bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug Hypersensitivity Reactions Targeting the Skin in Dogs and Cats
Authors: Voie K.L. , Campbell K.L. , Lavergne S.N.
Published: April 2012

Adverse drug reactions (ADRs) can be dose dependent or idiosyncratic. Most idiosyncratic reactions are believed to be immune‐mediated; such drug hypersensitivities and allergies are unpredictable. Cutaneous reactions are the most common presentation of drug allergies. In veterinary medicine it can be difficult to assess the true prevalence of adverse drug reactions, although reports available suggest that they occur quite commonly. There are multiple theories that attempt to explain how drug allergies occur, because the pathogenesis is not yet well understood. These include the (pro)‐hapten hypothesis, theDangerTheory, the pi concept, and the viral reactivation theory. Cutaneous drug allergies in veterinary medicine can have a variety of clinical manifestations, ranging from pruritus to often fatal toxic epidermal necrolysis. Diagnosis can be challenging, as the reactions are highly pleomorphic and may be mistaken for other dermatologic diseases. One must rely heavily on history and physical examination to rule out other possibilities. Dechallenge of the drug, histopathology, and other diagnostic tests can help to confirm the diagnosis. New diagnostic tools are beginning to be used, such as antibody or cellular testing, and may be used more in the future. There is much yet to learn about drug allergies, which makes future research vitally important. Treatment of drug allergies involves supportive care, and additional treatments, such as immunosuppressive medications, depend on the manifestation of the disease. Of utmost importance is to avoid the use of the incriminating drug in future treatment of the patient, as subsequent reactions can be worse, and ultimately can prove fatal.
Prevalence of Gastroesophageal Reflux Disease in Premature Calves
Authors: Guzelbektes H. , Coskun A. , Ok M. , Aydogdu U. , Sen I.
Published: April 2012

Background

Gastroesophageal reflux (GER) is the presence of gastric contents proximal to the stomach. Pathologic consequences secondary toGERare termed gastroesophageal reflux disease (GERD).

Objectives

The purpose of this study was to determine the prevalence ofGERandGERDin premature calves by endoscopic examination.

Animals

Ten healthy and 51 premature calves were included in the study. All premature calves also had respiratory distress syndrome.

Methods

Esophagoscopy of premature calves was conducted by fiber optic endoscopy. Abnormalities such as increased saliva, hyperemia, hemorrhage, petechiae, presence of abomasal content in the esophagus, and relaxation of the lower esophageal sphincter (LES) were evaluated by endoscopy.

Results

The prevalence ofGERDandGERin the premature calves was 55 and 67%, respectively. Hyperemia and hyperemia with hemorrhage or petechiation of the esophageal mucosa were determined by endoscopic examination.Hyperemia was commonly observed in the distal esophageal mucosa, although a few hyperemic areas also were observed in other portions of the esophagus. In addition to these abnormalities,LESrelaxation, abomasal fluid in the distal esophagus, abomasal content in the esophagus, and increased saliva also were observed in premature calves withGER.

Conclusions

The prevalence of bothGER(67%) andGERD(55%) in premature calves was high in the study. Endoscopy provides a practical, rapid, noninvasive, and reasonably accurate method for determining the presence ofGERandGERDin premature calves.
Cladding Glass Development for Semiconductor Core Optical Fibers
Authors: Morris Stephanie , Hawkins Thomas , Foy Paul , Ballato John , Martin Steve W. , Rice Robert
Published: April 2012

Glass‐clad optical fibers comprising a crystalline semiconductor core have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. To date, cladding compositions have relied on commercially‐available expedients and have not been tailored for the specific semiconductor core nor the application. In this work, more‐optimum silicate and nonoxide glass compositions are developed for unary (Si, Ge), binary (InSb, GaAs), and ternary (GaAlSb) semiconductor cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core and glass cladding and (2) matching the viscosity‐temperature dependences such that the cladding glass draws into fiber at a temperature slightly above the melting point of the semiconductor. While this latter requirement is critical to the molten core fabrication method, which offers a practical approach to long fiber lengths at acceptable manufacturing speeds (>m/s), these compositions are more broadly applicable to other semiconductor fiber processing methods. Preliminary experimental results on silicon core optical fiber are provided and show a marked diminution in oxygen content relative to analogous fibers drawn using a pure silica cladding.
Muscle cyclo‐oxygenase‐2 pathway contributes to the exaggerated muscle mechanoreflex in rats with congestive heart failure
Authors: Morales Ariel , Gao Wei , Lu Jian , Xing Jihong , Li Jianhua
Published: April 2012

Cyclo‐oxygenase (COX) enzymes are responsible for the formation from arachidonic acid of prostaglandins, among other metabolites. Prior studies have suggested that inhibition of the COX pathway attenuates the responses of sympathetic nerve activity and blood pressure during static muscle contraction. Static muscle contraction activates the exercise pressor reflex, which in turn increases sympathetic nerve activity and blood pressure. Also, COX products contribute to exaggeration of the exercise pressor reflex in heart failure (HF). This dysfunction of the exercise pressor reflex has previously been shown to be mediated primarily by muscle mechanoreflex overactivity. It is well known that COX‐1 and COX‐2 are two isoforms of the enzyme that lead to formation of these important biological mediators involved in the muscle reflex. Thus, in the present study, we determined whether the COX‐1 and/or COX‐2 pathway contribute(s) to the augmented mechanoreflex activity in HF. First, Western blot analysis was employed to examine protein expression of COX‐1 and COX‐2 in skeletal muscle tissue of control rats and rats with HF induced by myocardial infarction. Our data show that there is no significant difference in COX‐1 expression in both experimental groups. However, COX‐2 displays significant overexpression in rats with HF compared with control rats (optical density 1.06 ± 0.05 in control and 1.6 ± 0.05 in HF, P < 0.05 versus control). Second, the mechanoreflex was evoked by passive tendon stretch, and the reflex sympathetic and pressor responses to muscle stretch were examined after COX‐1 and COX‐2 inhibitors (FR‐122047 and SC‐236) were individually injected into the arterial blood supply of the hindlimb muscles. The results demonstrate that the stretch‐evoked reflex responses in rats with HF were significantly attenuated by administration of SC‐236, but not by FR‐122047, i.e. renal sympathetic nerve activity and mean arterial pressure responses evoked by 0.5 kg of muscle tension were 52.3 ± 8.9% and 19 ± 1.4 mmHg, respectively, in control conditions and 26.4 ± 5.6% and 5.7 ± 1.6 mmHg (P < 0.05 versus control group) after 0.25 mg kg−1 of SC‐236. Muscle stretch‐evoked renal sympathetic nerve activity and mean arterial pressure responses were 51.8 ± 8.2% and 18.7 ± 1.2 mmHg, respectively, in control conditions and 48.3 ± 5.3% and 17.5 ± 1.9 mmHg (P > 0.05 versus control group) after 1.0 mg kg−1 of FR‐122047. Accordingly, the results obtained from this study support our hypothesis that heightened COX‐2 expression within the hindlimb muscles contributes to the exaggerated muscle mechanoreflex in congestive HF.
The Ancient Drug Salicylate Directly Activates AMP-Activated Protein Kinase
Authors: Hawley Simon A. , Fullerton Morgan D. , Ross Fiona A. , Schertzer Jonathan D. , Chevtzoff Cyrille , Walker Katherine J. , Peggie Mark W. , Zibrova Darya , Green Kevin A. , Mustard Kirsty J. , Kemp Bruce E. , Sakamoto Kei , Steinberg Gregory R. , Hardie D. Grahame
Published: April 2012

An Aspirin a Day?

The protein kinase AMPK (adenosine monophosphate–activated protein kinase) directly monitors cellular energy stores as reflected by changes in cellular concentrations of AMP, adenosine diphosphate (ADP), and adenosine triphosphate (ATP). Through phosphorylation of its targets, it helps to control metabolism, polarity, autophagy, and the restraint of cell proliferation. Activation of AMPK is also proposed to be beneficial for the treatment of diseases, including cancer and diabetes.

Hawley
et al.

(p.
918
, published online 19 April; see the Perspective by

Shaw and Cantley

) report that AMPK can be activated by high concentrations of salicylate, a compound derived from the very commonly used drug aspirin. In mice, salicylate promoted fatty acid and carbohydrate metabolism in an AMPK-dependent fashion.
The Active Site of Methanol Synthesis over Cu/ZnO/Al
2
O
3
Industrial Catalysts
Authors: Behrens Malte , Studt Felix , Kasatkin Igor , Kühl Stefanie , Hävecker Michael , Abild-Pedersen Frank , Zander Stefan , Girgsdies Frank , Kurr Patrick , Kniep Benjamin-Louis , Tovar Michael , Fischer Richard W. , Nørskov Jens K. , Schlögl Robert
Published: April 2012

Mechanisms in Methanol Catalysis

The industrial production of methanol from hydrogen and carbon monoxide depends on the use of copper and zinc oxide nanoparticles on alumina oxide supports. This catalyst is “structure sensitive”; its activity can vary by orders of magnitude, depending on how it is prepared.

Behrens
et al.

(p.
893
, published online 19 April; see the Perspective by

Greeley

) used a combination of bulk and surface-sensitive analysis and imaging methods—along with insights from density functional theory calculations—to study several catalysts, including the one similar to that used industrially. High activity depended on the presence of steps on the copper nanoparticles stabilized by defects such as stacking faults. Partial coverage of the copper nanoparticles with zinc oxide was critical for stabilizing surface intermediates such as HCO and lowering energetic barriers to the methanol product.
Precise Manipulation of the Clostridium difficile Chromosome Reveals a Lack of Association between the
tcdC
Genotype and Toxin Production
Authors: Cartman Stephen T. , Kelly Michelle L. , Heeg Daniela , Heap John T. , Minton Nigel P.
Published: April 2012

Clostridium difficile
causes a potentially fatal diarrheal disease through the production of its principal virulence factors, toxin A and toxin B. The
tcdC
gene is thought to encode a negative regulator of toxin production. Therefore, increased toxin production, and hence increased virulence, is often inferred in strains with an aberrant
tcdC
genotype. This report describes the first allele exchange system for precise genetic manipulation of
C. difficile
, using the
codA
gene of
Escherichia coli
as a heterologous counterselection marker. It was used to systematically restore the Δ117 frameshift mutation and the 18-nucleotide deletion that occur naturally in the
tcdC
gene of
C. difficile
R20291 (PCR ribotype 027). In addition, the naturally intact
tcdC
gene of
C. difficile
630 (PCR ribotype 012) was deleted and then subsequently restored with a silent nucleotide substitution, or “watermark,” so the resulting strain was distinguishable from the wild type. Intriguingly, there was no association between the
tcdC
genotype and toxin production in either
C. difficile
R20291 or
C. difficile
630. Therefore, an aberrant
tcdC
genotype does not provide a broadly applicable rationale for the perceived notion that PCR ribotype 027 strains are “high-level” toxin producers. This may well explain why several studies have reported that an aberrant
tcdC
gene does not predict increased toxin production or, indeed, increased virulence.
Emergence of Atypical Mycoplasma agalactiae Strains Harboring a New Prophage and Associated with an Alpine Wild Ungulate Mortality Episode
Authors: Tardy Florence , Baranowski Eric , Nouvel Laurent-Xavier , Mick Virginie , Manso-Silvàn Lucía , Thiaucourt François , Thébault Patricia , Breton Marc , Sirand-Pugnet Pascal , Blanchard Alain , Garnier Alexandre , Gibert Philippe , Game Yvette , Poumarat François , Citti Christine
Published: April 2012

The bacterium
Mycoplasma agalactiae
is responsible for contagious agalactia (CA) in small domestic ruminants, a syndrome listed by the World Organization for Animal Health and responsible for severe damage to the dairy industry. Recently, we frequently isolated this pathogen from lung lesions of ibexes during a mortality episode in the French Alps. This situation was unusual in terms of host specificity and tissue tropism, raising the question of
M. agalactiae
emergence in wildlife. To address this issue, the ibex isolates were characterized using a combination of approaches that included antigenic profiles, molecular typing, optical mapping, and whole-genome sequencing. Genome analyses showed the presence of a new, large prophage containing 35 coding sequences (CDS) that was detected in most but not all ibex strains and has a homolog in
Mycoplasma conjunctivae
, a species causing keratoconjunctivitis in wild ungulates. This and the presence in all strains of large integrated conjugative elements suggested highly dynamic genomes. Nevertheless,
M. agalactiae
strains circulating in the ibex population were shown to be highly related, most likely originating from a single parental clone that has also spread to another wild ungulate species of the same geographical area, the chamois. These strains clearly differ from strains described in Europe so far, including those found nearby, before CA eradication a few years ago. While
M. agalactiae
pathogenicity in ibexes remains unclear, our data showed the emergence of atypical strains in Alpine wild ungulates, raising the question of a role for the wild fauna as a potential reservoir of pathogenic mycoplasmas.
Shifts in Identity and Activity of Methanotrophs in Arctic Lake Sediments in Response to Temperature Changes
Authors: He Ruo , Wooller Matthew J. , Pohlman John W. , Quensen John , Tiedje James M. , Leigh Mary Beth
Published: April 2012

Methane (CH
4
) flux to the atmosphere is mitigated via microbial CH
4
oxidation in sediments and water. As arctic temperatures increase, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is important to predicting future CH
4
emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), and pyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C, and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH
4
oxidation activity was measured in microcosm incubations containing sediments at all temperatures, with the highest CH
4
oxidation potential of 37.5 μmol g
−1
day
−1
in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of
pmoA
and of the 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in
13
C-labeled DNA obtained by SIP demonstrated that the type I methanotrophs
Methylobacter
,
Methylomonas
, and
Methylosoma
dominated carbon acquisition from CH
4
in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature. Methylotrophs were also abundant in the microbial community that derived carbon from CH
4
, especially in the deeper sediments (depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (
R
= 0.82) with the relative abundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophic communities in arctic lake sediments respond to temperature variations.
Two Systems for Targeted Gene Deletion in Coxiella burnetii
Authors: Beare Paul A. , Larson Charles L. , Gilk Stacey D. , Heinzen Robert A.
Published: April 2012

Coxiella burnetii
is a ubiquitous zoonotic bacterial pathogen and the cause of human acute Q fever, a disabling influenza-like illness.
C. burnetii
's former obligate intracellular nature significantly impeded the genetic characterization of putative virulence factors. However, recent host cell-free (axenic) growth of the organism has enabled development of shuttle vector, transposon, and inducible gene expression technologies, with targeted gene inactivation remaining an important challenge. In the present study, we describe two methods for generating targeted gene deletions in
C. burnetii
that exploit pUC/ColE1
ori
-based suicide plasmids encoding
sacB
for positive selection of mutants. As proof of concept,
C. burnetii
dotA and
dotB
, encoding structural components of the type IVB secretion system (T4BSS), were selected for deletion. The first method exploited Cre-
lox-
mediated recombination. Two suicide plasmids carrying different antibiotic resistance markers and a
loxP
site were integrated into 5′ and 3′ flanking regions of
dotA
. Transformation of this strain with a third suicide plasmid encoding Cre recombinase resulted in the deletion of
dotA
under sucrose counterselection. The second method utilized a loop-in/loop-out strategy to delete
dotA
and
dotB.
A single suicide plasmid was first integrated into 5′ or 3′ target gene flanking regions. Resolution of the plasmid cointegrant by a second crossover event under sucrose counterselection resulted in gene deletion that was confirmed by PCR and Southern blot. Δ
dotA
and Δ
dotB
mutants failed to secrete T4BSS substrates and to productively infect host cells. The repertoire of
C. burnetii
genetic tools now allows ready fulfillment of molecular Koch's postulates for suspected virulence genes.
Influence of Salinity on the Bacterial Community Composition in Lake Bosten, a Large Oligosaline Lake in Arid Northwestern China
Authors: Tang Xiangming , Xie Guijuan , Shao Keqiang , Sai·Bayartu  , Chen Yuangao , Gao Guang
Published: April 2012

Salinity was found to be the dominating contributor controlling bacterial community composition (BCC) and the abundance of
Betaproteobacteria
in the oligosaline Lake Bosten. The high percentage of unclassified bacteria inhabiting this unique habitat highlights the potential ecological importance of BCC in the early stage of lake salinization and eutrophication.
Infections and Coinfections of Questing Ixodes ricinus Ticks by Emerging Zoonotic Pathogens in Western Switzerland
Authors: Lommano Elena , Bertaiola Luce , Dupasquier Christèle , Gern Lise
Published: April 2012

In Europe,
Ixodes ricinus
is the vector of many pathogens of medical and veterinary relevance, among them
Borrelia burgdorferi
sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like
Rickettsia
spp.,
Babesia
spp., “
Candidatus
Neoehrlichia mikurensis,” and
Anaplasma phagocytophilum
in questing ticks. In this study, questing nymph and adult
I. ricinus
ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of
B. burgdorferi
sensu lato,
Rickettsia
spp.,
Babesia
spp., “
Candidatus
Neoehrlichia mikurensis,” and
A. phagocytophilum. B. burgdorferi
sensu lato,
Rickettsia
spp., and “
Candidatus
Neoehrlichia mikurensis” were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively.
Babesia
- and
A. phagocytophilum
-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like
Borrelia spielmanii
,
Borrelia lusitaniae
, and
Rickettsia monacensis
, were identified. Infections with more than one pathogenic species, involving mostly
Borrelia
spp. and
Rickettsia helvetica
, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in
I. ricinus
in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.
Centromere Binding and Evolution of Chromosomal Partition Systems in the Burkholderiales
Authors: Passot Fanny M. , Calderon Virginie , Fichant Gwennaele , Lane David , Pasta Franck
Published: April 2012

How split genomes arise and evolve in bacteria is poorly understood. Since each replicon of such genomes encodes a specific partition (Par) system, the evolution of Par systems could shed light on their evolution. The cystic fibrosis pathogenBurkholderia cenocepaciahas three chromosomes (c1, c2, and c3) and one plasmid (pBC), whose compatibility depends on strictly specific interactions of the centromere sequences (parS) with their cognate binding proteins (ParB). However, the Par systems ofB. cenocepaciac2, c3, and pBC share many features, suggesting that they arose within an extended family. Database searching revealed seven subfamilies of Par systems like those ofB. cenocepacia. All are from plasmids and secondary chromosomes of theBurkholderiales, which reinforces the proposal of an extended family. The subfamily of the Par system ofB. cenocepaciac3 includes plasmid variants withparSsequences divergent from that of c3. Using electrophoretic mobility shift assay (EMSA), we found that ParB-c3 binds specifically to centromeres of these variants, despite high DNA sequence divergence. We suggest that the Par system ofB. cenocepaciac3 has preserved the features of an ancestral system. In contrast, these features have diverged variably in the plasmid descendants. One such descendant is found both inRalstonia pickettii12D, on a free plasmid, and inRalstonia pickettii12J, on a plasmid integrated into the main chromosome. These observations suggest that we are witnessing a plasmid-chromosome interaction from which a third chromosome will emerge in a two-chromosome species.
Iron Regulates Expression of Bacillus cereus Hemolysin II via Global Regulator Fur
Authors: Sineva Elena , Shadrin Andrey , Rodikova Ekaterina A. , Andreeva-Kovalevskaya Zhanna I. , Protsenko Alexey S. , Mayorov Sergey G. , Galaktionova Darya Yu , Magelky Erica , Solonin Alexander S.
Published: April 2012

The capacity of pathogens to respond to environmental signals, such as iron concentration, is key to bacterial survival and establishment of a successful infection.
Bacillus cereus
is a widely distributed bacterium with distinct pathogenic properties. Hemolysin II (HlyII) is one of its pore-forming cytotoxins and has been shown to be involved in bacterial pathogenicity in a number of cell and animal models. Unlike many other
B. cereus
pathogenicity factors, HlyII is not regulated by pleiotropic transcriptional regulator PlcR but is controlled by its own regulator, HlyIIR. Using a combination of
in vivo
and
in vitro
techniques, we show that
hlyII
expression is also negatively regulated by iron by the global regulator Fur via direct interaction with the
hlyII
promoter. DNase I footprinting and
in vitro
transcription experiments indicate that Fur prevents RNA polymerase binding to the
hlyII
promoter. HlyII expression profiles demonstrate that both HlyIIR and Fur regulate HlyII expression in a concerted fashion, with the effect of Fur being maximal in the early stages of bacterial growth. In sum, these results show that Fur serves as a transcriptional repressor for
hlyII
expression.
Flagellar Hook Flexibility Is Essential for Bundle Formation in Swimming Escherichia coli Cells
Authors: Brown Mostyn T. , Steel Bradley C. , Silvestrin Claudio , Wilkinson David A. , Delalez Nicolas J. , Lumb Craig N. , Obara Boguslaw , Armitage Judith P. , Berry Richard M.
Published: April 2012

Swimming
Escherichia coli
cells are propelled by the rotary motion of their flagellar filaments. In the normal swimming pattern, filaments positioned randomly over the cell form a bundle at the posterior pole. It has long been assumed that the hook functions as a universal joint, transmitting rotation on the motor axis through up to ∼90° to the filament in the bundle. Structural models of the hook have revealed how its flexibility is expected to arise from dynamic changes in the distance between monomers in the helical lattice. In particular, each of the 11 protofilaments that comprise the hook is predicted to cycle between short and long forms, corresponding to the inside and outside of the curved hook, once each revolution of the motor when the hook is acting as a universal joint. To test this, we genetically modified the hook so that it could be stiffened by binding streptavidin to biotinylated monomers, impeding their motion relative to each other. We found that impeding the action of the universal joint resulted in atypical swimming behavior as a consequence of disrupted bundle formation, in agreement with the universal joint model.
The Azospirillum brasilense Che1 Chemotaxis Pathway Controls Swimming Velocity, Which Affects Transient Cell-to-Cell Clumping
Authors: Bible Amber , Russell Matthew H. , Alexandre Gladys
Published: April 2012

The Che1 chemotaxis-like pathway of
Azospirillum brasilense
contributes to chemotaxis and aerotaxis, and it has also been found to contribute to regulating changes in cell surface adhesive properties that affect the propensity of cells to clump and to flocculate. The exact contribution of Che1 to the control of chemotaxis and flocculation in
A. brasilense
remains poorly understood. Here, we show that Che1 affects reversible cell-to-cell clumping, a cellular behavior in which motile cells transiently interact by adhering to one another at their nonflagellated poles before swimming apart. Clumping precedes and is required for flocculation, and both processes appear to be independently regulated. The phenotypes of a Δ
aerC
receptor mutant and of mutant strains lacking
cheA1
,
cheY1
,
cheB1
, or
cheR1
(alone or in combination) or with
che1
deleted show that Che1 directly mediates changes in the flagellar swimming velocity and that this behavior directly modulates the transient nature of clumping. Our results also suggest that an additional receptor(s) and signaling pathway(s) are implicated in mediating other Che1-independent changes in clumping identified in the present study. Transient clumping precedes the transition to stable clump formation, which involves the production of specific extracellular polysaccharides (EPS); however, production of these clumping-specific EPS is not directly controlled by Che1 activity. Che1-dependent clumping may antagonize motility and prevent chemotaxis, thereby maintaining cells in a metabolically favorable niche.
Emerging concept: ‘central benefit model’ of exercise in falls prevention
Authors: Liu-Ambrose Teresa , Nagamatsu Lindsay S , Hsu Chun Liang , Bolandzadeh Niousha
Published: April 2012

Falls are a common geriatric syndrome and are the third leading cause of chonic disability worldwide. Falls are not random events and occur, at least in part, due to impaired physiological function, such as impaired balance, and cognitive impairment. The clinical syndrome of falls is important for Sports and Exercise Medicine Clinicians as there is Level 1 evidence that targeted exercise prescription is an effective intervention strategy. The widely accepted dogma is that improved physical function, balance and muscle strength, underlies the effectiveness of the exercise in reducing falls. However, findings from randomised controlled trials suggest that exercise reduce falls via mechanisms other than improved physiological function. The authors propose that improved cognitive function – specifically, executive functions – and associated functional plasticity may be an important yet underappreciated mechanism by which the exercise reduces falls in older adults.
Determination of future prevention strategies in elite track and field: analysis of Daegu 2011 IAAF Championships injuries and illnesses surveillance
Authors: Alonso Juan-Manuel , Edouard Pascal , Fischetto Giuseppe , Adams Bob , Depiesse Frédéric , Mountjoy Margo
Published: April 2012

Objective

To determine the incidence and characteristics of newly incurred injuries and illnesses during international Athletics Championships, by improving the medical surveillance coverage, in order to determine future prevention strategies.

Design

Prospective recording of newly occurred injuries and illnesses.

Setting

13th International Association of Athletics Federations World Championships in Athletics 2011 in Daegu, Korea.

Participants

National team and Local Organising Committee physicians; and 1851 registered athletes.

Main outcome measures

Incidence and characteristics of newly incurred injuries and illnesses.

Results

82% of athletes were covered by medical teams participating with a response rate of 94%. A total of 249 injuries were reported, representing an incidence of 134.5 injuries per 1000 registered athletes, and 119 (48%) resulted in time loss from sport. A total of 185 injuries affected the lower limb (74%). Hamstring strain was the main diagnosis and 67% resulted in absence from sport. Overuse (n=148; 59%) was the predominant cause. A total of 126 illnesses were reported, signifying an incidence of 68.1 per 1000 registered athletes. Upper respiratory tract infection was the most common reported diagnosis (18%), followed by exercise-induced dehydration (12%), and gastroenteritis/diarrhoea (10%). The highest incidences of injuries were found in combined events and middle and long-distance events, and of illness in race walking events.

Conclusion

During elite Athletics World Championships, 135 injuries, 60 time-loss injuries and 68 illnesses per 1000 registered athletes were reported. Higher risks of injuries were found in combined events and long-distance runs. Preventive interventions should focus on overuse injuries and hamstring strains, decreasing the risk of transmission of infectious diseases, appropriate event scheduling and heat acclimatisation.
Respiratory health of elite athletes – preventing airway injury: a critical review
Authors: Kippelen Pascale , Fitch Kenneth D , Anderson Sandra Doreen , Bougault Valerie , Boulet Louis-Philippe , Rundell Kenneth William , Sue-Chu Malcolm , McKenzie Donald C
Published: April 2012

Elite athletes, particularly those engaged in endurance sports and those exposed chronically to airborne pollutants/irritants or allergens, are at increased risk for upper and lower airway dysfunction. Airway epithelial injury may be caused by dehydration and physical stress applied to the airways during severe exercise hyperpnoea and/or by inhalation of noxious agents. This is thought to initiate an inflammatory cascade/repair process that, ultimately, could lead to airway hyperresponsiveness (AHR) and asthma in susceptible athletes. The authors review the evidence relating to prevention or reduction of the risk of AHR/asthma development. Appropriate measures should be implemented when athletes exercise strenuously in an attempt to attenuate the dehydration stress and reduce the exposure to noxious airborne agents. Environmental interventions are the most important. Non-pharmacological strategies can assist, but currently, pharmacological measures have not been demonstrated to be effective. Whether early prevention of airway injury in elite athletes can prevent or reduce progression to AHR/asthma remains to be established.
Associations between internet-based patient ratings and conventional surveys of patient experience in the English NHS: an observational study
Authors: Greaves Felix , Pape Utz J , King Dominic , Darzi Ara , Majeed Azeem , Wachter Robert M , Millett Christopher
Published: April 2012

Objective

Unsolicited web-based comments by patients regarding their healthcare are increasing, but controversial. The relationship between such online patient reports and conventional measures of patient experience (obtained via survey) is not known. The authors examined hospital level associations between web-based patient ratings on the National Health Service (NHS) Choices website, introduced in England during 2008, and paper-based survey measures of patient experience. The authors also aimed to compare these two methods of measuring patient experience.

Design

The authors performed a cross-sectional observational study of all (n=146) acute general NHS hospital trusts in England using data from 9997 patient web-based ratings posted on the NHS Choices website during 2009/2010. Hospital trust level indicators of patient experience from a paper-based survey (five measures) were compared with web-based patient ratings using Spearman's rank correlation coefficient. The authors compared the strength of associations among clinical outcomes, patient experience survey results and NHS Choices ratings.

Results

Web-based ratings of patient experience were associated with ratings derived from a national paper-based patient survey (Spearman ρ=0.31–0.49, p<0.001 for all). Associations with clinical outcomes were at least as strong for online ratings as for traditional survey measures of patient experience.

Conclusions

Unsolicited web-based patient ratings of their care, though potentially prone to many biases, are correlated with survey measures of patient experience. They may be useful tools for patients when choosing healthcare providers and for clinicians to improve the quality of their services.
Electrochemistry of the Nickel Electrode as a Cathode Catalyst in the Media of Acidic Peroxide for Application of the Peroxide Fuel Cell
Authors: Sanlı Ays¸e Elif , Aytaç Aylin
Published: April 2012

Hydrogen peroxide reduces on the nickel electrode surface in the acidic medium. On the nickel electrode the passive film layers such as NiS and NiOOH form in the peroxide free solution. However the nickel surface was activated with the addition of the peroxide. The cyclic voltammetry (CV) and impedance (EIS) studies verified the passivation and activation states in peroxide free acidic solution and the acidic peroxide solution. The electrochemical reactions of the sulphuric acid and peroxide at nickel electrode were electrochemically analyzed by cyclic voltammetry (CV) and impedance spectroscopy (EIS)
Use of Molten Carbonate Fuel Cell for CO2 Capture
Authors: Filipponi Mirko , Rossi Federico , Rossi Roberto
Published: April 2012

The adoption of technologies for the separation, capture and subsequent storage of CO2 for geological time periods through injection into the subsoil (CCS, Carbon Dioxide Capture & Storage), has emerged as a key approach to reduce CO2 emissions from upstream emitting sources, to comply with EU-ETS directives on emissions control, which force polluting industries to reduce their CO2 emissions below given limits. However, the significant investments required, and the energy intensive nature of conventional capture processes, have fuelled the ongoing debate on the effectiveness of this means of reducing CO2 emissions. This thesis considers, as an alternative to conventional CCS, non-conventional systems to capture and concentrate emissions, through the use of both a Molten-carbonate fuel cell (MCFC) configured as an electrical power generator, and the same fuel cell configured as an electrolyser (MCEC), therefore absorbing a limited amount of electrical power. These systems will be set up in a cascade in settings which reproduce typical conditions of large scale high- CO2 emission environments, and compared through a technical-economic analysis.
The Hydrogen Fuel Cell Vehicles Powertrain Roles in the Copenhagen Accord and Cancún Agreement Perspective
Authors: Romeri Mario Valentino
Published: April 2012

Copenhagen Accord's and Cancun Agreements' general perspective does not include any low-carbon technologies consideration and Hydrogen Fuel Cell (H2FC) Vehicles is still not considered as a relevant solution in the energy debate. In recent years I presented different analyses in which I argued that it's time to do so. I considered the "H2FC Powertrain" as power generation plant and the levelized cost of electricity (LCOE) was compared to costs of traditional power generation technologies. Using the U.S. DOE "H2FC Powertrain" data (referred to high projected production volume) the 2009-2010 LCOE would be in a range of USD 174.8-192.3 for MWh. Using 2015 data target the lower value of the LCOE cost range moves down and it appears competitive with almost all power generation technologies analyzed. The analysis confirms the new relevant "H2FC Powertrain" possible role in the Copenhagen Accord and Cancun Agreements perspective both in transport and power generation sectors.
36 kW Polymer Exchange Membrane Fuel Cell as Combined Heat and Power Unit
Authors: Milewski Jaroslaw , Wolowicz Marcin , Badyda Krzysztof , Misztal Zbigniew
Published: April 2012

The paper presents operational characteristics of start-up and shut-down of a 30kW micro Combined Heat and Power (µ-CHP) system. The plant is composed of three main units: reformer, CO oxidizer (reactor "water gas shift" and oxidation reactor - "prox") and PEMFC
A Sodium Borohydride - Hydrogen Peroxide Fuel Cell Employing a Bipolar Membrane Electrolyte
Authors: Reeve Robert W.
Published: April 2012

An air-independent fuel cell system has been demonstrated using a bipolar membrane electrolyte. The fuel cell was operated using an alkaline sodium borohydride fuel solution and an acid stabilized hydrogen peroxide oxidant solution. The unique water splitting nature of the bipolar membrane provided in-situ generation of the supporting electrolytes required to catalyze both the anode and cathode reactions. This was further shown to provide pH and chemical stability of the fuel cell reactants during discharge. It is estimated that by eliminating the requirement for storage of supporting electrolytes, a practical power system with a specific energy in excess of 300 Wh•kg-1 could be realized in the near-term.
Development of Proton Exchange Membrane Fuel Cell System for Portable Refrigerator
Authors: Han Hun Sik , Kim Yun Ho , Kim Seo Young , Karng Sarng Woo , Hyun Jae Min
Published: April 2012

A proton exchange membrane (PEM) fuel cell system for powering a portable refrigerator is developed. The PEM fuel cell system consists of an air-cooled stack with combined oxidant and coolant flow, a hydrogen supply subsystem with two metal hydride canisters, a power management subsystem with a DC-DC converter and a rechargeable battery, and a control electronics subsystem. To analyze the performance of the PEM fuel cell system, the stack power output, the balance-of-plant (BOP) power consumption and the battery charging power are measured at various external loading conditions. The BOP system shows low efficiency of 20.7% under no-load condition, while it increases to 72.3% at 200.5 W system power output.
On-Line Gas Measurements from PEM Fuel Cell Flow Fields by Electric Arc Emission Spectroscopy
Authors: Bettermann Hans , Reichelt Arno
Published: April 2012

This contribution presents an arc emission spectrometer for the investigation of exhaust gases of PEM fuel cell flow fields. The method bases on the electronic excitation of molecules by collision with charge carriers within an electric arc. The excited molecules undergo irradiant deactivations that lead to light emissions which are specific for each molecular species. The method enables the record of gas concentrations on a millisecond time scale. Detectable concentrations range from pure gases to concentrations of a few ppm. The gas detector was used to investigate the intrinsic cross over of gases through the MEA unit of a fuel cell. In particular, the passage of nitrogen from the cathode to the anode was studied under selected conditions of fuel cell operation. In addition, pre-stages of membrane degradation can be pursued.
Investigations on the Morphology and Water Inventory of GDLs Using µ-Computer Tomography and Monte Carlo Modeling
Authors: Seidenberger Katrin , Klages Merle , Wilhelm Florian , Scholta Joachim
Published: April 2012

The water inventory of a GDL plays an important role with respect to both gas diffusion properties and water saturation level of the MEA. In this paper, investigations on the morphology and on the water inventory of GDLs are reported. Based on image data obtained from µ-CT-experiments, 3D GDL structures were reconstructed and used for further analysis. Furthermore, the water inventory of the GDL was modeled using a Monte Carlo (MC) method. Both experimental (µ-CT) and modeling approaches are presented and discussed. Data on pressure dependent pore radius and water distribution are reported. Moreover, the dependence of the water inventory upon the operating conditions is discussed.
Development of a Metallic Separator for a Micro-PEFC
Authors: Yamauchi Makoto , Fujii Takumi , Sugiura Kimihiko
Published: April 2012

Although polymer electrolyte fuel cells (PEFCs) have recently gained popularity in domestic and automobile use, miniature fuel cells are expected to be the power supply of mobile electronic devices. Generally, the separator used for a PEFC is made of carbon. However, carbon is unsuitable as a separator material for a micro-PEFC. Because carbon is fragile, machining a detailed feature, such as a gas channel, is difficult. Machining the channel into the metallic separator can be achieved; however, the cost rises accordingly. However, if metal injection molding (MIM) is used, the detailed gas channel geometry can be formed in the separator, and the manufacturing cost can be reduced. Therefore, we aim to develop a metallic separator suitable for a micro-PEFC by the MIM method.
Development of a SOFC Hybrid System
Authors: Napoli Giuseppe , Ferraro Marco , Sergi Francesco , Brunaccini Giovanni , Dispenza Giorgio , Andaloro Laura , Yasin Aysar , Antonucci Vincenzo
Published: April 2012

With new technologies emerging and the existing ones evolving, the basis for having large centralised Combined Heat and Power (CHP) plants is slowly diminishing. Beside the increasing energy demand and the need to reduce CO2 emissions, the use of smaller decentralised CHP plants is becoming more interesting. Solid Oxide Fuel Cells (SOFC), thanks to their fuel flexibility (hydrogen, natural gas, propane, etc), are suitable to the above mentioned aims. From a storage point of view, in order to ensure increasing penetration of technologies related to renewable energies in decentralized generation, innovative devices that permit storage of energy must be considered. The most effective solution is the combination of renewable energies and secondary batteries. The paper explores the benefit of a hybrid system which combines the SOFC technology and a high temperature battery in a first step of the development process. A proper strategy is proposed using simulation and experimental results.
Power Generation Characteristics of a High-Power-Density 2.5 kW-Class SOFC Stack
Authors: Mizuki Kotoe , Yokoo Masayuki , Watanabe Kimitaka , Hayashi Katsuya
Published: April 2012

We have developed a 2.5-kW-class SOFC stack. By designing the height of the power generation unit to be two-thirds of a conventional 1.5-kW stack, the power density of the stack becomes 1.5 times that of our conventional 1.5-kW-class stack with few problems. Specifically, a power density per volume of 0.34 Wcm-3 is obtained when hydrogen is used as a fuel, the fuel utilization is 60%, and the number of stacked cells is 70.
Development of a Microchannel High Temperature Recuperator for Ultra-High Efficiency Fuel Cell/Turbine Systems
Authors: Lukas Michael D. , Ghezel-Ayagh Hossein , Sanderson Robert , Krishnan Shankar
Published: April 2012

FuelCell Energy (FCE) is developing microchannel high temperature recuperators and system concepts supporting high temperature fuel cell/turbine hybrid systems. Under this initiative recuperator candidate materials are screened and tested for strength and environmental resistance for high temperature, high humidity conditions. The program involves fabrication and testing of pilot-scale recuperators and will culminate in a MW-duty recuperator design supporting FCE's development toward a commercial MW-scale hybrid system. Recuperator designs are being developed for molten carbonate fuel cell (MCFC) and solid oxide fuel cell (SOFC) systems that integrate unfired gas turbines powered by waste heat recovered by a high temperature recuperator (HTR). Cost-of-electricity sensitivity analyses have been carried out on a MW-scale solid oxide fuel cell/turbine (SOFC/T) concept to establish system/recuperator optimal parameters and cost targets. A pilot-scale (15 kW duty) SOFC/T HTR has been designed along with an associated 1/20 scale trial component for initial testing.
Physiology and pathophysiology of splanchnic hypoperfusion and intestinal injury during exercise: strategies for evaluation and prevention
Authors: van Wijck Kim , Lenaerts Kaatje , Grootjans Joep , Wijnands Karolina A. P. , Poeze Martijn , van Loon Luc J. C. , Dejong Cornelis H. C. , Buurman Wim A.
Published: April 2012

Physical exercise places high demands on the adaptive capacity of the human body. Strenuous physical performance increases the blood supply to active muscles, cardiopulmonary system, and skin to meet the altered demands for oxygen and nutrients. The redistribution of blood flow, necessary for such an increased blood supply to the periphery, significantly reduces blood flow to the gut, leading to hypoperfusion and gastrointestinal (GI) compromise. A compromised GI system can have a negative impact on exercise performance and subsequent postexercise recovery due to abdominal distress and impairments in the uptake of fluid, electrolytes, and nutrients. In addition, strenuous physical exercise leads to loss of epithelial integrity, which may give rise to increased intestinal permeability with bacterial translocation and inflammation. Ultimately, these effects can deteriorate postexercise recovery and disrupt exercise training routine. This review provides an overview on the recent advances in our understanding of GI physiology and pathophysiology in relation to strenuous exercise. Various approaches to determine the impact of exercise on the individual athlete's GI tract are discussed. In addition, we elaborate on several promising components that could be exploited for preventive interventions.
The direct profibrotic and indirect immune antifibrotic balance of blocking the cannabinoid 2 receptor
Authors: Avraham Yosefa , Amer Johnny , Doron Sarit , Abu-Tair Lina , Mahamid Mahmud , Khatib Areej , Berry Elliot M. , Safadi Rifaat
Published: April 2012

Cannabinoid 2 (CB2) receptors expressed on immune cells are considered to be antifibrogenic. Hepatic stellate cells (HSCs) directly interact with phagocytosis lymphocytes, but the nature of this interaction is obscure. We aimed to study the effects of CB2 receptors on hepatic fibrosis via their role in mediating immunity. Hepatic fibrosis was induced by carbon-tetrachloride (CCl4) administration in C57BL/6 wild-type (WT) and CB2 knockout (CB2−/−) mice. Irradiated animals were reconstituted with WT or CB2−/−lymphocytes. Lymphocytes from naïve/fibrotic WT animals and healthy/cirrhotic hepatitis C virus were preincubated in vitro with or without CB2 antagonist, evaluated for proliferation and apoptosis, and then cocultured with primary mouse HSCs or a human HSC line (LX2), respectively. Lymphocyte phagocytosis was then evaluated. Following CCl4-administration, CB2−/−mice developed significant hepatic fibrosis but less necroinflammation. WT mice harbored decreased liver CD4+and NK+cells but increased CD8+subsets. Naïve CB2−/−mice had significantly decreased T cell subsets. Adoptive transfer of CB2−/−lymphocytes led to decreased fibrosis in the irradiated WT recipient compared with animals receiving WT lymphocytes. Moreover, necroinflammation also tended to decrease. In vitro, a CB2-antagonist directly increased human HSC activation and increased apoptosis and decreased proliferation of mice/human T cells (healthy/fibrotic) and their phagocytosis. We concluded that CB2−/−lymphocytes exert an antifibrotic activity, whereas lack of CB2 receptor in HSCs promotes fibrosis. These findings broaden our understanding of cannabinoid signaling in hepatic fibrosis beyond their activity solely in HSCs.