bluuebunny/crossref_metadata_2025 huggingface dataset:
Image Analysis of Microstructural Changes in Almond Cotyledon as a Result of Processing
Authors: Altan Aylin , McCarthy Kathryn L. , Tikekar Rohan , McCarthy Michael J. , Nitin N.
Published: February 2011

Abstract:  Release of oil from nuts due to damaged cellular structures can degrade the quality of products incorporating nuts. The aim of this study was to investigate the effects of different processing conditions on microstructure of almond tissue and to quantify these changes using image processing. Spinning disk confocal fluorescence microscopy was used for imaging changes in microstructure of almonds as a function of different thermal processing of almonds. Multiple staining of Nile Red and Calcofluor White was applied to differentiate cell wall structures and oil bodies within individual almond cells without chemical fixation. An algorithm for image processing, included image preprocessing, segmentation, and determination of morphological features of segmented objects, was developed. Oil‐roasting processes (140 °C and 150 °C) were found to have a significant impact on microstructure of almonds when compared to the hot air‐roasting and blanching processes. Oil‐roasted almond at 150 °C had a greater cellular damage due to cell wall and membrane rupture. These changes in microstructure of almonds would make them slightly more susceptible to release oil during storage. The image analysis presented allows quantitative evaluation for the effect of different processing on almond microstructure.
Glucose Tolerance and Antioxidant Activity of Spent Brewer's Yeast Hydrolysate with a High Content of Cyclo‐His‐Pro (CHP)
Authors: Jung Eun Young , Lee Hyun‐Sun , Choi Jang Won , Ra Kyung Soo , Kim Mi‐Ryung , Suh Hyung Joo
Published: February 2011

Abstract:  To elevate the Cyclo‐His‐Pro (CHP) content in yeast, the yeast hydrolysate that was obtained from enzymatic hydrolysis was subjected to various treatments. Flavourzyme‐treated hydrolysate showed the highest CHP content (674.0 μg/g) among the various proteases treatments. Ultrafiltration was selected as the best method for concentrating CHP in yeast hydrolysate, based on the yields and CHP contents. In addition, we evaluated the radical scavenge and glucose tolerance of yeast hydrolysate with a high content of CHP. Yeast hydrolysate showed intense scavenging abilities of both 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid) (ABTS) radicals. The IC50 values of yeast hydrolysate on DPPH and ABTS radicals were 1.9 and 0.9 mg/mL, respectively. There were significant differences in glucose level between the diabetes‐control and yeast hydrolysate group at 30, 60, 90, and 120 min after injection in a type 1 diabetes model (P < 0.01). Also, there were significant differences in blood glucose levels between the 2 groups at 30, 60, and 100 min after injection in the type 2 diabetes group (P < 0.05). Therefore, it is possible to use the yeast hydrolysate with high levels of CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods.

Practical Application:  This study tried to develop a material containing a high content of CHP using yeast for possible applications of this cyclic dipeptide in the therapy of metabolic disorders. The yeast hydrolysate prepared with Flavourzyme showed a high level of CHP. The hydrolysate with a high content of CHP showed high levels of radical scavenging activities and oral glucose tolerance activity. Therefore, it is possible to use the yeast hydrolysate with high levels of CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods.
Effect of Enzymes on Strawberry Volatiles during Storage, at Different Ripeness Level, in Different Cultivars, and during Eating
Authors: Ozcan G. , Barringer S.
Published: February 2011

Abstract:  Strawberry samples with enzyme activity and without enzyme activity (stannous chloride added) were measured for real‐time formation of lipoxygenase (LOX) derived aroma compounds after 5 min pureeing using selected ion flow tube‐mass spectrometry (SIFT‐MS). The concentration of (Z)‐3‐hexenal and (E)‐2‐hexenal increased immediately after blending and gradually decreased over time, while hexanal concentration increased for at least 5 min in ground strawberries. The formation of hexanal was slower than the formation of (Z)‐3‐hexenal and (E)‐2‐hexenal in the headspace of pureed strawberries. The concentration of LOX aldehydes and esters significantly increased during refrigerated storage. Damaging strawberries increased the concentration of LOX aldehydes but did not significantly affect the concentration of esters. The concentrations of many of the esters were strongly correlated to their corresponded acids and/or aldehydes. The concentration of LOX‐generated aldehydes decreased during ripening, while fruity esters increased. Different varieties had different aroma profiles and esters were the greatest percentage of the volatiles. The aroma release of some of the LOX‐derived aldehydes in the mouthspace in whole strawberries compared to chopped strawberries showed that these volatiles are formed in the mouth during chewing. The persistence of LOX‐derived compounds was higher than esters after swallowing. The mouthspace after and before swallowing persistence ratio of esters decreased as the chain length of the acid part of the ester compounds increased in whole strawberries.

Practical Application:  The storage studies showed that the concentrations of fruity and fresh volatiles increased during ripening and storage while damaging only increases the fresh volatiles. The nose, mouth, and headspace information can be used in the flavor industry to improve the formula of natural strawberry flavor by considering human perception during eating.
Multispectral Vision for Monitoring Peach Ripeness
Authors: Herrero‐Langreo Ana , Lunadei Loredana , Lleó Lourdes , Diezma Belén , Ruiz‐Altisent Margarita
Published: February 2011

Abstract:  The main objective of this research was to develop an automatic procedure able to classify Rich Lady commercial peaches according to their ripeness stage through multispectral imaging techniques. A classification procedure was applied to the ratio images calculated as red (R, 680 nm) divided by infrared (IR, 800 nm), that is, R/IR images. Four image‐based ripeness reference classes (A: unripe to D: overripe) were generated from 380 fruit images (season 1: 2006) by a nonsupervised classification method and evaluated according to reference measurements of the ripeness of the same samples: Magness‐Taylor penetrometry firmness, low‐mass impact firmness, reflectance at 680 nm (R680, and soluble solids content. The assignment of unknown sample images from those season 1 images (internal validation, n = 380) and of 240 images from the 2nd season (season 2: 2007) to the ripeness reference classes (external validation) was carried out by computing the minimum Euclidean distance (classification distance, Cd) between each unknown image histogram and the average histogram of each ripeness reference class. For both validation phases, firmness values decreased and R680 increased for increasing alphabetical order of image‐based class letter, reflecting the ripening process. Moreover, 70% (season 1) and 80% (season 2) of the samples below bruise susceptibility firmness were classified into class D.

Practical Application:  This work proposes and validates a procedure for assessing peach ripeness through spectral imaging. The control of ripeness in this fruit is crucial for ensuring its quality and the measurement of optimum peach ripeness at harvest and postharvest is a controversial issue, which needs to be balanced between a minimum ripeness, acceptable for the consumer, and a maximum ripeness, to minimize fruit losses during the postharvest process. The proposed method is nondestructive and quick, showing thus, a good perspective for its application in fresh fruit packing lines, either for peach ripeness assessment or for other fruits (providing adequate calibration).
Digital Element Earth
Authors: Xuejing XIE , Xueqiu WANG , Hangxin CHENG , Zhizhong CHENG , Wensheng YAO
Published: February 2011

The resources and environmental problems are the two most fundamental issues facing all nations in the world. Everything in and on the Earth – minerals, animals and plants – is made from one, or generally some combination of, chemical elements, which are scientifically listed in the periodic table. Thus it is important to understand the present abundance and spatial distribution of all the elements across the Earth's surface. Such kinds of data can only be obtained at present and for the foreseeable future by on‐earth geochemical mapping at all scales. The 30‐year efforts made by Chinese geochemists in carrying out multi‐element, multi‐media, multi‐scale geochemical mapping projects to delineate 39–76 element distribution at home and abroad culminated in a successful case of high‐quality geochemical data acquirement. The new idea for a four‐level plan for global geochemical mapping was advanced to obtain global data in the foreseeable future and the collection of updated geochemical information. Such information needs to be easily accessible not only by the science community, but also by industry, agriculture, governments, and even individuals, by all who would make an effort to promote sustainable living on our planet. The concept of a Digital Element Earth (DEE) fulfills the aims.
A New Hadrosauriform Dinosaur from the Early Cretaceous of Gansu Province, China
Authors: Hailu YOU , Daqing LI , Weichang LIU
Published: February 2011

A new basal hadrosauriform dinosaur, Xuwulong yueluni gen. et sp. nov., is reported based on an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle. The specimen is recovered from the Early Cretaceous Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. Xuwulong is among the most basal members of hadrosauriform dinosaurs, and distinguished by its unique lower jaw in having a V‐shaped rostral end of the dentary in lateral view and a mandibular articular surface which levels with mid‐height of the dentary ramus, as well as an enlarged and downturned prepubic process. Including Xuwulong, three basal hadrosauriforms have been discovered from the Early Cretaceous Xinminpu Group in the Mazongshan area, making it an important area to study the origin and early evolution of duck‐billed dinosaurs.
Systematics, Behavior and Living Environment of Shantungosaurus Giganteus (Dinosauria: Hadrosauridae)
Authors: Yannan JI , Xuri WANG , Yongqing LIU , Qiang JI
Published: February 2011

On the basis of the taphonomy, osteological anatomy and ontogenetic variation, Zhuchengosaurus maximus Zhao et al., 2007 is considered to be synonymic with Shantungosaurus giganteus Hu, 1973 herein. This paper also deals with the life behavior of S. giganteus and the environment in which S. giganteus lived. S. giganteus is considered to be a terrestrial and gregarious herbivorous dinosaur and lived in hills and intervales in warm weather with plentiful rain and flourishing vegetation.
Description and Phylogenetic Position of Dinosaur Eggshells from the Luanchuan Area of Western Henan Province, China
Authors: TANAKA Kohei , Junchang LÜ , KOBAYASHI Yoshitsugu , ZELENITSKY Dark K. , Li XU , Songhai JIA , Shuang QIN , Min'an TANG
Published: February 2011

Here, we examine 145 dinosaur eggshells from a new fossil locality in the Qiupa Formation (Upper Cretaceous) of the Luanchuan area in western Henan Province, China. The eggshells display elongatoolithid macro‐ and microstructures, including ridges and nodes on the outer surface, two ultrastructural layers, and an undulatory boundary between the mammillary and continuous layers. A phylogenic analysis shows that the Luanchuan eggshells belong to the ooclade Elongatoolithidae. Within Elongatoolithidae, the thickness ratio of the mammillary layer to the entire eggshell, and the porosity of the Luanchuan eggshells are comparable to the oogenera Macroolithus and Elongatoolithus. There is no direct evidence for the taxonomic identity of the Luanchuan eggshells; however, they were likely laid by oviraptorids based on their phylogenetic position and their similarities with known oviraptorid eggs.
Inter‐Regional Comparisons on the Quaternary Large Mammalian Faunas between China and Sub‐Saharan Africa
Authors: Haowen TONG , Nan HU , Jinyi LIU , CLARKE Ronald
Published: February 2011

The current and dominant theory about the origin of modern humans is the out‐of‐Africa hypothesis, which asserts that populations of Homo sapiens left Africa 100,000 years ago and replaced indigenous populations of humans in Eurasia. Many scholars equated the out‐of‐Africa dispersal of humans with paleoenvironmental changes. However, until now, few have paid special attention to the faunal data and whether or not faunal patterns are supportive of the popular theory. Recent comparative study of the Chinese fauna shows that the communication of faunas between Africa and East Asia could have occurred during the Neogene, but it was very limited during the Pleistocene. In the Chinese Quaternary fauna, only 16% of the genera are also present in the sub‐Saharan African fauna. There is also no element among the dominant taxa of the Chinese Quaternary fauna which can be related to the African fauna. There is no reliable proof for the existence of Hippopotamus and Giraffa, as well as Panthera leo, during the Quaternary in China. Two controversial taxa are Acinonyx and Crocuta, about which there is still argument concerning their species identification in Eurasia. It is possible that both of the genera have co‐specific taxa in Africa and Eurasia. Although the two genera are confined to Africa today, they did have a long evolutionary history in China. For the Out of Africa hypothesis for Homo sapiens, the implications of the limited faunal interchanges between China and Africa are not completely clear yet.
U‐Pb Dating of Volcanic Rocks and Granites along the Wuyishan Belt: Constraints on Tuning of Late Mesozoic Tectonic Events in Southeast China
Authors: Xianbing XU , Yueqiao ZHANG , Dong JIA , Liangshu SHU
Published: February 2011

Five volcanic rock samples and two granite samples taken from the volcanic basins in western Fujian and southern Jiangxi were dated by using the zircon laser albation‐inductively coupled plasma mass spectrometry U‐Pb method. Together with previously dated ages, the dates obtained provide important constraints on the timing of late Mesozoic tectonic events in SE China. The volcanic rock samples yield ages of 183.1±3.5 Ma, ca. 141 Ma to 135.8±1.1 Ma, 100.4±1.5 to 97.6±1.1 Ma, confirming three episodes of late Mesozoic volcanic activities, which peaked at 180±5 Ma, 140±5 Ma and 100±5 Ma, respectively, along the Wuyishan belt. Moreover, based on field investigations of these volcano‐sedimentary basins, we have recognized two compressional tectonic events along this belt The early one was characterized by Upper Triassic to Middle Jurassic NNE‐trending folds that were intruded by late Jurassic granites; and the late one caused the Lower Cretaceous volcano‐sedimentary layer to be tilted. The dated age 152.9±1.4 Ma of the granitic samples from the Hetian granitic pluton in the Changting Basin and that from the Baishiding granitic pluton, 100.2±1.8 Ma, in the Jianning Basin, give the upper boundaries of these two tectonic events respectively. Hence, the late Mesozoic tectonic evolution of SE China was alternated between extension and compression.
Equilibrium between Clinopyroxene and Host Rocks: Implication for the Magmatic Source and Evolution of Alkali Basalts of the Taohekou Formation in the Northern Daba Mountains, China
Authors: Zhongjin XIANG , Quanren YAN , Zhen YAN , Zongqi WANG , Tao WANG , Yingli ZHANG , Xiaofeng QIN
Published: February 2011

The Taohekou Formation is a volcanic‐sedimentary terrane formed in the early Silurian in the northern Daba Mountains, China. The volcanic rocks, with dominant alkali basalts and minor mantle xenoliths, are enriched in clinopyroxene phenocrysts. Geochemical analysis shows that the composition of clinopyroxenes from different lithofacies has a close affinity. There is a liner correlation present in composition of clinopyroxenes (including phenocryst, microcrystal and xenocryst) from coarse porphyritic basalts, pillow or fine porphyritic basalts to amygdaloidal basalts. All the clinopyroxenes, except the clinopyroxenes in mantle xenoliths, show a similar pattern of trace elements and REE, which indicates that they are likely products of successive fractional crystallization from cognate magma. Clinopyroxenes in mantle xenoliths, however, are mantle xenocrysts. The crystallization pressure of clinopyroxenes gradually decreases from mantle xenolith, deep‐seated xenocryst, coarse porphritic basalts, pillow or fine porphritic basalts, to amygdaloidal basalts, which are 1.92–4.41 GPa, 1.18–2.36 GPa, 1.13–2.05 GPa, 0.44–0.62 GPa and 0.14–0.28 GPa respectively. Calculation results suggest that the primary magma originated from a mantle region deeper than 68 km and stagnates in intervals of 37–68 km, 15–20 km and 5–9 km during its ascent. The alkali basalts are characterized by increasing concentrations of Si and alkaline with the magmatic evolution. Meanwhile, they are markedly enriched in LREE, and the patterns of trace elements and REE are similar to those of oceanic island basalts.
U and Th Contents and Th/U Ratios of Zircon in Felsic and Mafic Magmatic Rocks: Improved Zircon‐Melt Distribution Coefficients
Authors: Xiang WANG , GRIFFIN Williams L. , Jie CHEN , Pinyun HUANG , Xiang LI
Published: February 2011

High‐precision data on U and Th contents and Th/U ratios of zircon obtained using secondary ion mass spectrometry analysis have been collected from the literature. Zircon in the granitic rocks has median values of 350 ppm U, 140 ppm Th, and Th/U=0.52; the recommended zircon‐melt partition coefficients are 81 for DU and 8.2 for DTh. In zircon from mafic and intermediate rocks, the median values are 270 ppm U, 170 ppm Th, and Th/U=0.81, and the recommended zirconmelt partition coefficients are 169 for DU and 59 for DTh The U and Th contents and Th/U ratios of magmatic zircon are low when zircon crystallizes in equilibrium with the melt. Increasing magma temperature should promote higher Th contents relative to U contents, resulting in higher Th/U ratios for zircon in mafic to intermediate rocks than in granitic rocks. However, when zircon crystallizes in disequilibrium with the melt, U and Th are more easily able to enter the zircon lattice, and their contents and Th/U ratios depend mainly on the degree of disequilibrium. The behavior of U and Th in magmatic zircon can be used as a geochemical indicator to determine the origins and crystallization environments of magmatic zircon.
X‐ray Diffraction of Dust Particles in Spring Beijing
Authors: Nan ZHENG , Hejin WANG , Tingjing XU , Ting LI
Published: February 2011

X‐ray diffractometry was utilized to study the mineralogical characteristics of the inhalable particles (PM10) sampled during two dust storms in Beijing city on March 18th and May 21st, 2008. We confirm, for the first time, that there stably exists ammonium chloride in the atmosphere when temperature is low. The total sulfates particles were affected by relative humidity. Both species and concentration of sulfates decreased first and then grew back by the end of each dust storm. Koninckite, a phosphate mineral never reported as particulate aerosol before, was identified. Meanwhile, our result shows that a chemical modification on dust minerals occurs during long range transportation. PM10 samples collected during the period of dust storms were dominated by crustal minerals such as quartz, illite/ smectite, illite, chlorite, feldspar and calcite, and were notably higher in concentration than that in normal periods of time. The amounts of total sulfates, calcite and feldspar altered in each dust storm. It is derived from 24‐hour isentropic backward trajectories that two dust events in spring 2008 originated in different sources.
Fractions and Bioavailability of Soil Inorganic Phosphorus in the Loess Plateau of China under Different Vegetations
Authors: Xiaorong WEI , Mingan SHAO , Hongbo SHAO , Jianlun GAO , Gang XU
Published: February 2011

Plants play an important role in soil phosphorus nutrition. However, the effect of plants on phosphorus nutrition in soils of the Loess Plateau of China is not well understood. This study was conducted to reveal the relationships between plants and phosphorus' fractions and availability in the Loess Plateau of China. Twenty‐two plant communities were surveyed and soil samples under different plant canopies were collected for the determination of soil properties and inorganic phosphorus fractionation. The results showed that Leguminosae and Lilaceae reduced pH and increased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies, while Labiatae and Rosaceae increased pH and decreased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies. The contents of Ca2P, Ca8P, Al‐P and Fe‐P were highly related with soil Olsen phosphorus. They were all higher in soils under Leguminosae and Lilaceae and lower in soils under Labiatae and Rosaceae. The results of this study indicate that Leguminosae and Lilaceae improved phosphorus nutrition in soils, yet Labiatae and Rosaceae impeded the improvement of phosphorus nutrition in soils under their canopies, which will be of more help to instruct vegetation restoration in the region and provide information for soil development.
Using SAS PROC TCALIS for multigroup structural equation modelling with mean structures
Authors: Gu Fei , Wu Wei
Published: February 2011

Multigroup structural equation modelling (SEM) is a technique frequently used to evaluate measurement invariance in social and behavioural science research. Before version 9.2, SAS was incapable of handling multigroup SEM. However, this limitation is resolved in PROC TCALIS in SAS 9.2. For the purpose of illustration, this paper provides a step‐by‐step guide to programming the tests of measurement invariance and partial invariance using PROC TCALIS for multigroup SEM with mean structures. Fit indices and parameter estimates are validated, thus providing an alternative tool for researchers conducting both applied and simulated studies. Other new features (e.g., different types of modelling languages and estimation methods) and limitations (e.g., ordered‐categorical SEM and multilevel SEM) of the TCALIS procedure are also briefly discussed.
Assessing ‘good’ qualitative research in the work psychology field: A narrative analysis
Authors: Cassell Catherine , Symon Gillian
Published: February 2011

This paper considers how work psychologists define ‘good’ qualitative research in the work psychology domain. In addressing the assessment of quality in work psychology research, we draw on 22 in‐depth interviews with work psychologists about their current practices and expectations around qualitative research. Using narrative analysis, the various plots and narratives that constitute how interviewees understand good qualitative research are identified. The implications of the use of these narratives for both how quality is understood and the use of qualitative research in this area are addressed. Drawing on Weick's concept of sensemaking as a theoretical framework, it is argued that the narratives identified enable the construction of a hegemonic understanding of what is good methodological practice within the work psychology discipline. The implications of this for the work psychology field and the methodological practices of work psychologists are considered.
Is the function field of a reductive Lie algebra purely transcendental over the field of invariants for the adjoint action?
Authors: Colliot-Thélène Jean-Louis , Kunyavskiĭ Boris , Popov Vladimir L. , Reichstein Zinovy
Published: February 2011

Letkbe a field of characteristic zero, letGbe a connected reductive algebraic group overkand let 𝔤 be its Lie algebra. Letk(G), respectively,k(𝔤), be the field ofk-rational functions onG, respectively, 𝔤. The conjugation action of Gon itself induces the adjoint action of Gon 𝔤. We investigate the question whether or not the field extensionsk(G)/k(G)Gandk(𝔤)/k(𝔤)Gare purely transcendental. We show that the answer is the same fork(G)/k(G)Gandk(𝔤)/k(𝔤)G, and reduce the problem to the case whereGis simple. For simple groups we show that the answer is positive ifGis split of typeAnorCn, and negative for groups of other types, except possiblyG2. A key ingredient in the proof of the negative result is a recent formula for the unramified Brauer group of a homogeneous space with connected stabilizers. As a byproduct of our investigation we give an affirmative answer to a question of Grothendieck about the existence of a rational section of the categorical quotient morphism for the conjugating action of Gon itself.
Erythropoietic and non‐erythropoietic functions of erythropoietin in mouse models
Authors: Vogel Johannes , Gassmann Max
Published: February 2011

Abstract As the basic function of erythropoietin (Epo) is stimulation of red blood cell production, systemic overexpression of Epo results in erythrocytosis. The patho‐physiological consequences of chronically elevated red blood cell counts have been studied in Epo overexpressing mice. Genetically modified mice, however, have also played an important role in discovering multiple additional functions of Epo besides stimulating erythrocyte production. Non‐erythropoietic functions of Epo are widespread and play a role in organogenesis during early embryonic development and in tissue protection in ischaemic diseases. Future work in the field will most likely focus on these additional functions of Epo, which have great clinical potential.
Relaxation gating of the acetylcholine‐activated inward rectifier K+ current is mediated by intrinsic voltage sensitivity of the muscarinic receptor
Authors: Moreno‐Galindo Eloy G. , Sánchez‐Chapula José A. , Sachse Frank B. , Rodríguez‐Paredes J. Alberto , Tristani‐Firouzi Martin , Navarro‐Polanco Ricardo A.
Published: February 2011

Non‐technical summary  Normal heart rate variability is critically dependent upon the G‐protein‐coupled, acetylcholine (ACh)‐activated inward rectifier K+ current, IKACh. A unique feature of IKACh is the so‐called ‘relaxation’ gating property that contributes to increased current at hyperpolarized membrane potentials. Here, we consider a novel explanation for IKACh relaxation based upon the recent finding that G‐protein‐coupled receptors are intrinsically voltage sensitive and that the muscarinic agonists acetylcholine and pilocarpine manifest opposite voltage‐dependent IKACh modulation. Based on experimental and computational findings, we propose that IKACh relaxation represents a voltage‐dependent change in agonist affinity as a consequence of a voltage‐dependent conformational change in the muscarinic receptor.
Modeling MEMS Resonators Past Pull-In
Authors: Vyasarayani Chandrika P. , Abdel-Rahman Eihab M. , McPhee John , Birkett Stephen
Published: February 2011

In this paper, we develop a mathematical model of an electrostatic MEMS (Micro-Electro-Mechanical systems) beam undergoing impact with a stationary electrode subsequent to pull-in. We model the contact between the beam and the substrate using a nonlinear foundation of springs and dampers. The system partial differential equation is converted into coupled nonlinear ordinary differential equations using the Galerkin method. A numerical solution is obtained by treating all nonlinear terms as external forces. We use the model to predict the contact length, natural frequencies, and mode shapes of the beam past pull-in voltage as well as the dynamic response of a shunt switch in a closing and opening sequence.
Analytical Stability Analysis of Surface Vessel Trajectories for a Control-Oriented Model
Authors: Whitman Alan M. , Ashrafiuon Hashem , Muske Kenneth R.
Published: February 2011

An analytical stability analysis of the steady trajectory for a surface vessel with various damping models is presented in this work. The analysis is based on a control-oriented, three degrees-of-freedom model that considers vessel motion only in the horizontal plane. The goal of this study is to understand the vessel trajectories predicted by this reduced order model for model-based control design. Straight line and circular motion stability conditions for each trajectory are derived and presented for the various damping models. The results of this analysis show that either a straight line or a circular steady trajectory is possible, depending on the magnitude of the surge force and the form of the damping model used to represent viscous drag, vortex shedding, and losses due to the surface wake generated by the vessel motion. However, the straight line motion is much less likely for the vessel considered in this work.
Biologically Meaningful Keywords for Functional Terms of the Functional Basis
Authors: Cheong H. , Chiu I. , Shu L. H. , Stone R. B. , McAdams D. A.
Published: February 2011

Biology is recognized as an excellent source of analogies and stimuli for engineering design. Previous work focused on the systematic identification of relevant biological analogies by searching for instances of functional keywords in biological information in natural-language format. This past work revealed that engineering keywords could not always be used to identify the most relevant biological analogies as the vocabularies between biology and engineering are sufficiently distinct. Therefore, a retrieval algorithm was developed to identify potential biologically meaningful keywords that are more effective in searching biological text than corresponding engineering keywords. In our current work, we applied and refined the retrieval algorithm to translate functional terms of the functional basis into biologically meaningful keywords. The functional basis is widely accepted as a standardized representation of engineering product functionality. Therefore, our keywords could serve as a thesaurus for engineers to find biological analogies relevant to their design problems. We also describe specific semantic relationships that can be used to identify biologically meaningful keywords in excerpts describing biological phenomena. These semantic relations were applied as criteria to identify the most useful biologically meaningful keywords. Through a preliminary validation experiment, we observed that different translators were able to apply the criteria to identify biologically meaningful keywords with a high degree of agreement to those identified by the authors. In addition, we describe how fourth-year undergraduate mechanical engineering students used the biologically meaningful keywords to develop concepts for their design projects.
Mitochondrial Membrane Potential Is Required for MAVS-Mediated Antiviral Signaling
Authors: Koshiba Takumi , Yasukawa Kai , Yanagi Yusuke , Kawabata Shun-ichiro
Published: February 2011

The contribution of mitochondria to antiviral immune responses extends beyond their role as a platform for antiviral signaling molecules.
Wnt Signaling Regulates Hepatic Metabolism
Authors: Liu Hongjun , Fergusson Maria M. , Wu J. Julie , Rovira Ilsa I. , Liu Jie , Gavrilova Oksana , Lu Teng , Bao Jianjun , Han Donghe , Sack Michael N. , Finkel Toren
Published: February 2011

Nutrient deprivation triggers β-catenin–dependent expression of genes encoding gluconeogenic enzymes.
Flipping for Opsin
Authors: Adler Elizabeth M.
Published: February 2011

The G protein–coupled receptor opsin acts as a phospholipid flippase.
Intra- and Extracellular Activities of Dicloxacillin and Linezolid against a Clinical
Staphylococcus aureus
Strain with a Small-Colony-Variant Phenotype in an
In Vitro
Model of THP-1 Macrophages and an
In Vivo
Mouse Peritonitis Model
Authors: Sandberg Anne , Lemaire Sandrine , Van Bambeke Françoise , Tulkens Paul M. , Hughes Diarmaid , von Eiff Christof , Frimodt-Møller Niels
Published: February 2011

The small-colony-variant (SCV) phenotype of
Staphylococcus aureus
has been associated with difficult-to-treat infections, reduced antimicrobial susceptibility, and intracellular persistence. This study represents a detailed intra- and extracellular investigation of a clinical wild-type (WT)
S. aureus
strain and its counterpart with an SCV phenotype both
in vitro
and
in vivo
, using the THP-1 cell line model and the mouse peritonitis model, respectively. Bacteria of both phenotypes infected the mouse peritoneum intra- and extracellularly. The SCV phenotype was less virulent and showed distinct bacterial clearance, a reduced multiplication capacity, and a reduced internalization ability. However, some of the SCV-infected mice were still culture positive up to 96 h postinfection, and bacteria of this phenotype could spread to the mouse kidney and furthermore revert to the more virulent WT phenotype in both the mouse peritoneum and kidney. The SCV phenotype is therefore, despite reduced virulence, an important player in
S. aureus
pathogenesis. In the THP-1 cell line model, both dicloxacillin (DCX) and linezolid (LZD) reduced the intracellular inocula of bacteria of both phenotypes by approximately 1 to 1.5 log
10
in vitro
, while DCX was considerably more effective against extracellular bacteria. In the mouse peritonitis model, DCX and LZD were also able to control both intra- and extracellular infections caused by either phenotype. Treatment with a single dose of DCX and LZD was, however, insufficient to clear the SCVs in the kidneys, and the risk of recurrent infection remained. This stresses the importance of an optimal dosing of the antibiotic when SCVs are present.
Chitosan Augments Photodynamic Inactivation of Gram-Positive and Gram-Negative Bacteria
Authors: Tsai Tsuimin , Chien Hsiung-Fei , Wang Tze-Hsien , Huang Ching-Tsan , Ker Yaw-Bee , Chen Chin-Tin
Published: February 2011

Antimicrobial photodynamic inactivation (PDI) was shown to be a promising treatment modality for microbial infections. This study explores the effect of chitosan, a polycationic biopolymer, in increasing the PDI efficacy against Gram-positive bacteria, including
Staphylococcus aureus
,
Staphylococcus epidermidis
,
Streptococcus pyogenes
, and methicillin-resistant
S. aureus
(MRSA), as well as the Gram-negative bacteria
Pseudomonas aeruginosa
and
Acinetobacter baumannii
. Chitosan at <0.1% was included in the antibacterial process either by coincubation with hematoporphyrin (Hp) and subjection to light exposure to induce the PDI effect or by addition after PDI and further incubation for 30 min. Under conditions in which Hp-PDI killed the microbe on a 2- to 4-log scale, treatment with chitosan at concentrations of as low as 0.025% for a further 30 min completely eradicated the bacteria (which were originally at ∼10
8
CFU/ml). Similar results were also found with toluidine blue O (TBO)-mediated PDI in planktonic and biofilm cells. However, without PDI treatment, chitosan alone did not exert significant antimicrobial activity with 30 min of incubation, suggesting that the potentiated effect of chitosan worked after the bacterial damage induced by PDI. Further studies indicated that the potentiated PDI effect of chitosan was related to the level of PDI damage and the deacetylation level of the chitosan. These results indicate that the combination of PDI and chitosan is quite promising for eradicating microbial infections.
Lacticin Q-Mediated Selective Toxicity Depending on Physicochemical Features of Membrane Components
Authors: Yoneyama Fuminori , Ohno Kanako , Imura Yuichi , Li Mengqi , Zendo Takeshi , Nakayama Jiro , Matsuzaki Katsumi , Sonomoto Kenji
Published: February 2011

Lacticin Q, a lactococcal pore-forming bacteriocin, shows activity toward Gram-positive bacteria but not Gram-negative bacteria. Lacticin Q did not induce permeability of the outer membrane of Gram-negative bacteria. Experiments using model membranes containing outer membrane components suggested that lacticin Q binds to the outer membrane of Gram-negative bacteria but is unable to penetrate it. The lack of activity of lacticin Q was attributed to physicochemical features of the outer membrane components.
In Vivo
Efficacy of the Novel Aminoglycoside ACHN-490 in Murine Infection Models
Authors: Reyes Noe , Aggen James B. , Kostrub Corwin F.
Published: February 2011

Aminoglycosides are broad-spectrum antibiotics with particular clinical utility against life-threatening infections. As resistance to antibiotics, including aminoglycosides, continues to grow, there is a need for new and effective antimicrobial agents. ACHN-490 is a novel aminoglycoside in clinical development with activity against multidrug-resistant Gram-negative and select Gram-positive pathogens. Here we assess the
in vivo
efficacy of ACHN-490 against a variety of common pathogens in two murine models: the septicemia and neutropenic thigh models. When its activity against a gentamicin-susceptible strain of
Escherichia coli
was tested in the septicemia model, ACHN-490 improved 7-day survival with a dose-response profile similar to that of gentamicin, with 100% survival seen at doses of 1.6 mg/kg of body weight and above. In animals infected with a gentamicin-susceptible strain of
Pseudomonas aeruginosa
, treatment with either ACHN-490 or gentamicin led to 100% survival at doses of 16 mg/kg and above in the septicemia model. ACHN-490 was also effective in the neutropenic thigh model, reducing multidrug-resistant
Enterobacteriaceae
family and methicillin-resistant
Staphylococcus aureus
strains, as well as broadly susceptible strains, to static levels with dose-dependent activity. Against gentamicin-sensitive
Enterobacteriaceae
and methicillin-resistant
S. aureus
, the efficacy of ACHN-490 was comparable to that of gentamicin. However, gentamicin-resistant
Enterobacteriaceae
strains and those harboring the
Klebsiella pneumoniae
carbapenemase responded to ACHN-490 but not gentamicin, with static doses ranging from 12 mg/kg to 64 mg/kg for ACHN-490. These results suggest that ACHN-490 has the potential to become a clinically useful agent against drug-resistant pathogens, including
Enterobacteriaceae
,
P. aeruginosa
, and methicillin-resistant
S. aureus
, and support further development of this promising novel aminoglycoside.
C-Terminal Amino Acids of Alpha-Melanocyte-Stimulating Hormone Are Requisite for Its Antibacterial Activity against Staphylococcus aureus
Authors: Singh Madhuri , Mukhopadhyay Kasturi
Published: February 2011

Alpha-melanocyte-stimulating hormone (α-MSH) is an endogenous neuropeptide that is known for its anti-inflammatory and antipyretic activities. We recently demonstrated that α-MSH possesses staphylocidal activity and causes bacterial membrane damage. To understand the role of its amino acid sequences in the staphylocidal mechanism, in the present study we investigated the antimicrobial activities of different fragments of α-MSH, i.e., α-MSH(6-13), α-MSH(11-13), and α-MSH(1-5), and compared them with that of the entire peptide. Our results showed that peptides containing the C-terminal region of α-MSH, namely, α-MSH(6-13) and α-MSH(11-13), efficiently killed >90% of both methicillin-sensitive and -resistantStaphylococcus aureuscells in the micromolar range and ∼50% of these cells in the nanomolar range; their efficiency was comparable to that of the entire α-MSH, whereas the peptide containing the N-terminal region, α-MSH(1-5), was found to be ineffective againstS. aureus. The antimicrobial activity of α-MSH and its C-terminal fragments was not affected by the presence of NaCl or even divalent cations such as Ca2+and Mg2+. Similar to the case for the parent peptide, α-MSH(6-13) and α-MSH(11-13) also depolarized and permeabilizedStaphylococcuscells (∼70 to 80% of the cells were depolarized and lysed after 2 h of peptide exposure at micromolar concentrations). Furthermore, scanning and transmission electron microscopy showed remarkable morphological and ultrastructural changes onS. aureuscell surface due to exposure to α-MSH-based peptides. Thus, our observations indicate that C-terminal fragments of α-MSH retain the antimicrobial activity of entire peptide and that their mechanism of action is similar to that of full-length peptide. These observations are important and are critical in the rational design of α-MSH-based therapeutics with optimal efficacy.
Deciphering the Mode of Action of the Synthetic Antimicrobial Peptide Bac8c
Authors: Spindler E. C. , Hale J. D. F. , Giddings T. H. , Hancock R. E. W. , Gill R. T.
Published: February 2011

Bac8c (RIWVIWRR-NH
2
) is an 8-amino-acid peptide derived from Bac2A (RLARIVVIRVAR-NH
2
), a C3A/C11A variant of the naturally occurring bovine peptide, bactenecin (also known as bovine dodecapeptide), the smallest peptide with activity against a range of pathogenic Gram-positive and Gram-negative bacteria, as well as yeast. The effects of Bac8c on
Escherichia coli
were examined by studying its bacteriostatic and bactericidal properties, demonstrating its effects on proton motive force generation, and visually analyzing (via transmission electron microscopy) its effects on cells at different concentrations, in order to probe the complexities of the mechanism of action of Bac8c. Results were consistent with a two-stage model for the Bac8c mode of action. At sublethal concentrations (3 μg/ml), Bac8c addition resulted in transient membrane destabilization and metabolic imbalances, which appeared to be linked to inhibition of respiratory function. Although sublethal concentrations resulted in deleterious downstream events, such as methylglyoxal formation and free radical generation, native
E. coli
defense systems were sufficient for full recovery within 2 h. In contrast, at the minimal bactericidal concentration (6 μg/ml), Bac8c substantially but incompletely depolarized the cytoplasmic membrane within 5 min and disrupted electron transport, which in turn resulted in partial membrane permeabilization and cell death.
Differential Phenotypic and Genotypic Characteristics of
qnrS1
-Harboring Plasmids Carried by Hospital and Community Commensal Enterobacteria
Authors: Vien Le Thi Minh , AbuOun Manal , Morrison Victoria , Thomson Nicholas , Campbell James I. , Woodward Martin J. , Van Vinh Chau Nguyen , Farrar Jeremy , Schultsz Constance , Baker Stephen
Published: February 2011

The
qnrS1
gene induces reduced susceptibility to fluoroquinolones in enterobacteria. We investigated the structure, antimicrobial susceptibility phenotype, and antimicrobial resistance gene characteristics of
qnrS1
plasmids from hospitalized patients and community controls in southern Vietnam. We found that the antimicrobial susceptibilities, resistance gene characteristics, and plasmid structures of
qnrS1
plasmids from the hospital differed from those from the community. Our data imply that the characteristics of the two plasmid groups are indicative of distinct selective pressures in the differing environments.
In Vitro
Pharmacodynamics of Simulated Pulmonary Exposures of Tigecycline Alone and in Combination against
Klebsiella pneumoniae
Isolates Producing a KPC Carbapenemase
Authors: Wiskirchen Dora E. , Koomanachai Pornpan , Nicasio Anthony M. , Nicolau David P. , Kuti Joseph L.
Published: February 2011

Multidrug-resistant
Klebsiella pneumoniae
strains that produce a serine carbapenemase (KPC) are emerging worldwide, with few therapeutic options that retain consistent susceptibility. The objective of this study was to determine the effect of combination therapy with tigecycline versus tigecycline alone against KPC-producing isolates (KPC isolates). An
in vitro
pharmacodynamic model was used to simulate adult steady-state epithelial lining fluid concentrations of tigecycline (50 mg every 12 h) given alone and in combination with either meropenem (2 g by 3-hour infusion every 8 h) or rifampin (600 mg every 12 h). Five KPC isolates with various phenotypic profiles were exposed over 48 h. Time-kill curves were constructed, and the areas under the bacterial killing and regrowth curves (AUBCs) were calculated. No regimens tested were able to maintain bactericidal reductions in CFU over 48 h. The AUBCs for tigecycline and meropenem monotherapies at 48 h ranged from 375.37 to 388.11 and from 348.62 to 383.83 (CFU-h/ml), respectively. The combination of tigecycline plus meropenem significantly reduced the AUBCs at 24 and 48 h for isolates with tigecycline MICs of ≤2 μg/ml and meropenem MICs of ≤16 μg/ml (
P
< 0.001) but added no additional activity when the meropenem MIC was 64 μg/ml (
P
= 0.5). Rifampin provided no additional reduction in CFU or AUBC over tigecycline alone (
P
= 0.837). The combination of tigecycline with high-dose, prolonged-infusion meropenem warrants further study as a potential treatment option for these multidrug-resistant organisms.
Klebsiella pneumoniae
Outer Membrane Porins OmpK35 and OmpK36 Play Roles in both Antimicrobial Resistance and Virulence
Authors: Tsai Yu-Kuo , Fung Chang-Phone , Lin Jung-Chung , Chen Jiun-Han , Chang Feng-Yee , Chen Te-Li , Siu L. Kristopher
Published: February 2011

OmpK35 and OmpK36 are the major outer membrane porins of
Klebsiella pneumoniae
. In this study, a virulent clinical isolate was selected to study the role of these two porins in antimicrobial resistance and virulence. The single deletion of
ompK36
(Δ
ompK36
) resulted in MIC shifts of cefazolin, cephalothin, and cefoxitin from susceptible to resistant, while the single deletion of
ompK35
(Δ
ompK35
) had no significant effect. A double deletion of
ompK35
and
ompK36
(Δ
ompK35/36
) further increased these MICs to high-level resistance and led to 8- and 16-fold increases in the MICs of meropenem and cefepime, respectively. In contrast to the routine testing medium, which is of high osmolarity, susceptibility tests using low-osmolarity medium showed that the Δ
ompK35
mutation resulted in a significant (≥4-fold) increase in the MICs of cefazolin and ceftazidime, whereas a Δ
ompK36
deletion conferred a significantly (4-fold) lower increase in the MIC of cefazolin. In the virulence assays, a significant (
P
< 0.05) defect in the growth rate was found only in the Δ
ompK35/36
mutant, indicating the effect on metabolic fitness. A significant (
P
< 0.05) increase in susceptibility to neutrophil phagocytosis was observed in both Δ
ompK36
and Δ
ompK35/36
mutants. In a mouse peritonitis model, the Δ
ompK35
mutant showed no change in virulence, and the Δ
ompK36
mutant exhibited significantly (
P
< 0.01) lower virulence, whereas the Δ
ompK35/36
mutant presented the highest 50% lethal dose of these strains. In conclusion, porin deficiency in
K. pneumoniae
could increase antimicrobial resistance but decrease virulence at the same time.