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Antibacterial approaches in tissue engineering using metal ions and nanoparticles:From mechanisms to applications

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Bioactive Materials 2021年第12期6卷 4470-4490页

作者： Maria Godoy-Gallardo Ulrich Eckhard Luis M.Delgado Yolanda J.D.de Roo Puente Mireia Hoyos-Nogués F.Javier Gil roman a.perez Bioengineering Institute of Technology Universitat Internacional de CatalunyaCarrer de Josep Trueta08195del VallèsSant CugatBarcelonaSpain Proteolysis Lab Department of Structural BiologyMolecular Biology Institute of BarcelonaCSICBarcelona Science ParkBaldiri Reixac 15-2108028BarcelonaSpain

Bacterial infection of implanted scaffolds may have fatal consequences and,in combination with the emergence of multidrug bacterial resistance,the development of advanced antibacterial biomaterials and constructs is of great *** decades ago,metals and their ions had been used to minimize bacterial infection risk and,more recently,metal-based nanomaterials,with improved antimicrobial properties,have been advocated as a novel and tunable alternative.A comprehensive review is provided on how metal ions and ion nanoparticles have the potential to decrease or eliminate unwanted *** mechanisms such as oxidative stress induction,ion release and disruption of biomolecules are currently well ***,the exact antimicrobial mechanisms of the discussed metal compounds remain poorly *** combination of different metal ions and surface decorations of nanoparticles will lead to synergistic effects and improved microbial killing,and allow to mitigate potential side effects to the *** with a general overview of antibacterial mechanisms,we subsequently focus on specific metal ions such as silver,zinc,copper,iron and gold,and outline their distinct modes of ***,we discuss the use of these metal ions and nanoparticles in tissue engineering to prevent implant failure.

关键词： Metal ions Metal nanoparticles Mechanism of action Antibacterial activity Tissue engineering Biomaterials applications

Feed particle selection and nutrient intake altered by pecking stone consumption and beak length in free-range laying hens

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Animal Nutrition 2019年第2期5卷 140-147页

作者： Zafar Iqbal Kelly Drake Robert A.Swick Rider a.perez-Maldonado Isabelle Ruhnke School of Environmental and Rural Science Faculty of ScienceAgricultureBusiness and LawUniversity of New EnglandArmidaleNSW2351Australia South Australian Research and Development Institute Roseworthy CampusUniversity of AdelaideSouth Australia5371Australia DSM Nutritional Products Singapore117440Singapore

The present study investigated the effects of pecking stones on feeding behaviour of hens from 16 to 46 weeks of age. Eighteen flocks of Hy-Line Brown hens were housed in 2 commercial free-range housing systems. Farm A housed 10 flocks of beak trimmed(infrared beak treatment) hens in fixed sheds. Farm B housed 8 flocks of hens with intact beaks in mobile sheds. On each farm, flocks were equally assigned to control groups(no access to pecking stones) and treatment groups(access to pecking stones). Data were evaluated every 10 weeks. At each time point, 10 hens per flock were housed in individual pens, and each hen was provided with 250 g of mash diet and ad libitum water for 24 h. After 24 h, feed samples were collected and used to determine 24-h feed intake. Nutrient and particle selection was measured by subtracting nutrients and particles present in the leftover feed from the vaules obtained in the offered feed and expressed the change(A). In addition, pecking stone consumption was recorded for each *** were analysed separately for each farm using fixed effects of pecking stone availability and hen ***’s rho correlation coefficients and linear regression models were constructed to evaluate the relationship of beak length and pecking stone usage, discrete mean particle size(dMEAN) consumption(△ dMEAN), and △ nutrient intake. Hens with access to pecking stones consumed significantly lower quantities of large feed particles(>2.8 mm) on farm A(P = 0.029) and selected significantly more fine particles, on farm B(P = 0.013). Overall, positive relationships(P = 0.001) between beak length and pecking stone consumption, A dMEAN, and A phosphorus consumption were observed. In conclusion,pecking stone consumption resulted in reduced selection and consumption of feed particles in hens housed on both farms. Further research is warranted to investigate the effect of pecking stones on sensory innervation of the beak.

关键词： Poultry Welfare Feeding behaviour Nutrition Environmental enrichment

Impact of prehospital medical evacuation (MEDEVAC) transport time on combat mortality in patients with noncompressible torso injury and traumatic amputations: a retrospective study

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Military Medical Research 2019年第1期6卷 23-30页

作者： Joseph K.Maddry Crystal a.perez Alejandra G.Mora Jill D.Lear Shelia C.Savell Vikhyat S.Bebarta US Air Force En route Care Research Center 59th MDW/ST Chief Scientist's Office –US Army Institute of Surgical research JBSA Ft.Sam Houston Department of Emergency Medicine San Antonio Military Medical CenterJBSA Ft. Sam Houston US Air Force En route Care Research Center 59th MDW/ST Chief Scientist's Office –US Army Institute of Surgical researchJBSA Ft.Sam Houston Department of Emergency Medicine University of Colorado School of Medicine

Background: In combat operations, patients with traumatic injuries require expeditious evacuation to improve survival. Studies have shown that long transport times are associated with increased morbidity and mortality. Limited data exist on the influence of transport time on patient outcomes with specific injury types. The objective of this study was to determine the impact of the duration of time from the initial request for medical evacuation to arrival at a medical treatment facility on morbidity and mortality in casualties with traumatic extremity amputation and noncompressible torso injury(NCTI).Methods: We completed a retrospective review of MEDEVAC patient care records for United States military personnel who sustained traumatic amputations and NCTI during Operation Enduring Freedom between January 2011 and March 2014. We grouped patients as traumatic amputation and NCTI(AMP+NCTI), traumatic amputation only(AMP),and neither AMP nor NCTI(Non-AMP/NCTI). Analysis was performed using chi-squared tests, Fisher's exact tests,Cochran-Armitage Trend tests, Shapiro-Wilks tests, Wilcoxon and Kruskal-Wallis techniques and Cox proportional hazards regression ***: We reviewed 1267 records, of which 669 had an injury severity score(ISS) of 10 or greater and were included in the analysis. In the study population, 15.5% sustained only amputation injuries(n=104, AMP only), 10.8% sustained amputation and NCTI(n=72, AMP+NCTI), and 73.7% did not sustain either an amputation or an NCTI(n=493,Non-AMP/NCTI). AMP+NCTI had the highest mortality(16.7%) with transport time greater than 60 min. While the AMP+NCTI group had decreasing survival with longer transport times, AMP and Non-AMP/NCTI did not exhibit the same ***: A decreased transport time from the point of injury to a medical treatment facility was associated with decreased mortality in patients who suffered a combination of amputation injury and NCTI. No significant association between transport time

关键词： Transport time Non-compressible torso injury Traumatic amputation Combat

Self-reported dietary supplement use in deployed United States service members pre-deployment *** deployment,Afghanistan,2013-2014

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Military Medical Research 2018年第3期5卷 207-215页

作者： Shawn M.Varney Patrick C.Ng Crystal a.perez Allyson A.Arana Edwin R.Austin Rosemarie G.Ramos Vikhyat S.Bebartas University of Texas Health Science Center San Antonio 7709Floyd Curl DrSan AntonioTX 78229USA San Antonio Military Medical Center 3551Roger Brooke DriveSan AntonioTX 78234USA Rocky Mountain Poison and Drug Center Denver Health and Hospital AuthorityDenverCOUSA U.S.Army Institute of Surgical Research USAF En Route Care Research Center3698Chambers Pass STE BJBSA Ft Sam HoustonSan AntonioTX 78234USA Department of Emergency Medicine University of Colorado School of Medicine13001E 17th PlaceAuroraCO 80045USA

Background: Dietary supplement use(protein/amino acids, weight-loss supplements, performance enhancers) is common among U.S. military members. Reported dietary supplement use in deployed troops is limited and is of concern in settings where troops are exposed to high ambient temperatures, increased physical demands, and dehydration. Our objective was to describe dietary supplement use and adverse events(AEs) among deployed U.S. service members compared with their pre-deployment ***: We conducted an institutional review board(IRB) approved, descriptive study in Afghanistan using a written questionnaire and collected demographic information, dietary supplement use before and during deployment, AEs associated with supplement use, and physical workout routines. Participants were U.S. military personnel of all branches of service deployed to Afghanistan. They were recruited in high-traffic areas in the combat theater. We analyzed the data with descriptive statistics. Paired t-test/Wilcoxon signed-rank test was conducted to examine the before/during deployment changes for continuous data, and Mc Nemar's chi-square test was conducted for categorical data. We constructed separate logistic regression models to determine the best predictors of increases or decreases in dietary supplement use, with demographic information, reasons for using supplements, and education requested/received as covariates in each model. All statistical tests were two-sided at a significance level of 5%(P<0.05).Results: Data were collected on 1685 participants. Ninety-seven of the participants were in the Army or Air Force. The participants were more likely to work out daily or more than once a day during deployment. Thirty-five percent of the participants reported no supplement use before or during deployment. The remaining 65% of participants reported increased use and increased frequency of use of supplements(e.g., daily) during deployment compared with predeployment. Additionally, more pe

关键词： Military Dietary supplement Workout Exercise Adverse events

L^1→L^q Poincare Inequalities for 0

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Acta Mathematica Sinica,English Series 2002年第1期18卷 1-20页

作者： perez Carlos Departamento dr Matematicas. Universidad Autónoma de Madrid. 28049 Madrid. Spain

Civen two doubling measures μ and v in a metric apace (S.p)of homogeneous type. let B_0 S be a given ball. It has been a well-known result bv now (see)[1 4])theat the validity of an L^1→L^1 Poincaré inequality of the following form: f_B|f-f_B|dv≤cr(B)f_Bgdμ. for all metric balls B B_0 S, implies a variant of representation formula of fractonal integral type: |f(x)-f_(B(11))|≤C integral from n=B_(11) g(y)p(x, y)/μ(B(x, p(x, y)))dμ(y)+C(r(B_0))/(μ(B_0))integral from n=B_0 g(y)dμ(y). One of the main results of this paper shows that an L^1 to L^q Poincaré inequality for some 01, i.e.. (f_B|f-f_B|~q dv)^(1/q)≤cr(B) f_B gdμ, for all metric balls B B_0. will suffice to imply the above representation formula. As an immediate corollary, we can show that the weak-type condition. sup_(λ>0)(λv({x ∈ B:|f(x)-f_B|>λ}))/v(B)≤Gr (B)f_B gdμ. also implies the same formula. Analogous theorems related to high-order Poincaréinequalities and Sobolev spaces in metric spaces are also proved.

关键词： Sobolev spaces Representation formulas High-order derivatives Vector fields Metric spaces Polynomials Doubling measures Poincare inequalities

Role of dup A in virulence of Helicobacter pylori

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World Journal of Gastroenterology 2016年第46期22卷 10118-10123页

作者： Amin Talebi Bezmin Abadi Guillermo perez-perez Department of Bacteriology Faculty of Medical Sciences Tarbiat Modares University Departments of Medicine and Microbiology New York University School of Medicine and VA Medical Center

Helicobacter pylori(H. pylori) is a gastric human pathogen associated with acute and chronic gastritis, 70% of all gastric ulcers, 85% of all duodenal ulcers, and both forms of stomach cancer, mucosal-associated lymphoid tissue(MALT) lymphoma and adenocarcinoma. Recently, attention has focused on possible relationship between presence of certain virulence factor and H. pylori-associated diseases. Some contradictory data between this bacterium and related disorders has been observed since not all the colonized individuals develop to severe disease. The reported diseases plausibility related to H. pylori specific virulence factors became an interesting story about this organism. Although a number of putative virulence factors have been identified including cytotoxin-associated gene a(cag A) and vac A, there are conflicting data about their actual participation as specific risk factor for H. pylori-related diseases. Duodenal ulcer promoting gene a(dup A) is a virulence factor of H. pylori that is highly associated with duodenal ulcer development and reduced risk of gastric cancer. The prevalence of dup A in H. pylori strains isolated from western countries is relatively higher than in H. pylori strains from Asian countries. Current confusing epidemiological reports will continue unless future sophisticated and molecular studies provide data on functional and complete dup A cluster in H. pylori infected individuals. This paper elucidates available knowledge concerning role of dup A in virulence of H. pylori after a decade of its discovery.

关键词： Helicobacter pylori dup A Bacterial virulence infection Clinical outcome

Photosynthetic Regulation of the Cyanobacterium Synechocystis sp. PCC 6803 Thioredoxin System and Functional Analysis of TrxB （Trx x） and TrxQ （Trx y） Thioredoxins

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Molecular Plant 2009年第2期2卷 270-283页

作者： M. Esther perez-perez Eugenio Martin-Figueroa Francisco J. Florencio Instituto de Bioquimica Vegetal y Fotosintesis Universidad de Sevilla-CSIC Avda Americo Vespucio 49 41092-Sevilla Spain

The expression of the genes encoding the ferredoxin-thioredoxin system including the ferredoxin-thioredoxin reductase （FTR） genes ftrC and ftrV and the four different thioredoxin genes trxA （m-type; sir0623）, trxB （x-type; sir1139）, trxC （sll1057） and trxQ （y-type; sir0233） of the cyanobacterium Synechocystis sp. PCC 6803 has been studied according to changes in the photosynthetic conditions. Experiments of light-dark transition indicate that the expression of all these genes except trxQ decreases in the dark in the absence of glucose in the growth medium. The use of two electron transport inhibitors, 3-（3,4-dichlorophenyl）-1,1-dimethylurea （DCMU） and 2,5-dibromo-3-methyl-6-isopropyl-p- benzoquinone （DBMIB）, reveals a differential effect on thioredoxin genes expression being trxC and trxQ almost unaffected, whereas trxA, trxB, and the ftr genes are down-regulated. In the presence of glucose, DCMU does not affect gene expression but DBMIB still does. Analysis of the single TrxB or TrxQ and the double TrxB TrxQ Synechocystis mutant strains reveal different functions for each of these thioredoxins under different growth conditions. Finally, a Synechocystis strain was generated containing a mutated version of TrxB （TrxBC34S）, which was used to identify the potential in-vivo targets of this thioredoxin by a proteomic analysis.

关键词： Cyanobacteria photosynthetic electron transport Synechocystis oxidative stress thioredoxin.

The Finite-dimensional Decomposition Property in Non-Archimedean Banach Spaces

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Acta Mathematica Sinica,English Series 2014年第11期30卷 1833-1845页

作者： Albert KUBZDELA Cristina.perez-GARCIA Institute of Civil Engineering Poznań University of TechnologyUl.Piotrowo 561-138 PoznańPoland Department of Mathematics Facultad de CienciasUniversidad de CantabriaAvda.de los Castros s/n39071SantanderSpain

A non-Archimedean Banach space has the orthogonal finite-dimensional decomposition property（OFDDP） if it is the orthogonal direct sum of a sequence of finite-dimensional *** property has an influence in the non-Archimedean Grothendieck＇s approximation theory,where an open problem is the following： Let E be a non-Archimedean Banach space of countable type with the OFDDP and let D be a closed subspace of *** D have the OFDDP？ In this paper we give a negative answer to this question; we construct a Banach space of countable type with the OFDDP having a one-codimensional subspace without the *** we prove that,however,for certain classes of Banach spaces of countable type,the OFDDP is preserved by taking finite-codimensional subspaces.

关键词： Non-Archimedean Banach spaces finite-dimensional decomposition property orthogonal base

Bile-acid-induced cell injury and protection

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World Journal of Gastroenterology 2009年第14期15卷 1677-1689页

作者： Maria J perez Oscar Briz Research Unit University Hospital of Salamanca Laboratory of Experimental Hepatology and Drug Targeting CIBERehd University of Salamanca E.D. 129 37007 Salamanca Spain

Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids （BAs） in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyI-N- methylglycine or pharmacological properties. cholylsarcosine, interest owing have also aroused to their protective

关键词： Apoptosis Cholestasis Liver Necrosis Oxidative stress Ursodeoxycholic acid