bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Analysis of Transmission Lines Equation by new β-method Schemes
Authors: Allali Fatima , Alaa Nour Eddine , Ghammaz Abdelilah , Rouijaa Hicham
Published: September 2017

In this paper we develop a new β-method applied to the resolution of homogeneous transmission lines. A comparison with conventional methods used for this type of problems like FDTD method or classical β-method is also given. Furthermore, various numerical experiments are presented to confirm the accuracy, efficiency and stability of our proposed method. In particular, these simulations show that our new scheme is unconditionally stable and fourth-order accurate in space and time.
Almost principal ideals and tensor product of hyperlattices
Authors: Lashkenari A. Soltani , Davvaz B.
Published: September 2017

In this paper, by considering the notion of congruences on hyper- lattices we define almost principal ideals on hyperlattices. We investigate some properties and prove some results about them. Also, we define compatible functions on hyperlattices and investigate connection between these functions and almost principal ideals. Then, we define tensor product of two hyperlattices and present several properties such as completeness and distributivity on tensor product of hyperlattices.
Archimedean tiling graphs with Gallai’s property
Authors: Chang Zhikui , Yuan Liping
Published: September 2017

Gallai in 1966 raised the question about the existence of graphs with the property that every vertex is missed by some longest path. This property will be called Gallai’s property. In this paper we present some graphs embeddable into Archimedean tiling graphs, with both connectivity 1 and 2, satisfying Gallai’s property.
Best possible estimates of weak solutions of boundary value problems for quasi-linear elliptic equations in unbounded domains
Authors: Wiśniewski Damian
Published: September 2017

We investigate the behaviour of weak solutions of boundary value problems for quasi-linear elliptic divergence second order equations in unbounded domains. We show the boundedness of weak solutions to our problem. Using barrier function and applying the comparison principle, we find the exact exponent of weak solutions decreasing rate near the infinity.
Whistle-blowing and the employment relations implications of the ‘Protected Disclosures Act 2014’ in the Republic of Ireland
Authors: Halpin Lisa , Dundon Tony
Published: September 2017

This article explores the introduction of the 2014 Protected Disclosures Act in the Republic of Ireland. It does so by using a justice theory lens to examine the potential for the Act to protect workers who may feel the need to blow the whistle on employer wrongdoings. Data is collected from public records and documents, along with interviews with senior representatives from ‘all’ the social partner agents involved in drafting or contributing to the Act. The evidence suggests that the Act may have limited utility in ensuring fairness and justice for the whistle-blower. In particular, employers appear reluctant to embrace the idea of more legal protections, while cultural stigmas attached to the idea of ‘blowing the whistle’ may inhibit people coming forward. The article contributes to justice theory and employment regulation, as well as whistle-blowing practices, and some recommendations are suggested to improve awareness of whistle-blowing rights for workers.
Data-driven multichannel seismic impedance inversion with anisotropic total variation regularization
Authors: Wang Dehua , Gao Jinghuai , Zhou Hongan
Published: September 2017

Acoustic impedance (AI) inversion is a desirable tool to extract rock-physical properties from recorded seismic data. It plays an important role in seismic interpretation and reservoir characterization. When one of recursive inversion schemes is employed to obtain the AI, the spatial coherency of the estimated reflectivity section may be damaged through the trace-by-trace processing. Meanwhile, the results are sensitive to noise in the data or inaccuracies in the generated reflectivity function. To overcome the above disadvantages, in this paper, we propose a data-driven inversion scheme to directly invert the AI from seismic reflection data. We first explain in principle that the anisotropic total variation (ATV) regularization is more suitable for inverting the impedance with sharp interfaces than the total variation (TV) regularization, and then establish the nonlinear objective function of the AI model by using anisotropic total variation (ATV) regularization. Next, we solve the nonlinear impedance inversion problem via the alternating split Bregman iterative algorithm. Finally, we illustrate the performance of the proposed method and its robustness to noise with synthetic and real seismic data examples by comparing with the conventional methods.
Fast numerical method of solving 3D coefficient inverse problem for wave equation with integral data
Authors: Bakushinsky Anatoly B. , Leonov Alexander S.
Published: September 2017

An inverse coefficient problem for time-dependent wave
equation in three dimensions is under consideration. We are looking
for a spatially varying coefficient of this equation knowing special
time integrals of the wave field in an observation domain.
The inverse problem has applications to the reconstruction
of the refractive index of an inhomogeneous medium, as well as to acoustic
sounding, medical imaging, etc. In the article, a new linear three-dimensional Fredholm integral equation
of the first kind is introduced from which it is possible to find the unknown
coefficient. We present and substantiate a numerical algorithm for solving this integral
equation. The algorithm does not require significant computational
resources and a long solution time. It is based on the use
of fast Fourier transform under some a priori assumptions about
unknown coefficient and observation region of the wave
field. Typical results of solving this three-dimensional inverse problem on a
personal computer for simulated data demonstrate high
capabilities of the proposed algorithm.
Solution of the inverse elastography problem for parametric classes of inclusions with a posteriori error estimate
Authors: Leonov Alexander S. , Sharov Alexander N. , Yagola Anatoly G.
Published: September 2017

This article presents the solution of a special
inverse elastography problem: knowing vertical displacements of compressed
biological tissue to find a piecewise constant distribution of Young’s modulus in an investigated specimen. Our goal is to detect homogeneous inclusions in the tissue, which can be interpreted as oncological. To this end, we consider the specimen
as two-dimensional elastic solid, displacements of which satisfy the differential equations
of the linear static theory of elasticity in the plain strain statement.
The inclusions to be found are specified by parametric functions with unknown
geometric parameters and unknown Young’s modulus. Reducing this inverse problem
to the search for all unknown parameters, we solve it applying the modified method of
extending compacts by V. K. Ivanov and I. N. Dombrovskaya. A posteriori error
estimate is carried out for the obtained approximate solutions.
Carbohydrate-protein interactions characterized by dual polarization hybrid plasmonic waveguide
Authors: Chen Chen , Hou Xun , Si Jinhai
Published: September 2017

Optical biosensors present good performance for the affinity analysis of a molecular binding event. However, most of those excited with single optical mode are “blind” to the conformational change of bound molecules. We theoretically demonstrate a dual polarization hybrid plasmonic (DPHP) waveguide with nano-slots. By addressing the structure with dual polarizations, the optogeometrical properties (density and thickness) of protein layers have been determined without ambiguity. Differences in the hybrid mode dispersion between the transverse electric (TE) and transverse magnetic (TM) modes allow to separately determine the thickness and the density at all stages during the molecular interaction. In addition, nano-slots can be equated with an effective optical capacitance resulting in a strong field confinement; thereby, subtle changes in the ambient medium can be sensed. A proof of concept is conducted by analyzing the conformational change of HepV, a recombinant fragment of collagen V, during complicated molecular interaction. Integrated with adlayer thickness and density, we can conclude that a thick sparse layer formed after heparin capture and a thin dense layer arising from HepV bound. Accordingly, HepV undergoing conformational change has been traced and verified as molecular interaction occurs.
Localization of the Reversible Hydrogenase in Cyanobacteria
Authors: Kentemich Thomas , Bahnweg Margret , Mayer Frank , Bothe Hermann
Published: September 2017

The reversible hydrogenase of the cyanobacterium Anacystis nidulans was purified 250-fold by classical methods. Activity staining on gels obtained by native PAGE allowed to identify two bands. A ntibodies were raised against the electrophoretically homogeneous protein. The molecu­lar weight of the hydrogenase was determined by SD S-PAGE follow ed by Western blot analysis with these antibodies. Crude extracts from the unicellular Anacystis and from heterocysts and vegetative cells of Anabaena variabilis showed precipitation bands of 56 and 17 kd. The reversible hydrogenase appeared to be com posed o f a larger and a smaller subunit as the NiFeS-hydrogen-ases from other bacteria. The hydrogenase subunits, particularly the smaller on e, were subject to proteolysis. By application of the protein A-immuno-gold labeling technique the reversible hydro­ genase was shown to associate with the cytoplasmic membrane in Anacystis. When A nacystis was grown microaerobically, the increase in the specific activity of the reversible hydrogenase paral­leled the raise in the gold-labeling at the cell periphery as measured from the electron micro­ graphs. It is concluded that Anacystis has two different hydrogenases: the reversible or bidirec­tional hydrogenase which is located exclusively at the cytoplasmic membrane of the cells, and a thylakoid-bound enzyme which catalyzes only the uptake of H2.
The Active Species of "C02" Formed by Carbon Monoxide Dehydrogenase from Peptostreptococcus productus
Authors: Bott Michael , Thauer Rudolf K.
Published: September 2017

Carbon monoxide dehydrogenase of anaerobic bacteria catalyzes the reversible conversion of CO to "CO2" . With the enzyme from Peptostreptococcus productus it is shown that CO2 rather than HCO3
- (H2CO3) is the active species of "CO2" formed by this dehydrogenase.
The Primary Structures of the Core Antenna Polypeptides from Rhodopseudomonas marina
Authors: Brunisholz René A. , Bissig I. , Wagner-Huber R. , Frank G. , Suter F. , Niederer E. , Zuber H.
Published: September 2017

The antenna complex B 880 of Rp. marina has been isolated by applying ion-exchange chromatography on Whatman DE -52 resin and sucrose density centrifugation of LDAO-solubilized photosynthetic membranes. The antenna polypeptides B 880-α and B 880-β were pre­pared by organic solvent extraction of extensively dialyzed and freeze-dried B 880 antenna complex material or photosynthetic membranes. Gel filtration on Sephadex LH-60 and ion-exchange chromatography on Whatman DE -32 resin in the presence of organic solvents and an additional step on a C-8 reversed phase column yielded pure α-and β-apoproteins. Their complete primary structures have been elucidated using automated Edman degradation and carboxypeptidase diges­tion. According to quantitative Edman degradation the ratio of B 880-α and B 880-β has been determined as 1:1 in the isolated antenna complex as well as in the photosynthetic membrane. B 880-α of Rp. marina, presumably N -form ylated, consists of 52 amino acid residues and is 75, 56, 52 and 44% homologous to the corresponding core antenna polypeptides of Rs. rubrum, Rp. viridis, Rb. capsulatus and Rb. sphaeroides. In contrast, B 880-β (56 amino acid residues) is less homologous to the corresponding core β-antenna polypeptides of the same strains (57. 51. 41 and 42%). It shows an extended N-terminal domain as compared to the B 880-a polypeptide. Apart from the typical structural features of bacterial membrane-bound antenna polypeptides (three domain structure, His-residue in the hydrophobic stretch) the antenna polypeptides of Rp. marina are structurally related to polypeptides of core antenna complexes with strong near infra­red circular dichroism signals.
[125I]Azido-Ioxynil Labels Val249 of the Photosystem II D -1 Reaction Center Protein
Authors: Oettmeier Walter , Masson Klaus , Höhfeld Jörg
Published: September 2017

Azido-ioxynil (3,5-diiodo-2-azido-4-hydroxy-benzonitrile) is a potent photosystem II inhibitor (pI50-value 7.38) and as effective as the parent compound ioxynil itself. [125I]azido-ioxynil exhibits specific binding to isolated thylakoids with a binding constant Kb = 7.14. Upon UV -illumination it binds covalently to thylakoids or photosystem II particles. It labels predominantly the 32 kDa D-1 photosystem II reaction center protein . A 41 kDa protein is only tagged in trace amounts. After proteolytic treatment of labeled D -1 protein with Staphylococcus aureaus V8 -protease two major and two minor fragments are obtained. Automated gas phase sequencing of a 7 kDa cleavage peptide revealed that Val249 is the primary target of azido-ioxynil binding. Compared to urea type herbicides, this places the ioxynil binding site in a different environment of the D -1 photosystem II protein.
Topography of the Chloroplast Cytochrome b6: Orientation of the Cytochrome and Accessibility of the Lumen-Side Interhelix Loops
Authors: Szczepaniak A. , Black M. T. , Cramer W. A.
Published: September 2017

The to pography of chloroplast cytochromes f and b6 was probed with proteases carboxypeptidase A (CpA ), trypsin, and Staph, aureus V8. The cytochrome and its proteolytic products were detected by heme stain and, in most experiments, by immunoreaction. In thylakoids, the only protease that significantly affected the intactness of cytochrome f was CpA that caused a small (ΔMr = -1 - 2000) decrease in the apparent molecular weight. In SDS -treated thylakoids, both trypsin and V8 degraded cytochrome f. The inferred topography of cytochrom f , with the COOH -terminus on the stromal (n) side, one membrane-spanning a-helix n ear the COOH-terminus, and most of the Cyt f mass on the lumen (p) side, is consistent with that previously inferred by others. Cytochrome b6 was not sensitive to CpA . but was more sensitive to trypsin and V8 protease than cytochrome f , cytochrome b-559, or the 17 kDa OEC extrinsic protein. Trypsin caused a small decrease in size of cytochrome b6, which was observed using whole protein antibody as a single smaller band (ΔMr ≈ 2000) or two smaller discrete bands (ΔMr = -1000 and 2500, respectively) which, unlike the untreated protein , did not react with antibody generated to a peptide mimicking A sp-5 -Gln-14 near the NH2-terminus. These shorten ed tryptic fragments were attributed to cleavage after R-10 and K-23 n ear the NH2-terminus, implying an orientation with the NH2-terminus on the stromal side of the membrane. The sensitivity of cytochrome b6 toward this trypsin cleavage was increased if the membranes were first incubated with CpA , showing that the NH2 -terminal region of cytochrome b6 is masked by the COOH -terminal domain of one or more thylakoid proteins. Under conditions where degradation of cytochrome b-559, cytochrome f, or the 17 kDa OEC extrinsic protein on the lumen side of the membrane was small ( < 10-20% ). V8 protease degraded 80-90% of cytochrome b6. The main polypeptide fragment generated by V8 protease had an apparent molecular weight Mr = 16,000, reacted with antibody to a peptide mimicking Ala-146-Asp-155, and was more pronounced in membranes treated with SDS. The fragment could then result from cleavage at two sites, Glu-74 and /or Glu-166. It is concluded that the loop of cytochrome b6 protruding from the lumen side of the membrane between helices III and IV , and possibly that between helices I and II as w ell, contains a single Glu residue conferring a sensitivity to V8 protease greater than that of the lumen-side mass of cytochrome f which has many more Glu residues. This implies a lumen-skeletal structure in which one or two loops of cytochrome b6 on the lumen side are more exposed to the aqueous phase than cytochrome f.
Photophosphorylation as Function of ADP Concentration at Varying Transmembrane Proton Gradients
Authors: Heinen Georg , Strotmann Heinrich
Published: September 2017

Rates of photophosphorylation were measured at constant saturating phosphate concentration , varying ADP concentration , and varying light intensity. As the transmembrane proton gradient is decreased by phosphorylation to different extents depending on the concentration of ADP . rates of ATP formation obtained at the different ADP concentrations were plotted versus the actual steady state ΔpH (in the absence of ΔΨ) during the course of the reaction . ΔpH was monitored by the calibrated 9-aminoacridine fluorescence technique. In secondary plots phosphorylation as function of ADP concentration at different constant ΔpH values were obtained . The results indicate Michaelis-Menten kinetics. The true Km for ADP is virtually unaffected by ΔpH whereas Vmax (at ADP saturation ) strongly depends on ΔpH . The results are discussed in the framework of a simple enzyme kinetic model which considers the intrathylakoidal proton (at constant external pH ) as a third substrate for ATP formation. The model is capable o f explaining the reported results as well as a variety of important results from the literature.
Localization and Orientation of Subunit Delta of Spinach Chloroplast ATP-Synthase within the CF0 CF1 Complex 2. Identification of C-Terminal Residues of Delta, Exposed on the Thylakoid Membrane
Authors: Berzborn Richard J. , Finke Werner
Published: September 2017

The amino acid residues of spinach CF1 subunit delta are identified which are accessible and thus exposed within the quaternary structure of the ATP-synthase complex on the thylakoid membrane. Two types of antibodies in the monospecific polyclonal antiserum 306 against CF1, delta, described in the previous publication [Z. Naturforsch. 44c, 153 - 160 (1989)], were separated by virtue of their different affinity to thylakoid membranes and used for specific analysis of the products of proteolytic digestion of delta in situ. Polypeptide delta in situ, i.e. within the CF0C F1, complex on the membrane, is not susceptible to digestion by aminopeptidase M and trypsin, but is shortened by about 1 kDa by carboxypeptidase Y and digested at residues Glu173 and Glu179 by the Staphylococcus aureus protease V8 . The epitope on delta reacting with the agglutinating antibodies from serum 306 is lost after these proteolytical treatments and there fore situated on residues Met180-Val187. Since trypsin destroys this epitope only after prolonged incubation and with at least 50 μg trypsin/mg Chl, residue Lys169 of delta probably is inaccessible in situ. We conclude that the C -terminal am phipathic α-helix of spinach CF1 subunit delta is exposed on the thylakoid membrane, with the hydrophilic face directed to the outside, and th at CF1 delta starts to be shielded within the quaternary structure of the CF0CF1 complex between Glu173 and Lys169. The hydrophobic face of the c-terminal helix may be part of the binding surface towards CF0. Antibodies from serum 306 inhibit the PMS mediated cyclic photophosphorylation by reacting with C -terminal residues of δ.
Activation of a Chloroplast Type of Fructose Bisphosphatase from Chlamydomonas reinhardtii by Light-Mediated Agents
Authors: Huppe Heather C. , Buchanan Bob B.
Published: September 2017

A chloroplast type of fructose-1,6 -bisphosphatase, a central regulatory enzyme of photosynthetic carbon metabolism, has been partially purified from Chlamydomonas reinhardtii. Unlike its counterpart from spinach chloroplasts, the algal FBPase showed a strict requirement for a dithiol reductant irrespective of Mg2+ concentration. The enzymes from the two sources resembled each other immunologically, in subunit molecular mass and response to pH. In the presence of dithiothreitol, the pH optimum for both the algal and spinach enzymes shifted from 8.5 to a more physiological value of 8.0 as the Mg2+ concentration was increased from 1 to 16 mᴍ . At 1 mᴍ Mg2+, a concentration estimated to be close to physiological, the Chlamydomonas FBPase was active only in the presence of reduced thioredoxin and was most active with Chlamydomonas thioredoxin f. Under these conditions, the enzyme showed a pH optimum of 8.0. The data suggest that the Chlamydomonas enzyme resembles its spinach counterpart in most respects, but it has a stricter requirement for reduction and less strict reductant specificity. A comparison of the prop­erties of the FBPases from Chlamydomonas and spinach will be helpful for elucidating the mechanism of the reductive activation of this enzyme.
Uptake and Efflux of [35S] Sulfite by Protoplasts and their Chloroplasts of Oat (Avena sativa L.)
Authors: Miszalski Z. , Ziegler H.
Published: September 2017

Processes of 35S-labelled sulfite uptake and efflux by oat protoplasts and their chloroplasts are very rapid: during the first minutes (or perhaps even seconds) after sulfite supply a state of equilibrium is established between the protoplasts and their chloroplasts and the incubation medium. Bicarbonate concentrations ranging from 1 to 5 mᴍ in the medium had no significant effect on sulfite uptake. At pH 7.0 sulfite uptake is much greater than at pH 7.6. Light of low intensity (9 W m-2) had no significant effect on this uptake. The 35S concentration in chloroplasts was always much higher than in the whole protoplasts. One hour's incubation at sulfite concentra­ tions of 0.1 and 0.5 mᴍ in the medium, concentrations slightly stimulating or inhibiting photosyn­ thesis, results in sulfite concentrations of 0.004 to 0.230 mᴍ in chloroplasts. At a sulfite concentration photosynthesis, these values are 0.120 to 0.551 and 2.045 to 3.531, respectively.
Photoinhibitory Damage to Chloroplasts under Phosphate Deficiency and Alleviation of Deficiency and Damage by Photorespiratory Reactions
Authors: Heber U. , Viil J. , Neimanis S. , Mimura T. , Dietz K.-J.
Published: September 2017

Effects of Pi deficiency on photosynthesis ot isolated spinach chloroplasts were examined. The following observations were made: (1) Chloroplasts isolated in Pi-free media evolved oxygen in the light in the absence of added Pi until acid-extractable Pi in the chloroplasts had decreased to 1 to 2.5 m M . This Pi was unavailable for photophosphorylation as shown by the inability of the chloroplasts to respond by oxygen evolution to the addition of PGA. In the state of Pi-deficiency, stromal ATP to A DP ratios were in the light close to or below ratios observed in the dark. In the presence of 2 mᴍ PGA, addition of 20 μm Pi was insufficient to increase ATP to ADP ratios, but sufficient for appreciable oxygen evolution. (2) More Pi was available for oxygen evolution of phosphate-deficient chloroplasts at low levels of C02 than at high levels. This was due mainly to the suppression of oxygenation of RuBP by high C02 levels which prevented formation of phosphoglycolate and the subsequent release of Pi into the chloroplast stroma. (3) More oxygen was produced by phosphate-deficient chloroplasts at a low light intensity than at a high light intensity. This was due to increased availability of endogenous Pi under low light and to photoinhibition of the chloroplasts by high light. The main product of photosynthesis of phosphate-deficient chloroplasts in the presence of a high bicarbonate concentration was starch, and the main soluble product was PGA. (4) After phosphate-deficient chloroplasts had ceased to evolve oxygen in the light, they be­ came photosensitive. Part of the loss of the capacity for oxygen evolution is attributed to leakage of PGA, but the main reason for loss of function is photoinactivation of electron transport. Both photosystems of the electron transport chain were damaged by light. (5) Protection against photoinactivation was provided by coupled electron transport. Photo­ inactivation of phosphate-deficient chloroplasts was less extensive in the presence of low C02 concentrations which permitted oxygenation of RuBP than at high CO2 concentrations. Electron transport to C02 and other physiological electron acceptors and to the herbicide methylviologen was also protective. However, electron transport to oxygen in the Mehler reaction failed to provide appreciable protection against high light intensities, because oxygen reduction is slow and reactive oxygen species produced in the light contribute to photoinactivation.
Histidyl Residues Mediate Electron Transport in Plant Mitochondria
Authors: Arora Jaspreet , Sane P. V.
Published: September 2017

Plant The effect of chemical modification of histidyl residues using diethyl pyrocarbonate (DEP) on plant mitochondrial electron transport was studied. Mitochondrial membranes from potato tubers were isolated and electron flow from NADH to oxygen, NADH to ferricyanide and ascorbate to oxygen were monitored in pro», nee and/or absence of DEP. Measurements were made at various concentrations of DEP and at different pHs either by using an oxygen electrode or spectro-photometrically. The results show that DEP inhibits flow of electrons from NADH to oxygen, however partial electron transport from NADH to ferricyanide and ascorbate to oxygen was unaffected. Maximum inhibition was observed at pH 6.5. The time course of the DEP action revealed a biphasic nature of inhibition. Effects on the levels of reduction of cytochromes b and c by DEP during electron transport indicated that histidyl residues may be present before or at cytochrome b , which are being modified.
Mitochondrial DNA Double-Strand Breaks in Oligodendrocytes Cause Demyelination, Axonal Injury, and CNS Inflammation
Authors: Madsen Pernille M. , Pinto Milena , Patel Shreyans , McCarthy Stephanie , Gao Han , Taherian Mehran , Karmally Shaffiat , Pereira Claudia V. , Dvoriantchikova Galina , Ivanov Dmitry , Tanaka Kenji F. , Moraes Carlos T. , Brambilla Roberta
Published: September 2017

Mitochondrial dysfunction has been implicated in the pathophysiology of neurodegenerative disorders, including multiple sclerosis (MS). To date, the investigation of mitochondrial dysfunction in MS has focused exclusively on neurons, with no studies exploring whether dysregulation of mitochondrial bioenergetics and/or genetics in oligodendrocytes might be associated with the etiopathogenesis of MS and other demyelinating syndromes. To address this question, we established a mouse model where mitochondrial DNA (mtDNA) double-strand breaks (DSBs) were specifically induced in myelinating oligodendrocytes (PLP:mtPstI mice) by expressing a mitochondrial-targeted endonuclease, mtPstI, starting at 3 weeks of age. In both female and male mice, DSBs of oligodendroglial mtDNA caused impairment of locomotor function, chronic demyelination, glial activation, and axonal degeneration, which became more severe with time of induction. In addition, after short transient induction of mtDNA DSBs, PLP:mtPstI mice showed an exacerbated response to experimental autoimmune encephalomyelitis. Together, our data demonstrate that mtDNA damage can cause primary oligodendropathy, which in turn triggers demyelination, proving PLP:mtPstI mice to be a useful tool to study the pathological consequences of mitochondrial dysfunction in oligodendrocytes. In addition, the demyelination and axonal loss displayed by PLP:mtPstI mice recapitulate some of the key features of chronic demyelinating syndromes, including progressive MS forms, which are not accurately reproduced in the models currently available. For this reason, the PLP:mtPstI mouse represents a unique and much needed platform for testing remyelinating therapies.

SIGNIFICANCE STATEMENTIn this study, we show that oligodendrocyte-specific mitochondrial DNA double-strand breaks in PLP:mtPstI mice cause oligodendrocyte death and demyelination associated with axonal damage and glial activation. Hence, PLP:mtPstI mice represent a unique tool to study the pathological consequences of mitochondrial dysfunction in oligodendrocytes, as well as an ideal platform to test remyelinating and neuroprotective agents.
A Cross Talk between Neuronal Urokinase-type Plasminogen Activator (uPA) and Astrocytic uPA Receptor (uPAR) Promotes Astrocytic Activation and Synaptic Recovery in the Ischemic Brain
Authors: Diaz Ariel , Merino Paola , Manrique Luis Guillermo , Ospina Juan Pablo , Cheng Lihong , Wu Fang , Jeanneret Valerie , Yepes Manuel
Published: September 2017

Urokinase-type plasminogen activator (uPA) is a serine proteinase that, upon binding to its receptor (uPAR), catalyzes the conversion of plasminogen into plasmin on the cell surface. Our previous studies indicate that uPA and uPAR expression increase in the ischemic brain during the recovery phase from an acute ischemic injury and that uPA binding to uPAR promotes neurological recovery after an acute ischemic stroke. Here, we used male mice genetically deficient on either uPA (uPA−/−) or uPAR (uPAR−/−) or with a four-amino acid substitution into the growth factor domain of uPA that abrogates its binding to uPAR (PlatGFDhu/GFDhu) to investigate the mechanism whereby uPA promotes neurorepair in the ischemic brain. We found that neurons release uPA and astrocytes recruit uPAR to their plasma membrane during the recovery phase from a hypoxic injury and that binding of neuronal uPA to astrocytic uPAR induces astrocytic activation by a mechanism that does not require plasmin generation, but instead is mediated by extracellular signal-regulated kinase 1/2 (ERK1/2)-regulated phosphorylation of the signal transducer and activator of transcription 3 (STAT3). We report that uPA/uPAR binding is necessary and sufficient to induce astrocytic activation in the ischemic brain and that astrocytes activated by neuronal uPA promote synaptic recovery in neurons that have suffered an acute hypoxic injury via a mechanism mediated by astrocytic thrombospondin-1 (TSP1) and synaptic low-density lipoprotein receptor-related protein-1 (LRP1). In summary, we show that uPA/uPAR-induced astrocytic activation mediates a cross talk between astrocytes and injured neurons that promotes synaptic recovery in the ischemic brain.

SIGNIFICANCE STATEMENTTo date, there is no therapeutic strategy to promote synaptic recovery in the injured brain. Here, we show that neurons release urokinase-type plasminogen activator (uPA) and astrocytes recruit the uPA receptor (uPAR) to their plasma membrane during the recovery phase from a hypoxic injury. We found that binding of neuronal uPA to astrocytic uPAR promotes astrocytic activation and that astrocytes activated by uPA–uPAR binding promote synaptic recovery in neurons that have suffered a hypoxic injury by a mechanism that does not require plasmin generation, but instead is mediated by ERK1/2-regulated STAT3 phosphorylation, astrocytic thrombospondin-1 (TSP1) and synaptic low-density lipoprotein receptor-related protein-1 (LRP1). Our work unveils a new biological function for uPA–uPAR as mediator of a neuron–astrocyte cross talk that promotes synaptic recovery in the ischemic brain.
DrosophilaNeprilysin 1 Rescues Memory Deficits Caused by Amyloid-β Peptide
Authors: Turrel Oriane , Goguel Valérie , Preat Thomas
Published: September 2017

Neprilysins are Type II metalloproteinases known to degrade and inactivate a number of small peptides, in particular the mammalian amyloid-β peptide (Aβ). InDrosophila, several neprilysins expressed in the brain are required for middle-term (MTM) and long-term memory (LTM) in the dorsal paired medial (DPM) neurons, a pair of large neurons that broadly innervate the mushroom bodies (MB), the center of olfactory memory. These data indicate that one or several peptides need to be degraded for MTM and LTM. We have previously shown that the fly amyloid precursor protein (APPL) is required for memory in the MB. We show here that APPL is also required in adult DPM neurons for MTM and LTM formation. This finding prompted us to search for an interaction between neprilysins andDrosophilaAβ (dAβ), a cleavage product of APPL. To find out whether dAβ was a neprilysin's target, we used inducible drivers to modulate neprilysin 1 (Nep1) and dAβ expression in adult DPM neurons. Experiments were conducted either in both sexes or in females. We show that Nep1 inhibition makes dAβ expression detrimental to both MTM and LTM. Conversely, memory deficits displayed by dAβ-expressing flies are rescued by Nep1 overexpression. Consistent with behavioral data, biochemical analyses confirmed that Nep1 degrades dAβ. Together, our findings establish that Nep1 and dAβ expressed in DPM neurons are functionally linked for memory processes, suggesting that dAβ is a physiological target for Nep1.

SIGNIFICANCE STATEMENTNeprilysins are endopeptidases known to degrade a number of small peptides and in particular the amyloid peptide. We previously showed that all four neprilysins expressed in theDrosophilabrain are involved in specific phases of olfactory memory. Here we show that an increase in the level of the neprilysin 1 peptidase overcomes memory deficits induced by amyloid peptide in young flies. Together, the data reveal a functional interaction between neprilysin 1 and amyloid peptide, suggesting that neprilysin 1 degrades amyloid peptide. These findings raise the possibility that, under nonpathological conditions, mammalian neprilysins degrade amyloid peptide to ensure memory formation.
Ice and ocean velocity in the Arctic marginal ice zone: Ice roughness and momentum transfer
Authors: Cole Sylvia T. , Toole John M. , Lele Ratnaksha , Timmermans Mary-Louise , Gallaher Shawn G. , Stanton Timothy P. , Shaw William J. , Hwang Byongjun , Maksym Ted , Wilkinson Jeremy P. , Ortiz Macarena , Graber Hans , Rainville Luc , Petty Alek A. , Farrell Sinéad L. , Richter-Menge Jackie A. , Haas Christian
Published: September 2017

The interplay between sea ice concentration, sea ice roughness, ocean stratification, and momentum transfer to the ice and ocean is subject to seasonal and decadal variations that are crucial to understanding the present and future air-ice-ocean system in the Arctic. In this study, continuous observations in the Canada Basin from March through December 2014 were used to investigate spatial differences and temporal changes in under-ice roughness and momentum transfer as the ice cover evolved seasonally. Observations of wind, ice, and ocean properties from four clusters of drifting instrument systems were complemented by direct drill-hole measurements and instrumented overhead flights by NASA operation IceBridge in March, as well as satellite remote sensing imagery about the instrument clusters. Spatially, directly estimated ice-ocean drag coefficients varied by a factor of three with rougher ice associated with smaller multi-year ice floe sizes embedded within the first-year-ice/multi-year-ice conglomerate. Temporal differences in the ice-ocean drag coefficient of 20–30% were observed prior to the mixed layer shoaling in summer and were associated with ice concentrations falling below 100%. The ice-ocean drag coefficient parameterization was found to be invalid in September with low ice concentrations and small ice floe sizes. Maximum momentum transfer to the ice occurred for moderate ice concentrations, and transfer to the ocean for the lowest ice concentrations and shallowest stratification. Wind work and ocean work on the ice were the dominant terms in the kinetic energy budget of the ice throughout the melt season, consistent with free drift conditions. Overall, ice topography, ice concentration, and the shallow summer mixed layer all influenced mixed layer currents and the transfer of momentum within the air-ice-ocean system. The observed changes in momentum transfer show that care must be taken to determine appropriate parameterizations of momentum transfer, and imply that the future Arctic system could become increasingly seasonal.
Employer-Sponsored Plan Expenditures for Infants Born Preterm
Authors: Grosse Scott D. , Waitzman Norman J. , Yang Ninee , Abe Karon , Barfield Wanda D.
Published: September 2017

BACKGROUND:

Care for infants born preterm or with major birth defects is costly. Specific estimates of financial burden for different payers are lacking, in part because use of administrative data to identify preterm infants and costs is challenging.

METHODS:

We used private health insurance claims data and billing codes to identify live births during 2013 and calculated first-year expenditures for employer-sponsored health plans for infants born preterm, both overall and stratified by major birth defects.

RESULTS:

We conservatively estimated that 7.7% of insured infants born preterm accounted for 37% of $2.0 billion spent by participating plans on the care of infants born during 2013. With a mean difference in plan expenditures of ∼$47 100 per infant, preterm births cost the included plans an extra $600 million during the first year of life. Extrapolating to the national level, we projected aggregate employer-sponsored plan expenditures of $6 billion for infants born preterm during 2013. Infants with major birth defects accounted for 5.8% of preterm births but 24.5% of expenditures during infancy. By using an alternative algorithm to identify preterm infants, it was revealed that incremental expenditures were higher: $78 000 per preterm infant and $14 billion nationally.

CONCLUSION

Preterm births (especially in conjunction with major birth defects) represent a substantial burden on payers, and efforts to mitigate this burden are needed. In addition, researchers need to conduct studies using linked vital records, birth defects surveillance, and administrative data to accurately and longitudinally assess per-infant costs attributable to preterm birth and the interaction of preterm birth with major birth defects.
Farmers’ Perceptions on the Agricultural Use of Human Urine in the Central Amazon
Authors: Müller Patrícia , Borges Pedro João Paulo , De Castro Freitas Carlos Henrique
Published: September 2017

El Sanitario Seco con Separación de Orina (SSSO) es una tecnología alternativa para los desafíos ambientales en la Amazonia, teniendo la ventaja de no utilizar agua en sus procesos. Para verificar su viabilidad, sin embargo, es necesario comprender el comportamiento de los usuarios con relación al uso de los subproductos de los sanitarios. El objetivo del presente estudio fue evaluar la percepción de los agricultores sobre el uso de orina humana como fertilizante para cultivos agrícolas en la Amazonía Central. Se entrevistaron setenta y tres agricultores familiares de una villa rural de Tefé y del mercado municipal de agricultores de Tefé. Se verificó que el 12% de los agricultores tienen conocimiento del uso de orina humana en la agricultura y que más de un tercio consideran posible usar orina en sus jardines y cultivos. Sin embargo, más de la mitad no consideró la posibilidad del uso de orina, manifestando preocupaciones sobre el desarrollo de las culturas y dudas en cuanto a la eficacia de su uso como fertilizante. Pero los informantes creen que los cultivos irrigados con orina son adecuados para el consumo humano. Se concluye que la orina humana tiene potencial para ser utilizada en la agricultura en la región de estudio y entendemos que los sanitarios secos no deben ser tomados como la única alternativa para saneamiento en la Amazonia.
Total phenolic content, antioxidant activity, and anthocyanin profile of sprouted onion powder
Authors: Majid I. , Nanda V.
Published: September 2017

The effect of sprouting of onions on total phenolic content, antioxidant activity, and anthocyanin profile of freeze dried powders produced from Indian onion cultivars was examined. Sprouting was carried out at an average light intensity of 64 Lumen, average relative humidity of 80.2%, and average temperature of 15.22 °C for three weeks. Two way analyses of data revealed significant (P<0.05) effect of sprouting and cultivar on functional composition of freeze dried powders. In all sprouted powder samples, there were significant (P<0.05) enhancements in total phenolic content, total flavonoid content, vitamin C content, antioxidant activity, and colour due to increase in anthocyanin contents. The anthocyanin profile depicted an increase in total anthocyanin concentration in powders developed from all four cultivars with the highest increase in powder from PRO-6 (23.87–27.15 mg kg−1), followed by Punjab Naroya (9.97–12.92 mg kg−1), commercial (7.15–8.43 mg kg−1), and Punjab White cultivar (3.45–4.09 mg kg−1).
Why Rent When You Can Buy?
Authors: Monnet Cyril , Narajabad Borghan N.
Published: September 2017

Using a model with bilateral trades, we explain why agents prefer to rent the goods they can afford to buy. Absent bilateral trading frictions, renting has no role even with uncertainty about future valuations. With pairwise meetings, agents prefer to sell (or buy) durable goods whenever they have little doubt on the future value of the good. As uncertainty grows, renting becomes more prevalent. Pairwise matching alone is sufficient to explain why agents prefer to rent, and there is no need to introduce random matching, information asymmetries, or other market frictions.
On Targeting Frameworks and Optimal Monetary Policy
Authors: Bodenstein Martin , Zhao Junzhu
Published: September 2017

Speed limit policy, a monetary policy strategy that focuses on stabilizing inflation and the change in the output gap, consistently delivers better welfare outcomes than flexible inflation targeting or flexible price level targeting in empirical New Keynesian models when policymakers lack the ability to commit to future policies. Even if the policymaker can commit under an inflation targeting strategy, the discretionary speed limit policy performs better for most empirically plausible model parameterizations from a normative perspective.
La educación para la salud en la salud pública: un análisis pedagógico
Authors: Peñaranda Correa Fernando , López Ríos Jennifer Marcela , Molina Berrío Diana Patricia
Published: September 2017

Introducción: En la literatura sobre educación para la salud (EpS) se plantea la existencia de dos modelos pedagógicos en tensión, una contradicción entre la teoría y la práctica en aquellas experiencias que buscan promover propuestas críticas, y debilidad en la fundamentación pedagógica, que estarían explicadas por problemas en la formación del talento humano. Esta investigación se propone Objetivos: Cuestionar dichos planteamientos para ampliar la comprensión de los supuestos y perspectivas pedagógicas de la EpS en el campo de la salud pública. Materiales y métodos: Se realizó investigación documental de orientación cualitativa. Con base en tres criterios de inclusión, se tomaron 40 artículos de Brasil, Colombia, México y Cuba. Como producto de un proceso emergente se construyeron seis categorías para hacer el análisis. Resultados: Con la utilización de las categorías emergentes, se identificaron cuatro tendencias en los 17 estudios de "sistematización, análisis o evaluación de programas o proyectos" encontrados, y 3 tendencias en los estudios de revisión que abordaron las concepciones, modelos pedagógicos y los propósitos de la EpS. Conclusiones: Con base en las tendencias identificadas se plantea una situación más compleja y diversa que la dicotomía educación tradicional/crítica, y como reduccionista la idea de atribuir a la falta de formación del talento humano los problemas en la EpS y la contradicción entre la teoría y la práctica. La discusión de la EpS en la salud pública es un asunto más complejo que requiere abordar sus fundamentos pedagógicos y la teoría de la salud pública como disciplina.
Regulación del uso de marihuana en Colombia con fines medicinales
Authors: Calderón Vallejo Gustavo Adolfo , Pareja Hincapié Lina María , Caicedo Cano Catalina , Chica Ríos Rubiel Alberto
Published: September 2017

Objetivo: Interpretar el proceso de regulación del uso de marihuana con fines medicinales. Materiales y métodos: Cualitativo con enfoque hermenéutico, utiliza la técnica de entrevista, se aplicó a 15 expertos en octubre de 2015. Se hizo triangulación: expertos, artículos científicos e investigadores. Se realizó interpretación a partir de sistema categorial y de apoyo de programa Atlas. Ti. Resultados: El debate sobre la regulación de la marihuana con fines terapéuticos se continúa dando en el mundo, en especial en relación a los beneficios para la salud. Con el uso de algunos cannabinoides ya existen evidencias, pero expertos consultados reconocen que no son suficientes; en estos casos se recomienda más investigación. Los expertos de diversas disciplinas entrevistados respaldan el argumento que con la prohibición poco se ha conseguido y que los enfoques de salud pública traen una apertura científica no represiva a la situación, situando el debate en los posibles beneficios que puede traer para el tratamiento de algunas enfermedades. Estos procesos regulatorios deben considerar un control sobre la producción, fabricación, exportación, distribución, comercio y uso del cannabis con fines médicos e investigativos; proceso distinto al de la legalización del consumo con fines recreativos. Conclusión: Para el caso colombiano, la regulación del cannabis con fines medicinales hasta hace unos meses era solo una discusión con posiciones radicalizadas a favor y en contra. Hoy es una realidad en términos de legislación pues fue aprobada por decreto, pero con escaso debate y acción pedagógica de lo que implica la ley para población.
El prácticum: eje formador de la práctica reflexiva en enfermería
Authors: Rivera Álvarez Luz Nelly , Medina Moya José Luís
Published: September 2017

Objetivo: Caracterizar el papel que juegan las pedagogías de contextualización en la tutoría clínica y describir algunas estrategias didácticas que favorecen la práctica reflexiva del estudiante de enfermería en su prácticum. Materiales y métodos: Investigación cualitativa, etnográfica, desarrollada en el marco de las asignaturas prácticum hospitalario II y estancias clínicas II durante la formación de once estudiantes de enfermería en un Hospital Universitario de Barcelona (España) entre el 2011 y 2012. Los datos fueron recolectados por medio de observación participante y no participante, conversación informal, entrevista en profundidad y materiales escritos. Para el análisis se empleó el método de comparaciones constantes de Glaser y Strauss. Resultados: Emergieron ejes cualitativos como las pedagogías de contextualización y estrategias didácticas que favorecen el desarrollo del raciocinio y juicio clínico y la planificación de los cuidados de enfermería en la práctica hospitalaria, allí se hacen evidentes algunas estrategias de educación didácticas como el diálogo reflexivo y la interrogación didáctica, con las que las estudiantes verbalizan las razones de sus acciones, evitando así acciones mecánicas. Conclusión: las pedagogías de contextualización empleadas por las enfermeras favorecen el desarrollo del razonamiento y juicio clínico, llevando a las estudiantes a desarrollar un sentido de saliencia.