bluuebunny/crossref_metadata_2025 huggingface dataset:
No difference in portal and hepatic venous bacterial DNA in patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt insertion
Authors: Mortensen Christian , Karlsen Stine , Grønbæk Henning , Nielsen Dennis T. , Frevert Susanne , Clemmesen Jens O. , Møller Søren , Jensen Jørgen S. , Bendtsen Flemming
Published: May 2013

Background

Bacterial translocation (BT) with immune activation may lead to hemodynamical alterations and poor outcomes in patients with cirrhosis.

Aims

We investigated bacterial DNA (bDNA), a marker of BT, and its relation to portal pressure and markers of inflammation in the portal and hepatic veins in patients with cirrhosis undergoing TIPS insertion.

Methods

We analysed plasma for bDNA and markers of inflammation in 28 patients [median portal pressure gradient 15 (11‐19) mmHg] during TIPS treatment for refractory ascites (n = 19) or acute variceal bleeding (n = 9). Advanced cirrhosis was present in the majority [Child–Pugh class (A/B/C): 1/14/13], and most often caused by alcohol (n = 21).

Results

bDNA was detectable in one or both samples in 16 of 28 patients (57%).

bDNA was present in 39% of the samples from the portal vein vs 43% of the samples in the hepatic vein (P = 0.126). Antibiotics had no effect on bDNA or markers of inflammation. Markers of inflammation did not differ between the hepatic and portal veins with the exceptions of soluble urokinase plasminogen activating receptor (suPAR) and vascular endothelial growth factor (VEGF), both higher in the hepatic vein (P = 0.031 and 0.003 respectively).

Conclusions

No transhepatic gradient of bDNA was evident, suggesting that no major hepatic elimination of bDNA occurs in advanced liver disease. bDNA, in contrast to previous reports was largely unrelated to a panel of markers of inflammation and without relation to portal pressure.
Admixture increases diversity in managed honey bees: Reply to De la Rúa et al. (2013)
Authors: Harpur Brock A. , Minaei Shermineh , Kent Clement F. , Zayed Amro
Published: May 2013

De la Rúa et al. (2013) express some concerns about the conclusions of our recent study showing that management increases genetic diversity of honey bees (Apis mellifera) by promoting admixture (Harpur et al. 2012). We provide a brief review of the literature on the population genetics of A. mellifera and show that we utilized appropriate sampling methods to estimate genetic diversity in the focal populations. Our finding of higher genetic diversity in two managed A. mellifera populations on two different continents is expected to be the norm given the large number of studies documenting admixture in honey bees. Our study focused on elucidating how management affects genetic diversity in honey bees, not on how to best manage bee colonies. We do not endorse the intentional admixture of honey bee populations, and we agree with De la Rúa et al. (2013) that native honey bee subspecies should be conserved.
The (Normal) Rate of Capacity Utilization at the Firm Level
Authors: Nikiforos Michalis
Published: May 2013

This paper examines the endogeneity (or lack thereof) of the rate of capacity utilization in the long run at the firm level. The cost minimizing firm has an incentive to increase the utilization of its capital if the rate of the returns to scale decreases as its production increases. The theory of production provides justification for this kind of behavior of economies of scale. In that way the desired rate of utilization becomes endogenous to variations in demand.
HgrA is necessary and sufficient to drive hyphal growth in the dimorphic pathogen Penicillium marneffei
Authors: Bugeja Hayley E. , Hynes Michael J. , Andrianopoulos Alex
Published: May 2013

Fungi produce multiple morphological forms as part of developmental programs or in response to changing, often stressful, environmental conditions. An opportunistic pathogen of humans, Penicillium marneffei displays multicellular hyphal growth and asexual development (conidiation) in the environment at 25°C and unicellular yeast growth in macrophages at 37°C. We characterized the transcription factor, hgrA, which contains a C2H2 DNA binding domain closely related to that of the stress‐response regulators Msn2/4 of Saccharomyces cerevisiae. Northern hybridization analysis demonstrated that hgrA expression is specific to hyphal growth, and its constitutive overexpression prevents conidiation and yeast growth, even in the presence of inductive cues, and causes apical hyperbranching during hyphal growth. Consistent with its expression pattern, deletion of hgrA causes defects in hyphal morphogenesis and the dimorphic transition from yeast cells to hyphae. Specifically, loss of HgrA causes cell wall defects, reduced expression of cell wall biosynthetic enzymes and increased sensitvity to cell wall, oxidative, but not osmotic stress agents. These data suggest that HgrA does not have a direct role in the response to stress but is an inducer of the hyphal growth program and its activity must be downregulated to allow alternative developmental programs, including the morphogenesis of yeast cells in macrophages.
How the observed create ethical dilemmas for the observers: Experiences from studies conducted in clinical settings in the UK and Australia
Authors: Bloomer Melissa J. , Doman Maggie , Endacott Ruth
Published: May 2013

Observational research has a history of controversy, particularly when the research is conducted in a clinical setting. Existing ethical approval processes focus on protecting participants and the researcher's responsibilities, in particular where vulnerable populations are concerned. In this study, the authors explored the less overt and often understated ethical challenges that can arise when conducting observational research in a clinical setting. Reflecting on two recent studies conducted in different clinical settings, the authors described the challenges of blurring role boundaries, the risk of collecting redundant data, and the impact of reverse power relationships between researchers, clinicians, and managers. From their experiences, the authors suggested that the preparatory work undertaken with clinicians and managers onsite, which typically focuses on how the researchers will maintain the ethical robustness of the research and protect the rights of participants and the vulnerable, should also highlight the sometimes overlooked ethical issues associated with participatory research. This can help ensure that participants and managers understand the scope and limitations of the research, and consider the ways in which the observed can influence the researcher and the findings.
Prioritizing health disparities in medical education to improve care
Authors: Awosogba Temitope , Betancourt Joseph R. , Conyers F. Garrett , Estapé Estela S. , Francois Fritz , Gard Sabrina J. , Kaufman Arthur , Lunn Mitchell R. , Nivet Marc A. , Oppenheim Joel D. , Pomeroy Claire , Yeung Howa
Published: May 2013

Despite yearly advances in life‐saving and preventive medicine, as well as strategic approaches by governmental and social agencies and groups, significant disparities remain in health, health quality, and access to health care within the United States. The determinants of these disparities include baseline health status, race and ethnicity, culture, gender identity and expression, socioeconomic status, region or geography, sexual orientation, and age. In order to renew the commitment of the medical community to address health disparities, particularly at the medical school level, we must remind ourselves of the roles of doctors and medical schools as the gatekeepers and the value setters for medicine. Within those roles are responsibilities toward the social mission of working to eliminate health disparities. This effort will require partnerships with communities as well as with academic centers to actively develop and to implement diversity and inclusion strategies. Besides improving the diversity of trainees in the pipeline, access to health care can be improved, and awareness can be raised regarding population‐based health inequalities.
Bone Graft Substitutes for Anterior Lumbar Interbody Fusion
Authors: Mobbs Ralph J , Chung Mina , Rao Prashanth J
Published: May 2013

The procedure of anterior lumbar interbody fusion (ALIF) is commonly performed on patients suffering from pain and/or neurological symptoms associated with disorders of the lumbar spine caused by disc degeneration and trauma. Surgery is indicated when prolonged conservative management proves ineffective. Because an important objective of the ALIF procedure is solid arthrodesis of the degenerative spinal segment, bone graft selection is critical. Iliac crest bone grafts (ICBG) remain the “gold standard” for achieving lumbar fusion. However, patient dissatisfaction stemming from donor site morbidity, lengthier operating times and finite supply of ICBG has prompted a search for better alternatives. Here presented is a literature review evaluating available bone graft options assessed within the clinical setting. These options include autografts, allograft‐based, synthetic and cell‐based technologies. The emphasis is on the contentious use of recombinant human bone morphogenetic proteins, which is in widespread use and has demonstrated both significant osteogenic potential and risk of complications.
A review of 5434 percutaneous pediatric central venous catheters inserted by anesthesiologists
Authors: Malbezin Serge , Gauss Tobias , Smith Ian , Bruneau Beatrice , Mangalsuren Nyamjargal , Diallo Thierno , Skhiri Alia , Nivoche Yves , Dahmani Souhayl , Brasher Christopher
Published: May 2013

Objective

To review the results of an anesthesiologist led pediatric percutaneous central venous access service.

Methods

Prospective data on percutaneous pediatric central venous catheter (CVC) insertions were collected over 22 years. Data included age, gender, weight, previous central CVCs, venous thromboses, investigations for great vein patency, type of CVC, external diameter, previous CVC insertions, intended use, operator identity, and the vein into which the CVC was inserted. The default technique was internal jugular vein cannulation using landmark technique (LT). Complication was defined as the following: failure to cannulate any vein, hemothorax, pneumothorax, right atrial perforation, extravenous wire positioning or CVC position and whether the patient was taken back to theater for CVC repositioning.

Results

Five thousand four hundred and thirty‐four percutaneous CVC insertion procedures were performed on 3954 patients. One‐third involved children <1 year of age (n = 1823: 34%). Five thousand one hundred and twenty‐five CVCs (95.3%) were inserted into internal jugular veins. The majority were tunneled CVCs (n = 5190: 96.2%). The perioperative complication rate was 1.3%. Successful cannulation occurred in 99.5% of patients. Failure was more likely in children <3 kg, during large bore hemodialysis CVC insertions and during the first 4 years of the service – the latter suggesting a learning curve. Ninety‐nine percent of CVCs were inserted using LTs.

Conclusion

This study demonstrates a high success rate and low complication rate during pediatric percutaneous internal jugular vein CVC insertions by trained anesthesiologists using LTs. Smaller children, hemodialysis CVCs, and the team's learning curve were identified as risk factors for insertion failure.
Helping Teams to Help Themselves: Comparing two Team‐Led Debriefing Methods
Authors: Eddy Erik R. , Tannenbaum Scott I. , Mathieu John E.
Published: May 2013

Team‐based structures have become more widely used in organizations. Therefore, it is important for team members to perform well in their current team and to build skills and enthusiasm for working on future teams. This study examined team debriefing, an intervention in which team members reflect on recent experiences to prepare for subsequent tasks. Prior researchers have shown that facilitated team debriefs work, but they have not examined how to enable teams to conduct their own debriefs or studied how debriefs affect individual level outcomes. Therefore, we compared 2 team‐led debriefing techniques: (a) an unguided debrief and (b) a guided debrief designed to incorporate lessons learned from prior debriefs. We collected data from 174 business students who were members of 35 teams from 9 sections of a Strategic Management course. Class sections were randomly assigned to one of the debriefing conditions, and teams completed 4 business cases over 10 weeks. A multilevel design was employed and a multistage model building approach was used to test the hypotheses using hierarchical linear modeling techniques. Results of this cluster randomized, quasi‐experimental design suggest that the team‐led guided debrief intervention resulted in superior team processes as compared to the unguided debriefing method. Team processes, in turn, related significantly to greater team performance and increased individual readiness for teamwork and enthusiasm for teaming. Implications for future research and practice are discussed.
The Association between a Medical History of Depression and Gestational Diabetes in a Large Multi‐ethnic Cohort in the United States
Authors: Bowers Katherine , Laughon S. Katherine , Kim Sungduk , Mumford Sunni L. , Brite Jennifer , Kiely Michele , Zhang Cuilin
Published: May 2013

Background

Both major depression and gestational diabetes mellitus (GDM) are prevalent among women of reproductive age. Our objective was to determine whether a medical history of depression is related to subsequent development of GDM.

Methods

The Consortium on Safe Labor was a US retrospective cohort study of 228 562 births between 2002 and 2008. Exclusion criteria for the present analysis included multiple gestation pregnancies (n = 5059), pre‐existing diabetes (n = 12 771), deliveries <24 weeks (n = 395), site GDM prevalence (<1%) (n = 20 721) and missing data on pre‐pregnancy body mass index (BMI) (n = 61 321). Using generalised estimating equations, we estimated the association between a history of depression and a pregnancy complicated by GDM.

Results

The final analytic population included 121 260 women contributing 128 295 pregnancies, of which 5606 were affected by GDM. A history of depression was significantly associated with an increased risk of developing GDM (multivariate odds ratio [aOR] = 1.42 [95% confidence interval (CI) 1.26, 1.60]). Adjusting for pre‐pregnancy BMI and weight gain during pregnancy attenuated the association, although it remained statistically significant (aOR = 1.17 [95% CI 1.03, 1.33]).

Conclusions

A history of depression was significantly associated with an increased GDM risk among a large multi‐ethnic US cohort of women. If the association is confirmed, depression presents a potentially modifiable risk factor of GDM and provides additional clues to the underlying pathophysiology of GDM.
Reducing the financial impact of pathogen inactivation technology for platelet components: our experience
Authors: Girona‐Llobera Enrique , Jimenez‐Marco Teresa , Galmes‐Trueba Ana , Muncunill Josep , Serret Carmen , Serra Neus , Sedeño Matilde
Published: May 2013

Background

Pathogen inactivation (PI) technology for blood components enhances blood safety by inactivating viruses, bacteria, parasites, and white blood cells. Additionally, PI for platelet (PLT) components has the potential to extend PLT storage time from 5 to 7 days.

Study Design and Methods

A retrospective analysis was conducted into the percentage of outdated PLT components during the 3 years before and after the adoption of PLT PI technology in our institution. The PLT transfusion dose for both pre‐PI and post‐PI periods was similar. A retrospective analysis to study clinical safety and component utilization was also performed in the Balearic Islands University Hospital.

Results

As a result of PI implementation in our institution, the PLT production cost increased by 85.5%. However, due to the extension of PLT storage time, the percentage of outdated PLT units substantially decreased (−83.9%) and, consequently, the cost associated with outdated units (−69.8%). This decrease represented a 13.7% reduction of the initial cost increase which, together with the saving in blood transportation (0.1%), led to a saving of 13.8% over the initial cost. Therefore, the initial 85.5% increase in the cost of PLT production was markedly reduced to 71.7%. The mean number of PLT concentrates per patient was similar during both periods.

Conclusions

The extension of PLT storage time can substantially contribute to reducing the financial impact of PI by decreasing the percentage of outdated PLTs while improving blood safety. Since the adoption of PI, there have been no documented cases of PLT transfusion–related sepsis in our region.
Inactivation of Plasmodium falciparum in whole blood by riboflavin plus irradiation
Authors: El Chaar Mira , Atwal Sharan , Freimanis Graham L. , Dinko Bismarck , Sutherland Colin J. , Allain Jean‐Pierre
Published: May 2013

Background

Malaria parasites are frequently transmitted by unscreened blood transfusions in Africa. Pathogen reduction methods in whole blood would thus greatly improve blood safety. We aimed to determine the efficacy of riboflavin plus irradiation for treatment of whole blood infected with Plasmodium falciparum.

Study Design and Methods

Blood was inoculated with 104 or 105 parasites/mL and riboflavin treated with or without ultraviolet (UV) irradiation (40‐160 J/mL red blood cells [mLRBCs]). Parasite genome integrity was assessed by quantitative amplification inhibition assays, and P. falciparum viability was monitored in vitro.

Results

Riboflavin alone did not affect parasite genome integrity or parasite viability. Application of UV after riboflavin treatment disrupted parasite genome integrity, reducing polymerase‐dependent amplification by up to 2 logs (99%). At 80 J/mLRBCs, riboflavin plus irradiation prevented recovery of viable parasites in vitro for 2 weeks, whereas untreated controls typically recovered to approximately 2% parasitemia after 4 days of in vitro culture. Exposure of blood to 160 J/mLRBCs was not associated with significant hemolysis.

Conclusions

Riboflavin plus irradiation treatment of whole blood damages parasite genomes and drastically reduces P. falciparum viability in vitro. In the absence of suitable malaria screening assays, parasite inactivation should be investigated for prevention of transfusion‐transmitted malaria in highly endemic areas.
The use of COLD‐PCR, DHPLC and GeneScanning for the highly sensitive detection of c‐KIT somatic mutations in canine mast cell tumours
Authors: Gentilini F. , Mantovani V. , Turba M. E.
Published: May 2013

The conventional polymerase chain reaction (PCR)/sequencing methods may be poorly suited for the detection of somatic mutations in canine mast cell tumour (MCT) samples owing to limited sensitivity. This study was aimed at establishing novel and more sensitive methods, assessing their limit of detection and comparing their sensitivity with conventional methods.Two different ‘driver’ somatic mutations of c‐KIT, together with the wild‐type counterparts, were cloned in plasmids to prepare standard samples with known concentrations of mutated alleles in a background of wild‐type alleles; the plasmids standards were assayed using either conventional or novel, highly sensitive technique.
Conventional PCR/sequencing showed a sensitivity of 50–20%. Conversely, all the novel methods obtained higher sensitivities allowed reaching as low as 2.5–1.2% of the mutated DNA.The study demonstrates that early conventional methods could likely have underestimated the prevalence of KIT mutations of MCTs, therefore affecting the assessment of their relevance in prognosis and tyrosine kinase inhibitor (TKI) treatment effectiveness.
Mitochondrial phylogeography, contact zones and taxonomy of grass snakes (Natrix natrix,N. megalocephala)
Authors: Kindler Carolin , Böhme Wolfgang , Corti Claudia , Gvoždík Václav , Jablonski Daniel , Jandzik David , Metallinou Margarita , Široký Pavel , Fritz Uwe
Published: May 2013

Grass snakes (Natrix natrix) represent one of the most widely distributed snake species of the Palaearctic region, ranging from the North African Maghreb region and the Iberian Peninsula through most of Europe and western Asia eastward to the region of Lake Baikal in Central Asia. Within N. natrix, up to 14 distinct subspecies are regarded as valid. In addition, some authors recognize big‐headed grass snakes from western Transcaucasia as a distinct species, N. megalocephala. Based on phylogenetic analyses of a 1984‐bp‐long alignment of mtDNA sequences (ND4+tRNAs, cyt b) of 410 grass snakes, a nearly range‐wide phylogeography is presented for both species. Within N. natrix, 16 terminal mitochondrial clades were identified, most of which conflict with morphologically defined subspecies. These 16 clades correspond to three more inclusive clades from (i) the Iberian Peninsula plus North Africa, (ii) East Europe and Asia and (iii) West Europe including Corso‐Sardinia, the Apennine Peninsula and Sicily. Hypotheses regarding glacial refugia and postglacial range expansions are presented. Refugia were most likely located in each of the southern European peninsulas, Corso‐Sardinia, North Africa, Anatolia and the neighbouring Near and Middle East, where the greatest extant genetic diversity occurs. Multiple distinct microrefugia are inferred for continental Italy plus Sicily, the Balkan Peninsula, Anatolia and the Near and Middle East. Holocene range expansions led to the colonization of more northerly regions and the formation of secondary contact zones. Western Europe was invaded from a refuge within southern France, while Central Europe was reached by two distinct range expansions from the Balkan Peninsula. In Central Europe, there are two contact zones of three distinct mitochondrial clades, and one of these contact zones was theretofore completely unknown. Another contact zone is hypothesized for Eastern Europe, which was colonized, like north‐western Asia, from the Caucasus region. Further contact zones were identified for southern Italy, the Balkans and Transcaucasia. In agreement with previous studies using morphological characters and allozymes, there is no evidence for the distinctiveness of N. megalocephala. Therefore, N. megalocephala is synonymized with N. natrix.
Identification of Material Constitutive Laws Representative of Machining Conditions for Two Titanium Alloys: Ti6Al4V and Ti555-3
Authors: Germain G. , Morel A. , Braham-Bouchnak T.
Published: May 2013

Determining a material constitutive law that is representative of the extreme conditions found in the cutting zone during machining operations is a very challenging problem. In this study, dynamic shear tests, which reproduce, as faithfully as possible, these conditions in terms of strain, strain rate, and temperature, have been developed using hat-shaped specimens. The objective was to identify the parameters of a Johnson–Cook material behavior model by an inverse method for two titanium alloys: Ti6Al4V and Ti555-3. In order to be as representative as possible of the experimental results, the parameters of the Johnson–Cook model were not considered to be constant over the total range of the strain rate and temperature investigated. This reflects a change in the mechanisms governing the deformation. The shear zones observed in hat-shaped specimens were analyzed and compared to those produced in chips during conventional machining for both materials. It is concluded that the observed shear bands can be classified as white-etching bands only for the Ti555-3 alloy. These white bands are assumed to form more easily in the Ti555-3 alloy due to its predominately β phase microstructure compared to the Ti6Al4V alloy with a α + β microstructure.
Effect of Addition of Nano-Al2O3 and Copper Particulates and Heat Treatment on the Tensile Response of AZ61 Magnesium Alloy
Authors: Nguyen Q. B. , Chua Y. H. D. , Tun K. S. , Chan J. , Kwok R. , Wong W. L. E. , Gupta M.
Published: May 2013

In this paper, AZ61 magnesium alloy composites containing nanoalumina and micron-sized copper particulates are synthesized using the technique of disintegrated melt deposition followed by hot extrusion. The simultaneous addition of nano-Al2O3 and copper particulates led to an overall improvement in both microstructural characteristics in terms of distribution and morphology of secondary phases and mechanical response of AZ61. The presence of nanoalumina particulates broke down and dispersed the secondary phase Mg17Al12. The 0.2% yield strength increased from 216 MPa to 274 MPa. The ductility increased from 8.4% to 9.3% in the case of the AZ61-1.5Al2O3 sample. The results of aging heat treatment in the case of the AZ61-1.5Al2O3-1Cu sample showed significant improvement in both tensile strength, ductility, and work of fracture (54% increment). An attempt is made to correlate the tensile response of composites with their microstructural characteristics.
A Predictive Control Based on Neural Network for Dynamic Model of Proton Exchange Membrane Fuel Cell
Authors: Rezaei M. , Mohseni M.
Published: May 2013

This paper presents the development of dynamic models for proton exchange membrane fuel cells (PEMFC). The PEMFC control system has an important effect on operation of cell. Traditional controllers could not lead to acceptable responses because of time-change, long-hysteresis, uncertainty, strong-coupling and nonlinear characteristics of PEMFCs, This paper presents a dynamic model for PEMFC system, so an intelligent or adaptive controller is needed. In this paper, a neural network predictive controller have been designed to control the voltage of at the presence of fluctuations of temperature. The results of implementation of this designed NN Predictive controller on a dynamic electrochemical model of a small size 5 KW, PEM fuel cell have been simulated by matlab/SIMULINK.
Dynamic Attenuation and Compressive Characterization of Syntactic Foams
Authors: Ale Bhaskar , Rousseau Carl-Ernst
Published: May 2013

Hollow particulate composites are lightweight, have high compressive strength, are low moisture absorbent, have high damping materials, and are used extensively in aerospace, marine applications, and in the manufacture of sandwich composites core elements. The high performance of these materials is achieved by adding high strength hollow glass particulates (microballoons) to an epoxy matrix, forming epoxy-syntactic foams. The present study focuses on the effect of volume fraction and microballoon size on the ultrasonic and dynamic properties of Epoxy Syntactic Foams. Ultrasonic attenuation coefficient from an experiment is compared with a previously developed theoretical model for low volume fractions that takes into account attenuation loss due to scattering and absorption. The guidelines of ASTM Standard E 664-93 are used to compute the apparent attenuation. Quasi-static compressive tests were also conducted to fully characterize the material. Both quasi-static and dynamic properties, as well as coefficients of attenuation and ultrasonic velocities are found to be strongly dependent upon the volume fraction and size of the microballoons.
The Elastohydrodynamic Traction of a Grease LGLT2
Authors: Wang Yanshuang , Li Pu , Cao JiaWei , Li Yan
Published: May 2013

The elastohydrodynamic (EHD) traction coefficients of a lubricating grease LGLT2 were tested at various loads and rolling speeds on a self-made test rig. Traction coefficient versus slide-to-roll ratio curves were generated. Formulae which relate traction coefficient with normal load and rolling speed are put forth. The coefficients of the formulae may be computed by regression analysis of the experimental data. The results show that the calculated traction coefficients agree well with the experimental observation. The critical normal load exists when the traction coefficients change with the normal loads.
The Effect of Deposition Patterns on the Deformation of Substrates During Direct Laser Fabrication
Authors: Gao Ming , Wang Zemin , Li Xiangyou , Zeng Xiaoyan
Published: May 2013

The deformation of substrate caused by laser scanning pattern during direct laser fabrication (DLF) is ignored in spite of its importance to the final dimension accuracy. In this paper, in order to investigate the effect of deposition pattern on the deformation of substrate during DLF, eight laser scanning patterns are designed to build a cylinder on an asymmetrical IN718 arc substrate, respectively. Deformations of substrates along x, y, z-directions after DLF and heat treatment are compared and discussed. Meanwhile, the maximum displacement in z-direction of each substrate is calculated. Besides, a modified temperature gradient mechanism (TGM) is introduced to understand deformations of substrates under different laser scanning patterns. The results show that the deformation of substrate along z-direction is much larger than other two directions for all scanning patterns. The deformation of substrate strongly depends on x- and y-directional dimension of the substrate when a symmetrical build is fabricated. Compared with contour-offset scanning patterns, raster scanning patterns have distinct directional effect on deformations of substrates. Especially, the deformations of substrates caused by laser fabrication are permanent. In order to improve the fabrication efficiency, to and fro laser scan along the short dimension direction is preferred during DLF for generating the minimum deformation to substrate and reducing unnecessary movements of the working table.
Methane detection using Pt-gated AlGaN/GaN high electron mobility transistor based Schottky diodes
Authors: Xi Yuyin , Liu Lu , Ren Fan , Pearton Stephen J. , Kim Jihyun , Dabiran Amir , Chow Peter P.
Published: May 2013

Pt-gated AlGaN/GaN high electron mobility transistor based Schottky diodes were employed to detect methane. A detection sensitivity >100 was obtained for the diodes under reverse bias, and this was one order of magnitude higher than the sensitivity of the diodes operated under forward bias. A new method to extract the response time was demonstrated by taking the derivative of diode current, allowing a reduction in the sensor response time by 80%. Methane sensing experiments were conducted at different temperatures, and an Arrhenius plot of the data determined an activation energy of 57 kJ/mol for the sensing process.
Growth window and effect of substrate symmetry in hybrid molecular beam epitaxy of a Mott insulating rare earth titanate
Authors: Moetakef Pouya , Zhang Jack Y. , Raghavan Santosh , Kajdos Adam P. , Stemmer Susanne
Published: May 2013

The conditions for the growth of stoichiometric GdTiO3 thin films by molecular beam epitaxy (MBE) are investigated. It is shown that relatively high growth temperatures (>750 °C) are required to obtain an MBE growth window in which only the stoichiometric film grows for a range of cation flux ratios. This growth window narrows with increasing film thickness. It is also shown that single-domain films are obtained by the growth on a symmetry-matched substrate. The influence of lattice mismatch strain on the electrical and magnetic characteristics of the GdTiO3 thin film is investigated.
Multiscale Modeling of Membrane Rearrangement, Drainage, and Rupture in Evolving Foams
Authors: Saye Robert I. , Sethian James A.
Published: May 2013

Simulating Foam Formation

Foams are easily made whether in the kitchen sink in the form of soap bubbles or a frothy head on the top of a quickly poured beer.
Saye and Sethian
(p.
720
; see the Perspective by

Weaire

) describe the mathematical simulation of foam dynamics by decomposing the process into rearrangement, drainage, and rupture phases that are then linked by coupling the flux boundary conditions.
Robust Circadian Oscillations in Growing Cyanobacteria Require Transcriptional Feedback
Authors: Teng Shu-Wen , Mukherji Shankar , Moffitt Jeffrey R. , de Buyl Sophie , O’Shea Erin K.
Published: May 2013

Keeping in Synch

Although it differs from mammalian clocks, the circadian clock of cyanobacteria is a valuable model for understanding how such clocks function. At the heart of the cyanobacterial clock is a posttranslational regulation (PTR) circuit in which the phosphorylation of the clock protein KaiC oscillates. This circuit is apparently sufficient for generating rhythms, but it is connected to a transcriptional-translational (TTR) feedback loop more similar to the one that functions in mammals. This TTR loop is, at least in some conditions, dispensable. To understand the role of the TTR circuit,

Teng
et al.

(p.
737
) engineered cyanobacteria so that the circadian behavior of individual cells in a population of growing cells could be monitored. Cells engineered to lack the TTR mechanism had rhythmic clocks but fell out of synch with the other cells in a population over time. The experimental results together with mathematical modeling indicate that the TTR mechanism is important to allow cells to robustly stay in rhythm with one another in the absence of synchronizing external cues.
Delineating Antibody Recognition in Polyclonal Sera from Patterns of HIV-1 Isolate Neutralization
Authors: Georgiev Ivelin S. , Doria-Rose Nicole A. , Zhou Tongqing , Do Kwon Young , Staupe Ryan P. , Moquin Stephanie , Chuang Gwo-Yu , Louder Mark K. , Schmidt Stephen D. , Altae-Tran Han R. , Bailer Robert T. , McKee Krisha , Nason Martha , O’Dell Sijy , Ofek Gilad , Pancera Marie , Srivatsan Sanjay , Shapiro Lawrence , Connors Mark , Migueles Stephen A. , Morris Lynn , Nishimura Yoshiaki , Martin Malcolm A. , Mascola John R. , Kwong Peter D.
Published: May 2013

Building Better Vaccines

In the past few years, several highly potent, broadly neutralizing antibodies (bNAbs) specific for the gp120 envelope protein of HIV-1 have been discovered. The goal of this work is to use this information to inform the design of vaccines that are able to induce such antibodies (see the Perspective by

Crowe

). However, because of extensive somatic hypermutation, the epitope bound by these antibodies often does not bind to the germline sequence.

Jardine
et al.

(p.
711
, published online 28 March; see the cover) used computational analysis and in vitro screening to design an immunogen that could bind to VRC01-class bNAbs and to their germline precursors.

Georgiev
et al.

(p.
751
) took advantage of the fact that only four sites on the HIV viral envelope protein seem to bind bNAbs, and sera that contain particular bNAbs show characteristic patterns of neutralization. An algorithm was developed that could successfully delineate the neutralization specificity of antibodies present in polyclonal sera from HIV-infected patients.
Emergence of Individuality in Genetically Identical Mice
Authors: Freund Julia , Brandmaier Andreas M. , Lewejohann Lars , Kirste Imke , Kritzler Mareike , Krüger Antonio , Sachser Norbert , Lindenberger Ulman , Kempermann Gerd
Published: May 2013

Identical and Still Different

Even in monozygotic twins reared together, there are always observable differences reflecting the influence of individual responses.

Freund
et al.

(p.
756
; see the Perspective by

Bergmann and Frisén

) developed an inbred mouse model for studying the environmental influences on genetically identical animals and examined their effects on behavioral and neural development.
Bacterial Subversion of Host Innate Immune Pathways
Authors: Baxt Leigh A. , Garza-Mayers Anna Cristina , Goldberg Marcia B.
Published: May 2013

Defense and Counter-Defense

Provided a pathogen can enter the body and survive coughing and spluttering, peristalsis, and mucus, the first active responses the host evokes to an invading organism will be at the level of the first cell encountered, well before classical cellular immunity and antibody responses are initiated.

Randow
et al.

(p.
701
) review the range of intracellular defenses against incoming pathogens and describe how compartmental boundaries within the cell provide multiple levels at which pathogens can be thwarted in their attempts to subjugate the cell to do their bidding.

Baxt
et al.

(p.
697
) review the range of evasion tactics that bacterial pathogens can summon to counter host repulsion and establish a niche in which to replicate and ensure onward transmission.
Controlling Atomic Line Shapes
Authors: Lin C. D. , Chu Wei-Chun
Published: May 2013

Intense infrared lasers can be used to control the spectral line shapes of atoms, with implications for spectroscopy and quantum dynamical processes.

[Also see Report by

Ott
et al.

]
On Effective Leadership
Authors: Alberts Bruce
Published: May 2013

Many have pondered why some nations are much more successful than others. Is the central factor an abundance of natural resources, wise traditional systems of governance, or the absence of serious conflicts? Or does a nation thrive merely as the result of a series of historical accidents? I believe that a primary determinant of success, often neglected, is how the leaders of its major institutions,
*
governmental and nongovernmental, are selected; how they in turn choose their deputies; and under what incentives they must operate.
More Woes for Struggling HIV Vaccine Field
Authors: Cohen Jon
Published: May 2013

Devastating results from two trials have sent researchers scrambling—again.
Planetary Scientists Casting Doubt on Feasibility of Plan to Corral Asteroid
Authors: Kerr Richard A.
Published: May 2013

NASA's new plan to capture a tiny asteroid and lodge it in the Earth-moon system is certainly audacious, but many have doubts.
Boston Bombing Victims Aided by Biologist-Surgeon
Authors: Gura Trisha
Published: May 2013

Systems biologist Michael B. Yaffe tells
Science
how injuries to humans parallel insults to cells and about his "surreal" week.
How Big a Role Should Neonicotinoids Play in Food Security?
Authors: Stokstad Erik
Published: May 2013

Proponents of neonicotinoid-treated seeds claim that the chemicals offer many benefits, but how important are they for agriculture?
Insistence on Gathering Real Data Confirms Low Radiation Exposures
Authors: Normile Dennis
Published: May 2013

The massive evacuation and strict monitoring of food appear to have successfully limited the amount of radiocesium ingested by Fukushima residents.
MICROBIOMICS: The Germ Theory of Everything
Authors: Dove Alan
Published: May 2013

Fast, cheap DNA sequencing technology now allows scientists to study unculturable microbes; the results are challenging some of biology's most fundamental notions.
Live Cell Imaging: The Future for Discoveries
Authors: Turnbull Lynne , Campbell Edward M. , Thomas Nick
Published: May 2013

Cellular imaging remains one of the most important techniques in life science research based in part on the notion that "seeing is believing." For a variety of practical reasons including types of probes available and access of probes to their intracellular targets, imaging is currently most often performed on specimens that have been fixed and labeled. Although technically more challenging, live cell imaging enables researchers to study cellular events and processes that cannot be visualized in fixed specimens and to follow short- and long-term dynamic processes to gain deeper insights into the complex mechanisms of cell biology.
Evaluation of Immunogenicity and Efficacy of Anthrax Vaccine Adsorbed for Postexposure Prophylaxis
Authors: Ionin Boris , Hopkins Robert J. , Pleune Brett , Sivko Gloria S. , Reid Frances M. , Clement Kristin H. , Rudge Thomas L. , Stark Gregory V. , Innes Alison , Sari Suha , Guina Tina , Howard Cris , Smith Jeffrey , Swoboda M. Lisa , Vert-Wong Ekaterina , Johnson Virginia , Nabors Gary S. , Skiadopoulos Mario H.
Published: May 2013

Antimicrobials administered postexposure can reduce the incidence or progression of anthrax disease, but they do not protect against the disease resulting from the germination of spores that may remain in the body after cessation of the antimicrobial regimen. Such additional protection may be achieved by postexposure vaccination; however, no anthrax vaccine is licensed for postexposure prophylaxis (PEP). In a rabbit PEP study, animals were subjected to lethal challenge with aerosolized
Bacillus anthracis
spores and then were treated with levofloxacin with or without concomitant intramuscular (i.m.) vaccination with anthrax vaccine adsorbed (AVA) (BioThrax; Emergent BioDefense Operations Lansing LLC, Lansing, MI), administered twice, 1 week apart. A significant increase in survival rates was observed among vaccinated animals compared to those treated with antibiotic alone. In preexposure prophylaxis studies in rabbits and nonhuman primates (NHPs), animals received two i.m. vaccinations 1 month apart and were challenged with aerosolized anthrax spores at day 70. Prechallenge toxin-neutralizing antibody (TNA) titers correlated with animal survival postchallenge and provided the means for deriving an antibody titer associated with a specific probability of survival in animals. In a clinical immunogenicity study, 82% of the subjects met or exceeded the prechallenge TNA value that was associated with a 70% probability of survival in rabbits and 88% probability of survival in NHPs, which was estimated based on the results of animal preexposure prophylaxis studies. The animal data provide initial information on protective antibody levels for anthrax, as well as support previous findings regarding the ability of AVA to provide added protection to
B. anthracis
-infected animals compared to antimicrobial treatment alone.
Evaluation of Simplexa Flu A/B & RSV for Direct Detection of Influenza Viruses (A and B) and Respiratory Syncytial Virus in Patient Clinical Samples
Authors: Hindiyeh Musa , Kolet Liat , Meningher Tal , Weil Merav , Mendelson Ella , Mandelboim Michal
Published: May 2013

We evaluated the performance of the Simplexa Flu A/B & RSV kit on 170 prospective respiratory samples using a modified protocol, supplied by the manufacturer, that eliminates the RNA extraction step. Overall, compared against our laboratory-developed assay, the assay's sensitivity, specificity, and positive and negative predictive values were 95.1%, 99.6%, 98.7%, and 98.6%, respectively.
Targeting the Treponemal Microbiome of Digital Dermatitis Infections by High-Resolution Phylogenetic Analyses and Comparison with Fluorescent
In Situ
Hybridization
Authors: Klitgaard Kirstine , Foix Bretó Antoni , Boye Mette , Jensen Tim K.
Published: May 2013

Modern pyrosequencing technology allows for a more comprehensive approach than traditional Sanger sequencing for elucidating the etiology of bovine digital dermatitis. We sought to describe the composition and diversity of treponemes in digital dermatitis lesions by using deep sequencing of the V3 and V4 hypervariable regions of the 16S rRNA gene coupled with species-level taxonomic identification.
Treponema
-specific 16S rRNA gene PCRs and pyrosequencing were performed on biopsy specimens originating from 10 different Catalan dairy herds (
n
= 36) with digital dermatitis, and this analysis yielded 75,297 sequences. We identified 20 different taxa, including a potentially novel phylotype that displayed 95% sequence identity to members of the
Treponema denticola
/
Treponema pedis
-like cluster. Species frequencies and abundances that were determined by pyrosequencing analysis were highly correlated with the results of fluorescent
in situ
hybridization using phylotype-specific oligonucleotide probes. In a limited number of animals from a single geographic region, we detected most of the
Treponema
phylotypes that were described in previous investigations of digital dermatitis. Additionally, we identified a number of phylotypes that mapped to oral treponemes of humans and dogs that had not been reported for digital dermatitis lesions. The results presented here support previous observations of a polytreponemal etiology of infections, with
Treponema phagedenis
-like,
Treponema medium
/
Treponema vincentii
-like, and
T. denticola
/
T. pedis
-like phylotypes being highly associated with disease. Using this new approach, it has become feasible to study large herds and their surrounding environments, which might provide a basis for a better understanding of the pathogenesis of this disease.
Highly Sensitive Detection of Hepatitis B Virus Surface Antigen by Use of a Semiautomated Immune Complex Transfer Chemiluminescence Enzyme Immunoassay
Authors: Takeda Kazuhiko , Maruki Mari , Yamagaito Takahiro , Muramatsu Machiko , Sakai Yasuhiro , Tobimatsu Hiroaki , Kobayashi Hironori , Mizuno Yoshiteru , Hamaguchi Yukio
Published: May 2013

The performance of hepatitis B surface antigen (HBsAg) screening assays is continuously improved to reduce the risk of transfusion-associated hepatitis B. In this study, a semiautomated immune complex transfer chemiluminescence enzyme immunoassay (ICT-CLEIA) for the detection of HBsAg, which is as sensitive as hepatitis B virus (HBV) DNA PCR, was developed; the ICT-CLEIA assay performance was compared with the performance of the Architect HBsAg QT assay and HBV DNA PCR. The specificities in the initial assay and after retesting were 99.50% (1,988/1,998 samples) and 99.95% (1,997/1,998 samples), respectively. The analytical detection limit was determined to be 0.2 mIU/ml using the 2nd International WHO HBsAg standard, and the cutoff value (0.5 mIU/ml) of the ICT-CLEIA assay was 8.0 standard deviations (SD) above the mean of the HBsAg-negative specimens. The ICT-CLEIA assay could detect HBsAg even in the presence of anti-HBs antibodies and demonstrated a 23.6-day-shorter window period using commercially available HBsAg seroconversion panels than the Architect HBsAg QT assay. Furthermore, the monitoring of the viral kinetics by the ICT-CLEIA assay and the HBV DNA PCR produced very similarly shaped curves during both the HBsAg seroconversion and reverse seroconversion periods. Therefore, the ICT-CLEIA assay may be useful not only for an earlier detection of HBV reactivation but also for the monitoring of hepatitis B patients.
Rapid Molecular Microbiologic Diagnosis of Prosthetic Joint Infection
Authors: Cazanave Charles , Greenwood-Quaintance Kerryl E. , Hanssen Arlen D. , Karau Melissa J. , Schmidt Suzannah M. , Gomez Urena Eric O. , Mandrekar Jayawant N. , Osmon Douglas R. , Lough Lindsay E. , Pritt Bobbi S. , Steckelberg James M. , Patel Robin
Published: May 2013

We previously showed that culture of samples obtained by prosthesis vortexing and sonication was more sensitive than tissue culture for prosthetic joint infection (PJI) diagnosis. Despite improved sensitivity, culture-negative cases remained; furthermore, culture has a long turnaround time. We designed a genus-/group-specific rapid PCR assay panel targeting PJI bacteria and applied it to samples obtained by vortexing and sonicating explanted hip and knee prostheses, and we compared the results to those with sonicate fluid and periprosthetic tissue culture obtained at revision or resection arthroplasty. We studied 434 subjects with knee (
n
= 272) or hip (
n
= 162) prostheses; using a standardized definition, 144 had PJI. Sensitivities of tissue culture, of sonicate fluid culture, and of PCR were 70.1, 72.9, and 77.1%, respectively. Specificities were 97.9, 98.3, and 97.9%, respectively. Sonicate fluid PCR was more sensitive than tissue culture (
P
= 0.04). PCR of prosthesis sonication samples is more sensitive than tissue culture for the microbiologic diagnosis of prosthetic hip and knee infection and provides same-day PJI diagnosis with definition of microbiology. The high assay specificity suggests that typical PJI bacteria may not cause aseptic implant failure.