bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimicrobial Stewardship—the State of the Art in 2011 Focus on Outcome and Methods
Authors: McGowan John E.
Published: March 2012

Antimicrobial stewardship programs attempt to optimize prescribing of these drugs to benefit both current and future patients. Recent regulatory and other incentives have led to widespread adoption of such programs. Measurements of the success of these programs have focused primarily on process measures. However, evaluation of outcome measures will be needed to ensure sustainability of these efforts. Outcome efforts to date provide some evidence for improved care of individual patients, some evidence for minimizing emergence of resistance, and ample evidence for cost reduction. Attention to evaluation methods must be increased to provide convincing evidence for the continuation of such programs.
Audit and Feedback to Reduce Broad-Spectrum Antibiotic Use among Intensive Care Unit Patients A Controlled Interrupted Time Series Analysis
Authors: Elligsen Marion , Walker Sandra A. N. , Pinto Ruxandra , Simor Andrew , Mubareka Samira , Rachlis Anita , Allen Vanessa , Daneman Nick
Published: March 2012

Objective.

We aimed to rigorously evaluate the impact of prospective audit and feedback on broad-spectrum antimicrobial use among critical care patients.

Design.

Prospective, controlled interrupted time series.

Setting

Single tertiary care center with 3 intensive care units.

Patients and Interventions.

A formal review of all critical care patients on their third or tenth day of broad-spectrum antibiotic therapy was conducted, and suggestions for antimicrobial optimization were communicated to the critical care team.

Outcomes.

The primary outcome was broad-spectrum antibiotic use (days of therapy per 1000 patient-days; secondary outcomes included overall antibiotic use, gram-negative bacterial susceptibility, nosocomial Clostridium difficile infections, length of stay, and mortality.

Results.

The mean monthly broad-spectrum antibiotic use decreased from 644 days of therapy per 1,000 patient-days in the preintervention period to 503 days of therapy per 1,000 patient-days in the postintervention period (P < .0001); time series modeling confirmed an immediate decrease (± standard error) of 119 ± 37.9 days of therapy per 1,000 patient-days (P = .0054). In contrast, no changes were identified in the use of broad-spectrum antibiotics in the control group (nonintervention medical and surgical wards) or in the use of control medications in critical care (stress ulcer prophylaxis). The incidence of nosocomial C. difficile infections decreased from 11 to 6 cases in the study intensive care units, whereas the incidence increased from 87 to 116 cases in the control wards (P = .04). Overall gram-negative susceptibility to meropenem increased in the critical care units. Intensive care unit length of stay and mortality did not change.

Conclusions.

Institution of a formal prospective audit and feedback program appears to be a safe and effective means to improve broad-spectrum antimicrobial use in critical care.
Antimicrobial Stewardship at Transition of Care from Hospital to Community
Authors: Shrestha Nabin K. , Bhaskaran Archana , Scalera Nikole M. , Schmitt Steven K. , Rehm Susan J. , Gordon Steven M.
Published: March 2012

Mandatory infectious disease consultation for parenteral antimicrobials at hospital discharge resulted in avoiding postdischarge parenteral antimicrobials in 28% of patients. No emergency department visit or rehospitalization within 30 days for these patients was a consequence of parenteral antimicrobial avoidance. Antimicrobial stewardship at transition of care is effective in reducing unnecessary antimicrobial use.
Implementation of a Clinical Decision Support System for Antimicrobial Stewardship
Authors: Hermsen Elizabeth D. , VanSchooneveld Trevor C. , Sayles Harlan , Rupp Mark E.
Published: March 2012

Clinical decision support systems (CDSSs) for antimicrobial stewardship require considerable human resources and financial investments. This pre-/postimplementation study evaluated the effect of a CDSS on performance of prospective audit with intervention and feedback and demonstrated an increase in interventions and recommendation acceptance countered by a substantial number of non-actionable alerts.
Lack of Significant Variability among Different Methods for Calculating Antimicrobial Days of Therapy
Authors: Kubin Christine J. , Jia Haomiao , Alba Luis R. , Furuya E. Yoko
Published: March 2012

Days of therapy (DOTs) are an important measure to quantify antimicrobial use but may not reflect patients' true antimicrobial exposure. Three methods of calculating DOTs were compared to determine whether including “exposure days,” when antimicrobials are given less frequently than daily due to renal dysfunction, makes a difference.
Policy Statement on Antimicrobial Stewardship by the Society for Healthcare Epidemiology of America (SHEA), the Infectious Diseases Society of America (IDSA), and the Pediatric Infectious Diseases Society (PIDS)
Authors: Fishman Neil ,   Society for Healthcare Epidemiology of America,   Infectious Diseases Society of America,   Pediatric Infectious Diseases Society
Published: March 2012

Antimicrobial resistance has emerged as a significant healthcare quality and patient safety issue in the twenty-first century that, combined with a rapidly dwindling antimicrobial armamentarium, has resulted in a critical threat to the public health of the United States. Antimicrobial stewardship programs optimize antimicrobial use to achieve the best clinical outcomes while minimizing adverse events and limiting selective pressures that drive the emergence of resistance and may also reduce excessive costs attributable to suboptimal antimicrobial use. Therefore, antimicrobial stewardship must be a fiduciary responsibility for all healthcare institutions across the continuum of care. This position statement of the Society for Healthcare Epidemiology of America, the Infectious Diseases Society of America, and the Pediatric Infectious Diseases Society of America outlines recommendations for the mandatory implementation of antimicrobial stewardship throughout health care, suggests process and outcome measures to monitor these interventions, and addresses deficiencies in education and research in this field as well as the lack of accurate data on antimicrobial use in the United States.
Synthesis and investigations on CO catalytic oxidation activity of nanostructured Ce0.5Zr0.5O2 prepared by combustion method using polyvinyl alcohol
Authors: Nhiem Dao Ngoc , Dai Luu Minh
Published: March 2012

Nanostructured Ce
0.5
Zr
0.5
O
2 samples were synthesized by the combustion of the gel obtained from a mixture of polyvinyl alcohol (PVA) and metal nitrates at a temperature as low as 600 °C. The prepared samples were investigated by x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). Their specific surface areas were determined from N
2 adsorption measurement at 77 K by Brunauer–Emmet–Teller (BET) method and their CO catalytic oxidation activities were investigated using a Landcom II instrument. The XRD and FE-SEM results revealed that Ce
0.5
Zr
0.5
O
2 nanocrystallines began to grow isotropically at 600 °C with the nanostructure found in all prepared samples. Further thermal treatment at 600 °C for 2 h yields the single crystalline phase Ce
0.5
Zr
0.5
O
2 nanostructured samples with average crystalline size < 50 nm and specific surface area of about 73 m
2 
g
−1. Besides, the effects of a number of factors such as calcination temperature and Ce/Zr molar ratio on the formation of prepared samples as well as the oxidative conversion of carbon monoxide over nanostructured Ce
0.5
Zr
0.5
O
2 catalyst were also studied.
Germination Stimulants of Phelipanche ramosa in the Rhizosphere of Brassica napus Are Derived from the Glucosinolate Pathway
Authors: Auger Bathilde , Pouvreau Jean-Bernard , Pouponneau Karinne , Yoneyama Kaori , Montiel Grégory , Le Bizec Bruno , Yoneyama Koichi , Delavault Philippe , Delourme Régine , Simier Philippe
Published: March 2012

Phelipanche ramosa is a major parasitic weed of Brassica napus. The first step in a host-parasitic plant interaction is stimulation of parasite seed germination by compounds released from host roots. However, germination stimulants produced by B. napus have not been identified yet. In this study, we characterized the germination stimulants that accumulate in B. napus roots and are released into the rhizosphere. Eight glucosinolate-breakdown products were identified and quantified in B. napus roots by gas chromatography–mass spectrometry. Two (3-phenylpropanenitrile and 2-phenylethyl isothiocyanate [2-PEITC]) were identified in the B. napus rhizosphere. Among glucosinolate-breakdown products, P. ramosa germination was strongly and specifically triggered by isothiocyanates, indicating that 2-PEITC, in particular, plays a key role in the B. napus–P. ramosa interaction. Known strigolactones were not detected by ultraperformance liquid chromatography–tandem mass spectrometry, and seed of Phelipanche and Orobanche spp. that respond to strigolactones but not to isothiocyanates did not germinate in the rhizosphere of B. napus. Furthermore, both wild-type and strigolactone biosynthesis mutants of Arabidopsis thaliana Atccd7 and Atccd8 induced similar levels of P. ramosa seed germination, suggesting that compounds other than strigolactone function as germination stimulants for P. ramosa in other Brassicaceae spp. Our results open perspectives on the high adaptation potential of root-parasitic plants under host-driven selection pressures.
Qualitative and Quantitative Late Blight Resistance in the Potato Cultivar Sarpo Mira Is Determined by the Perception of Five Distinct RXLR Effectors
Authors: Rietman Hendrik , Bijsterbosch Gerard , Cano Liliana M. , Lee Heung-Ryul , Vossen Jack H. , Jacobsen Evert , Visser Richard G. F. , Kamoun Sophien , Vleeshouwers Vivianne G. A. A.
Published: March 2012

Potato defends against Phytophthora infestans infection by resistance (R)-gene-based qualitative resistance as well as a quantitative field resistance. R genes are renowned to be rapidly overcome by this oomycete, and potato cultivars with a decent and durable resistance to current P. infestans populations are hardly available. However, potato cultivar Sarpo Mira has retained resistance in the field over several years. We dissected the resistance of ‘Sarpo Mira’ in a segregating population by matching the responses to P. infestans RXLR effectors with race-specific resistance to differential strains. The resistance is based on the combination of four pyramided qualitative R genes and a quantitative R gene that was associated with field resistance. The qualitative R genes include R3a, R3b, R4, and the newly identified Rpi-Smira1. The qualitative resistances matched responses to avirulence (AVR)3a, AVR3b, AVR4, and AVRSmira1 RXLR effectors and were overcome by particular P. infestans strains. The quantitative resistance was determined to be conferred by a novel gene, Rpi-Smira2. It was only detected under field conditions and was associated with responses to the RXLR effector AvrSmira2. We foresee that effector-based resistance breeding will facilitate selecting and combining qualitative and quantitative resistances that may lead to a more durable resistance to late blight.
The Molecular Basis of Host Specialization in Bean Pathovars of Pseudomonas syringae
Authors: Baltrus David A. , Nishimura Marc T. , Dougherty Kevin M. , Biswas Surojit , Mukhtar M. Shahid , Vicente Joana , Holub Eric B. , Dangl Jeffery L.
Published: March 2012

Biotrophic phytopathogens are typically limited to their adapted host range. In recent decades, investigations have teased apart the general molecular basis of intraspecific variation for innate immunity of plants, typically involving receptor proteins that enable perception of pathogen-associated molecular patterns or avirulence elicitors from the pathogen as triggers for defense induction. However, general consensus concerning evolutionary and molecular factors that alter host range across closely related phytopathogen isolates has been more elusive. Here, through genome comparisons and genetic manipulations, we investigate the underlying mechanisms that structure host range across closely related strains of Pseudomonas syringae isolated from different legume hosts. Although type III secretion-independent virulence factors are conserved across these three strains, we find that the presence of two genes encoding type III effectors (hopC1 and hopM1) and the absence of another (avrB2) potentially contribute to host range differences between pathovars glycinea and phaseolicola. These findings reinforce the idea that a complex genetic basis underlies host range evolution in plant pathogens. This complexity is present even in host–microbe interactions featuring relatively little divergence among both hosts and their adapted pathogens.
A Novel Virus-Like Double-Stranded RNA in an Obligate Biotroph Arbuscular Mycorrhizal Fungus: A Hidden Player in Mycorrhizal Symbiosis
Authors: Ikeda Yoji , Shimura Hanako , Kitahara Ryoko , Masuta Chikara , Ezawa Tatsuhiro
Published: March 2012

Arbuscular mycorrhizal (AM) fungi form mutualistic associations with most land plants and enhance phosphorus uptake of the host plants. Fungal viruses (mycoviruses) that possess a double-stranded RNA (dsRNA) genome often affect plant–fungal interactions via altering phenotypic expression of their host fungi. The present study demonstrates, for the first time, the presence of dsRNAs, which are highly likely to be mycoviruses, in AM fungi. dsRNA was extracted from mycelia of Glomus sp. strain RF1, purified, and subjected to electrophoresis. The fungus was found to harbor various dsRNA segments that differed in size. Among them, a 4.5-kbp segment was termed Glomus sp. strain RF1 virus-like medium dsRNA (GRF1V-M) and characterized in detail. The GRF1V-M genome segment was 4,557 nucleotides in length and encoded RNA-dependent RNA polymerase and a structural protein. GRF1V-M was phylogenetically distinct and could not be assigned to known genera of mycovirus. The GRF1V-M-free culture line of Glomus sp. strain RF1, which was raised by single-spore isolation, produced twofold greater number of spores and promoted plant growth more efficiently than the GRF1V-M-positive lines. These observations suggest that mycoviruses in AM fungi, at least some of them, have evolved under unique selection pressures and are a biologically active component in the symbiosis.
Inhibition of Glutamine Synthetase by Phosphinothricin Leads to Transcriptome Reprograming in Root Nodules of Medicago truncatula
Authors: Seabra Ana R. , Pereira Patrícia A. , Becker Jörg D. , Carvalho Helena G.
Published: March 2012

Glutamine synthetase (GS) is a vital enzyme for the assimilation of ammonia into amino acids in higher plants. In legumes, GS plays a crucial role in the assimilation of the ammonium released by nitrogen-fixing bacteria in root nodules, constituting an important metabolic knob controlling the nitrogen (N) assimilatory pathways. To identify new regulators of nodule metabolism, we profiled the transcriptome of Medicago truncatula nodules impaired in N assimilation by specifically inhibiting GS activity using phosphinothricin (PPT). Global transcript expression of nodules collected before and after PPT addition (4, 8, and 24 h) was assessed using Affymetrix M. truncatula GeneChip arrays. Hundreds of genes were regulated at the three time points, illustrating the dramatic alterations in cell metabolism that are imposed on the nodules upon GS inhibition. The data indicate that GS inhibition triggers a fast plant defense response, induces premature nodule senescence, and promotes loss of root nodule identity. Consecutive metabolic changes were identified at the three time points analyzed. The results point to a fast repression of asparagine synthesis and of the glycolytic pathway and to the synthesis of glutamate via reactions alternative to the GS/GOGAT cycle. Several genes potentially involved in the molecular surveillance for internal organic N availability are identified and a number of transporters potentially important for nodule functioning are pinpointed. The data provided by this study contributes to the mapping of regulatory and metabolic networks involved in root nodule functioning and highlight candidate modulators for functional analysis.
Genetic and Molecular Mapping of Stripe Rust Resistance Gene in Wheat–Psathyrostachys huashanica Translocation Line H9020-1-6-8-3
Authors: Li Qiang , Huang Jing , Hou Lu , Liu Pei , Jing Jinxue , Wang Baotong , Kang Zhensheng
Published: March 2012

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat worldwide. The best strategy to control stripe rust is to grow resistant cultivars, but only a few effective genes are available. The wheat accession H9020-1-6-8-3 is a translocation line previously developed from interspecific hybridization between wheat genotype 7182 and Psathyrostachys huashanica, and is resistant to most Chinese Puccinia striiformis f. sp. tritici races. To identify the resistance genes in the translocation line, H9020-1-6-8-3 was crossed with susceptible genotype Mingxian 169, and seedlings of parents and F1, F2, and F3 progenies were tested with prevalent Chinese P. striiformis f. sp. tritici races CYR32 and CYR33 under controlled greenhouse conditions. The genetic results indicated that two single dominant genes in H9020-1-6-8-3 confer resistance to CYR32 and CYR33, respectively. The gene for resistance to CYR33 was temporarily designated as YrH9020. Six simple-sequence repeat markers were used to map the resistance gene to the short arm of wheat chromosome 2D, using 329 F2 plants tested with CYR33 in the greenhouse. The genetic distances of the two closest flanking markers, Xgwm261 and Xgwm455, were 4.4 and 5.8 centimorgans, respectively. Disease assessments and polymorphic tests of the flanking markers among the Psathyrostachys huashanica line and wheat lines 7182, H9020-1-6-8-3, and Mingxian169 suggested that the resistance gene YrH9020 in H9020-1-6-8-3 was originally from P. huashanica. The exotic stripe rust resistance gene and linked molecular markers should be useful for pyramiding with other genes to develop wheat cultivars with high-level and durable resistance to stripe rust.
Greenhouse Studies Reveal Increased Aggressiveness of Emergent Canadian Fusarium graminearum Chemotypes in Wheat
Authors: Foroud N. A. , McCormick S. P. , MacMillan T. , Badea A. , Kendra D. F. , Ellis B. E. , Eudes F.
Published: March 2012

The role of Fusarium graminearum trichothecene-chemotypes in disease outcomes was evaluated by point inoculation in a series of wheat lines with different levels of resistance to Fusarium head blight (FHB). Four inocula, each consisting of a composite of four strains with either 15-acetyldeoxynivalenol (ADON) chemotypes from “traditional” or emergent populations, a 3-ADON chemotype, or a nivalenol (NIV) chemotype, were compared. The evaluated wheat included Canadian lines with different levels of FHB resistance/susceptibility and double haploid lines developed from crosses of these lines. Highly resistant lines were resistant to infection by all of the F. graminearum chemotypes evaluated. In the moderately susceptible/resistant wheat lines, the 3-ADON producers and the emergent 15-ADON population were, in some instances, more aggressive and resulted in higher Fusarium damaged kernel scores and levels of trichothecene accumulation. The data presented in this study demonstrate the importance of growing highly resistant wheat cultivars in the current climate of an evolving F. graminearum population, and suggest that moderate levels of FHB resistance may not be sufficient to minimize trichothecene contamination of grain from F. graminearum–infected wheat.
Geographic Distribution of Trichothecene Chemotypes of the Fusarium graminearum Species Complex in Major Winter Wheat Production Areas of China
Authors: Shen Cheng-mei , Hu Ying-chun , Sun Hai-yan , Li Wei , Guo Jian-hua , Chen Huai-gu
Published: March 2012

Fusarium head blight, caused by members of the Fusarium graminearum species complex (FGSC), is among the most destructive and economically important diseases of small grain crops, including wheat. To determine the phylogenetic species and mycotoxin (trichothecene) chemotypes of the FGSC in the major winter-wheat-producing areas of China, 530 isolates were collected from diseased wheat during the years 2008, 2009, and 2010, and typed using a polymerase chain reaction-based trichothecene genotype assay. Virulence of isolates with different chemotypes was also compared. Of the 530 isolates typed, 348 were F. asiaticum and 182 were F. graminearum. Subdividing the 530 isolates by the trichothecene predicted to be expressed, 482 were of the deoxynivalenol (DON) chemotype and 48 were nivalenol (NIV). Acetylated derivatives of DON included 3-acetyldeoxynivalenol (3-AcDON; 300 isolates), and 15-acetyldeoxynivalenol (15-AcDON; 182 isolates). Chemotypes of the F. asiaticum isolates were either 3-AcDON or NIV, with 3-AcDON being predominant. F. graminearum isolates were all of the 15-AcDON chemotype. F. asiaticum was the predominant phylogenetic species in the Yangtze River Basin and F. graminearum was dominant in the north of China. Two areas of co-occurrence of trichothecene chemotypes were found. The 3-AcDON and 15-AcDON isolates had similar levels of virulence. The DON isolates were significantly more virulent than those of the NIV. The 3-AcDON and 15-AcDON chemotypes were predominant in the Yangtze River Basin and areas north of the Yangtze River Basin, respectively, and it is suggested that geographic distribution is associated with differences in temperature as well as crop rotation systems.
Resistance to Pyraclostrobin and Boscalid inBotrytis cinereaIsolates from Strawberry Fields in the Carolinas
Authors: Fernández-Ortuño Dolores , Chen Fengping , Schnabel Guido
Published: March 2012

Botrytis cinerea, the causal agent of gray mold disease, is one of the most important plant-pathogenic fungi affecting strawberry. During the last decade, control of gray mold disease in the southeastern United States has largely been dependent on captan and the use of at-risk fungicides with single-site modes of action, including a combination of the quinone outside inhibitor (QoI) fungicide pyraclostrobin and succinate dehydrogenase inhibitor (SDHI) fungicide boscalid formulated as Pristine 38WG. Reports about loss of efficacy of Pristine in experimental fields in North Carolina prompted us to collect and examine 216 single-spore isolates from 10 conventional fields and 1 organic field in North Carolina and South Carolina in early summer 2011. Sensitivity to pyraclostrobin or boscalid was determined using a conidial germination assay with previously published discriminatory doses. Pyraclostrobin- and pyraclostrobin+boscalid-resistant isolates were found in all conventional fields (with some populations revealing no sensitive isolates) and in the organic field. Among the isolates collected, 66.7% were resistant to pyraclostrobin and 61.5% were resistant to both pyraclostrobin and boscalid. No isolates were identified that were resistant to boscalid but sensitive to pyraclostrobin, indicating that dual resistance may have derived from a QoI-resistant population. The molecular basis of QoI and SDHI fungicide resistance was determined in a subset of isolates. Polymerase chain reaction–restriction fragment length polymorphism analysis of the partial cytochrome b (CYTB) gene showed that pyraclostrobin-resistant isolates possessed the G143A mutation known to confer high levels of QoI fungicide resistance in fungi. Boscalid-resistant isolates revealed point mutations at codon 272 leading to the substitution of histidine to arginine (H272R) or tyrosine (H272Y), affecting the third Fe-S cluster region of the iron-sulfur protein (SdhB) target of SDHIs. The results of the study show that resistance to QoI fungicides and dual resistance to QoI and SDHI fungicides is common in B. cinerea from strawberry fields in the Carolinas. Resistant strains were more frequent in locations heavily sprayed with QoI and SDHI fungicides. However, resistance to both fungicides was also found in the unsprayed, organic field, indicating that some resistant strains may have been introduced from the nursery.
Dexmedetomidine Administration before, but Not after, Ischemia Attenuates Intestinal Injury Induced by Intestinal Ischemia-Reperfusion in Rats
Authors: Zhang Xu-Yu , Liu Zi-Meng , Wen Shi-Hong , Li Yun-Sheng , Li Yi , Yao Xi , Huang Wen-Qi , Liu Ke-Xuan
Published: March 2012

Background

Intestinal ischemia-reperfusion (I/R) injury is a devastating complication in the perioperative period. Dexmedetomidine is commonly applied in the perioperative period. The authors aimed to determine the effects of different doses of dexmedetomidine (given before or after intestinal ischemia) on intestinal I/R injury and to explore the underlying mechanisms.

Methods

Intestinal I/R injury was produced in rat by clamping the superior mesenteric artery for 1 h followed by 2 h reperfusion. Intravenous infusion of dexmedetomidine was performed at 2.5, 5, and 10 μg · kg(-1) · h(-1) for 1 h before or after ischemic insult. In addition, yohimbine hydrochloride was administered intravenously to investigate the role of α2 adrenoreceptor in the intestinal protection conferred by dexmedetomidine.

Results

Intestinal I/R increased mortality of rats and caused notable intestinal injury, as evidenced by statistically significant increases in Chiu's scores; serum diamine oxidase and tumor necrosis factor-α concentration, accompanied by increases in the intestinal mucosal malondialdehyde concentration; myeloperoxidase activity; and epithelial cell apoptosis (all P < 0.05 vs. Sham). Except malondialdehyde and myeloperoxidase, all changes were improved by the administration of 5 μg · kg(-1) · h(-1) dexmedetomidine before ischemia (all P < 0.05 vs. Injury) but not after ischemia. Infusion of 2.5 μg · kg(-1) · h(-1) dexmedetomidine before or after ischemia produced no beneficial effects, and infusion of 10 μg · kg(-1) · h(-1) dexmedetomidine led to severe hemodynamic suppression. Yohimbine abolished the intestinal protective effect of the 5 μg · kg(-1) · h(-1) dexmedetomidine infusion before ischemia and was accompanied by the disappearance of its antiapoptotic and antiinflammatory effect.

Conclusion

Dexmedetomidine administration before, but not after, ischemia dose-dependently protects against I/R-induced intestinal injury, partly by inhibiting inflammatory response and intestinal mucosal epithelial apoptosis via α2 adrenoreceptor activation.
Supermicrosurgical Reconstruction of Large Defects on Ischemic Extremities Using Supercharging Techniques on Latissimus Dorsi Perforator Flaps
Authors: Kim Chang Yeon , Kim Youn Hwan
Published: March 2012

Background:

In patients with underlying vasculopathies, the unavailability of main vessels for conventional microsurgery may preclude limb salvage. However, with the evolution of supermicrosurgical techniques, anastomosis at the perforator level that is almost always spared by the underlying disease has become possible. To overcome insufficient flow in large flap issues following the procedure, a supercharging technique was used in reconstructions using a latissimus dorsi perforator free flap.

Methods:

From January of 2008 to June of 2010, a total of 21 patients underwent reconstructive procedures for large defects of the lower extremities using supermicrosurgery with arterial and/or venous supercharging techniques, including a latissimus dorsi perforator, an intercostal perforator, and the lateral thoracic vein.

Results:

All flaps survived completely without arterial or venous problems. There were three minor complications of infection, venous congestion, and donor-site hematoma. Except for a hematoma evacuation procedure, complications were managed conservatively.

Conclusions:

The latissimus dorsi perforator flap can be harvested with numerous latissimus dorsi perforators, intercostal perforators, and the lateral thoracic vein to perform the supercharging technique on reconstruction of large foot defects in patients with severe vasculopathy. This technique can be applied in various difficult situations, including traumatic injury of the main limb vessels, and can increase survival rates for limb salvage, particularly in ischemic limb reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
Leading edge vortex in a slow-flying passerine
Authors: Muijres Florian T. , Johansson L. Christoffer , Hedenström Anders
Published: March 2012

Most hovering animals, such as insects and hummingbirds, enhance lift by producing leading edge vortices (LEVs) and by using both the downstroke and upstroke for lift production. By contrast, most hovering passerine birds primarily use the downstroke to generate lift. To compensate for the nearly inactive upstroke, weight support during the downstroke needs to be relatively higher in passerines when compared with, e.g. hummingbirds. Here we show, by capturing the airflow around the wing of a freely flying pied flycatcher, that passerines may use LEVs during the downstroke to increase lift. The LEV contributes up to 49 per cent to weight support, which is three times higher than in hummingbirds, suggesting that avian hoverers compensate for the nearly inactive upstroke by generating stronger LEVs. Contrary to other animals, the LEV strength in the flycatcher is lowest near the wing tip, instead of highest. This is correlated with a spanwise reduction of the wing's angle-of-attack, partly owing to upward bending of primary feathers. We suggest that this helps to delay bursting and shedding of the particularly strong LEV in passerines.
Poly(lactide-
co
-glycolide) porous scaffolds for tissue engineering and regenerative medicine
Authors: Pan Zhen , Ding Jiandong
Published: March 2012

Porous scaffolds fabricated from biocompatible and biodegradable polymers play vital roles in tissue engineering and regenerative medicine. Among various scaffold matrix materials, poly(lactide-
co
-glycolide) (PLGA) is a very popular and an important biodegradable polyester owing to its tunable degradation rates, good mechanical properties and processibility, etc. This review highlights the progress on PLGA scaffolds. In the latest decade, some facile fabrication approaches at room temperature were put forward; more appropriate pore structures were designed and achieved; the mechanical properties were investigated both for dry and wet scaffolds; a long time biodegradation of the PLGA scaffold was observed and a three-stage model was established; even the effects of pore size and porosity on
in vitro
biodegradation were revealed; the PLGA scaffolds have also been implanted into animals, and some tissues have been regenerated
in vivo
after loading cells including stem cells.
Spatio-temporal development of the endothelial glycocalyx layer and its mechanical property
in vitro
Authors: Bai Ke , Wang Wen
Published: March 2012

The endothelial glycocalyx is a thin layer of polysaccharide matrix on the luminal surface of endothelial cells (ECs), which contains sulphated proteoglycans and glycoproteins. It is a mechanotransducer and functions as an amplifier of the shear stress on ECs. It controls the vessel permeability and mediates the blood–endothelium interaction. This study investigates the spatial distribution and temporal development of the glycocalyx on cultured ECs, and evaluates mechanical properties of the glycocalyx using atomic force microscopy (AFM) nano-indentation. The glycocalyx on human umbilical vein endothelial cells (HUVECs) is observed under a confocal microscope. Manipulation of the glycocalyx is achieved using heparanase or neuraminidase. The Young's modulus of the cell membrane is calculated from the force–distance curve during AFM indentation. Results show that the glycocalyx appears predominantly on the edge of cells in the early days in culture, e.g. up to day 5 after seeding. On day 7, the glycocalyx is also seen in the apical area of the cell membrane. The thickness of the glycocalyx is approximately 300 nm–1 μm. AFM indentation reveals the Young's modulus of the cell membrane decreases from day 3 (2.93 ± 1.16 kPa) to day 14 (0.35 ± 0.15 kPa) and remains unchanged to day 21 (0.33 ± 0.19 kPa). Significant difference in the Young's modulus is also seen between the apical (1.54 ± 0.58 kPa) and the edge (0.69 ± 0.55 kPa) of cells at day 7. By contrast, neuraminidase-treated cells (i.e. without the glycocalyx) have similar values between day 3 (3.18 ± 0.88 kPa), day 14 (2.12 ± 0.78 kPa) and day 21 (2.15 ± 0.48 kPa). The endothelial glycocalyx
in vitro
shows temporal development in the early days in culture. It covers predominantly the edge of cells initially and appears on the apical membrane of cells as time progresses. The Young's modulus of the glycocalyx is deduced from Young's moduli of cell membranes with and without the glycocalyx layer. Our results show the glycocalyx on cultured HUVECs has a Young's modulus of approximately 0.39 kPa.
Regulation of oscillation dynamics in biochemical systems with dual negative feedback loops
Authors: Nguyen Lan K.
Published: March 2012

Feedback controls are central to cellular regulation. Negative-feedback mechanisms are well known to underline oscillatory dynamics. However, the presence of multiple negative-feedback mechanisms is common in oscillatory cellular systems, raising intriguing questions of how they cooperate to regulate oscillations. In this work, we studied the dynamical properties of a set of general biochemical motifs with dual, nested negative-feedback structures. We showed analytically and then confirmed numerically that, in these motifs, each negative-feedback loop exhibits distinctly different oscillation-controlling functions. The longer, outer feedback loop was found to promote oscillations, whereas the short, inner loop suppresses and can even eliminate oscillations. We found that the position of the inner loop within the coupled motifs affects its repression strength towards oscillatory dynamics. Bifurcation analysis indicated that emergence of oscillations may be a strict parametric requirement and thus evolutionarily tricky. Investigation of the quantitative features of oscillations (i.e. frequency, amplitude and mean value) revealed that coupling negative feedback provides robust tuning of the oscillation dynamics. Finally, we demonstrated that the mitogen-activated protein kinase (MAPK) cascades also display properties seen in the general nested feedback motifs. The findings and implications in this study provide novel understanding of biochemical negative-feedback regulation in a mixed wiring context.
Apatite-forming ability of titanium in terms of pH of the exposed solution
Authors: Pattanayak Deepak K. , Yamaguchi Seiji , Matsushita Tomiharu , Nakamura Takashi , Kokubo Tadashi
Published: March 2012

In order to elucidate the main factor governing the capacity for apatite formation of titanium (Ti), Ti was exposed to HCl or NaOH solutions with different pH values ranging from approximately 0 to 14 and then heat-treated at 600°C. Apatite formed on the metal surface in a simulated body fluid, when Ti was exposed to solutions with a pH less than 1.1 or higher than 13.6, while no apatite formed upon exposure to solutions with an intermediate pH value. The apatite formation on Ti exposed to strongly acidic or alkaline solutions is attributed to the magnitude of the positive or negative surface charge, respectively, while the absence of apatite formation at an intermediate pH is attributed to its neutral surface charge. The positive or negative surface charge was produced by the effect of either the acidic or alkaline ions on Ti, respectively. It is predicted from the present results that the bone bonding of Ti depends upon the pH of the solution to which it is exposed, i.e. Ti forms a bone-like apatite on its surface in the living body and bonds to living bone through the apatite layer upon heat treatment after exposure to a strongly acidic or alkaline solution.
A new variant of the Zhang neural network for solving online time-varying linear inequalities
Authors: Guo Dongsheng , Zhang Yunong
Published: March 2012

Since March 2001, a special class of recurrent neural networks termed the Zhang neural network (ZNN) has been proposed by Zhang and co-workers for solving online a rich repertoire of time-varying problems. By extending Zhang
et al.
's design formula (or say, the ZNN design formula), a (new) variant of the ZNN design formula is proposed and investigated in this paper, which is also based on a matrix/vector-valued indefinite error function. In addition, by employing such a novel design formula, a new variant of the ZNN (NVZNN) is proposed, developed and investigated for online solution of time-varying linear inequalities (LIs). The resultant NVZNN models are depicted in implicit dynamics and methodologically exploit the time-derivative information of time-varying coefficients. Computer simulation results further demonstrate the novelty, efficacy and superiority of the proposed NVZNN models for solving online time-varying LIs.
Quantitative measurement of plastic strain field at a fatigue crack tip
Authors: Yang Y. , Crimp M. , Tomlinson R. A. , Patterson E. A.
Published: March 2012

A novel approach is introduced to map the mesoscale plastic strain distribution resulting from heterogeneous plastic deformation in complex loading and component geometries, by applying the discrete Fourier transform (DFT) to backscattered electron (BSE) images of polycrystalline patches. These DFTs are then calibrated against the full width at half the maximum of the central peak of the DFTs collected from the same material tested under
in situ
scanning electron microscopy uniaxial tensile conditions, which indicates a close relationship with the global tensile strain. In this work, the technique is demonstrated by measuring the residual strain distribution and plastic zone size around a fatigue crack tip in a commercially pure titanium compact tension specimen, by collecting BSE images in a 15×15 array of 115 μm square images around the fatigue crack tip. The measurement results show good agreement with the plastic zone size and shape measured using thermoelastic stress analysis.
Diagnosing eclipse-induced wind changes
Authors: Gray S. L. , Harrison R. G.
Published: March 2012

Responses in surface winds to solar eclipses have an almost mystical status but are difficult to detect in observations because of their transient nature. High spatial resolution (approx. 1.5 km grid) meteorological models now provide a new technique for their investigation. Measurements from the southern UK meteorological network during the 11 August 1999 total solar eclipse are compared with a high-resolution model ignorant of the lunar shadow's influence. Differences between the model output and measurements at the eclipse time show transient eclipse zone temperature decreases of up to 3
°
C, which also depressed the day's maximum temperature compared with the model prediction. Coherent responses in temperature, and wind speed and direction measurements are detected in the inland cloud-free region (from 51
°
to 52
°
 N and −2
°
to 0
°
 E). A mean regional wind speed decrease of 0.7 m s
−1
during the maximum eclipse hour is apparent with a mean anticlockwise wind direction change of 17
°
; no such changes occurred in the model output. Such regional circulation changes are consistent with Clayton's 1901 cold-cored eclipse cyclone hypothesis, which may be related to the anecdotal ‘eclipse wind’.
Metal–organic frameworks of the MIL-101 family as heterogeneous single-site catalysts
Authors: Maksimchuk Nataliya V. , Zalomaeva Olga V. , Skobelev Igor Y. , Kovalenko Konstantin A. , Fedin Vladimir P. , Kholdeeva Oxana A.
Published: March 2012

In this short review paper, we survey our recent findings in the catalytic applications of mesoporous metal–organic frameworks of the MIL-101 family (Fe- and Cr-MIL-101) and demonstrate their potential in two types of liquid-phase processes: (i) selective oxidation of hydrocarbons with green oxidants—O
2
and
tert
-butyl hydroperoxide—and (ii) coupling reaction of organic oxides with CO
2
. A comparison with conventional single-site catalysts is made with special attention to issues of the catalyst's resistance to metal leaching and the nature of catalysis.
A performance-based cost to honest signalling in male green anole lizards (Anolis carolinensis)
Authors: Lailvaux Simon P. , Gilbert Rebecca L. , Edwards Jessica R.
Published: March 2012

Sexual signals are considered costly to produce and maintain under the handicap paradigm, and the reliability of signals is in turn thought to be maintained by these costs. Although previous studies have investigated the costly nature of signal production, few have considered whether honesty might be maintained not by the costliness of the signal itself, but by the costs involved in producing the signalled trait. If such a trait is itself costly to produce, then the burden of energetic investment may fall disproportionately on that trait, in addition to any costs of signal maintenance that may also be operating. Under limited resource conditions, these costs may therefore be great enough to disrupt an otherwise reliable signal-to-trait relationship. We present experimental evidence showing that dietary restriction decouples the otherwise honest relationship between a signal (dewlap size) and a whole-organism performance trait (bite force) in young adult maleAnolis carolinensislizards. Specifically, while investment in dewlap size is sustained under low-resource condition relative to the high-resource treatment, investment in bite force is substantially lower. Disruption of the otherwise honest dewlap size to bite force relationship is therefore driven by costs associated with the expression of performance rather than the costs of signal production inA. carolinensis.
The sharpest tools in the box? Quantitative analysis of conodont element functional morphology
Authors: Jones David , Evans Alistair R. , Siu Karen K. W. , Rayfield Emily J. , Donoghue Philip C. J.
Published: March 2012

Conodonts have been considered the earliest skeletonizing vertebrates and their mineralized feeding apparatus interpreted as having performed a tooth function. However, the absence of jaws in conodonts and the small size of their oropharyngeal musculature limits the force available for fracturing food items, presenting a challenge to this interpretation. We address this issue quantitatively using engineering approaches previously applied to mammalian dentitions. We show that the morphology of conodont food-processing elements was adapted to overcome size limitations through developing dental tools of unparalleled sharpness that maximize applied pressure. Combined with observations of wear, we also show how this morphology was employed, demonstrating how
Wurmiella excavata
used rotational kinematics similar to other conodonts, suggesting that this occlusal style is typical for the clade. Our work places conodont elements within a broader dental framework, providing a phylogenetically independent system for examining convergence and scaling in dental tools.
Sounds like a winner: voice pitch influences perception of leadership capacity in both men and women
Authors: Klofstad Casey A. , Anderson Rindy C. , Peters Susan
Published: March 2012

It is well known that non-human animals respond to information encoded in vocal signals, and the same can be said of humans. Specifically, human voice pitch affects how speakers are perceived. As such, does voice pitch affect how we perceive and select our leaders? To answer this question, we recorded men and women saying ‘I urge you to vote for me this November’. Each recording was manipulated digitally to yield a higher- and lower-pitched version of the original. We then asked men and women to vote for either the lower- or higher-pitched version of each voice. Our results show that both men and women select male and female leaders with lower voices. These findings suggest that men and women with lower-pitched voices may be more successful in obtaining positions of leadership. This might also suggest that because women, on average, have higher-pitched voices than men, voice pitch could be a factor that contributes to fewer women holding leadership roles than men. Additionally, while people are free to choose their leaders, these results clearly demonstrate that these choices cannot be understood in isolation from biological influences.
Are stress responses to geomagnetic storms mediated by the cryptochrome compass system?
Authors: Close James
Published: March 2012

A controversial body of literature demonstrates associations of geomagnetic storms (GMS) with numerous cardiovascular, psychiatric and behavioural outcomes. Various
melatonin hypotheses
of GMS have suggested that temporal variation in the geomagnetic field (GMF) may be acting as an additional
zeitgeber
(a temporal synchronizer) for circadian rhythms, with GMS somehow interfering with the hypothesized system. The cryptochrome genes are known primarily as key components of the circadian pacemaker, ultimately involved in controlling the expression of the hormone melatonin. Cryptochrome is identified as a clear candidate for mediating the effect of GMS on humans, demonstrating the prior existence of several crucial pieces of evidence. A distinct scientific literature demonstrates the widespread use of geomagnetic information for navigation across a range of taxa. One mechanism of magnetoreception is thought to involve a light-dependent retinal molecular system mediated by cryptochrome, acting in a distinct functionality to its established role as a circadian oscillator. There is evidence suggesting that such a magnetosense—or at least the vestiges of it—may exist in humans. This paper argues that cryptochrome is not acting as secondary geomagnetic zeitgeber to influence melatonin synthesis. Instead, it is hypothesized that the cryptochrome compass system is mediating stress responses more broadly across the hypothalamic–pituitary–adrenal (HPA) axis (including alterations to circadian behaviour) in response to changes in the GMF. Two conceptual models are outlined for the existence of such responses—the first as a generalized migrational/dispersal strategy, the second as a stress response to unexpected signals to the magnetosense. It is therefore proposed that GMS lead to disorientation of hormonal systems in animals and humans, thus explaining the effects of GMS on human health and behaviour.
Evolutionary demography of iteroparous plants: incorporating non-lethal costs of reproduction into integral projection models
Authors: Miller Tom E. X. , Williams Jennifer L. , Jongejans Eelke , Brys Rein , Jacquemyn Hans
Published: March 2012

Understanding the selective forces that shape reproductive strategies is a central goal of evolutionary ecology. Selection on the timing of reproduction is well studied in semelparous organisms because the cost of reproduction (death) can be easily incorporated into demographic models. Iteroparous organisms also exhibit delayed reproduction and experience reproductive costs, although these are not necessarily lethal. How non-lethal costs shape iteroparous life histories remains unresolved. We analysed long-term demographic data for the iteroparous orchid
Orchis purpurea
from two habitat types (light and shade). In both the habitats, flowering plants had lower growth rates and this cost was greater for smaller plants. We detected an additional growth cost of fruit production in the light habitat. We incorporated these non-lethal costs into integral projection models to identify the flowering size that maximizes fitness. In both habitats, observed flowering sizes were well predicted by the models. We also estimated optimal parameters for size-dependent flowering effort, but found a strong mismatch with the observed flower production. Our study highlights the role of context-dependent non-lethal reproductive costs as selective forces in the evolution of iteroparous life histories, and provides a novel and broadly applicable approach to studying the evolutionary demography of iteroparous organisms.