried laver. The degree of lipid oxidation of dried laver was more dependent on the concentration of α‐tocopherol than that of either polyphenols or porphyran during storage in the dark. The results strongly suggest that the quality of dried laver can be improved by preserving tocopherols as much as possible while decreasing Aw during storage.
Content and Bioaccessibility of Aluminium in Duplicate Diets from Southern Spain
Authors: Cabrera‐Vique Carmen , Mesías Marta
Published: August 2013

Aluminium is found naturally in foods and beverages, but levels increase notably during processing, packaging, storage, and cooking, as a consequence of its presence in food additives and the wide use of aluminium utensils and vessels. Dietary intake of Al was estimated in 2 population groups in southern Spain (families and university students) in a duplicate diet sampling study. Diets were sampled for 7 consecutive days, and Al was determined in acid‐mineralized samples with electrothermal atomization‐atomic absorption spectrometry (ETA‐AAS). Mean values for Al intake were 2.93 and 1.01 mg/d in families and students, respectively, ranging from 0.12 to 10.00 mg/d. Assuming an average adult weight of 60 kg, the mean dietary exposures to aluminium were 0.34 and 0.12 mg/kg body weight/week in these groups, which amounted to 17% and 6% of the 2 mg/kg body weight estimated as the tolerable weekly intake by the Joint FAO/WHO Expert Committee on Food Additives. Bioaccessibility of dietary Al tested with in vitro studies ranged from 0.30 to 17.26% (absorbable fraction). The highest aluminium intakes were observed in subjects consuming diets with a low adherence to the Mediterranean diet, which were associated to high consumption of processed and canned food. On the contrary, subjects consuming diets with a high adherence to the Mediterranean diet patterns showed the lowest Al intakes. The present findings are useful for giving both a reliable estimate of total aluminium dietary intake and tolerable intake levels according to usual dietary habits.
Partial Characterization of Ultrafiltrated Soy Protein Hydrolysates with Antioxidant and Free Radical Scavenging Activities
Authors: Jiménez‐Ruiz Edgar I. , Calderón de la Barca Ana M. , Sotelo‐Mundo Rogerio R. , Arteaga‐Mackinney Guillermo E. , Valenzuela‐Melendez Martin , Peña‐Ramos E. Aida
Published: August 2013

Soy protein isolate (SPI) was hydrolyzed with Flavourzyme® (SHF) or chymotrypsin (SHC). Hydrolysates were sequencially fractionated by ultrafiltration using different membrane pore sizes (50, 10, and 3 kDa). The antioxidant ability of each hydrolysate protein fraction was tested in a liposome oxidizing system and their free radical scavenging activity (FRSA) was evaluated with the DPPH method (diphenylpicrilhydrazine radical). Molecular weight (MW) distribution, solubility, surface hydrophobicity, and amino acid composition of each SPI hydrolysate fraction were measured and their effect on antioxidant and scavenging activities was established by multivariate correlation. The most active ultrafiltrated peptide fractions (P < 0.05), from SHF and SHC, had of MW of <3 kDa (F3 and C3, respectively). These fractions decreased liposome oxidation by 83.2% and 84.5%, respectively, and also showed the highest FRSA (F3: 21.3% and C3: 24.4%). In addition to molecular size, the antioxidant activity and FRSA of soy protein fractions were related to their amino acid composition, especially to an increased content of Phe and a lowered content of Lys. Also, hydrophobicity of ultrafiltrated peptide fractions was an important characteristic (P < 0.001) associated with their ability to trap free radicals. Ultrafiltered peptide fractions with low MW have a high potential to be used as natural alternatives to prevent lipid oxidation in foods.
Quality of Dry‐Cured Ham Compared with Quality of Dry‐Cured Shoulder
Authors: Reina Raquel , Sánchez del Pulgar José , Tovar Jorge , López‐Buesa Pascual , García Carmen
Published: August 2013

The physicochemical and sensory properties of 30 dry‐cured hams and 30 dry‐cured shoulders were analyzed to determine the relationships between them. The variables used to characterize both products were: compositional parameters, instrumental texture, amino acid and fatty acid composition, and sensory profile. Despite being products from the same animal and composed mainly of fat, lean, and bone, their morphological differences determine the conditions of the processing time, which produced differences between products in most of the parameters evaluated. Dry‐cured shoulders showed lower moisture content and greater instrumental hardness due to their morphology and muscular structure. Besides, these samples showed lower amino acid content according to the shorter ripening time. For the same reason, the dry‐cured hams showed higher moisture content, lower instrumental hardness, and higher amino acid content. However, the differences in the muscular structure did not affect the sensory characteristics, which were more related with some compositional parameters, such as chloride, moisture, and amino acid content and with the length of the curing process.
Use of Whey Protein Soluble Aggregates for Thermal Stability—A Hypothesis Paper
Authors: Ryan Kelsey N. , Zhong Qixin , Foegeding Edward A.
Published: August 2013

Forming whey proteins into soluble aggregates is a modification shown to improve or expand the applications in foaming, emulsification, gelation, film‐formation, and encapsulation. Whey protein soluble aggregates are defined as aggregates that are intermediates between monomer proteins and an insoluble gel network or precipitate. The conditions under which whey proteins denature and aggregate have been extensively studied and can be used as guiding principles of producing soluble aggregates. These conditions are reviewed for pH, ion type and concentration, cosolutes, and protein concentration, along with heating temperature and duration. Combinations of these conditions can be used to design soluble aggregates with desired physicochemical properties including surface charge, surface hydrophobicity, size, and shape. These properties in turn can be used to obtain target macroscopic properties, such as viscosity, clarity, and stability, of the final product. A proposed approach to designing soluble aggregates with improved thermal stability for beverage applications is presented.
Preparation Methods for Monodispersed Garlic Oil Microspheres in Water Using the Microemulsion Technique and Their Potential as Antimicrobials
Authors: Zheng Hua Ming , Li Hou Bin , Wang Da Wei , Liu Dun
Published: August 2013

Garlic oil is considered as a natural broad‐spectrum antibiotic because of its well‐known antimicrobial activity. However, the characteristics of easy volatility and poor aqueous solubility limit the application of garlic oil in industry. The purpose of the present work is to develop and evaluate an oil‐free microemulsion by loading garlic oil in microemulsion system. Microemulsions were prepared with ethoxylated hydrogenated castor (Cremophor RH40) as surfactant, n‐butanol (or ethanol) as cosurfactant, oleic acid‐containing garlic oil as oil phase, and ultrapure water as water phase. The effects of the ratio of surfactant to cosurfactant and different oil concentration on the area of oil‐in‐water (O/W) microemulsion region in pseudoternary phase diagrams were investigated. The particle size and garlic oil encapsulation efficiency of the formed microemulsions with different formulations were also investigated. In addition, the antimicrobial activity in vitro against Escherichia coli and Staphylococcus aureus was assessed. The experimental results show that a stable microemulsion region can be obtained when the mass ratio of surfactant to cosurfactant is, respectively, 1:1, 2:1, and 3:1. Especially, when the mixture surfactants of RH40/n‐butanol 2/1 (w/w) is used in the microemulsion formulation, the area of O/W microemulsion region is 0.089 with the particle size 13.29 to 13.85 nm and garlic oil encapsulation efficiency 99.5%. The prepared microemulsion solution exhibits remarkable antibacterial activity against S. aureus.
Sensory Properties of Under‐Roasted Coffee Beverages
Authors: Masi Camilla , Dinnella Caterina , Barnabà Massimo , Navarini Luciano , Monteleone Erminio
Published: August 2013

Conditions milder than standard roasting (under‐roasting: 140 to 170 °C for 20 to 12 min) have been proposed to reduce the formation of potentially harmful compounds developing during standard coffee roasting. In the present study, sensory properties of brews prepared with under‐roasted coffees (140 to 165 °C for 20 min) were described by descriptive analysis. Two meta‐attributes were defined: “coffee” consisting of attributes positively related to the increasing of process temperature and “no‐coffee” consisting of those negatively related to temperature. The progressive lowering of “no‐coffee” and the corresponding increasing of “coffee” mean values were induced by temperature increasing in under‐roasting conditions. The processing temperature of 150 °C seems to represent the changing point between the 2 meta‐attributes with “no‐coffee” prevailing at lower and “coffee” at higher temperatures. Consumer responses indicate the positive effect of both product processing temperature and “coffee” attribute intensity on liking. Brews from coffee treated at temperature lower than 150 °C showed a sensory profile characterized by “no‐coffee” attributes and resulted the less preferred by regular coffee consumers.
Combined Effect of Dimethyl Dicarbonate (DMDC) and Nisin on Indigenous Microorganisms of Litchi Juice and its Microbial shelf life
Authors: Yu Yuanshan , Wu Jijun , Xiao Gengsheng , Xu Yujuan , Tang Daobang , Chen Yulong , Zhang Yousheng
Published: August 2013

The individual and combined influences of dimethyl dicarbonate (DMDC) and nisin (200 IU/mL) at mild heat on the inactivation of indigenous microorganisms in litchi juice, including bacteria, molds and yeasts (M&Y), were investigated. The fresh litchi juice with or without nisin were exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5, 1, 2, 3, 4, or 6 h. A complete inactivation of M&Y in the litchi juice with or without nisin was achieved as exposed to 250 mg/L DMDC at 30, 40, or 45 °C for 0.5 h. The bacteria, especially Bacillus sp. and Leuconstoc mesenteroides showed higher resistance than M&Y in the litchi juice. Bacillus sp. and Leuconstoc mesenteroides in the litchi juice was not completely inactivated by 250 mg/L DMDC at 30, 40, or 45 °C. However, nisin addition can enhanced the inactivation of these bacteria by DMDC, and nisin and DMDC also showed a synergistic effect on the inactivation of bacteria. M&Y and bacteria were not detected in the litchi juice added with 200 IU/mL nisin as exposed to 250 mg/L DMDC at 45 °C for 3 h. In addition, microbial shelf life of the litchi juice during storage at 4 °C also was evaluated as treated by 250 mg/L DMDC or combination with nisin at 45 °C for 3 h.
Bacterial and Fungal Communities in Pu'er Tea Samples of Different Ages
Authors: Tian Jianqing , Zhu Zixiang , Wu Bing , Wang Lin , Liu Xingzhong
Published: August 2013

Pu'er is a major kind of postfermented tea and is made with a “large leaf” variety of Camellia sinensis (C. sinensis assamica), whose distribution is limited to the mountains of southern Yunnan, China. The quality of Pu'er tea is believed to increase with storage (aging, maturing) because of postfermentation by microbes. The effect of storage period (from < 1 to 192 mo) on the bacteria and fungi in Pu'er tea was investigated by a culture‐dependent and a PCR‐DGGE method. The individual numbers of fungi and bacteria decreased with increasing storage time and were significantly greater in ripened tea than in raw Pu'er tea. Both methods indicated that yeast, Aspergillus spp., and Penicillium spp. were the dominant fungi in almost all the samples. However, the common bacteria detected by the culture‐dependent method were species of Pseudomonas, Achromobacter, Alcaligenes, Sporosarcina, and Bacillus, whereas those detected by PCR‐DGGE were species of Staphylococcus, Arthrobacter, and Streptomyces. According to ordination analysis, bacterial community structure differed between ripened and raw Pu'er tea. Bacterial diversity was positively correlated with aging time, while fungal diversity in both raw and ripened tea increased during the first 60 mo of aging and then decreased. Changes in polyphenol content were correlated with the changes in fungal diversity. These results suggest that the relationship between storage time and the quality of Pu'er tea is complex and involves changes in polyphenol content and microbial abundance and diversity.
Gross Anatomy of the Brachial Plexus in the Giant Anteater (Myrmecophaga tridactyla)
Authors: Souza P. R. , Cardoso J. R. , Araujo L. B. M. , Moreira P. C. , Cruz V. S. , Araujo E. G.
Published: August 2013

Ten forelimbs of five Myrmecophaga tridactyla were examined to study the anatomy of the brachial plexus. The brachial plexuses of the M. tridactyla observed in the present study were formed by the ventral rami of the last four cervical spinal nerves, C5 through C8, and the first thoracic spinal nerve, T1. These primary roots joined to form two trunks: a cranial trunk comprising ventral rami from C5‐C7 and a caudal trunk receiving ventral rami from C8‐T1. The nerves originated from these trunks and their most constant arrangement were as follows: suprascapular (C5‐C7), subscapular (C5‐C7), cranial pectoral (C5‐C8), caudal pectoral (C8‐T1), axillary (C5‐C7), musculocutaneous (C5‐C7), radial (C5‐T1), median (C5‐T1), ulnar (C5‐T1), thoracodorsal (C5‐C8), lateral thoracic (C7‐T1) and long thoracic (C6‐C7). In general, the brachial plexus in the M. tridactyla is similar to the plexuses in mammals, but the number of rami contributing to the formation of each nerve in the M. tridactyla was found to be larger than those of most mammals. This feature may be related to the very distinctive anatomical specializations of the forelimb of the anteaters.
Anticancer Activity of New Synthetic α‐Methylene‐δ‐Lactones on Two Breast Cancer Cell Lines
Authors: Wyrębska Anna , Gach Katarzyna , Lewandowska Urszula , Szewczyk Karolina , Hrabec Elżbieta , Modranka Jakub , Jakubowski Rafał , Janecki Tomasz , Szymański Jacek , Janecka Anna
Published: August 2013

Natural products are important leads in drug discovery. The search for effective plant‐derived anticancer agents or their synthetic analogues has continued to be of interest to biologists and chemists for a long time. In this report, cytotoxicity and anticancer activity of new synthetic α‐methylene‐δ‐lactones was tested against two breast cancer cell lines, invasive, hormone‐independent MDA‐MB‐231 and hormone‐dependent MCF‐7. Cytotoxicity was examined using MTT assay. The ability to induce apoptosis and changes in mitochondrial membrane potential was studied by flow cytometry. The expression levels of pro‐ and anti‐apoptotic genes were determined by quantitative real‐time PCR. Cancer cell migration and invasion were assessed by wound healing and Matrigel assays. Additionally, secretion of proteins associated with invasiveness, metalloproteinase‐9 (MMP‐9) and urokinase plasminogen activator (uPA) was investigated using commercial ELISA kits and MMP‐9 activity by gelatin zymography. A natural sesquiterpene lactone, parthenolide, was used as a positive control. Screening results showed all four analogues to be highly cytotoxic. The most potent compound of the series, 1‐isopropyl‐2‐methylene‐1,2‐dihydrobenzochromen‐3‐one, designated DL‐3, which reduced the number of viable MDA‐MB‐231 and MCF‐7 cells with the IC50 values of 5.3 μM and 3.54 μM, respectively, was selected for further research. DL‐3 activated the intrinsic pathway of apoptosis, associated with the loss of mitochondrial membrane potential and changes in Bax/Bcl‐2 ratio. DL‐3 also inhibited the movement of both types of breast cancer cells. Suppression of cell migration and invasion was the result of the decreased secretion of enzymes responsible for the degradation of the extracellular matrix, MMP‐9 and uPA. These findings show that the synthetic α‐methylene‐δ‐lactone, DL‐3, displays potential to be further explored in the development of new anticancer agents.