bluuebunny/crossref_metadata_2025 huggingface dataset:
CobB1 deacetylase activity in Streptomyces coelicolor
Authors: Mikulik Karel , Felsberg Jurgen , Kudrnáčová Eva , Bezoušková Silvia , Šetinová Dita , Stodůlková Eva , Zídková Jarmila , Zídek Václav
Published: March 2012

Silent information regulators are NAD+-dependent enzymes that display differential specificity toward acetylated substrates. This report provides first evidence for deacetylation activity of CobB1 in Streptomyces coelicolor. The protein is highly conserved in streptomycetes. The CobB1 protein catalytically removes the acetyl group from acetylated bovine serum albumin. In the absence of NAD+ or when NAD+ was substituted with nicotinamide, deacetylation was stopped. We isolated gene encoding AcetylCoA synthetaseA. The recombinant enzyme produces Acetyl-CoA from acetate. The highest acsA-mRNA level was detected in cells from the exponential phase of growth, and then decreased in transition and stationary phases of growth. Acetylated acsA loses the ability to transfer acetate to CoA. Deacetylation of the enzyme required CobB1, ATP-Mg2, and NAD+. Using specific antibodies against acetylated lys, CobB1, and acsA, we found relationship between level of CobB1 and acetylation of acsA, indicating that CobB1 is involved in regulating the acetylation level of acsA and consequently its activity. It was found that 1-acetyl-tetrahydroxy and 1-acetyl pentahydroxy antraquinone inhibit the deacetylation activity of CobB1.
Dihydroceramide accumulation and reactive oxygen species are distinct and nonessential events in 4-HPR-mediated leukemia cell death
Authors: Apraiz Aintzane , Idkowiak-Baldys Jolanta , Nieto-Rementería Naiara , Boyano María Dolores , Hannun Yusuf A , Asumendi Aintzane
Published: March 2012

4-(Hydroxyphenyl)retinamide (4-HPR) is a synthetic retinoid with a strong apoptotic effect towards different cancer cell lines in vitro, and it is currently tested in clinical trials. Increases of reactive oxygen species (ROS) and modulation of endogenous sphingolipid levels are well-described events observed upon 4-HPR treatment, but there is still a lack of understanding of their relationship and their contribution to cell death. LC–MS analysis of sphingolipids revealed that in human leukemia CCRF-CEM and Jurkat cells, 4-HPR induced dihydroceramide but not ceramide accumulation even at sublethal concentrations. Myriocin prevented the 4-HPR-induced dihydroceramide accumulation, but it did not prevent the loss of viability and increase of intracellular ROS production. On the other hand, ascorbic acid, Trolox, and vitamin E reversed 4-HPR effects on cell death but not dihydroceramide accumulation. NDGA, described as a lipoxygenase inhibitor, exerted a significantly higher antioxidant activity than vitamin E and abrogated 4-HPR-mediated ROS. It did not however rescue cellular viability. Taken together, this study demonstrates that early changes observed upon 4-HPR treatment, i.e., sphingolipid modulation and ROS production, are mechanistically independent events. Furthermore, the results indicate that 4-HPR-driven cell death may occur even in the absence of dihydroceramide or ROS accumulation. These observations should be taken into account for an improved design of drug combinations.
Effect of spatial correlation of standard penetration test (SPT) data on bearing capacity of driven piles in sand
Authors: Zhang Lianyang , Chen Jin-Jian
Published: March 2012

In this paper, the effect of spatial correlation of standard penetration test (SPT) data on the bearing capacity of driven piles in sand is analyzed. First, the direct approach for using SPT data to determine the bearing capacity of piles in sand is used to derive the expressions for probabilistic prediction of pile bearing capacity by considering the spatial correlation of the SPT data. To analyze the relationship between the probability of failure and the factor of safety, a procedure based on the advanced first-order, second-moment (FOSM) method is used. Then parametric studies are conducted on the spatial correlation between the spatial average of SPT numbers over the pile length, NLV, and the spatial average of SPT numbers over an interval near the pile base, NbV, and its effect on the bearing capacity of piles. The results indicate that it is important to consider the spatial correlation between NLVand NbVin the probabilistic prediction of pile bearing capacity. Ignoring this spatial correlation will underestimate the probability of failure and lead to unsafe design. Finally, three tested piles are analyzed to demonstrate the probabilistic analysis of piles by considering the spatial correlation of SPT data and the procedure for probabilistic analysis of pile bearing capacity is summarized.
Physical models of rock avalanche spreading behaviour with dynamic fragmentation
Authors: Bowman E.T. , Take W.A. , Rait K.L. , Hann C.
Published: March 2012

The dynamic fragmentation of rock during avalanche motion has been postulated as a mechanism explaining the long runout of large rock avalanches or Sturzströme. This paper investigates whether test conditions that produce dynamic fragmentation can lead to greater runout or spreading of physical model rock avalanches. Model avalanche experiments were carried out under enhanced acceleration to generate breakage in coal, a fragmentable, brittle solid. Coal blocks were released from a stationary position on a slope to run out on a plane. The motion of the ensuing fragmenting debris was captured using a high-speed camera placed above the horizontal plane. The average position of the front was tracked and the degree of fragmentation of the model avalanches was quantified. The paper presents results of the frontal velocity of the avalanches, corrected for centrifuge Coriolis effects. Comparison is made between the peak and impulsive front velocities, the final runout, and the degree of fragmentation of the model avalanches. Strong relationships are found between runout normalized by the cube root of volume, impulse velocity, and Hardin’s relative breakage parameter, BR. Results are discussed in light of the mechanics involved and are compared with field-scale events.
Quasi-classical trajectory calculation of the chemical reaction Sr + CF3I
Authors: Xia Wenwen , Huang Xinting , Yao Li , Zhong Haiyang
Published: March 2012

In this paper, the dynamical properties of the product SrI, which is formed in the reaction Sr + CF3I, were studied by means of the quasi-classical trajectory method based on the extended London–Eyring–Polanyi–Sato potential energy surface. The vibrational distribution, rotational distribution, reaction cross section, and rotational alignment of the product SrI were calculated, and the mechanism of the title reaction has also been discussed. The calculated vibrational and rotational distributions show that their peak values are located at v = 23 and J = 110 at a collision energy of Ecol = 0.83 eV. These results are in good agreement with the results in Stolte’s experiment. And the results obtained in this paper also indicate that the reaction cross section increases with increasing collision energy (from 0.5 to 1.5 eV), whereas the product rotational alignment decreases.
Reaction mechanism and kinetics of the atmospheric oxidation of 1,4-thioxane by NO3 — A theoretical study
Authors: Sandhiya L. , Kolandaivel P. , Senthilkumar K.
Published: March 2012

Volatile organic compounds (VOCs) are emitted as pollutants into the atmosphere from many natural and artificial sources. The oxidation of VOCs by atmospheric species plays a key role in the degradation of VOCs. In the present investigation, the atmospheric degradation of a cyclic organosulfur compound, 1,4-thioxane, by an NO3• radical is studied. Pathways for the reaction of 1,4-thioxane with the NO3• radical were modeled through electronic structure calculations using density functional theory methods B3LYP, M06-2X, and MP2 with the 6–31G(d,p) basis set. The NO3•-initiated reaction of 1,4-thioxane was found to proceed in three ways: by single-hydrogen atom abstraction, by direct transfer of the O atom of NO3• to the S atom moiety of 1,4-thioxane, or by two-hydrogen atom transfer reactions leading to the formation of a peroxy radical intermediate, which further undergoes secondary reactions with other atmospheric species. Structures, energies, and vibrational frequencies obtained from M06-2X/6–31G(d,p) electronic structure calculations were subsequently used to perform canonical variational transition-state theory calculations to determine the rate constants over the temperature range of 278–350 K and to study the lifetime of 1,4-thioxane in the atmosphere. The rate constant calculated for the reaction of 1,4-thioxane with the NO3• radical is in good agreement with the available experimental data.
Rainfall pulse primarily drives litterfall respiration and its contribution to soil respiration in a young exotic pine plantation in subtropical China
Authors: Wang Yidong , Wang Zhong-Liang , Wang Huimin , Guo Changcheng , Bao Wankui
Published: March 2012

Although litterfall respiration (RL) is a key process of soil carbon dynamics in forests, factors that drive RL and its contribution to soil respiration (RS) have not been sufficiently studied. Using a litter removal method, we researched RL and the ratio of RL:RS in a 20-year-old exotic slash pine ( Pinus elliottii Englem.) plantation in subtropical China. Soil temperature explained 67%, 78%, and 25% of variation in RS, mineral soil respiration (RS-L), and RL, respectively, but had little impact on RL:RS. To study influences besides temperature, measured RS and RS-L were normalized using the Arrhenius equation. Even though this subtropical plantation was characterized by a humid climate with abundant precipitation, a rainfall pulse induced increase in soil moisture primarily drove RL and its contribution to RS but depressed RS-L. The response of RL to rainfall and soil moisture was significantly more sensitive than that of RS-L. Furthermore, the effects of rainfall and soil moisture on RS, RL, and RL:RS were higher during the dry season (July–December) than during the wet season (January–June). In the context of climate change, RL and its contribution to RS are expected to decrease because of the predicted decrease in rainfall amount and frequency in subtropical regions.
Evaluation of nonlinear equations for predicting diameter from tree height
Authors: Bi Huiquan , Fox Julian C. , Li Yun , Lei Yuancai , Pang Yong
Published: March 2012

With the emergence and advancement of airborne laser scanning technology over the past decade, individual tree height can be easily measured over a large area of forests with a comparable degree of accuracy to conventional ground-based methods. In laser scanning based large-scale forest inventories, the need to predict diameter from remotely sensed tree height calls for a systematic evaluation of equation forms as the first step towards a well-developed approach to developing diameter–height equations. This study evaluated more than 30 height–diameter equations in the forest biometrics literature to select candidates for deriving equation forms for diameter–height equations. The evaluation was based on four criteria: (i) the height–diameter function is inversable; (ii) the inverse function is continuous and monotonically increasing over a specified working range of total tree height; (iii) diameter at breast height is equal to zero when tree height equals breast height in the inverse function; and preferably, (iv) the inverse function has an inflection point that is consistent with biological expectations. A total of 12 candidate equation forms were derived, which included five two-parameter and seven three-parameter equations. The estimation properties and predictive performance of these 12 equation forms were further evaluated and compared through repeated sampling and fitting using data from 3581 trees destructively sampled for taper measurements from Pinus radiata D. Don plantations across New South Wales, Australia. Three equation forms, including the constrained Richards, Weibull, and the combined power and exponential function, displayed superior prediction accuracy and estimation properties and so were recommended as the primary equation forms for developing diameter–height equations. The remaining equation forms were marred by either lower prediction accuracy or poorer estimation properties or both. The three recommended equation forms should only serve as basic deterministic specifications upon which other tree and stand variables should be incorporated as predictors to further improve their predictive performance.
A difference equation approach to developing tree profile equations
Authors: Matney Thomas G. , Schultz Emily B. , Crosby Michael K.
Published: March 2012

A second-order constant-coefficient nonhomogeneous difference equation is presented as a template for deriving a model form to predict above breast height tree stem profiles. Comparative analysis of the precision and bias of the model with several commonly used polynomial models on a white oak ( Quercus alba L.) tree profile data set indicates that the difference approach produces profile equations equivalent in precision and bias to the traditional methods for constructing profile equations. Because the fitted equations can be forced easily through two upper stem diameters, the model has the distinct advantage over other modeling methods by allowing the model to be adjustable for differing form classes and points. Also, because the solution of the difference equation is always path invariant, no matter which stem profile diameters the equation is forced through, the same tree profile is generated. As the method does not require a total height, it is adaptable to situations where profile measurements are only taken to an indefinite merchantable height.
Chemical transformations of deadwood and foliar litter of mixed boreal species during decomposition
Authors: Strukelj Manuella , Brais Suzanne , Quideau Sylvie A. , Oh Se-Woung
Published: March 2012

Deadwood constitutes an important input of carbon to soil, but its role in carbon sequestration over the long term is not well documented in the eastern boreal forests of Canada, especially when compared with foliar litter. The objectives of this study were to characterize and compare patterns of mass loss and changes in chemical composition of deadwood and foliar litter of trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.) during a 5- to 6-year period of field decomposition, using litterbags, solid-state 13C nuclear magnetic resonance analysis, and lignin monomer quantification by cupric oxide oxidation. The maximum decomposition limit was similar between foliar litter and wood material, but foliar litter decomposed faster, reached the estimated maximum decomposition limit, and converged to a composition rich in alkyl, phenolic, and carbonyl carbon. However, wood did not reach the estimated maximum decomposition limit and underwent relatively little chemical changes, remaining with high carbohydrate content. At the end of the experiment, aspen wood still had a lower lignin concentration than that of conifers, but contained higher proportions of alkyl and carbonyl carbon. Although wood contributes to a greater diversity in the chemical composition of the forest floor, foliar litter, which keeps a high alkyl C content throughout its decay, could generate more recalcitrant residual organic matter.
BINDING AND SEGMENTATION VIA A NEURAL MASS MODEL TRAINED WITH HEBBIAN AND ANTI-HEBBIAN MECHANISMS
Authors: CONA FILIPPO , ZAVAGLIA MELISSA , URSINO MAURO
Published: March 2012

Synchronization of neural activity in the gamma band, modulated by a slower theta rhythm, is assumed to play a significant role in binding and segmentation of multiple objects. In the present work, a recent neural mass model of a single cortical column is used to analyze the synaptic mechanisms which can warrant synchronization and desynchronization of cortical columns, during an autoassociation memory task. The model considers two distinct layers communicating via feedforward connections. The first layer receives the external input and works as an autoassociative network in the theta band, to recover a previously memorized object from incomplete information. The second realizes segmentation of different objects in the gamma band. To this end, units within both layers are connected with synapses trained on the basis of previous experience to store objects. The main model assumptions are: (i) recovery of incomplete objects is realized by excitatory synapses from pyramidal to pyramidal neurons in the same object; (ii) binding in the gamma range is realized by excitatory synapses from pyramidal neurons to fast inhibitory interneurons in the same object. These synapses (both at points i and ii) have a few ms dynamics and are trained with a Hebbian mechanism. (iii) Segmentation is realized with faster AMPA synapses, with rise times smaller than 1 ms, trained with an anti-Hebbian mechanism. Results show that the model, with the previous assumptions, can correctly reconstruct and segment three simultaneous objects, starting from incomplete knowledge. Segmentation of more objects is possible but requires an increased ratio between the theta and gamma periods.
ROBUST CONTROL OF CHAOTIC VIBRATION OF COMPOSITE PLATE IN THE PRESENCE OF NOISE USING SLIDING MODE METHOD
Authors: SHAMRAO  , NARAYANAN S.
Published: March 2012

Robust control of chaotic vibration in composite plate in the presence of noise using sliding mode control methodology is considered in this paper. The composite plate system has a combination of linear, quadratic and cubic stiffness terms. Robustness of the controller is analyzed with reference to the parametric variations of the system and external disturbances due to noise and compared with Pyragas control method. The composite plate considered is a six-layered rectangular antisymmetric cross-ply plate with immovable edges. The plate is assumed to be viscously damped and harmonically excited.
BURSTING INDUCED BY EXCITATORY SYNAPTIC COUPLING IN THE PRE-BÖTZINGER COMPLEX
Authors: DUAN LIXIA , ZHAI DEHONG , TANG XUHUI
Published: March 2012

In this paper, we study and classify the bursting in a two-cell network of excitatory neuron within the pre-Bötzinger complex of the mammalian brain stem. We investigate the effects of parameters g Na and g K on the bursting generation and pattern transitions in the two-cell model network with synaptic coupling by the fast–slow decomposition and bifurcation analysis approach. Comparing the firing patterns of the uncoupled and coupled cells, we found that the bursting patterns are the same both for a single and two-cell model network with the parameter g Na changed, while they are different with the parameter g K changed. Our results are instructive for further understanding the dependence of the complex firing activities of the network on the firing activities of the single cell in the network.
BIFURCATION OF PHASE AND EXACT TRAVELING WAVE SOLUTIONS OF A HIGHER-ORDER NONLINEAR SCHRÖDINGER EQUATION
Authors: YAN FANG , LIU HAIHONG
Published: March 2012

The dynamical behavior of a higher-order nonlinear Schrödinger equation is studied by using the bifurcation theory method of dynamical systems. With the aid of Maple, all bifurcations and phase portraits in the parametric space are obtained. Moreover, some new traveling wave solutions corresponding to the orbits on phase portraits are given, which include solitary wave solutions, kink and anti-kink wave solutions and periodic wave solutions.
Cognition in the Vegetative State
Authors: Monti Martin M.
Published: March 2012

Awake but not aware: This puzzling dissociation of the two central elements of consciousness defines the vegetative state. Traditionally, this condition has been believed to imply a brain with preserved hypothalamic and brainstem autonomic functions but with no capacity for cortical cognitive processes. As is discussed in this review, over a 20-year span neuroimaging techniques have clearly demonstrated that this characterization of patients in a vegetative state is incorrect. Contrary to the initial belief, the “vegetative” brain can retain several high-level aspects of cognitive functions, across sensory modalities, including language processing and learning dynamics. Nonetheless, the residual cognitive functions observed in vegetative patients might reflect intact but functionally disconnected cortical modules that do not give rise to the subjective feeling of phenomenological awareness.
From Dysfunction to Adaptation: An Interactionist Model of Dependency
Authors: Bornstein Robert F
Published: March 2012

Contrary to clinical lore, a dependent personality style is associated with active as well as passive behavior and may be adaptive in certain contexts (e.g., in fostering compliance with medical and psychotherapeutic treatment regimens). The cognitive/interactionist model conceptualizes dependency-related responding in terms of four components: (a) motivational (a marked need for guidance, support, and approval from others); (b) cognitive (a perception of oneself as powerless and ineffectual); (c) affective (a tendency to become anxious when required to function autonomously); and (d) behavioral (use of diverse self-presentation strategies to strengthen ties to potential caregivers). Clinicians' understanding of the etiology and dynamics of dependency has improved substantially in recent years; current challenges include delineating useful subtypes of dependency, developing valid symptom criteria for Dependent Personality Disorder in DSM-5 and beyond, and working effectively with dependent patients in the age of managed care.
Coping with Chronic Illness in Childhood and Adolescence
Authors: Compas Bruce E. , Jaser Sarah S. , Dunn Madeleine J. , Rodriguez Erin M.
Published: March 2012

Chronic illnesses and medical conditions present millions of children and adolescents with significant stress that is associated with risk for emotional and behavioral problems and interferes with adherence to treatment regimens. We review research on the role of child and adolescent coping with stress as an important feature of the process of adaptation to illness. Recent findings support a control-based model of coping that includes primary control or active coping (efforts to act on the source of stress or one's emotions), secondary control or accommodative coping (efforts to adapt to the source of stress), and disengagement or passive coping (efforts to avoid or deny the stressor). Evidence suggests the efficacy of secondary control coping in successful adaptation to chronic illness in children and adolescents, disengagement coping is associated with poorer adjustment, and findings for primary control coping are mixed. Avenues for future research are highlighted.
Obesity and Public Policy
Authors: Gearhardt Ashley N. , Bragg Marie A. , Pearl Rebecca L. , Schvey Natasha A. , Roberto Christina A. , Brownell Kelly D.
Published: March 2012

There is a pressing need to reduce both the prevalence and impact of obesity. This review begins with a discussion of the roles of treatment and prevention. Two overriding issues, weight bias and the addictive nature of food, are covered because of their importance not only to the individuals affected but also to public policy. We then cover promising policy areas in which changes can be implemented to support healthy behaviors: school policy, food marketing, food labeling and packaging, and taxes on unhealthy foods. The roles of the food industry and federal, state, and local governments are also discussed.
DEPTOR ubiquitination and destruction by SCFβ-TrCP
Authors: Wang Zhiwei , Zhong Jiateng , Gao Daming , Inuzuka Hiroyuki , Liu Pengda , Wei Wenyi
Published: March 2012

β-Transducin repeats-containing protein (β-TrCP) is the substrate recognition subunit of the SCF (SKP1, CUL1, and F-box protein)-type E3 ubiquitin ligase complex. SCFβ-TrCP ubiquitinates specifically phosphorylated substrates to promote their subsequent destruction by the 26S proteasome and plays a critical role in various human diseases including tumorigenesis. We and others (Duan S et al. Mol Cell 44: 317–324, 2011; Gao D et al. Mol Cell 44: 290–303, 2011; Zhao Y et al. Mol Cell 44: 304–316, 2011) recently reported that SCFβ-TrCP regulates cell growth and autophagy by controlling the ubiquitination and destruction of DEPTOR, an endogenous mammalian target of rapamycin inhibitor, in a phosphorylation-dependent manner. In this review, we discuss β-TrCP's new downstream substrate, DEPTOR, as well as summarize the novel functional aspects of β-TrCP in controlling cell growth and regulating autophagy, in part through governing the stability of DEPTOR.
Adipocyte expression of PU.1 transcription factor causes insulin resistance through upregulation of inflammatory cytokine gene expression and ROS production
Authors: Lin Ligen , Pang Weijun , Chen Keyun , Wang Fei , Gengler Jon , Sun Yuxiang , Tong Qiang
Published: March 2012

We have reported previously that ETS family transcription factor PU.1 is expressed in mature adipocytes of white adipose tissue. PU.1 expression is increased greatly in mouse models of genetic or diet-induced obesity. Here, we show that PU.1 expression is increased only in visceral but not subcutaneous adipose tissues of obese mice, and the adipocytes are responsible for this increase in PU.1 expression. To further address PU.1's physiological function in mature adipocytes, PU.1 was knocked down in 3T3-L1 cells using retroviral-mediated expression of PU.1-targeting shRNA. Consistent with previous findings that PU.1 regulates its target genes, such as NADPH oxidase subunits and proinflammatory cytokines in myeloid cells, the mRNA levels of proinflammatory cytokines (TNFα, IL-1β, and IL-6) and cytosolic components of NADPH oxidase (p47phox and p40phox) were downregulated significantly in PU.1-silenced adipocytes. NADPH oxidase is a main source for reactive oxygen species (ROS) generation. Indeed, silencing PU.1 suppressed NADPH oxidase activity and attenuated ROS in basal or hydrogen peroxide-treated adipocytes. Silencing PU.1 in adipocytes suppressed JNK1 activation and IRS-1 phosphorylation at Ser307. Consequently, PU.1 knockdown improved insulin signaling and increased glucose uptake in basal and insulin-stimulated conditions. Furthermore, knocking down PU.1 suppressed basal lipolysis but activated stimulated lipolysis. Collectively, these findings indicate that obesity induces PU.1 expression in adipocytes to upregulate the production of ROS and proinflammatory cytokines, both of which lead to JNK1 activation, insulin resistance, and dysregulation of lipolysis. Therefore, PU.1 might be a mediator for obesity-induced adipose inflammation and insulin resistance.
SDF-1 activates papillary label-retaining cells during kidney repair from injury
Authors: Oliver Juan A. , Maarouf Omar , Cheema Faisal H. , Liu Charles , Zhang Qing-Yin , Kraus Carl , Zeeshan Afzal M. , Firdous Mamoona , Klinakis Apostolos , Efstratiadis Argiris , Al-Awqati Qais
Published: March 2012

The adult kidney contains a population of low-cycling cells that resides in the papilla. These cells retain for long periods S-phase markers given as a short pulse early in life; i.e., they are label-retaining cells (LRC). In previous studies in adult rat and mice, we found that shortly after acute kidney injury many of the quiescent papillary LRC started proliferating (Oliver JA, Klinakis A, Cheema FH, Friedlander J, Sampogna RV, Martens TP, Liu C, Efstratiadis A, Al-Awqati Q. J Am Soc Nephrol 20: 2315–2327, 2009; Oliver JA, Maarouf O, Cheema FH, Martens TP, Al-Awqati Q. J Clin Invest 114: 795–804, 2004) and, with cell-tracking experiments, we found upward migration of some papillary cells including LRC (Oliver JA, Klinakis A, Cheema FH, Friedlander J, Sampogna RV, Martens TP, Liu C, Efstratiadis A, Al-Awqati Q. J Am Soc Nephrol 20: 2315–2327, 2009). To identify molecular cues involved in the activation (i.e., proliferation and/or migration) of the papillary LRC that follows injury, we isolated these cells from the H2B-GFP mice and found that they migrated and proliferated in response to the cytokine stromal cell-derived factor-1 (SDF-1). Moreover, in a papillary organ culture assay, the cell growth out of the upper papilla was dependent on the interaction of SDF-1 with its receptor Cxcr4. Interestingly, location of these two proteins in the kidney revealed a complementary location, with SDF-1 being preferentially expressed in the medulla and Cxcr4 more abundant in the papilla. Blockade of Cxcr4 in vivo prevented mobilization of papillary LRC after transient kidney ischemic injury and worsened its functional consequences. The data indicate that the SDF-1/Cxcr4 axis is a critical regulator of papillary LRC activation following transient kidney injury and during organ repair.
Cross-Leg as Salvage Procedure after Free Flaps Transfer Failure: A Case Report
Authors: Contedini F. , Negosanti L. , Fabbri E. , Pinto V. , Tavaniello B. , Sgarzani R. , Cipriani R.
Published: March 2012

Posttraumatic wounds of the lower leg with soft tissue defects and exposed fractures are a reconstructive challenge due to the scarce availability of local tissues and recipient vessels. Even when a free tissue transfer can be performed the risk of failure remains considerable. When a free flap is contraindicated or after a free flap failure, the cross-leg flap is still nowadays a possible option. We report a case of a male with a severe posttraumatic wound of the lower leg with exposed tibia fracture firstly treated with two consecutive latissimus dorsi muscular free flaps, failed for vascular thrombosis; the coverage was then achieved with a cross-leg flap with acceptable results.
Polysaccharides from the Medicinal MushroomCordyceps taiiShow Antioxidant and Immunoenhancing Activities in aD-Galactose-Induced Aging Mouse Model
Authors: Xiao Jian-Hui , Xiao Dai-Min , Chen Dai-Xiong , Xiao Yu , Liang Zong-Qi , Zhong Jian-Jiang
Published: March 2012

Cordyceps taii, an edible medicinal mushroom native to south China, is recognized as an unparalleled resource of healthy foods and drug discovery. In the present study, the antioxidant pharmacological properties ofC. taiiwere systematically investigated.In vitroassays revealed the scavenging activities of the aqueous extract and polysaccharides ofC. taiiagainst various free radicals, that is, 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical. The EC50values for superoxide anion-free radical ranged from 2.04 mg/mL to 2.49 mg/mL, which was at least 2.6-fold stronger than that of antioxidant thiourea. The polysaccharides also significantly enhanced the antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and markedly decreased the malondialdehyde production of lipid peroxidation in aD-galactose-induced aging mouse model. Interestingly, the immune function of the administration group was significantly boosted compared with theD-galactose-induced aging model group. Therefore, theC. taiipolysaccharides possessed potent antioxidant activity closely associated with immune function enhancement and free radical scavenging. These findings suggest that the polysaccharides are a promising source of natural antioxidants and antiaging drugs. Consequently, a preliminary chemical investigation was performed using gas chromatography-mass spectroscopy and revealed that the polysaccharides studied were mainly composed of glucose, mannose, and galactose. Fourier-transform infrared spectra also showed characteristic polysaccharide absorption bands.
An Algorithm to Automatically Detect the Smale Horseshoes
Authors: Li Qingdu , Zhang Lina , Yang Fangyan
Published: March 2012

Smale horseshoes, curvilinear rectangles and their U‐shaped images patterned on Smale′s famous example, provide a rigorous way to study chaos in dynamical systems. The paper is devoted to constructing them in two‐dimensional diffeomorphisms with the existence of transversal homoclinic saddles. We first propose an algorithm to automatically construct “horizontal” and “vertical” sides of the curvilinear rectangle near to segments of the stable and of the unstable manifolds, respectively, and then apply it to four classical chaotic maps (the Duffing map, the Hénon map, the Ikeda map, and the Lozi map) to verify its effectiveness.
Evaluation of RANKL/OPG Serum Concentration Ratio as a New Biomarker for Coronary Artery Calcification: A Pilot Study
Authors: Mohammadpour Amir Hooshang , Shamsara Jamal , Nazemi Saeed , Ghadirzadeh Samira , Shahsavand Shabnam , Ramezani Mohammad
Published: March 2012

Objective. There is a strong need for biomarkers to identify patients at risk for future cardiovascular events related with progressive atherosclerotic disease. Osteoprotegerin (OPG) protects the skeleton from excessive bone resorption by binding to receptor activator of nuclear factor-κB ligand (RANKL) and preventing it from binding to its receptor, receptor activator of nuclear factor-κB. However, conflicting results have been obtained about association of serum level of OPG or RANKL with coronary artery disease (CAD). Based on their role in inflammation and matrix degradation and the fact that atherosclerotic plaque formation is an inflammatory process, we hypothesized that RANKL : OPG ratio could be a better biomarker for CAD. Methods. In this cross-sectional study, the correlation between RANKL : OPG ratio serum concentration and coronary artery calcification (CAC) in 50 patients with ischemic coronary disease has been investigated. We used ELISA method for measuring RANKL and OPG serum concentrations. Results. There was a significant correlation between RANKL : OPG serum concentration ratio and CAC in our study population (P=0.01). Conclusion. Our results suggested that RANKL : OPG ratio concentration has a potential of being used as a marker for coronary artery disease.
Mechanisms Underlying Tolerance after Long-Term Benzodiazepine Use: A Future for Subtype-Selective Receptor Modulators?
Authors: Vinkers Christiaan H. , Olivier Berend
Published: March 2012

Despite decades of basic and clinical research, our understanding of how benzodiazepines tend to lose their efficacy over time (tolerance) is at least incomplete. In appears that tolerance develops relatively quickly for the sedative and anticonvulsant actions of benzodiazepines, whereas tolerance to anxiolytic and amnesic effects probably does not develop at all. In light of this evidence, we review the current evidence for the neuroadaptive mechanisms underlying benzodiazepine tolerance, including changes of (i) the receptor (subunit expression and receptor coupling), (ii) intracellular changes stemming from transcriptional and neurotrophic factors, (iii) ionotropic glutamate receptors, (iv) other neurotransmitters (serotonin, dopamine, and acetylcholine systems), and (v) the neurosteroid system. From the large variance in the studies, it appears that either different (simultaneous) tolerance mechanisms occur depending on the benzodiazepine effect, or that the tolerance-inducing mechanism depends on the activated receptor subtypes. Importantly, there is no convincing evidence that tolerance occurs withαsubunit subtype-selective compounds acting at the benzodiazepine site.
Epigenetics in Social Insects: A New Direction for Understanding the Evolution of Castes
Authors: Weiner Susan A. , Toth Amy L.
Published: March 2012

Epigenetic modifications to DNA, such as DNA methylation, can expand a genome’s regulatory flexibility, and thus may contribute to the evolution of phenotypic plasticity. Recent work has demonstrated the importance of DNA methylation in alternative queen and worker “castes” in social insects, particularly honeybees. Social insects are an excellent system for addressing questions about epigenetics and evolution because: (1) they have dramatic caste polyphenisms that appear to be tied to differential methylation, (2) DNA methylation is widespread in various groups of social insects, and (3) there are intriguing connections between the social environment and DNA methylation in many species, from insects to mammals. In this article, we review research on honeybees, and, when available, other social insects, on DNA methylation and queen and worker caste differences. We outline a conceptual framework for the effects of methylation on caste determination in honeybees that may help guide studies of epigenetic regulation in other polyphenic taxa. Finally, we suggest future paths of study for social insect epigenetic research, including the importance of comparative studies of DNA methylation on a broader range of species, and highlight some key unanswered mechanistic questions about how DNA methylation affects gene regulation.
Multichannel Communications in Wireless Automation: Interdependencies between Communication and Control Parameters
Authors: Nieminen Jari , Björkbom Mikael , Jäntti Riku , Eriksson Lasse
Published: March 2012

Exploitation of wireless communications in various automation applications brings indisputable benefits, which has proliferated research efforts in the field during the recent years. However, underlying wireless communication systems introduce problems to the wireless control systems, such as variable delays, information loss, and limited throughput. By using multiple frequency bands simultaneously, the performance of a wireless network can be enhanced. Since many control applications have strict requirements on delay and delay variations, it is important to understand the impact of communication systems on the performance of wireless automation systems with respect to delay. Hence, in this paper, we study how different communication parameters, such as packet arrival rate, number of channels, and packet size, affect the performance of control systems. We also derive bound on control system performance given the network properties. Our results show the tradeoff between the performance of the wireless multichannel communication system and the automation system. These results can, for example, be further exploited in system design to find out the maximum packet arrival rate with given control parameters.
Expression, Purification, and Characterization of Ras Protein (BmRas1) fromBombyx mori
Authors: Quan Yanping , Liu Guangqiang , Yu Wei , Nie Zuoming , Chen Jian , Lv Zhengbing , Zhang Yaozhou
Published: March 2012

The Ras subfamily is the member of small G proteins superfamily involved in cellular signal transduction. Activation of Ras signaling causes cell growth, differentiation, and survival.Bombyx moriRas-like protein (BmRas1) may belong to the Ras subfamily. It contained an H-N-K-Ras-like domain. The BmRas1 mRNA consisted of 1459 bp. The open reading frame contained 579 bp, encoding 192 amino acids. The protein had such secondary structures asα-helices, extended strand, and random coil. BmRas1 was expressed successfully inE. coliBL21. The recombinant protein was purified with metal-chelating affinity chromatography. The GTPase activity of purified protein was determined by FeSO4-(NH4)2MoO4assay. The results showed that purified recombinant protein had intrinsic activity of GTPase. High titer polyclonal antibodies were generated by New Zealand rabbit immunized with purified protein. The gene expression features of BmRas1 at different stages and in different organs of the fifth instar larvae were analyzed by Western blot. The results showed that BmRas1 was expressed highly in three development stages including egg, pupae, and adult, but low expression in larva. BmRas1 was expressed in these tissues including head, malpighian tubule, genital gland, and silk gland. The purified recombinant protein would be utilized to further function studies of BmRas1.
Advances in MicroRNA-Mediated Reprogramming Technology
Authors: Kuo Chih-Hao , Ying Shao-Yao
Published: March 2012

The use of somatic cells to generate induced-pluripotent stem cells (iPSCs), which have gene characteristic resembling those of human embryonic stem cells (hESCs), has opened up a new avenue to produce patient-specific stem cells for regenerative medicine. MicroRNAs (miRNAs) have gained much attention over the past few years due to their pivotal role in many biological activites, including metabolism, host immunity, and cancer. Soon after the discovery of embryonic-stem-cell- (ESC-) specific miRNAs, researchers began to investigate their functions in embryonic development and differentiation, as well as their potential roles in somatic cell reprogramming (SCR). Several approaches for ESC-specific miRNA-mediated reprogramming have been developed using cancer and somatic cells to generate ESC-like cells with similarity to iPSCs and/or hESCs. However, the use of virus-integration to introduce reprogramming factors limits future clinical applications. This paper discusses the possible underlying mechanism for miRNA-mediated somatic cell reprogramming and the approaches used by different groups to induce iPSCs with miRNAs.
Acute Appendicitis in a Man Undergoing Therapy for Mantle Cell Lymphoma
Authors: Linden Michael , Gopal Ajay , Edlefsen Kerstin
Published: March 2012

A 71-year-old man was diagnosed with an aggressive mantle cell lymphoma and was started on six cycles of R-CHOP chemotherapy. Approximately two weeks after starting his first cycle of chemotherapy, he complained of severe right lower quadrant abdominal pain, and an abdominal CT scan demonstrated an enlarged appendix with evidence of contained perforation. The man underwent open appendectomy for acute appendicitis and recovered. The appendectomy specimen was submitted for routine pathological analysis. There was histologic evidence of perforation in association with an inflammatory infiltrate with fibrin adhered to the serosal surface; scattered small lymphoid aggregates were present on the mucosal surface. Although the lymphoid aggregates in the submucosa and lamina propria were rather unremarkable by routine histologic examination, immunohistochemistry revealed the lymphocytes to be predominantly Cyclin D1-overexpressing B cells. To our knowledge, this is the first reported case of acute appendicitis in association with appendiceal involvement by mantle cell lymphoma.
Extracorporeal Membrane Oxygenation for Complex Multiorgan System Trauma
Authors: Firstenberg Michael S. , Nelson Karen , Abel Erik , McGregor John , Eiferman Daniel
Published: March 2012

With growing experience, the indications for salvage extracorporeal membrane oxygenation continue to expand. We describe a successful application of extracorporeal support in a polytrauma patient presenting with profound hypothermia, respiratory failure, and whom was later found to have an intracranial hemorrhage. We advocate the role of salvage therapy even in patients with complex pathophysiology despite perceived relative or absolute contraindications to extracorporeal support.
Atlantoaxial Synovial Cyst Associated with Instability in a Chihuahua
Authors: Forterre Franck , Vizcaino Reves Núria , Stahl Christina , Rupp Stephan , Gendron Karine
Published: March 2012

Objective. To describe an atlantoaxial degenerative cyst associated with instability.Animal. Chihuahua, male, 5 years old.Methods. Ever since colliding with a large dog two years prior to presentation, the dog suffered recurrent episodes of intractable cervical pain. Over time, the pain attacks increased in frequency and intensity. On presentation, pain was clinically localized to the high cervical region. No neurological deficits were observed. CT and MRI revealed an atlantoaxial degenerative articular cyst associated with instability, causing cervicomedullary compressive myelopathy. On MRI the cyst appeared hypointense in T1W and hyperintense in T2-weighted sequences, with rim enhancement. The dog was treated surgically by cyst fenestration and ventral stabilization using a 1.5 mm Butterfly Locking plate and cancellous bone graft placed within the atlantoaxial joint after cartilage removal. Histological examination of a sample of the cyst wall confirmed a degenerative articular cyst. The dog recovered uneventfully after surgery and remained pain free throughout the 2-year followup.Conclusion. Atlantoaxial degenerative articular cyst associated with instability is a rare finding in dogs.Clinical Relevance. The presence of an atlantoaxial degenerative articular cyst appears not to worsen the prognosis of instability treatment. Atlantoaxial fusion and cyst fenestration may provide good long-term results.
Regenerative Therapies for Diabetic Microangiopathy
Authors: Bassi Roberto , Trevisani Alessio , Tezza Sara , Ben Nasr Moufida , Gatti Francesca , Vergani Andrea , Farina Antonio , Fiorina Paolo
Published: March 2012

Hyperglycaemia occurring in diabetes is responsible for accelerated arterial remodeling and atherosclerosis, affecting the macro- and the microcirculatory system. Vessel injury is mainly related to deregulation of glucose homeostasis and insulin/insulin-precursors production, generation of advanced glycation end-products, reduction in nitric oxide synthesis, and oxidative and reductive stress. It occurs both at extracellular level with increased calcium and matrix proteins deposition and at intracellular level, with abnormalities of intracellular pathways and increased cell death. Peripheral arterial disease, coronary heart disease, and ischemic stroke are the main causes of morbidity/mortality in diabetic patients representing a major clinical and economic issue. Pharmacological therapies, administration of growth factors, and stem cellular strategies are the most effective approaches and will be discussed in depth in this comprehensive review covering the regenerative therapies of diabetic microangiopathy.
Management of Calcium Channel Antagonist Overdose with Hyperinsulinemia-Euglycemia Therapy: Case Series and Review of the Literature
Authors: Shah Shiwan K. , Goswami Sanjeev Kumar , Babu Rajesh V. , Sharma Gulshan , Duarte Alexander G.
Published: March 2012

Calcium channel antagonists (CCAs) are commonly involved in drug overdoses. Standard approaches to the management of CCA overdoses, including fluid resuscitation, gut decontamination, administration of calcium, glucagon, and atropine, as well as supportive care, are often ineffective. We report on two patients who improved after addition of hyperinsulinemia-euglycemia (HIE) therapy. We conclude with a literature review on hyperinsulinemia-euglycemia therapy with an exploration of the physiology behind its potential use.
Becoming Socialized into a New Professional Role: LPN to BN Student Nurses' Experiences with Legitimation
Authors: Melrose Sherri , Miller Jean , Gordon Kathryn , Janzen Katherine J.
Published: March 2012

This paper presents findings from a qualitative descriptive study that explored the professional socialization experiences of Licensed Practical Nurses (LPNs) who attended an online university to earn a Baccalaureate degree in nursing (BN), a prerequisite to writing the Canadian Registered Nurse (RN) qualifying exam. The project was framed from a constructivist worldview and Haas and Shaffir’s theory of legitimation. Participants were 27 nurses in a Post-LPN to BN program who came from across Canada to complete required practicums. Data was collected from digital recordings of four focus groups held in different cities. Transcripts were analyzed for themes and confirmed with participants through member checking. Two overarching themes were identified and are presented to explain how these unique adult learners sought to legitimize their emerging identity as Registered Nurses (RNs). First, Post-LPN to BN students need little, if any, further legitimation to affirm their identities as “nurse.” Second, practicum interactions with instructors and new clinical experiences are key socializing agents.